fill_yin_include(struct lys_module *module, struct lys_submodule *submodule, struct lyxml_elem *yin,
                 struct lys_include *inc, struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    struct lyxml_elem *child, *next, exts;
    const char *value;
    int r, c_ext = 0;
    void *reallocated;

    /* init */
    memset(&exts, 0, sizeof exts);

    LY_TREE_FOR_SAFE(yin->child, next, child) {
        if (!child->ns) {
            /* garbage */
            continue;
        } else if (strcmp(child->ns->value, LY_NSYIN)) {
            /* extension */
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ext, inc->ext_size, "extensions", "include", error);
            c_ext++;
            lyxml_unlink_elem(ctx, child, 2);
            lyxml_add_child(ctx, &exts, child);
        } else if (!strcmp(child->name, "revision-date")) {
            if (inc->rev[0]) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, "revision-date", yin->name);
                goto error;
            }
            GETVAL(ctx, value, child, "date");
            if (lyp_check_date(ctx, value)) {
                goto error;
            }
            memcpy(inc->rev, value, LY_REV_SIZE - 1);

            if (lyp_yin_parse_subnode_ext(module, inc, LYEXT_PAR_INCLUDE, child, LYEXT_SUBSTMT_REVISIONDATE, 0, unres)) {
                goto error;
            }
        } else if ((module->version >= 2) && !strcmp(child->name, "description")) {
            if (inc->dsc) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, child->name, yin->name);
                goto error;
            }
            if (lyp_yin_parse_subnode_ext(module, inc, LYEXT_PAR_INCLUDE, child, LYEXT_SUBSTMT_DESCRIPTION, 0, unres)) {
                goto error;
            }
            inc->dsc = read_yin_subnode(ctx, child, "text");
            if (!inc->dsc) {
                goto error;
            }
        } else if ((module->version >= 2) && !strcmp(child->name, "reference")) {
            if (inc->ref) {
                LOGVAL(ctx, LYE_TOOMANY, LY_VLOG_NONE, NULL, child->name, yin->name);
                goto error;
            }
            if (lyp_yin_parse_subnode_ext(module, inc, LYEXT_PAR_INCLUDE, child, LYEXT_SUBSTMT_REFERENCE, 0, unres)) {
                goto error;
            }
            inc->ref = read_yin_subnode(ctx, child, "text");
            if (!inc->ref) {
                goto error;
            }
        } else {
            LOGVAL(ctx, LYE_INSTMT, LY_VLOG_NONE, NULL, child->name);
            goto error;
        }
    }

    /* process extensions */
    if (c_ext) {
        /* some extensions may be already present from the substatements */
        reallocated = realloc(inc->ext, (c_ext + inc->ext_size) * sizeof *inc->ext);
        LY_CHECK_ERR_GOTO(!reallocated, LOGMEM(ctx), error);
        inc->ext = reallocated;

        /* init memory */
        memset(&inc->ext[inc->ext_size], 0, c_ext * sizeof *inc->ext);

        LY_TREE_FOR_SAFE(exts.child, next, child) {
            /* extension */
            r = lyp_yin_fill_ext(inc, LYEXT_PAR_INCLUDE, 0, 0, module, child, &inc->ext, &inc->ext_size, unres);
            if (r) {
                goto error;
            }
        }

        lyp_reduce_ext_list(&inc->ext, inc->ext_size, c_ext + inc->ext_size);
    }

    GETVAL(ctx, value, yin, "module");
    return lyp_check_include(submodule ? (struct lys_module *)submodule : module, value, inc, unres);

error:
    return -1;
}


read_yin_notif(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin,
               int options, struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    struct lyxml_elem *sub, *next, root;
    struct lys_node *node = NULL;
    struct lys_node *retval;
    struct lys_node_notif *notif;
    int r;
    int c_tpdf = 0, c_ftrs = 0, c_must = 0, c_ext = 0;
    void *reallocated;

    if (parent && (module->version < 2)) {
        LOGVAL(ctx, LYE_INSTMT, LY_VLOG_LYS, parent, "notification");
        return NULL;
    }

    memset(&root, 0, sizeof root);

    notif = calloc(1, sizeof *notif);
    LY_CHECK_ERR_RETURN(!notif, LOGMEM(ctx), NULL);

    notif->nodetype = LYS_NOTIF;
    notif->prev = (struct lys_node *)notif;
    retval = (struct lys_node *)notif;

    if (read_yin_common(module, parent, retval, LYEXT_PAR_NODE, yin, OPT_IDENT | OPT_MODULE, unres)) {
        goto error;
    }

    LOGDBG(LY_LDGYIN, "parsing %s statement \"%s\"", yin->name, retval->name);

    /* insert the node into the schema tree */
    if (lys_node_addchild(parent, lys_main_module(module), retval, options)) {
        goto error;
    }

    /* process rpc's specific children */
    LY_TREE_FOR_SAFE(yin->child, next, sub) {
        if (strcmp(sub->ns->value, LY_NSYIN)) {
            /* extension */
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ext, retval->ext_size, "extensions", "notification", error);
            c_ext++;
            continue;

        /* data statements */
        } else if (!strcmp(sub->name, "container") ||
                !strcmp(sub->name, "leaf-list") ||
                !strcmp(sub->name, "leaf") ||
                !strcmp(sub->name, "list") ||
                !strcmp(sub->name, "choice") ||
                !strcmp(sub->name, "uses") ||
                !strcmp(sub->name, "grouping") ||
                !strcmp(sub->name, "anyxml") ||
                !strcmp(sub->name, "anydata")) {
            lyxml_unlink_elem(ctx, sub, 2);
            lyxml_add_child(ctx, &root, sub);

            /* array counters */
        } else if (!strcmp(sub->name, "typedef")) {
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_tpdf, notif->tpdf_size, "typedefs", "notification", error);
            c_tpdf++;
        } else if (!strcmp(sub->name, "if-feature")) {
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_ftrs, retval->iffeature_size, "if-features", "notification", error);
            c_ftrs++;
        } else if ((module->version >= 2) && !strcmp(sub->name, "must")) {
            YIN_CHECK_ARRAY_OVERFLOW_GOTO(ctx, c_must, notif->must_size, "musts", "notification", error);
            c_must++;
        } else {
            LOGVAL(ctx, LYE_INSTMT, LY_VLOG_LYS, retval, sub->name);
            goto error;
        }
    }

    /* middle part - process nodes with cardinality of 0..n except the data nodes */
    if (c_tpdf) {
        notif->tpdf = calloc(c_tpdf, sizeof *notif->tpdf);
        LY_CHECK_ERR_GOTO(!notif->tpdf, LOGMEM(ctx), error);
    }
    if (c_ftrs) {
        notif->iffeature = calloc(c_ftrs, sizeof *notif->iffeature);
        LY_CHECK_ERR_GOTO(!notif->iffeature, LOGMEM(ctx), error);
    }
    if (c_must) {
        notif->must = calloc(c_must, sizeof *notif->must);
        LY_CHECK_ERR_GOTO(!notif->must, LOGMEM(ctx), error);
    }
    if (c_ext) {
        /* some extensions may be already present from the substatements */
        reallocated = realloc(retval->ext, (c_ext + retval->ext_size) * sizeof *retval->ext);
        LY_CHECK_ERR_GOTO(!reallocated, LOGMEM(ctx), error);
        retval->ext = reallocated;

        /* init memory */
        memset(&retval->ext[retval->ext_size], 0, c_ext * sizeof *retval->ext);
    }

    LY_TREE_FOR_SAFE(yin->child, next, sub) {
        if (strcmp(sub->ns->value, LY_NSYIN)) {
            /* extension */
            r = lyp_yin_fill_ext(retval, LYEXT_PAR_NODE, 0, 0, module, sub, &retval->ext, &retval->ext_size, unres);
            if (r) {
                goto error;
            }
        } else if (!strcmp(sub->name, "typedef")) {
            r = fill_yin_typedef(module, retval, sub, &notif->tpdf[notif->tpdf_size], unres);
            notif->tpdf_size++;
            if (r) {
                goto error;
            }
        } else if (!strcmp(sub->name, "if-feature")) {
            r = fill_yin_iffeature(retval, 0, sub, &notif->iffeature[notif->iffeature_size], unres);
            notif->iffeature_size++;
            if (r) {
                goto error;
            }
        } else if (!strcmp(sub->name, "must")) {
            r = fill_yin_must(module, sub, &notif->must[notif->must_size], unres);
            notif->must_size++;
            if (r) {
                goto error;
            }
        }
    }

    lyp_reduce_ext_list(&retval->ext, retval->ext_size, c_ext + retval->ext_size);

    /* last part - process data nodes */
    options |= LYS_PARSE_OPT_CFG_IGNORE;
    LY_TREE_FOR_SAFE(root.child, next, sub) {
        if (!strcmp(sub->name, "container")) {
            node = read_yin_container(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "leaf-list")) {
            node = read_yin_leaflist(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "leaf")) {
            node = read_yin_leaf(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "list")) {
            node = read_yin_list(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "choice")) {
            node = read_yin_choice(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "uses")) {
            node = read_yin_uses(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "grouping")) {
            node = read_yin_grouping(module, retval, sub, options, unres);
        } else if (!strcmp(sub->name, "anyxml")) {
            node = read_yin_anydata(module, retval, sub, LYS_ANYXML, options, unres);
        } else if (!strcmp(sub->name, "anydata")) {
            node = read_yin_anydata(module, retval, sub, LYS_ANYDATA, options, unres);
        }
        if (!node) {
            goto error;
        }

        lyxml_free(ctx, sub);
    }

    /* check XPath dependencies */
    if (!(ctx->models.flags & LY_CTX_TRUSTED) && notif->must) {
        if (options & LYS_PARSE_OPT_INGRP) {
            if (lyxp_node_check_syntax(retval)) {
                goto error;
            }
        } else {
            if (unres_schema_add_node(module, unres, retval, UNRES_XPATH, NULL) == -1) {
                goto error;
            }
        }
    }

    return retval;

error:
    lys_node_free(ctx, retval, NULL, 0);
    while (root.child) {
        lyxml_free(ctx, root.child);
    }
    return NULL;
}

yin parser BUGFIX invalid memory access

... in case there were some unresolved
extensions.
Fixes #1454
Fixes #1455


fill_yin_unique(struct lys_module *module, struct lys_node *parent, struct lyxml_elem *yin, struct lys_unique *unique,
                struct unres_schema *unres)
{
    struct ly_ctx *ctx = module->ctx;
    int i, j, ret = EXIT_FAILURE;
    const char *orig;
    char *value, *vaux, *start = NULL, c = 0;
    struct unres_list_uniq *unique_info;

    /* get unique value (list of leafs supposed to be unique */
    GETVAL(ctx, orig, yin, "tag");

    /* count the number of unique leafs in the value */
    start = value = vaux = strdup(orig);
    LY_CHECK_ERR_GOTO(!vaux, LOGMEM(ctx), error);
    while ((vaux = strpbrk(vaux, " \t\n"))) {
        YIN_CHECK_ARRAY_OVERFLOW_CODE(ctx, unique->expr_size, unique->expr_size, "referenced items", "unique",
                                      unique->expr_size = 0; goto error);
        unique->expr_size++;
        while (isspace(*vaux)) {
            vaux++;
        }
    }
    unique->expr_size++;
    unique->expr = calloc(unique->expr_size, sizeof *unique->expr);
    LY_CHECK_ERR_GOTO(!unique->expr, LOGMEM(ctx), error);

    for (i = 0; i < unique->expr_size; i++) {
        vaux = strpbrk(value, " \t\n");
        if (vaux) {
            c = *vaux;
            *vaux = '\0';
        }

        /* store token into unique structure */
        unique->expr[i] = transform_schema2json(module, value);
        if (vaux) {
            *vaux = c;
        }

        /* check that the expression does not repeat */
        for (j = 0; j < i; j++) {
            if (ly_strequal(unique->expr[j], unique->expr[i], 1)) {
                LOGVAL(ctx, LYE_INARG, LY_VLOG_NONE, NULL, unique->expr[i], "unique");
                LOGVAL(ctx, LYE_SPEC, LY_VLOG_NONE, NULL, "The identifier is not unique");
                goto error;
            }
        }

        /* try to resolve leaf */
        if (unres) {
            unique_info = malloc(sizeof *unique_info);
            LY_CHECK_ERR_GOTO(!unique_info, LOGMEM(ctx), error);
            unique_info->list = parent;
            unique_info->expr = unique->expr[i];
            unique_info->trg_type = &unique->trg_type;
            if (unres_schema_add_node(module, unres, unique_info, UNRES_LIST_UNIQ, NULL) == -1){
                goto error;
            }
        } else {
            if (resolve_unique(parent, unique->expr[i], &unique->trg_type)) {
                goto error;
            }
        }

        /* move to next token */
        value = vaux;
        while (value && isspace(*value)) {
            value++;
        }
    }

    ret =  EXIT_SUCCESS;

error:
    free(start);
    return ret;
}


fill_yin_iffeature(struct lys_node *parent, int parent_is_feature, struct lyxml_elem *yin, struct lys_iffeature *iffeat,
                   struct unres_schema *unres)
{
    int r, c_ext = 0;
    const char *value;
    struct lyxml_elem *node, *next;
    struct ly_ctx *ctx = parent->module->ctx;

    GETVAL(ctx, value, yin, "name");

    if ((lys_node_module(parent)->version != 2) && ((value[0] == '(') || strchr(value, ' '))) {
        LOGVAL(ctx, LYE_INARG, LY_VLOG_NONE, NULL, value, "if-feature");
error:
        return EXIT_FAILURE;
    }

    if (!(value = transform_iffeat_schema2json(parent->module, value))) {
        return EXIT_FAILURE;
    }

    r = resolve_iffeature_compile(iffeat, value, parent, parent_is_feature, unres);
    lydict_remove(ctx, value);
    if (r) {
        return EXIT_FAILURE;
    }

    LY_TREE_FOR_SAFE(yin->child, next, node) {
        if (!node->ns) {
            /* garbage */
            lyxml_free(ctx, node);
        } else if (strcmp(node->ns->value, LY_NSYIN)) {
            /* extension */
            YIN_CHECK_ARRAY_OVERFLOW_RETURN(ctx, c_ext, iffeat->ext_size, "extensions", "if-feature", EXIT_FAILURE);
            c_ext++;
        } else {
            LOGVAL(ctx, LYE_INSTMT, LY_VLOG_NONE, NULL, node->name, "if-feature");
            return EXIT_FAILURE;
        }
    }
    if (c_ext) {
        iffeat->ext = calloc(c_ext, sizeof *iffeat->ext);
        LY_CHECK_ERR_RETURN(!iffeat->ext, LOGMEM(ctx), EXIT_FAILURE);
        LY_TREE_FOR_SAFE(yin->child, next, node) {
            /* extensions */
            r = lyp_yin_fill_ext(iffeat, LYEXT_PAR_IDENT, 0, 0, parent->module, node,
                                 &iffeat->ext, &iffeat->ext_size, unres);
            if (r) {
                return EXIT_FAILURE;
            }
        }

        lyp_reduce_ext_list(&iffeat->ext, iffeat->ext_size, c_ext + iffeat->ext_size);
    }

    return EXIT_SUCCESS;
}


rb_str_index(VALUE str, VALUE sub, long offset)
{
    long pos;
    char *s, *sptr, *e;
    long len, slen;
    rb_encoding *enc;

    enc = rb_enc_check(str, sub);
    if (is_broken_string(sub)) {
	return -1;
    }
    len = str_strlen(str, enc);
    slen = str_strlen(sub, enc);
    if (offset < 0) {
	offset += len;
	if (offset < 0) return -1;
    }
    if (len - offset < slen) return -1;
    s = RSTRING_PTR(str);
    e = s + RSTRING_LEN(str);
    if (offset) {
	offset = str_offset(s, RSTRING_END(str), offset, enc, single_byte_optimizable(str));
	s += offset;
    }
    if (slen == 0) return offset;
    /* need proceed one character at a time */
    sptr = RSTRING_PTR(sub);
    slen = RSTRING_LEN(sub);
    len = RSTRING_LEN(str) - offset;
    for (;;) {
	char *t;
	pos = rb_memsearch(sptr, slen, s, len, enc);
	if (pos < 0) return pos;
	t = rb_enc_right_char_head(s, s+pos, e, enc);
	if (t == s + pos) break;
	if ((len -= t - s) <= 0) return -1;
	offset += t - s;
	s = t;
    }
    return pos + offset;
}

