Initial revisionv1_0_r2

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@2 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2302 insertions, 0 deletions

diff --git a/string.c b/string.c
new file mode 100644
index 0000000000..64b5347833
--- /dev/null
+++ b/string.c
@@ -0,0 +1,2302 @@
+/************************************************
+
+  string.c -
+
+  $Author$
+  $Date$
+  created at: Mon Aug  9 17:12:58 JST 1993
+
+  Copyright (C) 1993-1996 Yukihiro Matsumoto
+
+************************************************/
+
+#include "ruby.h"
+#include "re.h"
+
+#define BEG(no) regs->beg[no]
+#define END(no) regs->end[no]
+
+#include <stdio.h>
+#include <ctype.h>
+
+VALUE cString;
+
+#define STRLEN(s) RSTRING(s)->len
+
+#define STR_FREEZE FL_USER1
+#define STR_TAINT  FL_USER2
+VALUE str_taint();
+VALUE str_tainted();
+
+VALUE
+str_new(ptr, len)
+    UCHAR *ptr;
+    UINT len;
+{
+    NEWOBJ(str, struct RString);
+    OBJSETUP(str, cString, T_STRING);
+
+    if (rb_safe_level() >= 3) {
+	FL_SET(str, STR_TAINT);
+    }
+    str->len = len;
+    str->orig = 0;
+    str->ptr = ALLOC_N(char,len+1);
+    if (ptr) {
+	memcpy(str->ptr, ptr, len);
+    }
+    str->ptr[len] = '\0';
+    return (VALUE)str;
+}
+
+VALUE
+str_new2(ptr)
+    UCHAR *ptr;
+{
+    return str_new(ptr, strlen(ptr));
+}
+
+VALUE
+str_new3(str)
+    struct RString *str;
+{
+    NEWOBJ(str2, struct RString);
+    OBJSETUP(str2, cString, T_STRING);
+
+    str2->len = str->len;
+    str2->ptr = str->ptr;
+    str2->orig = str;
+
+    if (rb_safe_level() >= 3) {
+	FL_SET(str2, STR_TAINT);
+    }
+
+    return (VALUE)str2;
+}
+
+VALUE
+str_new4(orig)
+    struct RString *orig;
+{
+    NEWOBJ(str, struct RString);
+    OBJSETUP(str, cString, T_STRING);
+
+    str->len = orig->len;
+    str->ptr = orig->ptr;
+    if (orig->orig) {
+	str->orig = orig->orig;
+    }
+    else {
+	orig->orig = str;
+	str->orig = 0;
+    }
+    if (rb_safe_level() >= 3) {
+	FL_SET(str, STR_TAINT);
+    }
+
+    return (VALUE)str;
+}
+
+#define as_str(str) (struct RString*)obj_as_string(str)
+
+static ID pr_str;
+
+VALUE
+obj_as_string(obj)
+    VALUE obj;
+{
+    VALUE str;
+
+    if (TYPE(obj) == T_STRING) {
+	return obj;
+    }
+    str = rb_funcall(obj, pr_str, 0);
+    if (TYPE(str) != T_STRING)
+	return any_to_s(obj);
+    return str;
+}
+
+static VALUE
+str_clone(orig)
+    struct RString *orig;
+{
+    VALUE str;
+
+    if (orig->orig)
+	str = str_new3(orig->orig);
+    else
+	str = str_new(orig->ptr, orig->len);
+    CLONESETUP(str, orig);
+    return str;
+}
+
+VALUE
+str_dup(str)
+    struct RString *str;
+{
+    VALUE s = str_new(str->ptr, str->len);
+    if (str_tainted(str)) s = str_taint(s);
+    return s;
+}
+
+static VALUE
+str_s_new(class, orig)
+    VALUE class;
+    struct RString *orig;
+{
+    NEWOBJ(str, struct RString);
+    OBJSETUP(str, class, T_STRING);
+
+    orig = as_str(orig);
+    str->len = orig->len;
+    str->ptr = ALLOC_N(char, orig->len+1);
+    if (str->ptr) {
+	memcpy(str->ptr, orig->ptr, orig->len);
+    }
+    str->ptr[orig->len] = '\0';
+    str->orig = 0;
+
+    if (rb_safe_level() >= 3) {
+	FL_SET(str, STR_TAINT);
+    }
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_length(str)
+    struct RString *str;
+{
+    return INT2FIX(str->len);
+}
+
+VALUE
+str_plus(str1, str2)
+    struct RString *str1, *str2;
+{
+    struct RString *str3;
+
+    str2 = as_str(str2);
+    str3 = (struct RString*)str_new(0, str1->len+str2->len);
+    memcpy(str3->ptr, str1->ptr, str1->len);
+    memcpy(str3->ptr+str1->len, str2->ptr, str2->len);
+    str3->ptr[str3->len] = '\0';
+
+    if (str_tainted(str1) || str_tainted(str2))
+	return str_taint(str3);
+    return (VALUE)str3;
+}
+
+VALUE
+str_times(str, times)
+    struct RString *str;
+    VALUE times;
+{
+    struct RString *str2;
+    int i, len;
+
+    len = NUM2INT(times);
+    if (len < 0) {
+	ArgError("negative argument");
+    }
+
+    str2 = (struct RString*)str_new(0, str->len*len);
+    for (i=0; i<len; i++) {
+	memcpy(str2->ptr+(i*str->len), str->ptr, str->len);
+    }
+    str2->ptr[str2->len] = '\0';
+
+    if (str_tainted(str))
+	return str_taint(str2);
+
+    return (VALUE)str2;
+}
+
+VALUE
+str_substr(str, start, len)
+    struct RString *str;
+    int start, len;
+{
+    struct RString *str2;
+
+    if (start < 0) {
+	start = str->len + start;
+    }
+    if (str->len <= start || len < 0) {
+	return str_new(0,0);
+    }
+    if (str->len < start + len) {
+	len = str->len - start;
+    }
+
+    str2 = (struct RString*)str_new(str->ptr+start, len);
+
+    return (VALUE)str2;
+}
+
+static VALUE
+str_subseq(str, beg, end)
+    struct RString *str;
+    int beg, end;
+{
+    int len;
+
+    if ((beg > 0 && end > 0 || beg < 0 && end < 0) && beg > end) {
+	IndexError("end smaller than beg [%d..%d]", beg, end);
+    }
+
+    if (beg < 0) {
+	beg = str->len + beg;
+	if (beg < 0) beg = 0;
+    }
+    if (end < 0) {
+	end = str->len + end;
+	if (end < 0) end = -1;
+	else if (str->len < end) {
+	    end = str->len;
+	}
+    }
+
+    if (beg >= str->len) {
+	return str_new(0, 0);
+    }
+
+    len = end - beg + 1;
+    if (len < 0) {
+	len = 0;
+    }
+
+    return str_substr(str, beg, len);
+}
+
+extern VALUE ignorecase;
+
+void
+str_modify(str)
+    struct RString *str;
+{
+    UCHAR *ptr;
+
+    if (rb_safe_level() >= 5) {
+	extern VALUE eSecurityError;
+	Raise(eSecurityError, "cannot change string status");
+    }
+    if (FL_TEST(str, STR_FREEZE))
+	TypeError("can't modify frozen string");
+    if (!str->orig) return;
+    ptr = str->ptr;
+    str->ptr = ALLOC_N(char, str->len+1);
+    if (str->ptr) {
+	memcpy(str->ptr, ptr, str->len);
+	str->ptr[str->len] = 0;
+    }
+    str->orig = 0;
+}
+
+VALUE
+str_freeze(str)
+    VALUE str;
+{
+    FL_SET(str, STR_FREEZE);
+    return str;
+}
+
+static VALUE
+str_frozen_p(str)
+    VALUE str;
+{
+    if (FL_TEST(str, STR_FREEZE))
+	return TRUE;
+    return FALSE;
+}
+
+VALUE
+str_dup_freezed(str)
+    VALUE str;
+{
+    str = str_dup(str);
+    str_freeze(str);
+    return str;
+}
+
+VALUE
+str_taint(str)
+    VALUE str;
+{
+    if (TYPE(str) == T_STRING) {
+	FL_SET(str, STR_TAINT);
+    }
+    return str;
+}
+
+VALUE
+str_tainted(str)
+    VALUE str;
+{
+    if (FL_TEST(str, STR_TAINT))
+	return TRUE;
+    return FALSE;
+}
+
+VALUE
+str_resize(str, len)
+    struct RString *str;
+    int len;
+{
+    str_modify(str);
+
+    if (len >= 0) {
+	if (str->len < len || str->len - len > 1024) {
+	    REALLOC_N(str->ptr, char, len + 1);
+	}
+	str->len = len;
+	str->ptr[len] = '\0';	/* sentinel */
+    }
+    return (VALUE)str;
+}
+
+VALUE
+str_cat(str, ptr, len)
+    struct RString *str;
+    UCHAR *ptr;
+    UINT len;
+{
+    if (len > 0) {
+	str_modify(str);
+	REALLOC_N(str->ptr, char, str->len + len + 1);
+	if (ptr)
+	    memcpy(str->ptr + str->len, ptr, len);
+	str->len += len;
+	str->ptr[str->len] = '\0'; /* sentinel */
+    }
+    return (VALUE)str;
+}
+
+static VALUE
+str_concat(str1, str2)
+    struct RString *str1, *str2;
+{
+    str2 = as_str(str2);
+    str_cat(str1, str2->ptr, str2->len);
+    return (VALUE)str1;
+}
+
+int
+str_hash(str)
+    struct RString *str;
+{
+    int len = str->len;
+    UCHAR *p = str->ptr;
+    int key = 0;
+
+    if (ignorecase) {
+	while (len--) {
+	    key = key*65599 + toupper(*p);
+	    p++;
+	}
+    }
+    else {
+	while (len--) {
+	    key = key*65599 + *p;
+	    p++;
+	}
+    }
+    return key;
+}
+
+static VALUE
+str_hash_method(str)
+    VALUE str;
+{
+    int key = str_hash(str);
+    return INT2FIX(key);
+}
+
+#define min(a,b) (((a)>(b))?(b):(a))
+
+int
+str_cmp(str1, str2)
+    struct RString *str1, *str2;
+{
+    UINT len;
+    int retval;
+
+    if (ignorecase != FALSE) {
+	return str_cicmp(str1, str2);
+    }
+
+    len = min(str1->len, str2->len);
+    retval = memcmp(str1->ptr, str2->ptr, len);
+    if (retval == 0) {
+	return str1->ptr[len] - str2->ptr[len];
+    }
+    return retval;
+}
+
+static VALUE
+str_equal(str1, str2)
+    struct RString *str1, *str2;
+{
+    if (TYPE(str2) != T_STRING)
+	return FALSE;
+
+    if (str1->len == str2->len
+	&& str_cmp(str1, str2) == 0) {
+	return TRUE;
+    }
+    return FALSE;
+}
+
+static VALUE
+str_cmp_method(str1, str2)
+    VALUE str1, str2;
+{
+    int result;
+
+    str2 = obj_as_string(str2);
+    result = str_cmp(str1, str2);
+    return INT2FIX(result);
+}
+
+VALUE Freg_match();
+
+static VALUE
+str_match(x, y)
+    struct RString *x, *y;
+{
+    VALUE reg;
+    int start;
+
+    switch (TYPE(y)) {
+      case T_REGEXP:
+	return reg_match(y, x);
+
+      case T_STRING:
+	reg = reg_regcomp(y);
+	start = reg_search(reg, x, 0, 0);
+	if (start == -1) {
+	    return FALSE;
+	}
+	return INT2FIX(start);
+
+      default:
+	TypeError("type mismatch");
+	break;
+    }
+}
+
+static VALUE
+str_match2(str)
+    struct RString *str;
+{
+    return reg_match2(reg_regcomp(str));
+}
+
+static int
+str_index(str, sub, offset)
+    struct RString *str, *sub;
+    int offset;
+{
+    UCHAR *s, *e, *p;
+    int len;
+
+    if (str->len - offset < sub->len) return -1;
+    s = str->ptr+offset;
+    p = sub->ptr;
+    len = sub->len;
+    e = s + str->len - len + 1;
+    while (s < e) {
+	if (*s == *(sub->ptr) && memcmp(s, p, len) == 0) {
+	    return (s-(str->ptr));
+	}
+	s++;
+    }
+    return -1;
+}
+
+static VALUE
+str_index_method(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString *str;
+{
+    struct RString *sub;
+    VALUE initpos;
+    int pos;
+
+    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
+	pos = NUM2INT(initpos);
+    }
+    else {
+	pos = 0;
+    }
+
+    switch (TYPE(sub)) {
+      case T_REGEXP:
+	pos = reg_search(sub, str, pos, (struct re_registers *)-1);
+	break;
+
+      case T_STRING:
+	pos = str_index(str, sub, pos);
+	break;
+
+      default:
+	TypeError("Type mismatch: %s given", rb_class2name(CLASS_OF(sub)));
+    }
+
+    if (pos == -1) return Qnil;
+    return INT2FIX(pos);
+}
+
+static VALUE
+str_rindex(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString *str;
+{
+    struct RString *sub;
+    VALUE initpos;
+    int pos, len;
+    UCHAR *s, *sbeg, *t;
+