* string.c (rb_str_justify): CVE-2009-4124.
  Fixes a bug reported by
  Emmanouel Kellinis <Emmanouel.Kellinis AT kpmg.co.uk>, KPMG London;
  Patch by nobu.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@26038 b2dd03c8-39d4-4d8f-98ff-823fe69b080e


str_utf8_offset(const char *p, const char *e, long nth)
{
    const char *pp = str_utf8_nth(p, e, nth);
    return pp - p;
}


enc_succ_alnum_char(char *p, long len, rb_encoding *enc, char *carry)
{
    enum neighbor_char ret;
    unsigned int c;
    int ctype;
    int range;
    char save[ONIGENC_CODE_TO_MBC_MAXLEN];

    c = rb_enc_mbc_to_codepoint(p, p+len, enc);
    if (rb_enc_isctype(c, ONIGENC_CTYPE_DIGIT, enc))
        ctype = ONIGENC_CTYPE_DIGIT;
    else if (rb_enc_isctype(c, ONIGENC_CTYPE_ALPHA, enc))
        ctype = ONIGENC_CTYPE_ALPHA;
    else
        return NEIGHBOR_NOT_CHAR;

    MEMCPY(save, p, char, len);
    ret = enc_succ_char(p, len, enc);
    if (ret == NEIGHBOR_FOUND) {
        c = rb_enc_mbc_to_codepoint(p, p+len, enc);
        if (rb_enc_isctype(c, ctype, enc))
            return NEIGHBOR_FOUND;
    }
    MEMCPY(p, save, char, len);
    range = 1;
    while (1) {
        MEMCPY(save, p, char, len);
        ret = enc_pred_char(p, len, enc);
        if (ret == NEIGHBOR_FOUND) {
            c = rb_enc_mbc_to_codepoint(p, p+len, enc);
            if (!rb_enc_isctype(c, ctype, enc)) {
                MEMCPY(p, save, char, len);
                break;
            }
        }
        else {
            MEMCPY(p, save, char, len);
            break;
        }
        range++;
    }
    if (range == 1) {
        return NEIGHBOR_NOT_CHAR;
    }

    if (ctype != ONIGENC_CTYPE_DIGIT) {
        MEMCPY(carry, p, char, len);
        return NEIGHBOR_WRAPPED;
    }

    MEMCPY(carry, p, char, len);
    enc_succ_char(carry, len, enc);
    return NEIGHBOR_WRAPPED;
}


rb_str_empty(VALUE str)
{
    if (RSTRING_LEN(str) == 0)
	return Qtrue;
    return Qfalse;
}


rb_str_append(VALUE str, VALUE str2)
{
    rb_encoding *enc;
    int cr, cr2;

    StringValue(str2);
    if (RSTRING_LEN(str2) > 0 && STR_ASSOC_P(str)) {
        long len = RSTRING_LEN(str)+RSTRING_LEN(str2);
        enc = rb_enc_check(str, str2);
        cr = ENC_CODERANGE(str);
        if ((cr2 = ENC_CODERANGE(str2)) > cr) cr = cr2;
        rb_str_modify(str);
        REALLOC_N(RSTRING(str)->as.heap.ptr, char, len+1);
        memcpy(RSTRING(str)->as.heap.ptr + RSTRING(str)->as.heap.len,
               RSTRING_PTR(str2), RSTRING_LEN(str2)+1);
        RSTRING(str)->as.heap.len = len;
        rb_enc_associate(str, enc);
        ENC_CODERANGE_SET(str, cr);
        OBJ_INFECT(str, str2);
        return str;
    }
    return rb_str_buf_append(str, str2);
}


str_new3(VALUE klass, VALUE str)
{
    return str_new_shared(klass, str);
}


str_alloc(VALUE klass)
{
    NEWOBJ(str, struct RString);
    OBJSETUP(str, klass, T_STRING);

    str->as.heap.ptr = 0;
    str->as.heap.len = 0;
    str->as.heap.aux.capa = 0;

    return (VALUE)str;
}


rb_str_rindex_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE vpos;
    rb_encoding *enc = STR_ENC_GET(str);
    long pos, len = str_strlen(str, enc);

    if (rb_scan_args(argc, argv, "11", &sub, &vpos) == 2) {
	pos = NUM2LONG(vpos);
	if (pos < 0) {
	    pos += len;
	    if (pos < 0) {
		if (TYPE(sub) == T_REGEXP) {
		    rb_backref_set(Qnil);
		}
		return Qnil;
	    }
	}
	if (pos > len) pos = len;
    }
    else {
	pos = len;
    }

    switch (TYPE(sub)) {
      case T_REGEXP:
	/* enc = rb_get_check(str, sub); */
	pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
			 STR_ENC_GET(str), single_byte_optimizable(str));

	if (!RREGEXP(sub)->ptr || RREGEXP_SRC_LEN(sub)) {
	    pos = rb_reg_search(sub, str, pos, 1);
	    pos = rb_str_sublen(str, pos);
	}
	if (pos >= 0) return LONG2NUM(pos);
	break;

      default: {
	VALUE tmp;

	tmp = rb_check_string_type(sub);
	if (NIL_P(tmp)) {
	    rb_raise(rb_eTypeError, "type mismatch: %s given",
		     rb_obj_classname(sub));
	}
	sub = tmp;
      }
	/* fall through */
      case T_STRING:
	pos = rb_str_rindex(str, sub, pos);
	if (pos >= 0) return LONG2NUM(pos);
	break;
    }
    return Qnil;
}


rb_str_downcase_bang(VALUE str)
{
    rb_encoding *enc;
    char *s, *send;
    int modify = 0;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    rb_str_check_dummy_enc(enc);
    s = RSTRING_PTR(str); send = RSTRING_END(str);
    if (single_byte_optimizable(str)) {
	while (s < send) {
	    unsigned int c = *(unsigned char*)s;

	    if (rb_enc_isascii(c, enc) && 'A' <= c && c <= 'Z') {
		*s = 'a' + (c - 'A');
		modify = 1;
	    }
	    s++;
	}
    }
    else {
	int ascompat = rb_enc_asciicompat(enc);

	while (s < send) {
	    unsigned int c;
	    int n;

	    if (ascompat && (c = *(unsigned char*)s) < 0x80) {
		if (rb_enc_isascii(c, enc) && 'A' <= c && c <= 'Z') {
		    *s = 'a' + (c - 'A');
		    modify = 1;
		}
		s++;
	    }
	    else {
		c = rb_enc_codepoint_len(s, send, &n, enc);
		if (rb_enc_isupper(c, enc)) {
		    /* assuming toupper returns codepoint with same size */
		    rb_enc_mbcput(rb_enc_tolower(c, enc), s, enc);
		    modify = 1;
		}
		s += n;
	    }
	}
    }

    if (modify) return str;
    return Qnil;
}


get_pat(VALUE pat, int quote)
{
    VALUE val;

    switch (TYPE(pat)) {
      case T_REGEXP:
	return pat;

      case T_STRING:
	break;

      default:
	val = rb_check_string_type(pat);
	if (NIL_P(val)) {
	    Check_Type(pat, T_REGEXP);
	}
	pat = val;
    }

    if (quote) {
	pat = rb_reg_quote(pat);
    }

    return rb_reg_regcomp(pat);
}


str_mod_check(VALUE s, const char *p, long len)
{
    if (RSTRING_PTR(s) != p || RSTRING_LEN(s) != len){
	rb_raise(rb_eRuntimeError, "string modified");
    }
}


rb_check_string_type(VALUE str)
{
    str = rb_check_convert_type(str, T_STRING, "String", "to_str");
    return str;
}


rb_str_bytesize(VALUE str)
{
    return INT2NUM(RSTRING_LEN(str));
}


rb_str_unlocktmp(VALUE str)
{
    if (!FL_TEST(str, STR_TMPLOCK)) {
	rb_raise(rb_eRuntimeError, "temporal unlocking already unlocked string");
    }
    FL_UNSET(str, STR_TMPLOCK);
    return str;
}


rb_str_match_m(int argc, VALUE *argv, VALUE str)
{
    VALUE re, result;
    if (argc < 1)
	rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
    re = argv[0];
    argv[0] = str;
    result = rb_funcall2(get_pat(re, 0), rb_intern("match"), argc, argv);
    if (!NIL_P(result) && rb_block_given_p()) {
	return rb_yield(result);
    }
    return result;
}


rb_str_buf_cat_ascii(VALUE str, const char *ptr)
{
    /* ptr must reference NUL terminated ASCII string. */
    int encindex = ENCODING_GET(str);
    rb_encoding *enc = rb_enc_from_index(encindex);
    if (rb_enc_asciicompat(enc)) {
        return rb_enc_cr_str_buf_cat(str, ptr, strlen(ptr),
            encindex, ENC_CODERANGE_7BIT, 0);
    }
    else {
        char *buf = ALLOCA_N(char, rb_enc_mbmaxlen(enc));
        while (*ptr) {
            unsigned int c = (unsigned char)*ptr;
            int len = rb_enc_codelen(c, enc);
            rb_enc_mbcput(c, buf, enc);
            rb_enc_cr_str_buf_cat(str, buf, len,
                encindex, ENC_CODERANGE_VALID, 0);
            ptr++;
        }
        return str;
    }
}


rb_str_delete_bang(int argc, VALUE *argv, VALUE str)
{
    char squeez[256];
    rb_encoding *enc = 0;
    char *s, *send, *t;
    VALUE del = 0, nodel = 0;
    int modify = 0;
    int i, ascompat, cr;

    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    if (argc < 1) {
	rb_raise(rb_eArgError, "wrong number of arguments");
    }
    for (i=0; i<argc; i++) {
	VALUE s = argv[i];

	StringValue(s);
	enc = rb_enc_check(str, s);
	tr_setup_table(s, squeez, i==0, &del, &nodel, enc);
    }

    str_modify_keep_cr(str);
    ascompat = rb_enc_asciicompat(enc);
    s = t = RSTRING_PTR(str);
    send = RSTRING_END(str);
    cr = ascompat ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID;
    while (s < send) {
	unsigned int c;
	int clen;

	if (ascompat && (c = *(unsigned char*)s) < 0x80) {
	    if (squeez[c]) {
		modify = 1;
	    }
	    else {
		if (t != s) *t = c;
		t++;
	    }
	    s++;
	}
	else {
	    c = rb_enc_codepoint_len(s, send, &clen, enc);

	    if (tr_find(c, squeez, del, nodel)) {
		modify = 1;
	    }
	    else {
		if (t != s) rb_enc_mbcput(c, t, enc);
		t += clen;
		if (cr == ENC_CODERANGE_7BIT) cr = ENC_CODERANGE_VALID;
	    }
	    s += clen;
	}
    }
    *t = '\0';
    STR_SET_LEN(str, t - RSTRING_PTR(str));
    ENC_CODERANGE_SET(str, cr);

    if (modify) return str;
    return Qnil;
}


rb_str_crypt(VALUE str, VALUE salt)
{
    extern char *crypt(const char *, const char *);
    VALUE result;
    const char *s, *saltp;
#ifdef BROKEN_CRYPT
    char salt_8bit_clean[3];
#endif

    StringValue(salt);
    if (RSTRING_LEN(salt) < 2)
	rb_raise(rb_eArgError, "salt too short (need >=2 bytes)");

    s = RSTRING_PTR(str);
    if (!s) s = "";
    saltp = RSTRING_PTR(salt);
#ifdef BROKEN_CRYPT
    if (!ISASCII((unsigned char)saltp[0]) || !ISASCII((unsigned char)saltp[1])) {
	salt_8bit_clean[0] = saltp[0] & 0x7f;
	salt_8bit_clean[1] = saltp[1] & 0x7f;
	salt_8bit_clean[2] = '\0';
	saltp = salt_8bit_clean;
    }
#endif
    result = rb_str_new2(crypt(s, saltp));
    OBJ_INFECT(result, str);
    OBJ_INFECT(result, salt);
    return result;
}


rb_to_id(VALUE name)
{
    VALUE tmp;
    ID id;

    switch (TYPE(name)) {
      default:
	tmp = rb_check_string_type(name);
	if (NIL_P(tmp)) {
	    tmp = rb_inspect(name);
	    rb_raise(rb_eTypeError, "%s is not a symbol",
		     RSTRING_PTR(tmp));
	}
	name = tmp;
	/* fall through */
      case T_STRING:
	name = rb_str_intern(name);
	/* fall through */
      case T_SYMBOL:
	return SYM2ID(name);
    }
    return id;
}


rb_str_aref_m(int argc, VALUE *argv, VALUE str)
{
    if (argc == 2) {
	if (TYPE(argv[0]) == T_REGEXP) {
	    return rb_str_subpat(str, argv[0], argv[1]);
	}
	return rb_str_substr(str, NUM2LONG(argv[0]), NUM2LONG(argv[1]));
    }
    if (argc != 1) {
	rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
    }
    return rb_str_aref(str, argv[0]);
}


sym_aref(int argc, VALUE *argv, VALUE sym)
{
    return rb_str_aref_m(argc, argv, rb_sym_to_s(sym));
}


rb_str_new_cstr(const char *ptr)
{
    if (!ptr) {
	rb_raise(rb_eArgError, "NULL pointer given");
    }
    return rb_str_new(ptr, strlen(ptr));
}


rb_str_coderange_scan_restartable(const char *s, const char *e, rb_encoding *enc, int *cr)
{
    const char *p = s;

    if (*cr == ENC_CODERANGE_BROKEN)
	return e - s;

    if (rb_enc_to_index(enc) == 0) {
	/* enc is ASCII-8BIT.  ASCII-8BIT string never be broken. */
	p = search_nonascii(p, e);
	*cr = (!p && *cr != ENC_CODERANGE_VALID) ? ENC_CODERANGE_7BIT : ENC_CODERANGE_VALID;
	return e - s;
    }
    else if (rb_enc_asciicompat(enc)) {
	p = search_nonascii(p, e);
	if (!p) {
	    if (*cr != ENC_CODERANGE_VALID) *cr = ENC_CODERANGE_7BIT;
	    return e - s;
	}
	while (p < e) {
	    int ret = rb_enc_precise_mbclen(p, e, enc);
	    if (!MBCLEN_CHARFOUND_P(ret)) {
		*cr = MBCLEN_INVALID_P(ret) ? ENC_CODERANGE_BROKEN: ENC_CODERANGE_UNKNOWN;
		return p - s;
	    }
	    p += MBCLEN_CHARFOUND_LEN(ret);
	    if (p < e) {
		p = search_nonascii(p, e);
		if (!p) {
		    *cr = ENC_CODERANGE_VALID;
		    return e - s;
		}
	    }
	}
	*cr = e < p ? ENC_CODERANGE_BROKEN: ENC_CODERANGE_VALID;
	return p - s;
    }
    else {
	while (p < e) {
	    int ret = rb_enc_precise_mbclen(p, e, enc);
	    if (!MBCLEN_CHARFOUND_P(ret)) {
		*cr = MBCLEN_INVALID_P(ret) ? ENC_CODERANGE_BROKEN: ENC_CODERANGE_UNKNOWN;
		return p - s;
	    }
	    p += MBCLEN_CHARFOUND_LEN(ret);
	}
	*cr = e < p ? ENC_CODERANGE_BROKEN: ENC_CODERANGE_VALID;
	return p - s;
    }
}


sym_encoding(VALUE sym)
{
    return rb_obj_encoding(rb_id2str(SYM2ID(sym)));
}


sym_cmp(VALUE sym, VALUE other)
{
    if (!SYMBOL_P(other)) {
	return Qnil;
    }
    return rb_str_cmp_m(rb_sym_to_s(sym), rb_sym_to_s(other));
}


rb_str_intern(VALUE s)
{
    VALUE str = RB_GC_GUARD(s);
    ID id;

    id = rb_intern_str(str);
    return ID2SYM(id);
}


count_utf8_lead_bytes_with_word(const VALUE *s)
{
    VALUE d = *s;
    d |= ~(d>>1);
    d >>= 6;
    d &= NONASCII_MASK >> 7;
    d += (d>>8);
    d += (d>>16);
#if SIZEOF_VALUE == 8
    d += (d>>32);
#endif
    return (d&0xF);
}


rb_str_index_m(int argc, VALUE *argv, VALUE str)
{
    VALUE sub;
    VALUE initpos;
    long pos;

    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
	pos = NUM2LONG(initpos);
    }
    else {
	pos = 0;
    }
    if (pos < 0) {
	pos += str_strlen(str, STR_ENC_GET(str));
	if (pos < 0) {
	    if (TYPE(sub) == T_REGEXP) {
		rb_backref_set(Qnil);
	    }
	    return Qnil;
	}
    }

    switch (TYPE(sub)) {
      case T_REGEXP:
	if (pos > str_strlen(str, STR_ENC_GET(str)))
	    return Qnil;
	pos = str_offset(RSTRING_PTR(str), RSTRING_END(str), pos,
			 rb_enc_check(str, sub), single_byte_optimizable(str));

	pos = rb_reg_search(sub, str, pos, 0);
	pos = rb_str_sublen(str, pos);
	break;

      default: {
	VALUE tmp;

	tmp = rb_check_string_type(sub);
	if (NIL_P(tmp)) {
	    rb_raise(rb_eTypeError, "type mismatch: %s given",
		     rb_obj_classname(sub));
	}
	sub = tmp;
      }
	/* fall through */
      case T_STRING:
	pos = rb_str_index(str, sub, pos);
	pos = rb_str_sublen(str, pos);
	break;
    }

    if (pos == -1) return Qnil;
    return LONG2NUM(pos);
}


tr_setup_table(VALUE str, char stable[256], int first,
	       VALUE *tablep, VALUE *ctablep, rb_encoding *enc)
{
    const unsigned int errc = -1;
    char buf[256];
    struct tr tr;
    unsigned int c;
    VALUE table = 0, ptable = 0;
    int i, l, cflag = 0;

    tr.p = RSTRING_PTR(str); tr.pend = tr.p + RSTRING_LEN(str);
    tr.gen = tr.now = tr.max = 0;

    if (RSTRING_LEN(str) > 1 && rb_enc_ascget(tr.p, tr.pend, &l, enc) == '^') {
	cflag = 1;
	tr.p += l;
    }
    if (first) {
	for (i=0; i<256; i++) {
	    stable[i] = 1;
	}
    }
    for (i=0; i<256; i++) {
	buf[i] = cflag;
    }

    while ((c = trnext(&tr, enc)) != errc) {
	if (c < 256) {
	    buf[c & 0xff] = !cflag;
	}
	else {
	    VALUE key = UINT2NUM(c);

	    if (!table) {
		table = rb_hash_new();
		if (cflag) {
		    ptable = *ctablep;
		    *ctablep = table;
		}
		else {
		    ptable = *tablep;
		    *tablep = table;
		}
	    }
	    if (!ptable || !NIL_P(rb_hash_aref(ptable, key))) {
		rb_hash_aset(table, key, Qtrue);
	    }
	}
    }
    for (i=0; i<256; i++) {
	stable[i] = stable[i] && buf[i];
    }
}


rb_str_associate(VALUE str, VALUE add)
{
    /* sanity check */
    if (OBJ_FROZEN(str)) rb_error_frozen("string");
    if (STR_ASSOC_P(str)) {
	/* already associated */
	rb_ary_concat(RSTRING(str)->as.heap.aux.shared, add);
    }
    else {
	if (STR_SHARED_P(str)) {
	    VALUE assoc = RSTRING(str)->as.heap.aux.shared;
	    str_make_independent(str);
	    if (STR_ASSOC_P(assoc)) {
		assoc = RSTRING(assoc)->as.heap.aux.shared;
		rb_ary_concat(assoc, add);
		add = assoc;
	    }
	}
	else if (STR_EMBED_P(str)) {
	    str_make_independent(str);
	}
	else if (RSTRING(str)->as.heap.aux.capa != RSTRING_LEN(str)) {
	    RESIZE_CAPA(str, RSTRING_LEN(str));
	}
	FL_SET(str, STR_ASSOC);
	RBASIC(add)->klass = 0;
	RSTRING(str)->as.heap.aux.shared = add;
    }
}


rb_str_memsize(VALUE str)
{
    if (!STR_EMBED_P(str) && !STR_SHARED_P(str)) {
	return RSTRING(str)->as.heap.aux.capa;
    }
    else {
	return 0;
    }
}


rb_str_strip_bang(VALUE str)
{
    VALUE l = rb_str_lstrip_bang(str);
    VALUE r = rb_str_rstrip_bang(str);

    if (NIL_P(l) && NIL_P(r)) return Qnil;
    return str;
}


rb_str_plus(VALUE str1, VALUE str2)
{
    VALUE str3;
    rb_encoding *enc;

    StringValue(str2);
    enc = rb_enc_check(str1, str2);
    str3 = rb_str_new(0, RSTRING_LEN(str1)+RSTRING_LEN(str2));
    memcpy(RSTRING_PTR(str3), RSTRING_PTR(str1), RSTRING_LEN(str1));
    memcpy(RSTRING_PTR(str3) + RSTRING_LEN(str1),
	   RSTRING_PTR(str2), RSTRING_LEN(str2));
    RSTRING_PTR(str3)[RSTRING_LEN(str3)] = '\0';

    if (OBJ_TAINTED(str1) || OBJ_TAINTED(str2))
	OBJ_TAINT(str3);
    ENCODING_CODERANGE_SET(str3, rb_enc_to_index(enc),
			   ENC_CODERANGE_AND(ENC_CODERANGE(str1), ENC_CODERANGE(str2)));
    return str3;
}


rb_str_clear(VALUE str)
{
    str_discard(str);
    STR_SET_EMBED(str);
    STR_SET_EMBED_LEN(str, 0);
    RSTRING_PTR(str)[0] = 0;
    if (rb_enc_asciicompat(STR_ENC_GET(str)))
	ENC_CODERANGE_SET(str, ENC_CODERANGE_7BIT);
    else
	ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID);
    return str;
}


rb_str_tr_s(VALUE str, VALUE src, VALUE repl)
{
    str = rb_str_dup(str);
    tr_trans(str, src, repl, 1);
    return str;
}


rb_str_resurrect(VALUE str)
{
    return str_replace(str_alloc(rb_cString), str);
}


rb_str_aset(VALUE str, VALUE indx, VALUE val)
{
    long idx, beg;

    switch (TYPE(indx)) {
      case T_FIXNUM:
	idx = FIX2LONG(indx);
      num_index:
	rb_str_splice(str, idx, 1, val);
	return val;

      case T_REGEXP:
	rb_str_subpat_set(str, indx, INT2FIX(0), val);
	return val;

      case T_STRING:
	beg = rb_str_index(str, indx, 0);
	if (beg < 0) {
	    rb_raise(rb_eIndexError, "string not matched");
	}
	beg = rb_str_sublen(str, beg);
	rb_str_splice(str, beg, str_strlen(indx, 0), val);
	return val;

      default:
	/* check if indx is Range */
	{
	    long beg, len;
	    if (rb_range_beg_len(indx, &beg, &len, str_strlen(str, 0), 2)) {
		rb_str_splice(str, beg, len, val);
		return val;
	    }
	}
	idx = NUM2LONG(indx);
	goto num_index;
    }
}


rb_string_value_cstr(volatile VALUE *ptr)
{
    VALUE str = rb_string_value(ptr);
    char *s = RSTRING_PTR(str);

    if (!s || RSTRING_LEN(str) != (long)strlen(s)) {
	rb_raise(rb_eArgError, "string contains null byte");
    }
    return s;
}


rb_str_to_i(int argc, VALUE *argv, VALUE str)
{
    int base;

    if (argc == 0) base = 10;
    else {
	VALUE b;

	rb_scan_args(argc, argv, "01", &b);
	base = NUM2INT(b);
    }
    if (base < 0) {
	rb_raise(rb_eArgError, "invalid radix %d", base);
    }
    return rb_str_to_inum(str, base, FALSE);
}


sym_swapcase(VALUE sym)
{
    return rb_str_intern(rb_str_swapcase(rb_id2str(SYM2ID(sym))));
}


rb_str_scan(VALUE str, VALUE pat)
{
    VALUE result;
    long start = 0;
    long last = -1, prev = 0;
    char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str);

    pat = get_pat(pat, 1);
    if (!rb_block_given_p()) {
	VALUE ary = rb_ary_new();

	while (!NIL_P(result = scan_once(str, pat, &start))) {
	    last = prev;
	    prev = start;
	    rb_ary_push(ary, result);
	}
	if (last >= 0) rb_reg_search(pat, str, last, 0);
	return ary;
    }

    while (!NIL_P(result = scan_once(str, pat, &start))) {
	last = prev;
	prev = start;
	rb_yield(result);
	str_mod_check(str, p, len);
    }
    if (last >= 0) rb_reg_search(pat, str, last, 0);
    return str;
}


str_duplicate(VALUE klass, VALUE str)
{
    VALUE dup = str_alloc(klass);
    str_replace(dup, str);
    return dup;
}


rb_str_sum(int argc, VALUE *argv, VALUE str)
{
    VALUE vbits;
    int bits;
    char *ptr, *p, *pend;
    long len;

    if (argc == 0) {
	bits = 16;
    }
    else {
	rb_scan_args(argc, argv, "01", &vbits);
	bits = NUM2INT(vbits);
    }
    ptr = p = RSTRING_PTR(str);
    len = RSTRING_LEN(str);
    pend = p + len;
    if (bits >= (int)sizeof(long)*CHAR_BIT) {
	VALUE sum = INT2FIX(0);

	while (p < pend) {
	    str_mod_check(str, ptr, len);
	    sum = rb_funcall(sum, '+', 1, INT2FIX((unsigned char)*p));
	    p++;
	}
	if (bits != 0) {
	    VALUE mod;

	    mod = rb_funcall(INT2FIX(1), rb_intern("<<"), 1, INT2FIX(bits));
	    mod = rb_funcall(mod, '-', 1, INT2FIX(1));
	    sum = rb_funcall(sum, '&', 1, mod);
	}
	return sum;
    }
    else {
       unsigned long sum = 0;

	while (p < pend) {
	    str_mod_check(str, ptr, len);
	    sum += (unsigned char)*p;
	    p++;
	}
	if (bits != 0) {
           sum &= (((unsigned long)1)<<bits)-1;
	}
	return rb_int2inum(sum);
    }
}


rb_str_splice(VALUE str, long beg, long len, VALUE val)
{
    long slen;
    char *p, *e;
    rb_encoding *enc;
    int singlebyte = single_byte_optimizable(str);
    int cr;

    if (len < 0) rb_raise(rb_eIndexError, "negative length %ld", len);

    StringValue(val);
    enc = rb_enc_check(str, val);
    slen = str_strlen(str, enc);

    if (slen < beg) {
      out_of_range:
	rb_raise(rb_eIndexError, "index %ld out of string", beg);
    }
    if (beg < 0) {
	if (-beg > slen) {
	    goto out_of_range;
	}
	beg += slen;
    }
    if (slen < len || slen < beg + len) {
	len = slen - beg;
    }
    str_modify_keep_cr(str);
    p = str_nth(RSTRING_PTR(str), RSTRING_END(str), beg, enc, singlebyte);
    if (!p) p = RSTRING_END(str);
    e = str_nth(p, RSTRING_END(str), len, enc, singlebyte);
    if (!e) e = RSTRING_END(str);
    /* error check */
    beg = p - RSTRING_PTR(str);	/* physical position */
    len = e - p;		/* physical length */
    rb_str_splice_0(str, beg, len, val);
    rb_enc_associate(str, enc);
    cr = ENC_CODERANGE_AND(ENC_CODERANGE(str), ENC_CODERANGE(val));
    if (cr != ENC_CODERANGE_BROKEN)
	ENC_CODERANGE_SET(str, cr);
}


rb_str_rindex(VALUE str, VALUE sub, long pos)
{
    long len, slen;
    char *s, *sbeg, *e, *t;
    rb_encoding *enc;
    int singlebyte = single_byte_optimizable(str);

    enc = rb_enc_check(str, sub);
    if (is_broken_string(sub)) {
	return -1;
    }
    len = str_strlen(str, enc);
    slen = str_strlen(sub, enc);
    /* substring longer than string */
    if (len < slen) return -1;
    if (len - pos < slen) {
	pos = len - slen;
    }
    if (len == 0) {
	return pos;
    }
    sbeg = RSTRING_PTR(str);
    e = RSTRING_END(str);
    t = RSTRING_PTR(sub);
    slen = RSTRING_LEN(sub);
    for (;;) {
	s = str_nth(sbeg, e, pos, enc, singlebyte);
	if (!s) return -1;
	if (memcmp(s, t, slen) == 0) {
	    return pos;
	}
	if (pos == 0) break;
	pos--;
    }
    return -1;
}


rb_str_inspect(VALUE str)
{
    rb_encoding *enc = STR_ENC_GET(str);
    const char *p, *pend, *prev;
#define CHAR_ESC_LEN 12 /* sizeof(\x{ hex of 32bit unsigned int }) */
    char buf[CHAR_ESC_LEN + 1];
    VALUE result = rb_str_buf_new(0);
    rb_encoding *resenc = rb_default_internal_encoding();
    int unicode_p = rb_enc_unicode_p(enc);

    if (resenc == NULL) resenc = rb_default_external_encoding();
    if (!rb_enc_asciicompat(resenc)) resenc = rb_usascii_encoding();
    rb_enc_associate(result, resenc);
    str_buf_cat2(result, "\"");

    p = RSTRING_PTR(str); pend = RSTRING_END(str);
    prev = p;
    while (p < pend) {
	unsigned int c, cc;
	int n;

        n = rb_enc_precise_mbclen(p, pend, enc);
        if (!MBCLEN_CHARFOUND_P(n)) {
	    if (p > prev) str_buf_cat(result, prev, p - prev);
	    snprintf(buf, CHAR_ESC_LEN, "\\x%02X", *p & 0377);
	    str_buf_cat(result, buf, strlen(buf));
            prev = ++p;
	    continue;
	}
        n = MBCLEN_CHARFOUND_LEN(n);
	c = rb_enc_mbc_to_codepoint(p, pend, enc);
	p += n;
	if (c == '"'|| c == '\\' ||
	    (c == '#' &&
             p < pend &&
             MBCLEN_CHARFOUND_P(rb_enc_precise_mbclen(p,pend,enc)) &&
             (cc = rb_enc_codepoint(p,pend,enc),
              (cc == '$' || cc == '@' || cc == '{')))) {
	    if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
	    str_buf_cat2(result, "\\");
	    prev = p - n;
	    continue;
	}
	switch (c) {
	  case '\n': cc = 'n'; break;
	  case '\r': cc = 'r'; break;
	  case '\t': cc = 't'; break;
	  case '\f': cc = 'f'; break;
	  case '\013': cc = 'v'; break;
	  case '\010': cc = 'b'; break;
	  case '\007': cc = 'a'; break;
	  case 033: cc = 'e'; break;
	  default: cc = 0; break;
	}
	if (cc) {
	    if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
	    buf[0] = '\\';
	    buf[1] = (char)cc;
	    str_buf_cat(result, buf, 2);
	    prev = p;
	    continue;
	}
	if ((enc == resenc && rb_enc_isprint(c, enc)) ||
	    (rb_enc_isascii(c, enc) && ISPRINT(c))) {
	    continue;
	}
	else {
	    if (p - n > prev) str_buf_cat(result, prev, p - n - prev);
	    if (unicode_p) {
		if (c < 0x10000) {
		    snprintf(buf, CHAR_ESC_LEN, "\\u%04X", c);
		}
		else {
		    snprintf(buf, CHAR_ESC_LEN, "\\u{%X}", c);
		}
		str_buf_cat(result, buf, strlen(buf));
	    }
	    else {
		if (c < 0x100) {
		    snprintf(buf, CHAR_ESC_LEN, "\\x%02X", c);
		}
		else {
		    snprintf(buf, CHAR_ESC_LEN, "\\x{%X}", c);
		}
		str_buf_cat(result, buf, strlen(buf));
	    }
	    prev = p;
	    continue;
	}
    }
    if (p > prev) str_buf_cat(result, prev, p - prev);
    str_buf_cat2(result, "\"");