+    if (rb_scan_args(argc, argv, "11", &sub, &initpos) == 2) {
+	pos = NUM2INT(initpos);
+	if (pos >= str->len) pos = str->len;
+    }
+    else {
+	pos = str->len;
+    }
+
+    Check_Type(sub, T_STRING);
+    if (pos > str->len) return Qnil; /* substring longer than string */
+    sbeg = str->ptr; s = sbeg + pos - sub->len;
+    t = sub->ptr;
+    len = sub->len;
+    while (sbeg <= s) {
+	if (*s == *t && memcmp(s, t, len) == 0) {
+	    return INT2FIX(s - sbeg);
+	}
+	s--;
+    }
+    return Qnil;
+}
+
+static UCHAR
+succ_char(s)
+    UCHAR *s;
+{
+    char c = *s;
+
+    /* numerics */
+    if ('0' <= c && c < '9') (*s)++;
+    else if (c == '9') {
+	*s = '0';
+	return '1';
+    }
+    /* small alphabets */
+    else if ('a' <= c && c < 'z') (*s)++;
+    else if (c == 'z') {
+	return *s = 'a';
+    }
+    /* capital alphabets */
+    else if ('A' <= c && c < 'Z') (*s)++;
+    else if (c == 'Z') {
+	return *s = 'A';
+    }
+    return 0;
+}
+
+static VALUE
+str_succ(orig)
+    struct RString *orig;
+{
+    struct RString *str, *str2;
+    UCHAR *sbeg, *s;
+    char c = -1;
+
+    str = (struct RString*)str_new(orig->ptr, orig->len);
+
+    sbeg = str->ptr; s = sbeg + str->len - 1;
+
+    while (sbeg <= s) {
+	if (isalnum(*s) && (c = succ_char(s)) == 0) break;
+	s--;
+    }
+    if (s < sbeg) {
+	if (c == -1 && str->len > 0) {
+	    str->ptr[str->len-1] += 1;
+	}
+	else {
+	    str2 = (struct RString*)str_new(0, str->len+1);
+	    str2->ptr[0] = c;
+	    memcpy(str2->ptr+1, str->ptr, str->len);
+	    str = str2;
+	}
+    }
+
+    if (str_tainted(orig))
+	return str_taint(str);
+
+    return (VALUE)str;
+}
+
+VALUE
+str_upto(beg, end)
+    VALUE beg, end;
+{
+    VALUE current;
+
+    Check_Type(end, T_STRING);
+    if (RTEST(rb_funcall(beg, '>', 1, end))) 
+	return Qnil;
+
+    current = beg;
+    for (;;) {
+	rb_yield(current);
+	if (str_equal(current, end)) break;
+	current = str_succ(current);
+	if (RSTRING(current)->len > RSTRING(end)->len)
+	    break;
+    }
+
+    return Qnil;
+}
+
+static VALUE
+str_aref(str, indx)
+    struct RString *str;
+    VALUE indx;
+{
+    int idx;
+
+    switch (TYPE(indx)) {
+      case T_FIXNUM:
+	idx = FIX2INT(indx);
+
+	if (idx < 0) {
+	    idx = str->len + idx;
+	}
+	if (idx < 0 || str->len <= idx) {
+	    return Qnil;
+	}
+	return (VALUE)INT2FIX(str->ptr[idx] & 0xff);
+
+      case T_REGEXP:
+	if (str_match(str, indx))
+	    return reg_last_match(0);
+	return Qnil;
+
+      case T_STRING:
+	if (str_index(str, indx, 0) != -1) return indx;
+	return Qnil;
+
+      default:
+	/* check if indx is Range */
+	{
+	    int beg, end;
+	    if (range_beg_end(indx, &beg, &end)) {
+		return str_subseq(str, beg, end);
+	    }
+	}
+	IndexError("Invalid index for string");
+    }
+}
+
+static VALUE
+str_aref_method(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString *str;
+{
+    VALUE arg1, arg2;
+
+    if (rb_scan_args(argc, argv, "11", &arg1, &arg2) == 2) {
+	return str_substr(str, NUM2INT(arg1), NUM2INT(arg2));
+    }
+    return str_aref(str, arg1);
+}
+
+static void
+str_replace(str, beg, len, val)
+    struct RString *str, *val;
+    int beg, len;
+{
+    if (len < val->len) {
+	/* expand string */
+	REALLOC_N(str->ptr, char, str->len+val->len-len+1);
+    }
+
+    if (len != val->len) {
+	memmove(str->ptr+beg+val->len, str->ptr+beg+len, str->len-(beg+len));
+    }
+    memcpy(str->ptr+beg, val->ptr, val->len);
+    str->len += val->len - len;
+    str->ptr[str->len] = '\0';
+}
+
+/* str_replace2() understands negatice offset */
+static void
+str_replace2(str, beg, end, val)
+    struct RString *str, *val;
+    int beg, end;
+{
+    int len;
+
+    if ((beg > 0 && end > 0 || beg < 0 && end < 0) && beg > end) {
+	IndexError("end smaller than beg [%d..%d]", beg, end);
+    }
+
+    if (beg < 0) {
+	beg = str->len + beg;
+	if (beg < 0) {
+	    beg = 0;
+	}
+    }
+    if (str->len <= beg) {
+	beg = str->len;
+    }
+    if (end < 0) {
+	end = str->len + end;
+	if (end < 0) {
+	    end = 0;
+	}
+    }
+    if (str->len <= end) {
+	end = str->len - 1;
+    }
+    len = end - beg + 1;	/* length of substring */
+    if (len < 0) {
+	len = 0;
+    }
+
+    str_replace(str, beg, len, val);
+}
+
+static VALUE
+str_sub_s(str, pat, val, once)
+    struct RString *str;
+    struct RRegexp *pat;
+    VALUE val;
+    int once;
+{
+    VALUE result, repl;
+    int beg, offset, n;
+    struct re_registers *regs;
+
+    switch (TYPE(pat)) {
+      case T_REGEXP:
+	break;
+
+      case T_STRING:
+	pat = (struct RRegexp*)reg_regcomp(pat);
+	break;
+
+      default:
+	/* type failed */
+	Check_Type(pat, T_REGEXP);
+    }
+
+    val = obj_as_string(val);
+    result = str_new(0,0);
+    offset=0; n=0; 
+    while ((beg=reg_search(pat, str, offset, 0)) >= 0) {
+	n++;
+
+	regs = RMATCH(backref_get())->regs;
+	str_cat(result, str->ptr+offset, beg-offset);
+
+	repl = reg_regsub(val, str, regs);
+	str_cat(result, RSTRING(repl)->ptr, RSTRING(repl)->len);
+	if (END(0) == offset) {
+	    /*
+	     * Always consume at least one character of the input string
+	     * in order to prevent infinite loops.