    OBJ_INFECT(result, str);
    return result;
}


sym_capitalize(VALUE sym)
{
    return rb_str_intern(rb_str_capitalize(rb_id2str(SYM2ID(sym))));
}


sym_match(VALUE sym, VALUE other)
{
    return rb_str_match(rb_sym_to_s(sym), other);
}


rb_str_drop_bytes(VALUE str, long len)
{
    char *ptr = RSTRING_PTR(str);
    long olen = RSTRING_LEN(str), nlen;

    str_modifiable(str);
    if (len > olen) len = olen;
    nlen = olen - len;
    if (nlen <= RSTRING_EMBED_LEN_MAX) {
	char *oldptr = ptr;
	int fl = (int)(RBASIC(str)->flags & (STR_NOEMBED|ELTS_SHARED));
	STR_SET_EMBED(str);
	STR_SET_EMBED_LEN(str, nlen);
	ptr = RSTRING(str)->as.ary;
	memmove(ptr, oldptr + len, nlen);
	if (fl == STR_NOEMBED) xfree(oldptr);
    }
    else {
	if (!STR_SHARED_P(str)) rb_str_new4(str);
	ptr = RSTRING(str)->as.heap.ptr += len;
	RSTRING(str)->as.heap.len = nlen;
    }
    ptr[nlen] = 0;
    ENC_CODERANGE_CLEAR(str);
    return str;
}


rb_str_rstrip(VALUE str)
{
    str = rb_str_dup(str);
    rb_str_rstrip_bang(str);
    return str;
}


rb_str_tr(VALUE str, VALUE src, VALUE repl)
{
    str = rb_str_dup(str);
    tr_trans(str, src, repl, 0);
    return str;
}


str_enc_copy(VALUE str1, VALUE str2)
{
    rb_enc_set_index(str1, ENCODING_GET(str2));
}


rb_str_eql(VALUE str1, VALUE str2)
{
    if (TYPE(str2) != T_STRING) return Qfalse;
    return str_eql(str1, str2);
}


rb_str_oct(VALUE str)
{
    rb_encoding *enc = rb_enc_get(str);

    if (!rb_enc_asciicompat(enc)) {
	rb_raise(rb_eEncCompatError, "ASCII incompatible encoding: %s", rb_enc_name(enc));
    }
    return rb_str_to_inum(str, -8, FALSE);
}


str_offset(const char *p, const char *e, long nth, rb_encoding *enc, int singlebyte)
{
    const char *pp = str_nth(p, e, nth, enc, singlebyte);
    if (!pp) return e - p;
    return pp - p;
}


rb_str_sub(int argc, VALUE *argv, VALUE str)
{
    str = rb_str_dup(str);
    rb_str_sub_bang(argc, argv, str);
    return str;
}


rb_memhash(const void *ptr, long len)
{
    return st_hash(ptr, len, rb_hash_start(0));
}


rb_str_each_char(VALUE str)
{
    VALUE orig = str;
    long i, len, n;
    const char *ptr;
    rb_encoding *enc;

    RETURN_ENUMERATOR(str, 0, 0);
    str = rb_str_new4(str);
    ptr = RSTRING_PTR(str);
    len = RSTRING_LEN(str);
    enc = rb_enc_get(str);
    switch (ENC_CODERANGE(str)) {
      case ENC_CODERANGE_VALID:
      case ENC_CODERANGE_7BIT:
	for (i = 0; i < len; i += n) {
	    n = rb_enc_fast_mbclen(ptr + i, ptr + len, enc);
	    rb_yield(rb_str_subseq(str, i, n));
	}
	break;
      default:
	for (i = 0; i < len; i += n) {
	    n = rb_enc_mbclen(ptr + i, ptr + len, enc);
	    rb_yield(rb_str_subseq(str, i, n));
	}
    }
    return orig;
}


rb_str_upto(int argc, VALUE *argv, VALUE beg)
{
    VALUE end, exclusive;
    VALUE current, after_end;
    ID succ;
    int n, excl, ascii;
    rb_encoding *enc;

    rb_scan_args(argc, argv, "11", &end, &exclusive);
    RETURN_ENUMERATOR(beg, argc, argv);
    excl = RTEST(exclusive);
    CONST_ID(succ, "succ");
    StringValue(end);
    enc = rb_enc_check(beg, end);
    ascii = (is_ascii_string(beg) && is_ascii_string(end));
    /* single character */
    if (RSTRING_LEN(beg) == 1 && RSTRING_LEN(end) == 1 && ascii) {
	char c = RSTRING_PTR(beg)[0];
	char e = RSTRING_PTR(end)[0];

	if (c > e || (excl && c == e)) return beg;
	for (;;) {
	    rb_yield(rb_enc_str_new(&c, 1, enc));
	    if (!excl && c == e) break;
	    c++;
	    if (excl && c == e) break;
	}
	return beg;
    }
    /* both edges are all digits */
    if (ascii && ISDIGIT(RSTRING_PTR(beg)[0]) && ISDIGIT(RSTRING_PTR(end)[0])) {
	char *s, *send;
	VALUE b, e;
	int width;

	s = RSTRING_PTR(beg); send = RSTRING_END(beg);
	width = rb_long2int(send - s);
	while (s < send) {
	    if (!ISDIGIT(*s)) goto no_digits;
	    s++;
	}
	s = RSTRING_PTR(end); send = RSTRING_END(end);
	while (s < send) {
	    if (!ISDIGIT(*s)) goto no_digits;
	    s++;
	}
	b = rb_str_to_inum(beg, 10, FALSE);
	e = rb_str_to_inum(end, 10, FALSE);
	if (FIXNUM_P(b) && FIXNUM_P(e)) {
	    long bi = FIX2LONG(b);
	    long ei = FIX2LONG(e);
	    rb_encoding *usascii = rb_usascii_encoding();

	    while (bi <= ei) {
		if (excl && bi == ei) break;
		rb_yield(rb_enc_sprintf(usascii, "%.*ld", width, bi));
		bi++;
	    }
	}
	else {
	    ID op = excl ? '<' : rb_intern("<=");
	    VALUE args[2], fmt = rb_obj_freeze(rb_usascii_str_new_cstr("%.*d"));

	    args[0] = INT2FIX(width);
	    while (rb_funcall(b, op, 1, e)) {
		args[1] = b;
		rb_yield(rb_str_format(numberof(args), args, fmt));
		b = rb_funcall(b, succ, 0, 0);
	    }
	}
	return beg;
    }
    /* normal case */
  no_digits:
    n = rb_str_cmp(beg, end);
    if (n > 0 || (excl && n == 0)) return beg;

    after_end = rb_funcall(end, succ, 0, 0);
    current = rb_str_dup(beg);
    while (!rb_str_equal(current, after_end)) {
	VALUE next = Qnil;
	if (excl || !rb_str_equal(current, end))
	    next = rb_funcall(current, succ, 0, 0);
	rb_yield(current);
	if (NIL_P(next)) break;
	current = next;
	StringValue(current);
	if (excl && rb_str_equal(current, end)) break;
	if (RSTRING_LEN(current) > RSTRING_LEN(end) || RSTRING_LEN(current) == 0)
	    break;
    }

    return beg;
}


Init_String(void)
{
#undef rb_intern
#define rb_intern(str) rb_intern_const(str)

    rb_cString  = rb_define_class("String", rb_cObject);
    rb_include_module(rb_cString, rb_mComparable);
    rb_define_alloc_func(rb_cString, str_alloc);
    rb_define_singleton_method(rb_cString, "try_convert", rb_str_s_try_convert, 1);
    rb_define_method(rb_cString, "initialize", rb_str_init, -1);
    rb_define_method(rb_cString, "initialize_copy", rb_str_replace, 1);
    rb_define_method(rb_cString, "<=>", rb_str_cmp_m, 1);
    rb_define_method(rb_cString, "==", rb_str_equal, 1);
    rb_define_method(rb_cString, "===", rb_str_equal, 1);
    rb_define_method(rb_cString, "eql?", rb_str_eql, 1);
    rb_define_method(rb_cString, "hash", rb_str_hash_m, 0);
    rb_define_method(rb_cString, "casecmp", rb_str_casecmp, 1);
    rb_define_method(rb_cString, "+", rb_str_plus, 1);
    rb_define_method(rb_cString, "*", rb_str_times, 1);
    rb_define_method(rb_cString, "%", rb_str_format_m, 1);
    rb_define_method(rb_cString, "[]", rb_str_aref_m, -1);
    rb_define_method(rb_cString, "[]=", rb_str_aset_m, -1);
    rb_define_method(rb_cString, "insert", rb_str_insert, 2);
    rb_define_method(rb_cString, "length", rb_str_length, 0);
    rb_define_method(rb_cString, "size", rb_str_length, 0);
    rb_define_method(rb_cString, "bytesize", rb_str_bytesize, 0);
    rb_define_method(rb_cString, "empty?", rb_str_empty, 0);
    rb_define_method(rb_cString, "=~", rb_str_match, 1);
    rb_define_method(rb_cString, "match", rb_str_match_m, -1);
    rb_define_method(rb_cString, "succ", rb_str_succ, 0);
    rb_define_method(rb_cString, "succ!", rb_str_succ_bang, 0);
    rb_define_method(rb_cString, "next", rb_str_succ, 0);
    rb_define_method(rb_cString, "next!", rb_str_succ_bang, 0);
    rb_define_method(rb_cString, "upto", rb_str_upto, -1);
    rb_define_method(rb_cString, "index", rb_str_index_m, -1);
    rb_define_method(rb_cString, "rindex", rb_str_rindex_m, -1);
    rb_define_method(rb_cString, "replace", rb_str_replace, 1);
    rb_define_method(rb_cString, "clear", rb_str_clear, 0);
    rb_define_method(rb_cString, "chr", rb_str_chr, 0);
    rb_define_method(rb_cString, "getbyte", rb_str_getbyte, 1);
    rb_define_method(rb_cString, "setbyte", rb_str_setbyte, 2);

    rb_define_method(rb_cString, "to_i", rb_str_to_i, -1);
    rb_define_method(rb_cString, "to_f", rb_str_to_f, 0);
    rb_define_method(rb_cString, "to_s", rb_str_to_s, 0);
    rb_define_method(rb_cString, "to_str", rb_str_to_s, 0);
    rb_define_method(rb_cString, "inspect", rb_str_inspect, 0);
    rb_define_method(rb_cString, "dump", rb_str_dump, 0);

    rb_define_method(rb_cString, "upcase", rb_str_upcase, 0);
    rb_define_method(rb_cString, "downcase", rb_str_downcase, 0);
    rb_define_method(rb_cString, "capitalize", rb_str_capitalize, 0);
    rb_define_method(rb_cString, "swapcase", rb_str_swapcase, 0);

    rb_define_method(rb_cString, "upcase!", rb_str_upcase_bang, 0);
    rb_define_method(rb_cString, "downcase!", rb_str_downcase_bang, 0);
    rb_define_method(rb_cString, "capitalize!", rb_str_capitalize_bang, 0);
    rb_define_method(rb_cString, "swapcase!", rb_str_swapcase_bang, 0);

    rb_define_method(rb_cString, "hex", rb_str_hex, 0);
    rb_define_method(rb_cString, "oct", rb_str_oct, 0);
    rb_define_method(rb_cString, "split", rb_str_split_m, -1);
    rb_define_method(rb_cString, "lines", rb_str_each_line, -1);
    rb_define_method(rb_cString, "bytes", rb_str_each_byte, 0);
    rb_define_method(rb_cString, "chars", rb_str_each_char, 0);
    rb_define_method(rb_cString, "codepoints", rb_str_each_codepoint, 0);
    rb_define_method(rb_cString, "reverse", rb_str_reverse, 0);
    rb_define_method(rb_cString, "reverse!", rb_str_reverse_bang, 0);
    rb_define_method(rb_cString, "concat", rb_str_concat, 1);
    rb_define_method(rb_cString, "<<", rb_str_concat, 1);
    rb_define_method(rb_cString, "crypt", rb_str_crypt, 1);
    rb_define_method(rb_cString, "intern", rb_str_intern, 0);
    rb_define_method(rb_cString, "to_sym", rb_str_intern, 0);
    rb_define_method(rb_cString, "ord", rb_str_ord, 0);

    rb_define_method(rb_cString, "include?", rb_str_include, 1);
    rb_define_method(rb_cString, "start_with?", rb_str_start_with, -1);
    rb_define_method(rb_cString, "end_with?", rb_str_end_with, -1);

    rb_define_method(rb_cString, "scan", rb_str_scan, 1);

    rb_define_method(rb_cString, "ljust", rb_str_ljust, -1);
    rb_define_method(rb_cString, "rjust", rb_str_rjust, -1);
    rb_define_method(rb_cString, "center", rb_str_center, -1);

    rb_define_method(rb_cString, "sub", rb_str_sub, -1);
    rb_define_method(rb_cString, "gsub", rb_str_gsub, -1);
    rb_define_method(rb_cString, "chop", rb_str_chop, 0);
    rb_define_method(rb_cString, "chomp", rb_str_chomp, -1);
    rb_define_method(rb_cString, "strip", rb_str_strip, 0);
    rb_define_method(rb_cString, "lstrip", rb_str_lstrip, 0);
    rb_define_method(rb_cString, "rstrip", rb_str_rstrip, 0);

    rb_define_method(rb_cString, "sub!", rb_str_sub_bang, -1);
    rb_define_method(rb_cString, "gsub!", rb_str_gsub_bang, -1);
    rb_define_method(rb_cString, "chop!", rb_str_chop_bang, 0);
    rb_define_method(rb_cString, "chomp!", rb_str_chomp_bang, -1);
    rb_define_method(rb_cString, "strip!", rb_str_strip_bang, 0);
    rb_define_method(rb_cString, "lstrip!", rb_str_lstrip_bang, 0);
    rb_define_method(rb_cString, "rstrip!", rb_str_rstrip_bang, 0);

    rb_define_method(rb_cString, "tr", rb_str_tr, 2);
    rb_define_method(rb_cString, "tr_s", rb_str_tr_s, 2);
    rb_define_method(rb_cString, "delete", rb_str_delete, -1);
    rb_define_method(rb_cString, "squeeze", rb_str_squeeze, -1);
    rb_define_method(rb_cString, "count", rb_str_count, -1);

    rb_define_method(rb_cString, "tr!", rb_str_tr_bang, 2);
    rb_define_method(rb_cString, "tr_s!", rb_str_tr_s_bang, 2);
    rb_define_method(rb_cString, "delete!", rb_str_delete_bang, -1);
    rb_define_method(rb_cString, "squeeze!", rb_str_squeeze_bang, -1);

    rb_define_method(rb_cString, "each_line", rb_str_each_line, -1);
    rb_define_method(rb_cString, "each_byte", rb_str_each_byte, 0);
    rb_define_method(rb_cString, "each_char", rb_str_each_char, 0);
    rb_define_method(rb_cString, "each_codepoint", rb_str_each_codepoint, 0);

    rb_define_method(rb_cString, "sum", rb_str_sum, -1);

    rb_define_method(rb_cString, "slice", rb_str_aref_m, -1);
    rb_define_method(rb_cString, "slice!", rb_str_slice_bang, -1);