+	     */
+	    if (str->len) str_cat(result, str->ptr+END(0), 1);
+	    offset = END(0)+1;
+	}
+	else {
+	    offset = END(0);
+	}
+
+	if (once) break;
+	if (offset >= STRLEN(str)) break;
+    }
+    if (n == 0) return Qnil;
+    if (str->len > offset) {
+	str_cat(result, str->ptr+offset, str->len-offset);
+    }
+
+    if (str_tainted(val)) str_taint(result);
+    return result;
+}
+
+static VALUE
+str_sub_f(str, pat, val, once)
+    struct RString *str;
+    VALUE pat;
+    VALUE val;
+    int once;
+{
+    VALUE result;
+
+    str_modify(str);
+    result = str_sub_s(str, pat, val, once);
+
+    if (NIL_P(result)) return Qnil;
+    str_resize(str, RSTRING(result)->len);
+    memcpy(str->ptr, RSTRING(result)->ptr, RSTRING(result)->len);
+    if (str_tainted(result)) str_taint(str);
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_sub_iter_s(str, pat, once)
+    struct RString *str;
+    VALUE pat;
+    int once;
+{
+    VALUE val, result;
+    int beg, offset, n, null;
+    struct re_registers *regs;
+
+    if (!iterator_p()) {
+	ArgError("Wrong # of arguments(1 for 2)");
+    }
+
+    switch (TYPE(pat)) {
+      case T_REGEXP:
+	break;
+
+      case T_STRING:
+	pat = reg_regcomp(pat);
+	break;
+
+      default:
+	/* type failed */
+	Check_Type(pat, T_REGEXP);
+    }
+
+    result = str_new(0,0);
+    n = 0; offset = 0;
+    while ((beg=reg_search(pat, str, offset, 0)) >= 0) {
+	n++;
+
+	null = 0;
+	regs = RMATCH(backref_get())->regs;
+	str_cat(result, str->ptr+offset, beg-offset);
+
+	if (END(0) == offset) {
+	    null = 1;
+	    offset = END(0)+1;
+	}
+	else {
+	    offset = END(0);
+	}
+
+	val = rb_yield(reg_nth_match(0, backref_get()));
+	val = obj_as_string(val);
+	str_cat(result, RSTRING(val)->ptr, RSTRING(val)->len);
+	if (null && str->len) {
+	    str_cat(result, str->ptr+offset-1, 1);
+	}
+
+	if (once) break;
+	if (offset >= STRLEN(str)) break;
+    }
+    if (n == 0) return Qnil;
+    if (str->len > offset) {
+	str_cat(result, str->ptr+offset, str->len-offset);
+    }
+
+    return result;
+}
+
+static VALUE
+str_sub_iter_f(str, pat, once)
+    struct RString *str;
+    VALUE pat;
+    int once;
+{
+    VALUE result;
+
+    str_modify(str);
+    result = str_sub_iter_s(str, pat, once);
+
+    if (NIL_P(result)) return Qnil;
+    str_resize(str, RSTRING(result)->len);
+    memcpy(str->ptr, RSTRING(result)->ptr, RSTRING(result)->len);
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_aset(str, indx, val)
+    struct RString *str;
+    VALUE indx, val;
+{
+    int idx, beg, end, offset;
+
+    switch (TYPE(indx)) {
+      case T_FIXNUM:
+	idx = NUM2INT(indx);
+	if (idx < 0) {
+	    idx = str->len + idx;
+	}
+	if (idx < 0 || str->len <= idx) {
+	    IndexError("index %d out of range [0..%d]", idx, str->len-1);
+	}
+	str->ptr[idx] = FIX2INT(val) & 0xff;
+	return val;
+
+      case T_REGEXP:
+	str_sub_f(str, indx, val, 0);
+	return val;
+
+      case T_STRING:
+	for (offset=0;
+	     (beg=str_index(str, indx, offset)) >= 0;
+	     offset=beg+STRLEN(val)) {
+	    end = beg + STRLEN(indx) - 1;
+	    str_replace2(str, beg, end, val);
+	}
+	if (offset == 0) return Qnil;
+	return val;
+
+      default:
+	/* check if indx is Range */
+	{
+	    int beg, end;
+	    if (range_beg_end(indx, &beg, &end)) {
+		str_replace2(str, beg, end, val);
+		return val;
+	    }
+	}
+	IndexError("Invalid index for string");
+    }
+}
+
+static VALUE
+str_aset_method(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString *str;
+{
+    VALUE arg1, arg2, arg3;
+
+    str_modify(str);
+
+    if (rb_scan_args(argc, argv, "21", &arg1, &arg2, &arg3) == 3) {
+	int beg, len;
+
+	Check_Type(arg3, T_STRING);
+
+	beg = NUM2INT(arg1);
+	if (beg < 0) {
+	    beg = str->len + beg;
+	    if (beg < 0) beg = 0;
+	}
+	len = NUM2INT(arg2);
+	if (len < 0) IndexError("negative length %d", len);
+	if (beg + len > str->len) {
+	    len = str->len - beg;
+	}
+	str_replace(str, beg, len, arg3);
+	return arg3;
+    }
+    return str_aset(str, arg1, arg2);
+}
+
+static VALUE
+str_sub_bang(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    VALUE str;
+{
+    VALUE pat, val;
+
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	return str_sub_iter_f(str, pat, 1);
+    }
+    return str_sub_f(str, pat, val, 1);
+}
+
+static VALUE
+str_sub(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    VALUE str;
+{
+    VALUE pat, val, v;
+
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	v = str_sub_iter_s(str, pat, 1);
+    }
+    else {
+	v = str_sub_s(str, pat, val, 1);
+    }
+    if (NIL_P(v)) return str;
+    return v;
+}
+
+static VALUE
+str_gsub_bang(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    VALUE str;
+{
+    VALUE pat, val;
+
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	return str_sub_iter_f(str, pat, 0);
+    }
+    return str_sub_f(str, pat, val, 0);
+}
+
+static VALUE
+str_gsub(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    VALUE str;
+{
+    VALUE pat, val, v;
+
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	v =  str_sub_iter_s(str, pat, 0);
+    }
+    else {
+	v = str_sub_s(str, pat, val, 0);
+    }
+    if (NIL_P(v)) return str;
+    return v;    
+}
+
+static VALUE
+uscore_get()
+{
+    VALUE line;
+
+    line = lastline_get();
+    if (TYPE(line) != T_STRING) {
+	TypeError("$_ value need to be String");
+    }
+    return line;
+}
+
+static VALUE
+f_sub_bang(argc, argv)
+    int argc;
+    VALUE *argv;
+{
+    VALUE pat, val, line;
+
+    line = uscore_get();
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	return str_sub_iter_f(line, pat, 1);
+    }
+    return str_sub_f(line, pat, val, 1);
+}
+
+static VALUE
+f_sub(argc, argv)
+    int argc;
+    VALUE *argv;
+{
+    VALUE pat, val, line, v;
+
+    line = uscore_get();
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	v = str_sub_iter_s(line, pat, 1);
+    }
+    else {
+	v = str_sub_s(line, pat, val, 1);
+    }
+    if (!NIL_P(v)) {
+	lastline_set(v);
+	return v;
+    }
+    return line;
+}
+
+static VALUE
+f_gsub_bang(argc, argv)
+    int argc;
+    VALUE *argv;
+{
+    VALUE pat, val, line;
+
+    line = uscore_get();
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	return str_sub_iter_f(line, pat, 0);
+    }
+    return str_sub_f(line, pat, val, 0);
+}
+
+static VALUE
+f_gsub(argc, argv)
+    int argc;
+    VALUE *argv;
+{
+    VALUE pat, val, line, v;
+
+    line = uscore_get();
+    if (rb_scan_args(argc, argv, "11", &pat, &val) == 1) {
+	v = str_sub_iter_s(line, pat, 0);
+    }
+    else {
+	v = str_sub_s(line, pat, val, 0);
+    }
+    if (!NIL_P(v)) {
+	lastline_set(v);
+	return v;
+    }
+    return line;
+}
+
+static VALUE
+str_reverse_bang(str)
+    struct RString *str;
+{
+    UCHAR *s, *e, *p;
+
+    s = str->ptr;
+    e = s + str->len - 1;
+    p = ALLOCA_N(char, str->len);
+
+    while (e >= s) {
+	*p++ = *e--;
+    }
+    MEMCPY(str->ptr, p, char, str->len);
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_reverse(str)
+    struct RString *str;
+{
+    VALUE obj = str_new(0, str->len);
+    UCHAR *s, *e, *p;
+
+    s = str->ptr; e = s + str->len - 1;
+    p = RSTRING(obj)->ptr;
+
+    while (e >= s) {
+	*p++ = *e--;
+    }
+
+    return obj;
+}
+
+static VALUE
+str_to_i(str)
+    struct RString *str;
+{
+    return str2inum(str->ptr, 10);
+}
+
+#ifndef atof
+double atof();
+#endif
+
+static VALUE
+str_to_f(str)
+    struct RString *str;
+{
+    double f = atof(str->ptr);
+
+    return float_new(f);
+}
+
+static VALUE
+str_to_s(str)
+    VALUE str;
+{
+    return str;
+}
+
+VALUE
+str_inspect(str)
+    struct RString *str;
+{
+#define STRMAX 80
+    UCHAR buf[STRMAX];
+    UCHAR *p, *pend;
+    UCHAR *b;
+
+    p = str->ptr; pend = p + str->len;
+    b = buf;
+    *b++ = '"';
+
+#define CHECK(n) {\
+    if (b - buf + n > STRMAX - 4) {\
+	strcpy(b, "...");\
+	b += 3;\
+        break;\
+    }\
+}
+
+    while (p < pend) {
+	UCHAR c = *p++;
+	if (ismbchar(c) && p < pend) {
+	    CHECK(2);
+	    *b++ = c;
+	    *b++ = *p++;
+	}
+	else if (c == '"') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = '"';
+	}
+	else if (c == '\\') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = '\\';
+	}
+	else if (isprint(c)) {
+	    CHECK(1);
+	    *b++ = c;
+	}
+	else if (c == '\n') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 'n';
+	}
+	else if (c == '\r') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 'r';
+	}
+	else if (c == '\t') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 't';
+	}
+	else if (c == '\f') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 'f';
+	}
+	else if (c == '\13') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 'v';
+	}
+	else if (c == '\007') {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 'a';
+	}
+	else if (c == 033) {
+	    CHECK(2);
+	    *b++ = '\\';
+	    *b++ = 'e';
+	}
+	else {
+	    CHECK(4);
+	    *b++ = '\\';
+	    sprintf(b, "%03o", c);
+	    b += 3;
+	}
+    }
+    *b++ = '"';
+    return str_new(buf, b - buf);
+}
+
+static VALUE
+str_upcase_bang(str)
+    struct RString *str;
+{
+    UCHAR *s, *send;
+
+    str_modify(str);
+    s = str->ptr; send = s + str->len;
+    while (s < send) {
+	if (islower(*s)) {
+	    *s = toupper(*s);
+	}
+	s++;
+    }
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_upcase(str)
+    struct RString *str;
+{
+    return str_upcase_bang(str_dup(str));
+}
+
+static VALUE
+str_downcase_bang(str)
+    struct RString *str;
+{
+    UCHAR *s, *send;
+
+    str_modify(str);
+    s = str->ptr; send = s + str->len;
+    while (s < send) {
+	if (isupper(*s)) {
+	    *s = tolower(*s);
+	}
+	s++;
+    }
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_downcase(str)
+    struct RString *str;
+{
+    return str_downcase_bang(str_dup(str));
+}
+
+static VALUE
+str_capitalize_bang(str)
+    struct RString *str;
+{
+    UCHAR *s, *send;
+
+    str_modify(str);
+    s = str->ptr; send = s + str->len;
+    if (islower(*s))
+	*s = toupper(*s);
+    while (++s < send) {
+	if (isupper(*s)) {
+	    *s = tolower(*s);
+	}
+    }
+    return (VALUE)str;
+}
+
+static VALUE
+str_capitalize(str)
+    struct RString *str;
+{
+    return str_capitalize_bang(str_dup(str));
+}
+
+static VALUE
+str_swapcase_bang(str)
+    struct RString *str;
+{
+    UCHAR *s, *send;