    rb_define_method(rb_cString, "partition", rb_str_partition, 1);
    rb_define_method(rb_cString, "rpartition", rb_str_rpartition, 1);

    rb_define_method(rb_cString, "encoding", rb_obj_encoding, 0); /* in encoding.c */
    rb_define_method(rb_cString, "force_encoding", rb_str_force_encoding, 1);
    rb_define_method(rb_cString, "valid_encoding?", rb_str_valid_encoding_p, 0);
    rb_define_method(rb_cString, "ascii_only?", rb_str_is_ascii_only_p, 0);

    id_to_s = rb_intern("to_s");

    rb_fs = Qnil;
    rb_define_variable("$;", &rb_fs);
    rb_define_variable("$-F", &rb_fs);

    rb_cSymbol = rb_define_class("Symbol", rb_cObject);
    rb_include_module(rb_cSymbol, rb_mComparable);
    rb_undef_alloc_func(rb_cSymbol);
    rb_undef_method(CLASS_OF(rb_cSymbol), "new");
    rb_define_singleton_method(rb_cSymbol, "all_symbols", rb_sym_all_symbols, 0); /* in parse.y */

    rb_define_method(rb_cSymbol, "==", sym_equal, 1);
    rb_define_method(rb_cSymbol, "===", sym_equal, 1);
    rb_define_method(rb_cSymbol, "inspect", sym_inspect, 0);
    rb_define_method(rb_cSymbol, "to_s", rb_sym_to_s, 0);
    rb_define_method(rb_cSymbol, "id2name", rb_sym_to_s, 0);
    rb_define_method(rb_cSymbol, "intern", sym_to_sym, 0);
    rb_define_method(rb_cSymbol, "to_sym", sym_to_sym, 0);
    rb_define_method(rb_cSymbol, "to_proc", sym_to_proc, 0);
    rb_define_method(rb_cSymbol, "succ", sym_succ, 0);
    rb_define_method(rb_cSymbol, "next", sym_succ, 0);

    rb_define_method(rb_cSymbol, "<=>", sym_cmp, 1);
    rb_define_method(rb_cSymbol, "casecmp", sym_casecmp, 1);
    rb_define_method(rb_cSymbol, "=~", sym_match, 1);

    rb_define_method(rb_cSymbol, "[]", sym_aref, -1);
    rb_define_method(rb_cSymbol, "slice", sym_aref, -1);
    rb_define_method(rb_cSymbol, "length", sym_length, 0);
    rb_define_method(rb_cSymbol, "size", sym_length, 0);
    rb_define_method(rb_cSymbol, "empty?", sym_empty, 0);
    rb_define_method(rb_cSymbol, "match", sym_match, 1);

    rb_define_method(rb_cSymbol, "upcase", sym_upcase, 0);
    rb_define_method(rb_cSymbol, "downcase", sym_downcase, 0);
    rb_define_method(rb_cSymbol, "capitalize", sym_capitalize, 0);
    rb_define_method(rb_cSymbol, "swapcase", sym_swapcase, 0);

    rb_define_method(rb_cSymbol, "encoding", sym_encoding, 0);
}


str_utf8_nth(const char *p, const char *e, long nth)
{
    if ((int)SIZEOF_VALUE < e - p && (int)SIZEOF_VALUE * 2 < nth) {
	const VALUE *s, *t;
	const VALUE lowbits = sizeof(VALUE) - 1;
	s = (const VALUE*)(~lowbits & ((VALUE)p + lowbits));
	t = (const VALUE*)(~lowbits & (VALUE)e);
	while (p < (const char *)s) {
	    if (is_utf8_lead_byte(*p)) nth--;
	    p++;
	}
	do {
	    nth -= count_utf8_lead_bytes_with_word(s);
	    s++;
	} while (s < t && (int)sizeof(VALUE) <= nth);
	p = (char *)s;
    }
    while (p < e) {
	if (is_utf8_lead_byte(*p)) {
	    if (nth == 0) break;
	    nth--;
	}
	p++;
    }
    return (char *)p;
}


rb_str_check_dummy_enc(rb_encoding *enc)
{
    if (rb_enc_dummy_p(enc)) {
	rb_raise(rb_eEncCompatError, "incompatible encoding with this operation: %s",
		 rb_enc_name(enc));
    }
}


search_nonascii(const char *p, const char *e)
{
#if SIZEOF_VALUE == 8
# define NONASCII_MASK 0x8080808080808080LL
#elif SIZEOF_VALUE == 4
# define NONASCII_MASK 0x80808080UL
#endif
#ifdef NONASCII_MASK
    if ((int)sizeof(VALUE) * 2 < e - p) {
        const VALUE *s, *t;
        const VALUE lowbits = sizeof(VALUE) - 1;
        s = (const VALUE*)(~lowbits & ((VALUE)p + lowbits));
        while (p < (const char *)s) {
            if (!ISASCII(*p))
                return p;
            p++;
        }
        t = (const VALUE*)(~lowbits & (VALUE)e);
        while (s < t) {
            if (*s & NONASCII_MASK) {
                t = s;
                break;
            }
            s++;
        }
        p = (const char *)t;
    }
#endif
    while (p < e) {
        if (!ISASCII(*p))
            return p;
        p++;
    }
    return NULL;
}


rb_locale_str_new(const char *ptr, long len)
{
    return rb_external_str_new_with_enc(ptr, len, rb_locale_encoding());
}


rb_str_ljust(int argc, VALUE *argv, VALUE str)
{
    return rb_str_justify(argc, argv, str, 'l');
}


rb_str_capitalize_bang(VALUE str)
{
    rb_encoding *enc;
    char *s, *send;
    int modify = 0;
    unsigned int c;
    int n;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    rb_str_check_dummy_enc(enc);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    s = RSTRING_PTR(str); send = RSTRING_END(str);

    c = rb_enc_codepoint_len(s, send, &n, enc);
    if (rb_enc_islower(c, enc)) {
	rb_enc_mbcput(rb_enc_toupper(c, enc), s, enc);
	modify = 1;
    }
    s += n;
    while (s < send) {
	c = rb_enc_codepoint_len(s, send, &n, enc);
	if (rb_enc_isupper(c, enc)) {
	    rb_enc_mbcput(rb_enc_tolower(c, enc), s, enc);
	    modify = 1;
	}
	s += n;
    }

    if (modify) return str;
    return Qnil;
}


rb_str_init(int argc, VALUE *argv, VALUE str)
{
    VALUE orig;

    if (argc > 0 && rb_scan_args(argc, argv, "01", &orig) == 1)
	rb_str_replace(str, orig);
    return str;
}


rb_str_end_with(int argc, VALUE *argv, VALUE str)
{
    int i;
    char *p, *s, *e;
    rb_encoding *enc;

    for (i=0; i<argc; i++) {
	VALUE tmp = rb_check_string_type(argv[i]);
	if (NIL_P(tmp)) continue;
	enc = rb_enc_check(str, tmp);
	if (RSTRING_LEN(str) < RSTRING_LEN(tmp)) continue;
	p = RSTRING_PTR(str);
        e = p + RSTRING_LEN(str);
	s = e - RSTRING_LEN(tmp);
	if (rb_enc_left_char_head(p, s, e, enc) != s)
	    continue;
	if (memcmp(s, RSTRING_PTR(tmp), RSTRING_LEN(tmp)) == 0)
	    return Qtrue;
    }
    return Qfalse;
}


rb_str_shared_replace(VALUE str, VALUE str2)
{
    rb_encoding *enc;
    int cr;
    if (str == str2) return;
    enc = STR_ENC_GET(str2);
    cr = ENC_CODERANGE(str2);
    str_discard(str);
    OBJ_INFECT(str, str2);
    if (RSTRING_LEN(str2) <= RSTRING_EMBED_LEN_MAX) {
	STR_SET_EMBED(str);
	memcpy(RSTRING_PTR(str), RSTRING_PTR(str2), RSTRING_LEN(str2)+1);
	STR_SET_EMBED_LEN(str, RSTRING_LEN(str2));
        rb_enc_associate(str, enc);
        ENC_CODERANGE_SET(str, cr);
	return;
    }
    STR_SET_NOEMBED(str);
    STR_UNSET_NOCAPA(str);
    RSTRING(str)->as.heap.ptr = RSTRING_PTR(str2);
    RSTRING(str)->as.heap.len = RSTRING_LEN(str2);
    if (STR_NOCAPA_P(str2)) {
	FL_SET(str, RBASIC(str2)->flags & STR_NOCAPA);
	RSTRING(str)->as.heap.aux.shared = RSTRING(str2)->as.heap.aux.shared;
    }
    else {
	RSTRING(str)->as.heap.aux.capa = RSTRING(str2)->as.heap.aux.capa;
    }
    STR_SET_EMBED(str2);	/* abandon str2 */
    RSTRING_PTR(str2)[0] = 0;
    STR_SET_EMBED_LEN(str2, 0);
    rb_enc_associate(str, enc);
    ENC_CODERANGE_SET(str, cr);
}


rb_filesystem_str_new_cstr(const char *ptr)
{
    return rb_external_str_new_with_enc(ptr, strlen(ptr), rb_filesystem_encoding());
}


enc_strlen(const char *p, const char *e, rb_encoding *enc, int cr)
{
    long c;
    const char *q;

    if (rb_enc_mbmaxlen(enc) == rb_enc_mbminlen(enc)) {
        return (e - p + rb_enc_mbminlen(enc) - 1) / rb_enc_mbminlen(enc);
    }
    else if (rb_enc_asciicompat(enc)) {
        c = 0;
	if (cr == ENC_CODERANGE_7BIT || cr == ENC_CODERANGE_VALID) {
	    while (p < e) {
		if (ISASCII(*p)) {
		    q = search_nonascii(p, e);
		    if (!q)
			return c + (e - p);
		    c += q - p;
		    p = q;
		}
		p += rb_enc_fast_mbclen(p, e, enc);
		c++;
	    }
	}
	else {
	    while (p < e) {
		if (ISASCII(*p)) {
		    q = search_nonascii(p, e);
		    if (!q)
			return c + (e - p);
		    c += q - p;
		    p = q;
		}
		p += rb_enc_mbclen(p, e, enc);
		c++;
	    }
	}
        return c;
    }

    for (c=0; p<e; c++) {
        p += rb_enc_mbclen(p, e, enc);
    }
    return c;
}


rb_str_subpat_set(VALUE str, VALUE re, VALUE backref, VALUE val)
{
    int nth;
    VALUE match;
    long start, end, len;
    rb_encoding *enc;
    struct re_registers *regs;

    if (rb_reg_search(re, str, 0, 0) < 0) {
	rb_raise(rb_eIndexError, "regexp not matched");
    }
    match = rb_backref_get();
    nth = rb_reg_backref_number(match, backref);
    regs = RMATCH_REGS(match);
    if (nth >= regs->num_regs) {
      out_of_range:
	rb_raise(rb_eIndexError, "index %d out of regexp", nth);
    }
    if (nth < 0) {
	if (-nth >= regs->num_regs) {
	    goto out_of_range;
	}
	nth += regs->num_regs;
    }

    start = BEG(nth);
    if (start == -1) {
	rb_raise(rb_eIndexError, "regexp group %d not matched", nth);
    }
    end = END(nth);
    len = end - start;
    StringValue(val);
    enc = rb_enc_check(str, val);
    rb_str_splice_0(str, start, len, val);
    rb_enc_associate(str, enc);
}


rb_str_format_m(VALUE str, VALUE arg)
{
    volatile VALUE tmp = rb_check_array_type(arg);

    if (!NIL_P(tmp)) {
	return rb_str_format(RARRAY_LENINT(tmp), RARRAY_PTR(tmp), str);
    }
    return rb_str_format(1, &arg, str);
}


sym_to_sym(VALUE sym)
{
    return sym;
}


str_replace(VALUE str, VALUE str2)
{
    long len;

    len = RSTRING_LEN(str2);
    if (STR_ASSOC_P(str2)) {
	str2 = rb_str_new4(str2);
    }
    if (STR_SHARED_P(str2)) {
	VALUE shared = RSTRING(str2)->as.heap.aux.shared;
	assert(OBJ_FROZEN(shared));
	STR_SET_NOEMBED(str);
	RSTRING(str)->as.heap.len = len;
	RSTRING(str)->as.heap.ptr = RSTRING_PTR(str2);
	FL_SET(str, ELTS_SHARED);
	FL_UNSET(str, STR_ASSOC);
	RSTRING(str)->as.heap.aux.shared = shared;
    }
    else {
	str_replace_shared(str, str2);
    }

    OBJ_INFECT(str, str2);
    rb_enc_cr_str_exact_copy(str, str2);
    return str;
}


rb_str_sublen(VALUE str, long pos)
{
    if (single_byte_optimizable(str) || pos < 0)
        return pos;
    else {
	char *p = RSTRING_PTR(str);
        return enc_strlen(p, p + pos, STR_ENC_GET(str), ENC_CODERANGE(str));
    }
}


rb_str_to_str(VALUE str)
{
    return rb_convert_type(str, T_STRING, "String", "to_str");
}


rb_str_hash_cmp(VALUE str1, VALUE str2)
{
    long len;

    if (!rb_str_comparable(str1, str2)) return 1;
    if (RSTRING_LEN(str1) == (len = RSTRING_LEN(str2)) &&
	memcmp(RSTRING_PTR(str1), RSTRING_PTR(str2), len) == 0) {
	return 0;
    }
    return 1;
}


rb_str_squeeze_bang(int argc, VALUE *argv, VALUE str)
{
    char squeez[256];
    rb_encoding *enc = 0;
    VALUE del = 0, nodel = 0;
    char *s, *send, *t;
    int i, modify = 0;
    int ascompat, singlebyte = single_byte_optimizable(str);
    unsigned int save;

    if (argc == 0) {
	enc = STR_ENC_GET(str);
    }
    else {
	for (i=0; i<argc; i++) {
	    VALUE s = argv[i];

	    StringValue(s);
	    enc = rb_enc_check(str, s);
	    if (singlebyte && !single_byte_optimizable(s))
		singlebyte = 0;
	    tr_setup_table(s, squeez, i==0, &del, &nodel, enc);
	}
    }

    str_modify_keep_cr(str);
    s = t = RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return Qnil;
    send = RSTRING_END(str);
    save = -1;
    ascompat = rb_enc_asciicompat(enc);

    if (singlebyte) {
        while (s < send) {
	    unsigned int c = *(unsigned char*)s++;
	    if (c != save || (argc > 0 && !squeez[c])) {
	        *t++ = save = c;
	    }
	}
    } else {
	while (s < send) {
	    unsigned int c;
	    int clen;

	    if (ascompat && (c = *(unsigned char*)s) < 0x80) {
		if (c != save || (argc > 0 && !squeez[c])) {
		    *t++ = save = c;
		}
		s++;
	    }
	    else {
		c = rb_enc_codepoint_len(s, send, &clen, enc);

		if (c != save || (argc > 0 && !tr_find(c, squeez, del, nodel))) {
		    if (t != s) rb_enc_mbcput(c, t, enc);
		    save = c;
		    t += clen;
		}
		s += clen;
	    }
	}
    }

    *t = '\0';
    if (t - RSTRING_PTR(str) != RSTRING_LEN(str)) {
	STR_SET_LEN(str, t - RSTRING_PTR(str));
	modify = 1;
    }

    if (modify) return str;
    return Qnil;
}


str_new_shared(VALUE klass, VALUE str)
{
    return str_replace_shared(str_alloc(klass), str);
}


rb_str_match(VALUE x, VALUE y)
{
    switch (TYPE(y)) {
      case T_STRING:
	rb_raise(rb_eTypeError, "type mismatch: String given");

      case T_REGEXP:
	return rb_reg_match(y, x);

      default:
	return rb_funcall(y, rb_intern("=~"), 1, x);
    }
}


rb_str_upcase_bang(VALUE str)
{
    rb_encoding *enc;
    char *s, *send;
    int modify = 0;
    int n;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    rb_str_check_dummy_enc(enc);
    s = RSTRING_PTR(str); send = RSTRING_END(str);
    if (single_byte_optimizable(str)) {
	while (s < send) {
	    unsigned int c = *(unsigned char*)s;

	    if (rb_enc_isascii(c, enc) && 'a' <= c && c <= 'z') {
		*s = 'A' + (c - 'a');
		modify = 1;
	    }
	    s++;
	}
    }
    else {
	int ascompat = rb_enc_asciicompat(enc);

	while (s < send) {
	    unsigned int c;

	    if (ascompat && (c = *(unsigned char*)s) < 0x80) {
		if (rb_enc_isascii(c, enc) && 'a' <= c && c <= 'z') {
		    *s = 'A' + (c - 'a');
		    modify = 1;
		}
		s++;
	    }
	    else {
		c = rb_enc_codepoint_len(s, send, &n, enc);
		if (rb_enc_islower(c, enc)) {
		    /* assuming toupper returns codepoint with same size */
		    rb_enc_mbcput(rb_enc_toupper(c, enc), s, enc);
		    modify = 1;
		}
		s += n;
	    }
	}
    }

    if (modify) return str;
    return Qnil;
}


rb_str_freeze(VALUE str)
{
    if (STR_ASSOC_P(str)) {
	VALUE ary = RSTRING(str)->as.heap.aux.shared;
	OBJ_FREEZE(ary);
    }
    return rb_obj_freeze(str);
}


rb_str_setbyte(VALUE str, VALUE index, VALUE value)
{
    long pos = NUM2LONG(index);
    int byte = NUM2INT(value);

    rb_str_modify(str);

    if (pos < -RSTRING_LEN(str) || RSTRING_LEN(str) <= pos)
        rb_raise(rb_eIndexError, "index %ld out of string", pos);
    if (pos < 0)
        pos += RSTRING_LEN(str);

    RSTRING_PTR(str)[pos] = byte;

    return value;
}


rb_str_valid_encoding_p(VALUE str)
{
    int cr = rb_enc_str_coderange(str);

    return cr == ENC_CODERANGE_BROKEN ? Qfalse : Qtrue;
}


rb_str_hash_m(VALUE str)
{
    st_index_t hval = rb_str_hash(str);
    return INT2FIX(hval);
}


rb_external_str_new_with_enc(const char *ptr, long len, rb_encoding *eenc)
{
    VALUE str;

    str = rb_tainted_str_new(ptr, len);
    if (eenc == rb_usascii_encoding() &&
	rb_enc_str_coderange(str) != ENC_CODERANGE_7BIT) {
	rb_enc_associate(str, rb_ascii8bit_encoding());
	return str;
    }
    rb_enc_associate(str, eenc);
    return rb_str_conv_enc(str, eenc, rb_default_internal_encoding());
}


rb_enc_str_new(const char *ptr, long len, rb_encoding *enc)
{
    VALUE str = rb_str_new(ptr, len);
    rb_enc_associate(str, enc);
    return str;
}


rb_enc_nth(const char *p, const char *e, long nth, rb_encoding *enc)
{
    if (rb_enc_mbmaxlen(enc) == 1) {
        p += nth;
    }
    else if (rb_enc_mbmaxlen(enc) == rb_enc_mbminlen(enc)) {
        p += nth * rb_enc_mbmaxlen(enc);
    }
    else if (rb_enc_asciicompat(enc)) {
        const char *p2, *e2;
        int n;

        while (p < e && 0 < nth) {
            e2 = p + nth;
            if (e < e2)
                return (char *)e;
            if (ISASCII(*p)) {
                p2 = search_nonascii(p, e2);
                if (!p2)
                    return (char *)e2;
                nth -= p2 - p;
                p = p2;
            }
            n = rb_enc_mbclen(p, e, enc);
            p += n;
            nth--;
        }
        if (nth != 0)
            return (char *)e;
        return (char *)p;
    }
    else {
        while (p<e && nth--) {
            p += rb_enc_mbclen(p, e, enc);
        }
    }
    if (p > e) p = e;
    return (char*)p;
}


rb_str_insert(VALUE str, VALUE idx, VALUE str2)
{
    long pos = NUM2LONG(idx);

    if (pos == -1) {
	return rb_str_append(str, str2);
    }
    else if (pos < 0) {
	pos++;
    }
    rb_str_splice(str, pos, 0, str2);
    return str;
}


rb_enc_str_buf_cat(VALUE str, const char *ptr, long len, rb_encoding *ptr_enc)
{
    return rb_enc_cr_str_buf_cat(str, ptr, len,
        rb_enc_to_index(ptr_enc), ENC_CODERANGE_UNKNOWN, NULL);
}


sym_upcase(VALUE sym)
{
    return rb_str_intern(rb_str_upcase(rb_id2str(SYM2ID(sym))));
}


rb_str_chop_bang(VALUE str)
{
    str_modify_keep_cr(str);
    if (RSTRING_LEN(str) > 0) {
	long len;
	len = chopped_length(str);
	STR_SET_LEN(str, len);
	RSTRING_PTR(str)[len] = '\0';
	if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) {
	    ENC_CODERANGE_CLEAR(str);
	}
	return str;
    }
    return Qnil;
}


rb_str_force_encoding(VALUE str, VALUE enc)
{
    str_modifiable(str);
    rb_enc_associate(str, rb_to_encoding(enc));
    ENC_CODERANGE_CLEAR(str);
    return str;
}


rb_enc_strlen_cr(const char *p, const char *e, rb_encoding *enc, int *cr)
{
    long c;
    const char *q;
    int ret;

    *cr = 0;
    if (rb_enc_mbmaxlen(enc) == rb_enc_mbminlen(enc)) {
	return (e - p + rb_enc_mbminlen(enc) - 1) / rb_enc_mbminlen(enc);
    }
    else if (rb_enc_asciicompat(enc)) {
	c = 0;
	while (p < e) {
	    if (ISASCII(*p)) {
		q = search_nonascii(p, e);
		if (!q) {
		    if (!*cr) *cr = ENC_CODERANGE_7BIT;
		    return c + (e - p);
		}
		c += q - p;
		p = q;
	    }
	    ret = rb_enc_precise_mbclen(p, e, enc);
	    if (MBCLEN_CHARFOUND_P(ret)) {
		*cr |= ENC_CODERANGE_VALID;
		p += MBCLEN_CHARFOUND_LEN(ret);
	    }
	    else {
		*cr = ENC_CODERANGE_BROKEN;
		p++;
	    }
	    c++;
	}
	if (!*cr) *cr = ENC_CODERANGE_7BIT;
	return c;
    }

    for (c=0; p<e; c++) {
	ret = rb_enc_precise_mbclen(p, e, enc);
	if (MBCLEN_CHARFOUND_P(ret)) {
	    *cr |= ENC_CODERANGE_VALID;
	    p += MBCLEN_CHARFOUND_LEN(ret);
	}
	else {
	    *cr = ENC_CODERANGE_BROKEN;
	    p++;
	}
    }
    if (!*cr) *cr = ENC_CODERANGE_7BIT;
    return c;
}


rb_str_conv_enc(VALUE str, rb_encoding *from, rb_encoding *to)
{
    return rb_str_conv_enc_opts(str, from, to, 0, Qnil);
}


rb_str_update(VALUE str, long beg, long len, VALUE val)
{
    rb_str_splice(str, beg, len, val);
}


rb_str_buf_cat(VALUE str, const char *ptr, long len)
{
    if (len == 0) return str;
    if (len < 0) {
	rb_raise(rb_eArgError, "negative string size (or size too big)");
    }
    return str_buf_cat(str, ptr, len);
}


rb_str_buf_new(long capa)
{
    VALUE str = str_alloc(rb_cString);

    if (capa < STR_BUF_MIN_SIZE) {
	capa = STR_BUF_MIN_SIZE;
    }
    FL_SET(str, STR_NOEMBED);
    RSTRING(str)->as.heap.aux.capa = capa;
    RSTRING(str)->as.heap.ptr = ALLOC_N(char, capa+1);
    RSTRING(str)->as.heap.ptr[0] = '\0';

    return str;
}


rb_str_to_f(VALUE str)
{
    return DBL2NUM(rb_str_to_dbl(str, FALSE));
}


rb_str_replace(VALUE str, VALUE str2)
{
    if (str == str2) return str;

    StringValue(str2);
    str_discard(str);
    return str_replace(str, str2);
}


tr_trans(VALUE str, VALUE src, VALUE repl, int sflag)
{
    const unsigned int errc = -1;
    unsigned int trans[256];
    rb_encoding *enc, *e1, *e2;
    struct tr trsrc, trrepl;
    int cflag = 0;
    unsigned int c, c0;
    int last = 0, modify = 0, i, l;
    char *s, *send;
    VALUE hash = 0;
    int singlebyte = single_byte_optimizable(str);
    int cr;

#define CHECK_IF_ASCII(c) \
    (void)((cr == ENC_CODERANGE_7BIT && !rb_isascii(c)) ? \
	   (cr = ENC_CODERANGE_VALID) : 0)

    StringValue(src);
    StringValue(repl);
    if (RSTRING_LEN(str) == 0 || !RSTRING_PTR(str)) return Qnil;
    if (RSTRING_LEN(repl) == 0) {
	return rb_str_delete_bang(1, &src, str);
    }

    cr = ENC_CODERANGE(str);
    e1 = rb_enc_check(str, src);
    e2 = rb_enc_check(str, repl);
    if (e1 == e2) {
	enc = e1;
    }
    else {
	enc = rb_enc_check(src, repl);
    }
    trsrc.p = RSTRING_PTR(src); trsrc.pend = trsrc.p + RSTRING_LEN(src);
    if (RSTRING_LEN(src) > 1 &&
	rb_enc_ascget(trsrc.p, trsrc.pend, &l, enc) == '^' &&
	trsrc.p + l < trsrc.pend) {
	cflag = 1;
	trsrc.p += l;
    }
    trrepl.p = RSTRING_PTR(repl);
    trrepl.pend = trrepl.p + RSTRING_LEN(repl);
    trsrc.gen = trrepl.gen = 0;
    trsrc.now = trrepl.now = 0;
    trsrc.max = trrepl.max = 0;

    if (cflag) {
	for (i=0; i<256; i++) {
	    trans[i] = 1;
	}
	while ((c = trnext(&trsrc, enc)) != errc) {
	    if (c < 256) {
		trans[c] = errc;
	    }
	    else {
		if (!hash) hash = rb_hash_new();
		rb_hash_aset(hash, UINT2NUM(c), Qtrue);
	    }
	}
	while ((c = trnext(&trrepl, enc)) != errc)
	    /* retrieve last replacer */;
	last = trrepl.now;
	for (i=0; i<256; i++) {
	    if (trans[i] != errc) {
		trans[i] = last;
	    }
	}
    }
    else {
	unsigned int r;

	for (i=0; i<256; i++) {
	    trans[i] = errc;
	}
	while ((c = trnext(&trsrc, enc)) != errc) {
	    r = trnext(&trrepl, enc);
	    if (r == errc) r = trrepl.now;
	    if (c < 256) {
		trans[c] = r;
		if (rb_enc_codelen(r, enc) != 1) singlebyte = 0;
	    }
	    else {
		if (!hash) hash = rb_hash_new();
		rb_hash_aset(hash, UINT2NUM(c), UINT2NUM(r));
	    }
	}
    }

    if (cr == ENC_CODERANGE_VALID)
	cr = ENC_CODERANGE_7BIT;
    str_modify_keep_cr(str);
    s = RSTRING_PTR(str); send = RSTRING_END(str);
    if (sflag) {
	int clen, tlen;
	long offset, max = RSTRING_LEN(str);
	unsigned int save = -1;
	char *buf = ALLOC_N(char, max), *t = buf;

	while (s < send) {
	    int may_modify = 0;

	    c0 = c = rb_enc_codepoint_len(s, send, &clen, e1);
	    tlen = enc == e1 ? clen : rb_enc_codelen(c, enc);

	    s += clen;
	    if (c < 256) {
		c = trans[c];
	    }
	    else if (hash) {
		VALUE tmp = rb_hash_lookup(hash, UINT2NUM(c));
		if (NIL_P(tmp)) {
		    if (cflag) c = last;
		    else c = errc;
		}
		else if (cflag) c = errc;
		else c = NUM2INT(tmp);
	    }
	    else {
		c = errc;
	    }
	    if (c != (unsigned int)-1) {
		if (save == c) {
		    CHECK_IF_ASCII(c);
		    continue;
		}
		save = c;
		tlen = rb_enc_codelen(c, enc);
		modify = 1;
	    }
	    else {
		save = -1;
		c = c0;
		if (enc != e1) may_modify = 1;
	    }
	    while (t - buf + tlen >= max) {
		offset = t - buf;
		max *= 2;
		REALLOC_N(buf, char, max);
		t = buf + offset;
	    }
	    rb_enc_mbcput(c, t, enc);
	    if (may_modify && memcmp(s, t, tlen) != 0) {
		modify = 1;
	    }
	    CHECK_IF_ASCII(c);
	    t += tlen;
	}
	*t = '\0';
	RSTRING(str)->as.heap.ptr = buf;
	RSTRING(str)->as.heap.len = t - buf;
	STR_SET_NOEMBED(str);
	RSTRING(str)->as.heap.aux.capa = max;
    }
    else if (rb_enc_mbmaxlen(enc) == 1 || (singlebyte && !hash)) {
	while (s < send) {
	    c = (unsigned char)*s;
	    if (trans[c] != errc) {
		if (!cflag) {
		    c = trans[c];
		    *s = c;
		    modify = 1;
		}
		else {
		    *s = last;
		    modify = 1;
		}
	    }
	    CHECK_IF_ASCII(c);
	    s++;
	}
    }
    else {
	int clen, tlen, max = (int)(RSTRING_LEN(str) * 1.2);
	long offset;
	char *buf = ALLOC_N(char, max), *t = buf;

	while (s < send) {
	    int may_modify = 0;
	    c0 = c = rb_enc_codepoint_len(s, send, &clen, e1);
	    tlen = enc == e1 ? clen : rb_enc_codelen(c, enc);

	    if (c < 256) {
		c = trans[c];
	    }
	    else if (hash) {
		VALUE tmp = rb_hash_lookup(hash, UINT2NUM(c));
		if (NIL_P(tmp)) {
		    if (cflag) c = last;
		    else c = errc;
		}
		else if (cflag) c = errc;
		else c = NUM2INT(tmp);
	    }
	    else {
		c = errc;
	    }
	    if (c != errc) {
		tlen = rb_enc_codelen(c, enc);
		modify = 1;
	    }
	    else {
		c = c0;
		if (enc != e1) may_modify = 1;
	    }
	    while (t - buf + tlen >= max) {
		offset = t - buf;
		max *= 2;
		REALLOC_N(buf, char, max);
		t = buf + offset;
	    }
	    if (s != t) {
		rb_enc_mbcput(c, t, enc);
		if (may_modify && memcmp(s, t, tlen) != 0) {
		    modify = 1;
		}
	    }
	    CHECK_IF_ASCII(c);
	    s += clen;
	    t += tlen;
	}
	if (!STR_EMBED_P(str)) {
	    xfree(RSTRING(str)->as.heap.ptr);
	}
	*t = '\0';
	RSTRING(str)->as.heap.ptr = buf;
	RSTRING(str)->as.heap.len = t - buf;
	STR_SET_NOEMBED(str);
	RSTRING(str)->as.heap.aux.capa = max;
    }

    if (modify) {
	if (cr != ENC_CODERANGE_BROKEN)
	    ENC_CODERANGE_SET(str, cr);
	rb_enc_associate(str, enc);
	return str;
    }
    return Qnil;
}


rb_str_slice_bang(int argc, VALUE *argv, VALUE str)
{
    VALUE result;
    VALUE buf[3];
    int i;

    if (argc < 1 || 2 < argc) {
	rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
    }
    for (i=0; i<argc; i++) {
	buf[i] = argv[i];
    }
    str_modify_keep_cr(str);
    buf[i] = rb_str_new(0,0);
    result = rb_str_aref_m(argc, buf, str);
    if (!NIL_P(result)) {
	rb_str_aset_m(argc+1, buf, str);
    }
    return result;
}