+
+    str_modify(str);
+    s = str->ptr; send = s + str->len;
+    while (s < send) {
+	if (isupper(*s)) {
+	    *s = tolower(*s);
+	}
+	else if (islower(*s)) {
+	    *s = toupper(*s);
+	}
+	s++;
+    }
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_swapcase(str)
+    struct RString *str;
+{
+    return str_swapcase_bang(str_dup(str));
+}
+
+typedef UCHAR *USTR;
+
+static struct tr {
+    int gen, now, max;
+    UCHAR *p, *pend;
+} trsrc, trrepl;
+
+static int
+trnext(t)
+    struct tr *t;
+{
+    for (;;) {
+	if (!t->gen) {
+	    if (t->p == t->pend) return -1;
+	    t->now = *t->p++;
+	    if (t->p < t->pend && *t->p == '-') {
+		t->p++;
+		if (t->p < t->pend) {
+		    if (t->now > *(USTR)t->p) {
+			t->p++;
+			continue;
+		    }
+		    t->gen = 1;
+		    t->max = *(USTR)t->p++;
+		}
+	    }
+	    return t->now;
+	}
+	else if (++t->now < t->max) {
+	    return t->now;
+	}
+	else {
+	    t->gen = 0;
+	    return t->max;
+	}
+    }
+}
+
+static VALUE str_delete_bang();
+
+static VALUE
+tr_trans(str, src, repl, sflag)
+    struct RString *str, *src, *repl;
+    int sflag;
+{
+    struct tr trsrc, trrepl;
+    int cflag = 0;
+    UCHAR trans[256];
+    int i, c, c0;
+    UCHAR *s, *send, *t;
+
+    Check_Type(src, T_STRING);
+    trsrc.p = src->ptr; trsrc.pend = trsrc.p + src->len;
+    if (src->len > 2 && src->ptr[0] == '^') {
+	cflag++;
+	trsrc.p++;
+    }
+    Check_Type(repl, T_STRING);
+    if (repl->len == 0) return str_delete_bang(str, src);
+    trrepl.p = repl->ptr; trrepl.pend = trrepl.p + repl->len;
+    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)) >= 0) {
+	    trans[c & 0xff] = 0;
+	}
+	for (i=0; i<256; i++) {
+	    if (trans[i] == 0) {
+		trans[i] = i;
+	    }
+	    else {
+		c = trnext(&trrepl);
+		if (c == -1) {
+		    trans[i] = trrepl.now;
+		}
+		else {
+		    trans[i] = c;
+		}
+	    }
+	}
+    }
+    else {
+	char r;
+
+	for (i=0; i<256; i++) {
+	    trans[i] = i;
+	}
+	while ((c = trnext(&trsrc)) >= 0) {
+	    r = trnext(&trrepl);
+	    if (r == -1) r = trrepl.now;
+	    trans[c & 0xff] = r;
+	}
+    }
+
+    str_modify(str);
+    t = s = str->ptr; send = s + str->len;
+    c0 = -1;
+    if (sflag) {
+	while (s < send) {
+	    c = trans[*s++ & 0xff] & 0xff;
+	    if (s[-1] == c || c != c0) {
+		c0 = (s[-1] == c)?-1:c;
+		*t++ = c;
+	    }
+	}
+    }
+    else {
+	while (s < send) {
+	    c = trans[*s++ & 0xff] & 0xff;
+	    *t++ = c;
+	}
+    }
+    *t = '\0';
+    if (sflag) str->len = (t - str->ptr);
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_tr_bang(str, src, repl)
+    VALUE str, src, repl;
+{
+    return tr_trans(str, src, repl, 0);
+}
+
+static VALUE
+str_tr(str, src, repl)
+    VALUE str, src, repl;
+{
+    return tr_trans(str_dup(str), src, repl, 0);
+}
+
+static void
+tr_setup_table(str, table)
+    struct RString *str;
+    UCHAR table[256];
+{
+    struct tr tr;
+    int i, cflag = 0;
+    int c;
+
+    tr.p = str->ptr; tr.pend = tr.p + str->len;
+    tr.gen = tr.now = tr.max = 0;
+    if (str->len > 1 && str->ptr[0] == '^') {
+	cflag++;
+	tr.p++;
+    }
+
+    for  (i=0; i<256; i++) {
+	table[i] = cflag ? 1 : 0;
+    }
+    while ((c = trnext(&tr)) >= 0) {
+	table[c & 0xff] = cflag ? 0 : 1;
+    }
+}
+
+static VALUE
+str_delete_bang(str1, str2)
+    struct RString *str1, *str2;
+{
+    UCHAR *s, *send, *t;
+    UCHAR squeez[256];
+
+    Check_Type(str2, T_STRING);
+    tr_setup_table(str2, squeez);
+
+    str_modify(str1);
+
+    s = t = str1->ptr;
+    send = s + str1->len;
+    while (s < send) {
+	if (!squeez[*s & 0xff]) {
+	    *t++ = *s;
+	}
+	s++;
+    }
+    *t = '\0';
+    str1->len = t - str1->ptr;
+
+    return (VALUE)str1;
+}
+
+static VALUE
+str_delete(str1, str2)
+    struct RString *str1, *str2;
+{
+    return str_delete_bang(str_dup(str1), str2);
+}
+
+static VALUE
+tr_squeeze(str1, str2)
+    struct RString *str1, *str2;
+{
+    UCHAR squeez[256];
+    UCHAR *s, *send, *t;
+    char c, save;
+
+    if (!NIL_P(str2)) {
+	tr_setup_table(str2, squeez);
+    }
+    else {
+	int i;
+
+	for (i=0; i<256; i++) {
+	    squeez[i] = 1;
+	}
+    }
+
+    str_modify(str1);
+
+    s = t = str1->ptr;
+    send = s + str1->len;
+    save = -1;
+    while (s < send) {
+	c = *s++ & 0xff;
+	if (c != save || !squeez[c & 0xff]) {
+	    *t++ = save = c;
+	}
+    }
+    *t = '\0';
+    str1->len = t - str1->ptr;
+
+    return (VALUE)str1;
+}
+
+static VALUE
+str_squeeze_bang(argc, argv, str1)
+    int argc;
+    VALUE *argv;
+    VALUE str1;
+{
+    VALUE str2;
+
+    rb_scan_args(argc, argv, "01", &str2);
+    if (!NIL_P(str2)) {
+	Check_Type(str2, T_STRING);
+    }
+    return tr_squeeze(str1, str2);
+}
+
+static VALUE
+str_squeeze(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    VALUE str;
+{
+    return str_squeeze_bang(argc, argv, str_dup(str));
+}
+
+static VALUE
+str_tr_s_bang(str, src, repl)
+    VALUE str, src, repl;
+{
+    Check_Type(src, T_STRING);
+    Check_Type(repl, T_STRING);
+
+    return tr_trans(str, src, repl, 1);
+}
+
+static VALUE
+str_tr_s(str, src, repl)
+    VALUE str, src, repl;
+{
+    return str_tr_s_bang(str_dup(str), src, repl);
+}