rb_str_each_codepoint(VALUE str)
{
    VALUE orig = str;
    long len;
    int n;
    unsigned int c;
    const char *ptr, *end;
    rb_encoding *enc;

    if (single_byte_optimizable(str)) return rb_str_each_byte(str);
    RETURN_ENUMERATOR(str, 0, 0);
    str = rb_str_new4(str);
    ptr = RSTRING_PTR(str);
    len = RSTRING_LEN(str);
    end = RSTRING_END(str);
    enc = STR_ENC_GET(str);
    while (ptr < end) {
	c = rb_enc_codepoint_len(ptr, end, &n, enc);
	rb_yield(UINT2NUM(c));
	ptr += n;
    }
    return orig;
}


rb_str_squeeze(int argc, VALUE *argv, VALUE str)
{
    str = rb_str_dup(str);
    rb_str_squeeze_bang(argc, argv, str);
    return str;
}


rb_str_lstrip_bang(VALUE str)
{
    rb_encoding *enc;
    char *s, *t, *e;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    s = RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return Qnil;
    e = t = RSTRING_END(str);
    /* remove spaces at head */
    while (s < e) {
	int n;
	unsigned int cc = rb_enc_codepoint_len(s, e, &n, enc);

	if (!rb_isspace(cc)) break;
	s += n;
    }

    if (s > RSTRING_PTR(str)) {
	STR_SET_LEN(str, t-s);
	memmove(RSTRING_PTR(str), s, RSTRING_LEN(str));
	RSTRING_PTR(str)[RSTRING_LEN(str)] = '\0';
	return str;
    }
    return Qnil;
}


rb_str_hash(VALUE str)
{
    int e = ENCODING_GET(str);
    if (e && rb_enc_str_coderange(str) == ENC_CODERANGE_7BIT) {
	e = 0;
    }
    return rb_memhash((const void *)RSTRING_PTR(str), RSTRING_LEN(str)) ^ e;
}


rb_filesystem_str_new(const char *ptr, long len)
{
    return rb_external_str_new_with_enc(ptr, len, rb_filesystem_encoding());
}


rb_str_new_with_class(VALUE obj, const char *ptr, long len)
{
    return str_new(rb_obj_class(obj), ptr, len);
}


str_discard(VALUE str)
{
    str_modifiable(str);
    if (!STR_SHARED_P(str) && !STR_EMBED_P(str)) {
	xfree(RSTRING_PTR(str));
	RSTRING(str)->as.heap.ptr = 0;
	RSTRING(str)->as.heap.len = 0;
    }
}


rb_str_reverse(VALUE str)
{
    rb_encoding *enc;
    VALUE rev;
    char *s, *e, *p;
    int single = 1;

    if (RSTRING_LEN(str) <= 1) return rb_str_dup(str);
    enc = STR_ENC_GET(str);
    rev = rb_str_new5(str, 0, RSTRING_LEN(str));
    s = RSTRING_PTR(str); e = RSTRING_END(str);
    p = RSTRING_END(rev);

    if (RSTRING_LEN(str) > 1) {
	if (single_byte_optimizable(str)) {
	    while (s < e) {
		*--p = *s++;
	    }
	}
	else if (ENC_CODERANGE(str) == ENC_CODERANGE_VALID) {
	    while (s < e) {
		int clen = rb_enc_fast_mbclen(s, e, enc);

		if (clen > 1 || (*s & 0x80)) single = 0;
		p -= clen;
		memcpy(p, s, clen);
		s += clen;
	    }
	}
	else {
	    while (s < e) {
		int clen = rb_enc_mbclen(s, e, enc);

		if (clen > 1 || (*s & 0x80)) single = 0;
		p -= clen;
		memcpy(p, s, clen);
		s += clen;
	    }
	}
    }
    STR_SET_LEN(rev, RSTRING_LEN(str));
    OBJ_INFECT(rev, str);
    if (ENC_CODERANGE(str) == ENC_CODERANGE_UNKNOWN) {
	if (single) {
	    ENC_CODERANGE_SET(str, ENC_CODERANGE_7BIT);
	}
	else {
	    ENC_CODERANGE_SET(str, ENC_CODERANGE_VALID);
	}
    }
    rb_enc_cr_str_copy_for_substr(rev, str);

    return rev;
}


rb_str_tr_s_bang(VALUE str, VALUE src, VALUE repl)
{
    return tr_trans(str, src, repl, 1);
}


trnext(struct tr *t, rb_encoding *enc)
{
    int n;

    for (;;) {
	if (!t->gen) {
	    if (t->p == t->pend) return -1;
	    if (t->p < t->pend - 1 && *t->p == '\\') {
		t->p++;
	    }
	    t->now = rb_enc_codepoint_len(t->p, t->pend, &n, enc);
	    t->p += n;
	    if (t->p < t->pend - 1 && *t->p == '-') {
		t->p++;
		if (t->p < t->pend) {
		    unsigned int c = rb_enc_codepoint_len(t->p, t->pend, &n, enc);
		    t->p += n;
		    if (t->now > c) {
			if (t->now < 0x80 && c < 0x80) {
			    rb_raise(rb_eArgError,
				     "invalid range \"%c-%c\" in string transliteration",
				     t->now, c);
			}
			else {
			    rb_raise(rb_eArgError, "invalid range in string transliteration");
			}
			continue; /* not reached */
		    }
		    t->gen = 1;
		    t->max = c;
		}
	    }
	    return t->now;
	}
	else if (++t->now < t->max) {
	    return t->now;
	}
	else {
	    t->gen = 0;
	    return t->max;
	}
    }
}


rb_str_rpartition(VALUE str, VALUE sep)
{
    long pos = RSTRING_LEN(str);
    int regex = FALSE;

    if (TYPE(sep) == T_REGEXP) {
	pos = rb_reg_search(sep, str, pos, 1);
	regex = TRUE;
    }
    else {
	VALUE tmp;

	tmp = rb_check_string_type(sep);
	if (NIL_P(tmp)) {
	    rb_raise(rb_eTypeError, "type mismatch: %s given",
		     rb_obj_classname(sep));
	}
	sep = tmp;
	pos = rb_str_sublen(str, pos);
	pos = rb_str_rindex(str, sep, pos);
    }
    if (pos < 0) {
	return rb_ary_new3(3, rb_str_new(0,0),rb_str_new(0,0), str);
    }
    if (regex) {
	sep = rb_reg_nth_match(0, rb_backref_get());
    }
    return rb_ary_new3(3, rb_str_substr(str, 0, pos),
		          sep,
		          rb_str_substr(str,pos+str_strlen(sep,STR_ENC_GET(sep)),RSTRING_LEN(str)));
}


rb_str_new(const char *ptr, long len)
{
    return str_new(rb_cString, ptr, len);
}


rb_str_setter(VALUE val, ID id, VALUE *var)
{
    if (!NIL_P(val) && TYPE(val) != T_STRING) {
	rb_raise(rb_eTypeError, "value of %s must be String", rb_id2name(id));
    }
    *var = val;
}


rb_str_upcase(VALUE str)
{
    str = rb_str_dup(str);
    rb_str_upcase_bang(str);
    return str;
}


rb_str_cmp_m(VALUE str1, VALUE str2)
{
    long result;

    if (TYPE(str2) != T_STRING) {
	if (!rb_respond_to(str2, rb_intern("to_str"))) {
	    return Qnil;
	}
	else if (!rb_respond_to(str2, rb_intern("<=>"))) {
	    return Qnil;
	}
	else {
	    VALUE tmp = rb_funcall(str2, rb_intern("<=>"), 1, str1);

	    if (NIL_P(tmp)) return Qnil;
	    if (!FIXNUM_P(tmp)) {
		return rb_funcall(LONG2FIX(0), '-', 1, tmp);
	    }
	    result = -FIX2LONG(tmp);
	}
    }
    else {
	result = rb_str_cmp(str1, str2);
    }
    return LONG2NUM(result);
}


rb_enc_cr_str_exact_copy(VALUE dest, VALUE src)
{
    str_enc_copy(dest, src);
    ENC_CODERANGE_SET(dest, ENC_CODERANGE(src));
}


rb_str_conv_enc_opts(VALUE str, rb_encoding *from, rb_encoding *to, int ecflags, VALUE ecopts)
{
    rb_econv_t *ec;
    rb_econv_result_t ret;
    long len;
    VALUE newstr;
    const unsigned char *sp;
    unsigned char *dp;

    if (!to) return str;
    if (from == to) return str;
    if ((rb_enc_asciicompat(to) && ENC_CODERANGE(str) == ENC_CODERANGE_7BIT) ||
	to == rb_ascii8bit_encoding()) {
	if (STR_ENC_GET(str) != to) {
	    str = rb_str_dup(str);
	    rb_enc_associate(str, to);
	}
	return str;
    }

    len = RSTRING_LEN(str);
    newstr = rb_str_new(0, len);

  retry:
    ec = rb_econv_open_opts(from->name, to->name, ecflags, ecopts);
    if (!ec) return str;

    sp = (unsigned char*)RSTRING_PTR(str);
    dp = (unsigned char*)RSTRING_PTR(newstr);
    ret = rb_econv_convert(ec, &sp, (unsigned char*)RSTRING_END(str),
			   &dp, (unsigned char*)RSTRING_END(newstr), 0);
    rb_econv_close(ec);
    switch (ret) {
      case econv_destination_buffer_full:
	/* destination buffer short */
	len *= 2;
	rb_str_resize(newstr, len);
	goto retry;

      case econv_finished:
	len = dp - (unsigned char*)RSTRING_PTR(newstr);
	rb_str_set_len(newstr, len);
	rb_enc_associate(newstr, to);
	return newstr;

      default:
	/* some error, return original */
	return str;
    }
}


rb_str_dump(VALUE str)
{
    rb_encoding *enc = rb_enc_get(str);
    long len;
    const char *p, *pend;
    char *q, *qend;
    VALUE result;
    int u8 = (enc == rb_utf8_encoding());

    len = 2;			/* "" */
    p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str);
    while (p < pend) {
	unsigned char c = *p++;
	switch (c) {
	  case '"':  case '\\':
	  case '\n': case '\r':
	  case '\t': case '\f':
	  case '\013': case '\010': case '\007': case '\033':
	    len += 2;
	    break;

	  case '#':
	    len += IS_EVSTR(p, pend) ? 2 : 1;
	    break;

	  default:
	    if (ISPRINT(c)) {
		len++;
	    }
	    else {
		if (u8) {	/* \u{NN} */
		    char buf[32];
		    int n = rb_enc_precise_mbclen(p-1, pend, enc);
		    if (MBCLEN_CHARFOUND_P(n)) {
			int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc);
			sprintf(buf, "%x", cc);
			len += strlen(buf)+4;
			p += MBCLEN_CHARFOUND_LEN(n)-1;
			break;
		    }
		}
		len += 4;	/* \xNN */
	    }
	    break;
	}
    }
    if (!rb_enc_asciicompat(enc)) {
	len += 19;		/* ".force_encoding('')" */
	len += strlen(enc->name);
    }

    result = rb_str_new5(str, 0, len);
    p = RSTRING_PTR(str); pend = p + RSTRING_LEN(str);
    q = RSTRING_PTR(result); qend = q + len + 1;

    *q++ = '"';
    while (p < pend) {
	unsigned char c = *p++;

	if (c == '"' || c == '\\') {
	    *q++ = '\\';
	    *q++ = c;
	}
	else if (c == '#') {
	    if (IS_EVSTR(p, pend)) *q++ = '\\';
	    *q++ = '#';
	}
	else if (c == '\n') {
	    *q++ = '\\';
	    *q++ = 'n';
	}
	else if (c == '\r') {
	    *q++ = '\\';
	    *q++ = 'r';
	}
	else if (c == '\t') {
	    *q++ = '\\';
	    *q++ = 't';
	}
	else if (c == '\f') {
	    *q++ = '\\';
	    *q++ = 'f';
	}
	else if (c == '\013') {
	    *q++ = '\\';
	    *q++ = 'v';
	}
	else if (c == '\010') {
	    *q++ = '\\';
	    *q++ = 'b';
	}
	else if (c == '\007') {
	    *q++ = '\\';
	    *q++ = 'a';
	}
	else if (c == '\033') {
	    *q++ = '\\';
	    *q++ = 'e';
	}
	else if (ISPRINT(c)) {
	    *q++ = c;
	}
	else {
	    *q++ = '\\';
	    if (u8) {
		int n = rb_enc_precise_mbclen(p-1, pend, enc) - 1;
		if (MBCLEN_CHARFOUND_P(n)) {
		    int cc = rb_enc_mbc_to_codepoint(p-1, pend, enc);
		    p += n;
		    snprintf(q, qend-q, "u{%x}", cc);
		    q += strlen(q);
		    continue;
		}
	    }
	    snprintf(q, qend-q, "x%02X", c);
	    q += 3;
	}
    }
    *q++ = '"';
    *q = '\0';
    if (!rb_enc_asciicompat(enc)) {
	snprintf(q, qend-q, ".force_encoding(\"%s\")", enc->name);
	enc = rb_ascii8bit_encoding();
    }
    OBJ_INFECT(result, str);
    /* result from dump is ASCII */
    rb_enc_associate(result, enc);
    ENC_CODERANGE_SET(result, ENC_CODERANGE_7BIT);
    return result;
}


sym_inspect(VALUE sym)
{
    VALUE str;
    ID id = SYM2ID(sym);
    rb_encoding *enc;

    sym = rb_id2str(id);
    enc = STR_ENC_GET(sym);
    str = rb_enc_str_new(0, RSTRING_LEN(sym)+1, enc);
    RSTRING_PTR(str)[0] = ':';
    memcpy(RSTRING_PTR(str)+1, RSTRING_PTR(sym), RSTRING_LEN(sym));
    if (RSTRING_LEN(sym) != (long)strlen(RSTRING_PTR(sym)) ||
	!rb_enc_symname_p(RSTRING_PTR(sym), enc) ||
	!sym_printable(RSTRING_PTR(sym), RSTRING_END(sym), enc)) {
	str = rb_str_inspect(str);
	memcpy(RSTRING_PTR(str), ":\"", 2);
    }
    return str;
}


str_replace_shared(VALUE str2, VALUE str)
{
    if (RSTRING_LEN(str) <= RSTRING_EMBED_LEN_MAX) {
	STR_SET_EMBED(str2);
	memcpy(RSTRING_PTR(str2), RSTRING_PTR(str), RSTRING_LEN(str)+1);
	STR_SET_EMBED_LEN(str2, RSTRING_LEN(str));
    }
    else {
	FL_SET(str2, STR_NOEMBED);
	str = rb_str_new_frozen(str);
	RSTRING(str2)->as.heap.len = RSTRING_LEN(str);
	RSTRING(str2)->as.heap.ptr = RSTRING_PTR(str);
	RSTRING(str2)->as.heap.aux.shared = str;
	FL_SET(str2, ELTS_SHARED);
    }
    rb_enc_cr_str_exact_copy(str2, str);

    return str2;
}


rb_enc_cr_str_buf_cat(VALUE str, const char *ptr, long len,
    int ptr_encindex, int ptr_cr, int *ptr_cr_ret)
{
    int str_encindex = ENCODING_GET(str);
    int res_encindex;
    int str_cr, res_cr;
    int str_a8 = ENCODING_IS_ASCII8BIT(str);
    int ptr_a8 = ptr_encindex == 0;

    str_cr = ENC_CODERANGE(str);

    if (str_encindex == ptr_encindex) {
        if (str_cr == ENC_CODERANGE_UNKNOWN ||
            (ptr_a8 && str_cr != ENC_CODERANGE_7BIT)) {
            ptr_cr = ENC_CODERANGE_UNKNOWN;
        }
        else if (ptr_cr == ENC_CODERANGE_UNKNOWN) {
            ptr_cr = coderange_scan(ptr, len, rb_enc_from_index(ptr_encindex));
        }
    }
    else {
        rb_encoding *str_enc = rb_enc_from_index(str_encindex);
        rb_encoding *ptr_enc = rb_enc_from_index(ptr_encindex);
        if (!rb_enc_asciicompat(str_enc) || !rb_enc_asciicompat(ptr_enc)) {
            if (len == 0)
                return str;
            if (RSTRING_LEN(str) == 0) {
                rb_str_buf_cat(str, ptr, len);
                ENCODING_CODERANGE_SET(str, ptr_encindex, ptr_cr);
                return str;
            }
            goto incompatible;
        }
	if (ptr_cr == ENC_CODERANGE_UNKNOWN) {
	    ptr_cr = coderange_scan(ptr, len, ptr_enc);
	}
        if (str_cr == ENC_CODERANGE_UNKNOWN) {
            if (str_a8 || ptr_cr != ENC_CODERANGE_7BIT) {
                str_cr = rb_enc_str_coderange(str);
            }
        }
    }
    if (ptr_cr_ret)
        *ptr_cr_ret = ptr_cr;

    if (str_encindex != ptr_encindex &&
        str_cr != ENC_CODERANGE_7BIT &&
        ptr_cr != ENC_CODERANGE_7BIT) {
      incompatible:
        rb_raise(rb_eEncCompatError, "incompatible character encodings: %s and %s",
            rb_enc_name(rb_enc_from_index(str_encindex)),
            rb_enc_name(rb_enc_from_index(ptr_encindex)));
    }

    if (str_cr == ENC_CODERANGE_UNKNOWN) {
        res_encindex = str_encindex;
        res_cr = ENC_CODERANGE_UNKNOWN;
    }
    else if (str_cr == ENC_CODERANGE_7BIT) {
        if (ptr_cr == ENC_CODERANGE_7BIT) {
            res_encindex = !str_a8 ? str_encindex : ptr_encindex;
            res_cr = ENC_CODERANGE_7BIT;
        }
        else {
            res_encindex = ptr_encindex;
            res_cr = ptr_cr;
        }
    }
    else if (str_cr == ENC_CODERANGE_VALID) {
        res_encindex = str_encindex;
        res_cr = str_cr;
    }
    else { /* str_cr == ENC_CODERANGE_BROKEN */
        res_encindex = str_encindex;
        res_cr = str_cr;
        if (0 < len) res_cr = ENC_CODERANGE_UNKNOWN;
    }

    if (len < 0) {
	rb_raise(rb_eArgError, "negative string size (or size too big)");
    }
    str_buf_cat(str, ptr, len);
    ENCODING_CODERANGE_SET(str, res_encindex, res_cr);
    return str;
}


rb_str_aset_m(int argc, VALUE *argv, VALUE str)
{
    if (argc == 3) {
	if (TYPE(argv[0]) == T_REGEXP) {
	    rb_str_subpat_set(str, argv[0], argv[1], argv[2]);
	}
	else {
	    rb_str_splice(str, NUM2LONG(argv[0]), NUM2LONG(argv[1]), argv[2]);
	}
	return argv[2];
    }
    if (argc != 2) {
	rb_raise(rb_eArgError, "wrong number of arguments (%d for 2)", argc);
    }
    return rb_str_aset(str, argv[0], argv[1]);
}


rb_str_comparable(VALUE str1, VALUE str2)
{
    int idx1, idx2;
    int rc1, rc2;

    if (RSTRING_LEN(str1) == 0) return TRUE;
    if (RSTRING_LEN(str2) == 0) return TRUE;
    idx1 = ENCODING_GET(str1);
    idx2 = ENCODING_GET(str2);
    if (idx1 == idx2) return TRUE;
    rc1 = rb_enc_str_coderange(str1);
    rc2 = rb_enc_str_coderange(str2);
    if (rc1 == ENC_CODERANGE_7BIT) {
	if (rc2 == ENC_CODERANGE_7BIT) return TRUE;
	if (rb_enc_asciicompat(rb_enc_from_index(idx2)))
	    return TRUE;
    }
    if (rc2 == ENC_CODERANGE_7BIT) {
	if (rb_enc_asciicompat(rb_enc_from_index(idx1)))
	    return TRUE;
    }
    return FALSE;
}


rb_str_length(VALUE str)
{
    long len;

    len = str_strlen(str, STR_ENC_GET(str));
    return LONG2NUM(len);
}


rb_str_modify(VALUE str)
{
    if (!str_independent(str))
	str_make_independent(str);
    ENC_CODERANGE_CLEAR(str);
}


rb_str_capitalize(VALUE str)
{
    str = rb_str_dup(str);
    rb_str_capitalize_bang(str);
    return str;
}


single_byte_optimizable(VALUE str)
{
    rb_encoding *enc;

    /* Conservative.  It may be ENC_CODERANGE_UNKNOWN. */
    if (ENC_CODERANGE(str) == ENC_CODERANGE_7BIT)
        return 1;

    enc = STR_ENC_GET(str);
    if (rb_enc_mbmaxlen(enc) == 1)
        return 1;

    /* Conservative.  Possibly single byte.
     * "\xa1" in Shift_JIS for example. */
    return 0;
}


sym_downcase(VALUE sym)
{
    return rb_str_intern(rb_str_downcase(rb_id2str(SYM2ID(sym))));
}


rb_str_count(int argc, VALUE *argv, VALUE str)
{
    char table[256];
    rb_encoding *enc = 0;
    VALUE del = 0, nodel = 0;
    char *s, *send;
    int i;
    int ascompat;

    if (argc < 1) {
	rb_raise(rb_eArgError, "wrong number of arguments");
    }
    for (i=0; i<argc; i++) {
	VALUE tstr = argv[i];
	unsigned char c;

	StringValue(tstr);
	enc = rb_enc_check(str, tstr);
	if (argc == 1 && RSTRING_LEN(tstr) == 1 && rb_enc_asciicompat(enc) &&
	    (c = RSTRING_PTR(tstr)[0]) < 0x80 && !is_broken_string(str)) {
	    int n = 0;

	    s = RSTRING_PTR(str);
	    if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0);
	    send = RSTRING_END(str);
	    while (s < send) {
		if (*(unsigned char*)s++ == c) n++;
	    }
	    return INT2NUM(n);
	}
	tr_setup_table(tstr, table, i==0, &del, &nodel, enc);
    }

    s = RSTRING_PTR(str);
    if (!s || RSTRING_LEN(str) == 0) return INT2FIX(0);
    send = RSTRING_END(str);
    ascompat = rb_enc_asciicompat(enc);
    i = 0;
    while (s < send) {
	unsigned int c;
	int clen;

	if (ascompat && (c = *(unsigned char*)s) < 0x80) {
	    clen = 1;
	    if (table[c]) {
		i++;
	    }
	    s++;
	}
	else {
	    c = rb_enc_codepoint_len(s, send, &clen, enc);
	    if (tr_find(c, table, del, nodel)) {
		i++;
	    }
	    s += clen;
	}
    }

    return INT2NUM(i);
}


rb_tainted_str_new_cstr(const char *ptr)
{
    VALUE str = rb_str_new2(ptr);

    OBJ_TAINT(str);
    return str;
}


rb_str_swapcase_bang(VALUE str)
{
    rb_encoding *enc;
    char *s, *send;
    int modify = 0;
    int n;

    str_modify_keep_cr(str);
    enc = STR_ENC_GET(str);
    rb_str_check_dummy_enc(enc);
    s = RSTRING_PTR(str); send = RSTRING_END(str);
    while (s < send) {
	unsigned int c = rb_enc_codepoint_len(s, send, &n, enc);

	if (rb_enc_isupper(c, enc)) {
	    /* assuming toupper returns codepoint with same size */
	    rb_enc_mbcput(rb_enc_tolower(c, enc), s, enc);
	    modify = 1;
	}
	else if (rb_enc_islower(c, enc)) {
	    /* assuming tolower returns codepoint with same size */
	    rb_enc_mbcput(rb_enc_toupper(c, enc), s, enc);
	    modify = 1;
	}
	s += n;
    }

    if (modify) return str;
    return Qnil;
}


rb_usascii_str_new(const char *ptr, long len)
{
    VALUE str = rb_str_new(ptr, len);
    ENCODING_CODERANGE_SET(str, rb_usascii_encindex(), ENC_CODERANGE_7BIT);
    return str;
}


str_modify_keep_cr(VALUE str)
{
    if (!str_independent(str))
	str_make_independent(str);
    if (ENC_CODERANGE(str) == ENC_CODERANGE_BROKEN)
	/* Force re-scan later */
	ENC_CODERANGE_CLEAR(str);
}


rb_str_each_line(int argc, VALUE *argv, VALUE str)
{
    rb_encoding *enc;
    VALUE rs;
    unsigned int newline;
    const char *p, *pend, *s, *ptr;
    long len, rslen;
    VALUE line;
    int n;
    VALUE orig = str;

    if (argc == 0) {
	rs = rb_rs;
    }
    else {
	rb_scan_args(argc, argv, "01", &rs);
    }
    RETURN_ENUMERATOR(str, argc, argv);
    if (NIL_P(rs)) {
	rb_yield(str);
	return orig;
    }
    str = rb_str_new4(str);
    ptr = p = s = RSTRING_PTR(str);
    pend = p + RSTRING_LEN(str);
    len = RSTRING_LEN(str);
    StringValue(rs);
    if (rs == rb_default_rs) {
	enc = rb_enc_get(str);
	while (p < pend) {
	    char *p0;

	    p = memchr(p, '\n', pend - p);
	    if (!p) break;
	    p0 = rb_enc_left_char_head(s, p, pend, enc);
	    if (!rb_enc_is_newline(p0, pend, enc)) {
		p++;
		continue;
	    }
	    p = p0 + rb_enc_mbclen(p0, pend, enc);
	    line = rb_str_new5(str, s, p - s);
	    OBJ_INFECT(line, str);
	    rb_enc_cr_str_copy_for_substr(line, str);
	    rb_yield(line);
	    str_mod_check(str, ptr, len);
	    s = p;
	}
	goto finish;
    }

    enc = rb_enc_check(str, rs);
    rslen = RSTRING_LEN(rs);
    if (rslen == 0) {
	newline = '\n';
    }
    else {
	newline = rb_enc_codepoint(RSTRING_PTR(rs), RSTRING_END(rs), enc);
    }

    while (p < pend) {
	unsigned int c = rb_enc_codepoint_len(p, pend, &n, enc);

      again:
	if (rslen == 0 && c == newline) {
	    p += n;
	    if (p < pend && (c = rb_enc_codepoint_len(p, pend, &n, enc)) != newline) {
		goto again;
	    }
	    while (p < pend && rb_enc_codepoint(p, pend, enc) == newline) {
		p += n;
	    }
	    p -= n;
	}
	if (c == newline &&
	    (rslen <= 1 || memcmp(RSTRING_PTR(rs), p, rslen) == 0)) {
	    line = rb_str_new5(str, s, p - s + (rslen ? rslen : n));
	    OBJ_INFECT(line, str);
	    rb_enc_cr_str_copy_for_substr(line, str);
	    rb_yield(line);
	    str_mod_check(str, ptr, len);
	    s = p + (rslen ? rslen : n);
	}
	p += n;
    }

  finish:
    if (s != pend) {
	line = rb_str_new5(str, s, pend - s);
	OBJ_INFECT(line, str);
	rb_enc_cr_str_copy_for_substr(line, str);
	rb_yield(line);
    }

    return orig;
}


sym_succ(VALUE sym)
{
    return rb_str_intern(rb_str_succ(rb_sym_to_s(sym)));
}


sym_empty(VALUE sym)
{
    return rb_str_empty(rb_id2str(SYM2ID(sym)));
}


rb_str_substr(VALUE str, long beg, long len)
{
    rb_encoding *enc = STR_ENC_GET(str);
    VALUE str2;
    char *p, *s = RSTRING_PTR(str), *e = s + RSTRING_LEN(str);

    if (len < 0) return Qnil;
    if (!RSTRING_LEN(str)) {
	len = 0;
    }
    if (single_byte_optimizable(str)) {
	if (beg > RSTRING_LEN(str)) return Qnil;
	if (beg < 0) {
	    beg += RSTRING_LEN(str);
	    if (beg < 0) return Qnil;
	}
	if (beg + len > RSTRING_LEN(str))
	    len = RSTRING_LEN(str) - beg;
	if (len <= 0) {
	    len = 0;
	    p = 0;
	}
	else
	    p = s + beg;
	goto sub;
    }
    if (beg < 0) {
	if (len > -beg) len = -beg;
	if (-beg * rb_enc_mbmaxlen(enc) < RSTRING_LEN(str) / 8) {
	    beg = -beg;
	    while (beg-- > len && (e = rb_enc_prev_char(s, e, e, enc)) != 0);
	    p = e;
	    if (!p) return Qnil;
	    while (len-- > 0 && (p = rb_enc_prev_char(s, p, e, enc)) != 0);
	    if (!p) return Qnil;
	    len = e - p;
	    goto sub;
	}
	else {
	    beg += str_strlen(str, enc);
	    if (beg < 0) return Qnil;
	}
    }
    else if (beg > 0 && beg > str_strlen(str, enc)) {
	return Qnil;
    }
    if (len == 0) {
	p = 0;
    }
#ifdef NONASCII_MASK
    else if (ENC_CODERANGE(str) == ENC_CODERANGE_VALID &&
        enc == rb_utf8_encoding()) {
        p = str_utf8_nth(s, e, beg);
        len = str_utf8_offset(p, e, len);
    }
#endif
    else if (rb_enc_mbmaxlen(enc) == rb_enc_mbminlen(enc)) {
	int char_sz = rb_enc_mbmaxlen(enc);

	p = s + beg * char_sz;
	if (p > e) {
	    p = e;
	    len = 0;
	}
        else if (len * char_sz > e - p)
            len = e - p;
        else
	    len *= char_sz;
    }
    else if ((p = str_nth(s, e, beg, enc, 0)) == e) {
	len = 0;
    }
    else {
	len = str_offset(p, e, len, enc, 0);
    }
  sub:
    if (len > RSTRING_EMBED_LEN_MAX && beg + len == RSTRING_LEN(str)) {
	str2 = rb_str_new4(str);
	str2 = str_new3(rb_obj_class(str2), str2);
	RSTRING(str2)->as.heap.ptr += RSTRING(str2)->as.heap.len - len;
	RSTRING(str2)->as.heap.len = len;
    }
    else {
	str2 = rb_str_new5(str, p, len);
	rb_enc_cr_str_copy_for_substr(str2, str);
	OBJ_INFECT(str2, str);
    }

    return str2;
}


rb_str_hex(VALUE str)
{
    rb_encoding *enc = rb_enc_get(str);

    if (!rb_enc_asciicompat(enc)) {
	rb_raise(rb_eEncCompatError, "ASCII incompatible encoding: %s", rb_enc_name(enc));
    }
    return rb_str_to_inum(str, 16, FALSE);
}


enc_succ_char(char *p, long len, rb_encoding *enc)
{
    long i;
    int l;
    while (1) {
        for (i = len-1; 0 <= i && (unsigned char)p[i] == 0xff; i--)
            p[i] = '\0';
        if (i < 0)
            return NEIGHBOR_WRAPPED;
        ++((unsigned char*)p)[i];
        l = rb_enc_precise_mbclen(p, p+len, enc);
        if (MBCLEN_CHARFOUND_P(l)) {
            l = MBCLEN_CHARFOUND_LEN(l);
            if (l == len) {
                return NEIGHBOR_FOUND;
            }
            else {
                memset(p+l, 0xff, len-l);
            }
        }
        if (MBCLEN_INVALID_P(l) && i < len-1) {
            long len2;
            int l2;
            for (len2 = len-1; 0 < len2; len2--) {
                l2 = rb_enc_precise_mbclen(p, p+len2, enc);
                if (!MBCLEN_INVALID_P(l2))
                    break;
            }
            memset(p+len2+1, 0xff, len-(len2+1));
        }
    }
}


rb_str_s_try_convert(VALUE dummy, VALUE str)
{
    return rb_check_string_type(str);
}