+
+static VALUE
+str_split_method(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString *str;
+{
+    extern VALUE FS;
+    struct RRegexp *spat;
+    VALUE limit;
+    char char_sep = 0;
+    int beg, end, lim, i;
+    VALUE result, tmp;
+
+    rb_scan_args(argc, argv, "02", &spat, &limit);
+    if (!NIL_P(limit)) {
+	lim = NUM2INT(limit);
+	if (lim == 0) limit = Qnil;
+	else if (lim == 1) return ary_new3(1, str);
+	i = 1;
+    }
+
+    if (NIL_P(spat)) {
+	if (!NIL_P(FS)) {
+	    spat = (struct RRegexp*)FS;
+	    goto fs_set;
+	}
+	char_sep = ' ';
+    }
+    else {
+	switch (TYPE(spat)) {
+	  case T_STRING:
+	  fs_set:
+	    if (STRLEN(spat) == 1) {
+		char_sep = RSTRING(spat)->ptr[0];
+	    }
+	    else {
+		spat = (struct RRegexp*)reg_regcomp(spat);
+	    }
+	    break;
+	  case T_REGEXP:
+	    break;
+	  default:
+	    ArgError("split(): bad separator");
+	}
+    }
+
+    result = ary_new();
+    beg = 0;
+    if (char_sep != 0) {
+	UCHAR *ptr = str->ptr;
+	int len = str->len;
+	UCHAR *eptr = ptr + len;
+
+	if (char_sep == ' ') {	/* AWK emulation */
+	    int skip = 1;
+
+	    for (end = beg = 0; ptr<eptr; ptr++) {
+		if (skip) {
+		    if (isspace(*ptr)) {
+			beg++;
+		    }
+		    else {
+			end = beg+1;
+			skip = 0;
+		    }
+		}
+		else {
+		    if (isspace(*ptr)) {
+			ary_push(result, str_substr(str, beg, end-beg));
+			skip = 1;
+			beg = end + 1;
+			if (!NIL_P(limit) && lim <= ++i) break;
+		    }
+		    else {
+			end++;
+		    }
+		}
+	    }
+	}
+	else {
+	    for (end = beg = 0; ptr<eptr; ptr++) {
+		if (*ptr == char_sep) {
+		    ary_push(result, str_substr(str, beg, end-beg));
+		    beg = end + 1;
+		    if (!NIL_P(limit) && lim <= ++i) break;
+		}
+		end++;
+	    }
+	}
+    }
+    else {
+	int start = beg;
+	int last_null = 0;
+	int idx;
+	struct re_registers *regs;
+
+	while ((end = reg_search(spat, str, start, 0)) >= 0) {
+	    regs = RMATCH(backref_get())->regs;
+	    if (start == end && BEG(0) == END(0)) {
+		if (last_null == 1) {
+		    if (ismbchar(str->ptr[beg]))
+			ary_push(result, str_substr(str, beg, 2));
+		    else
+			ary_push(result, str_substr(str, beg, 1));
+		    beg = start;
+		}
+		else {
+		    start += ismbchar(str->ptr[start])?2:1;
+		    last_null = 1;
+		    continue;
+		}
+	    }
+	    else {
+		ary_push(result, str_substr(str, beg, end-beg));
+		beg = start = END(0);
+	    }
+	    last_null = 0;
+
+	    for (idx=1; idx < regs->num_regs; idx++) {
+		if (BEG(idx) == -1) continue;
+		if (BEG(idx) == END(idx))
+		    tmp = str_new(0, 0);
+		else
+		    tmp = str_subseq(str, BEG(idx), END(idx)-1);
+		ary_push(result, tmp);
+	    }
+	    if (!NIL_P(limit) && lim <= ++i) break;
+	}
+    }
+    if (str->len > beg) {
+	ary_push(result, str_subseq(str, beg, -1));
+    }
+
+    return result;
+}
+
+VALUE
+str_split(str, sep0)
+    struct RString* str;
+    char *sep0;
+{
+    VALUE sep;
+
+    Check_Type(str, T_STRING);
+    sep = str_new2(sep0);
+    return str_split_method(1, &sep, str);
+}
+
+static VALUE
+f_split(argc, argv)
+    int argc;
+    VALUE *argv;
+{
+    return str_split_method(argc, argv, uscore_get());
+}
+
+static VALUE
+str_each_line(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString* str;
+{
+    extern VALUE RS;
+    VALUE rs;
+    int newline;
+    int rslen;
+    UCHAR *p = str->ptr, *pend = p + str->len, *s;
+    UCHAR *ptr = p;
+    int len = str->len;
+    VALUE line;
+
+    if (rb_scan_args(argc, argv, "01", &rs) == 1) {
+	if (!NIL_P(rs)) Check_Type(rs, T_STRING);
+    }
+    else {
+	rs = RS;
+    }
+
+    if (NIL_P(rs)) {
+	rb_yield(str);
+	return Qnil;
+    }
+
+    rslen = RSTRING(rs)->len;
+    if (rslen == 0) {
+	newline = '\n';
+    }
+    else {
+	newline = RSTRING(rs)->ptr[rslen-1];
+    }
+
+    for (s = p, p += rslen; p < pend; p++) {
+	if (rslen == 0 && *p == '\n') {
+	    if (*(p+1) != '\n') continue;
+	    while (*p == '\n') p++;
+	    p--;
+	}
+	if (*p == newline &&
+	    (rslen <= 1 ||
+	     memcmp(RSTRING(rs)->ptr, p-rslen+1, rslen) == 0)) {
+	    line = str_new(s, p - s + 1);
+	    lastline_set(line);
+	    rb_yield(line);
+	    if (str->ptr != ptr || str->len != len)
+		Fail("string modified");
+	    s = p + 1;
+	}
+    }
+
+    if (s != pend) {
+	line = str_new(s, p - s);
+	lastline_set(line);
+	rb_yield(line);
+    }
+
+    return Qnil;
+}
+
+static VALUE
+str_each_byte(str)
+    struct RString* str;
+{
+    int i;
+
+    for (i=0; i<str->len; i++) {
+	rb_yield(INT2FIX(str->ptr[i] & 0xff));
+    }
+    return Qnil;
+}
+
+static VALUE
+str_chop_bang(str)
+    struct RString *str;
+{
+    str_modify(str);
+
+    if (str->len > 0) {
+	str->len--;
+	if (str->ptr[str->len] == '\n') {
+	    if (str->len > 0 && str->ptr[str->len-1] == '\r') {
+		str->len--;
+	    }
+	}
+	str->ptr[str->len] = '\0';
+    }
+
+    return (VALUE)str;
+}
+
+static VALUE
+str_chop(str)
+    struct RString *str;
+{
+    return str_chop_bang(str_dup(str));
+}
+
+static VALUE
+f_chop_bang(str)
+    struct RString *str;
+{
+    return str_chop_bang(uscore_get());
+}
+
+static VALUE
+f_chop()
+{
+    return str_chop_bang(str_dup(uscore_get()));
+}
+
+static VALUE
+str_strip_bang(str)
+    struct RString *str;
+{
+    UCHAR *s, *t, *e;
+
+    str_modify(str);
+
+    s = str->ptr;
+    e = t = s + str->len;
+    /* remove spaces at head */
+    while (s < t && isspace(*s)) s++;
+
+    /* remove trailing spaces */
+    t--;
+    while (s <= t && isspace(*t)) t--;
+    t++;
+
+    str->len = t-s;
+    if (s > str->ptr) { 
+	UCHAR *p = str->ptr;
+
+	str->ptr = ALLOC_N(char, str->len+1);
+	memcpy(str->ptr, s, str->len);
+	str->ptr[str->len] = '\0';
+	free(p);
+    }
+    else if (t < e) {
+	str->ptr[str->len] = '\0';
+    }
+
+    return (VALUE)str;
+}
+
+static VALUE
+scan_once(str, pat, start)
+    struct RString *str;
+    struct RRegexp *pat;
+    int *start;
+{
+    VALUE result;
+    struct re_registers *regs;
+    int idx;
+
+    if (reg_search(pat, str, *start, 0) >= 0) {
+	regs = RMATCH(backref_get())->regs;
+	result = ary_new2(regs->num_regs);
+	for (idx=1; idx < regs->num_regs; idx++) {
+	    if (BEG(idx) == -1) {
+		ary_push(result, Qnil);
+	    }
+	    else if (BEG(idx) == END(idx)) {
+		ary_push(result, str_new(0, 0));
+	    }
+	    else {
+		ary_push(result, str_subseq(str, BEG(idx), END(idx)-1));
+	    }
+	}
+	if (END(0) == *start) {
+	    *start = END(0)+1;
+	}
+	else {
+	    *start = END(0);
+	}
+
+	return result;
+    }
+    return Qnil;
+}
+
+static VALUE
+str_scan(str, pat)
+    struct RString *str;
+    struct RRegexp *pat;
+{
+    VALUE result;
+    int start = 0;
+
+    switch (TYPE(pat)) {
+      case T_STRING:
+	pat = (struct RRegexp*)reg_regcomp(pat);
+	break;
+      case T_REGEXP:
+	break;
+      default:
+	Check_Type(pat, T_REGEXP);
+    }
+
+    if (!iterator_p()) {
+	return scan_once(str, pat, &start);
+    }
+
+    while (!NIL_P(result = scan_once(str, pat, &start))) {
+	rb_yield(result);
+    }
+    return Qnil;
+}
+
+static VALUE
+str_strip(str)
+    struct RString *str;
+{
+    return str_strip_bang(str_dup(str));
+}
+
+static VALUE
+str_hex(str)
+    struct RString *str;
+{
+    return str2inum(str->ptr, 16);
+}
+
+static VALUE
+str_oct(str)
+    struct RString *str;
+{
+    return str2inum(str->ptr, 8);
+}
+
+static VALUE
+str_crypt(str, salt)
+    struct RString *str, *salt;
+{
+    salt = as_str(salt);
+    if (salt->len < 2)
+	ArgError("salt too short(need >2 bytes)");
+    return str_new2(crypt(str->ptr, salt->ptr));
+}
+
+static VALUE
+str_intern(str)
+    struct RString *str;
+{
+    ID id;
+
+    if (strlen(str->ptr) != str->len)
+	ArgError("string contains `\0'");
+    id = rb_intern(str->ptr);
+    return INT2FIX(id);
+}
+
+static VALUE
+str_sum(argc, argv, str)
+    int argc;
+    VALUE *argv;
+    struct RString *str;
+{
+    VALUE vbits;
+    int   bits;
+    UCHAR *p, *pend;
+
+    rb_scan_args(argc, argv, "01", &vbits);
+    if (NIL_P(vbits)) bits = 16;
+    else bits = NUM2INT(vbits);
+
+    p = str->ptr; pend = p + str->len;
+    if (bits > 32) {
+	VALUE res = INT2FIX(0);
+	VALUE mod;
+
+	mod = rb_funcall(INT2FIX(1), rb_intern("<<"), 1, INT2FIX(bits));
+	mod = rb_funcall(mod, '-', 1, INT2FIX(1));
+
+	while (p < pend) {
+	    res = rb_funcall(res, '+', 1, INT2FIX((UINT)*p));
+	    res = rb_funcall(res, '%', 1, mod);
+	    p++;
+	}
+	return res;
+    }
+    else {
+	UINT res = 0;
+	UINT mod = (1<<bits)-1;
+
+	while (p < pend) {
+	    res += (UINT)*p;
+	    res %= mod;
+	    p++;
+	}
+	return int2inum(res);
+    }
+}
+
+static VALUE
+str_ljust(str, w)
+    struct RString *str;
+    VALUE w;
+{
+    int width = NUM2INT(w);
+    struct RString *res;
+    UCHAR *p, *pend;
+
+    if (str->len >= width) return (VALUE)str;
+    res = (struct RString*)str_new(0, width);
+    memcpy(res->ptr, str->ptr, str->len);
+    p = res->ptr + str->len; pend = res->ptr + width;
+    while (p < pend) {
+	*p++ = ' ';
+    }
+    return (VALUE)res;
+}
+
+static VALUE
+str_rjust(str, w)
+    struct RString *str;
+    VALUE w;
+{
+    int width = NUM2INT(w);
+    struct RString *res;
+    UCHAR *p, *pend;
+
+    if (str->len >= width) return (VALUE)str;
+    res = (struct RString*)str_new(0, width);
+    p = res->ptr; pend = p + width - str->len;
+    while (p < pend) {
+	*p++ = ' ';
+    }
+    memcpy(pend, str->ptr, str->len);
+    return (VALUE)res;
+}
+
+static VALUE
+str_center(str, w)
+    struct RString *str;
+    VALUE w;
+{
+    int width = NUM2INT(w);
+    struct RString *res;
+    UCHAR *p, *pend;
+    int n;
+
+    if (str->len >= width) return (VALUE)str;
+    res = (struct RString*)str_new(0, width);
+    n = (width - str->len)/2;
+    p = res->ptr; pend = p + n;
+    while (p < pend) {
+	*p++ = ' ';
+    }
+    memcpy(pend, str->ptr, str->len);
+    p = pend + str->len; pend = res->ptr + width;
+    while (p < pend) {
+	*p++ = ' ';
+    }
+    return (VALUE)res;
+}
+
+extern VALUE mKernel;
+extern VALUE mComparable;
+extern VALUE mEnumerable;
+
+void
+Init_String()
+{
+    cString  = rb_define_class("String", cObject);
+    rb_include_module(cString, mComparable);
+    rb_include_module(cString, mEnumerable);
+    rb_define_singleton_method(cString, "new", str_s_new, 1);
+    rb_define_method(cString, "clone", str_clone, 0);
+    rb_define_method(cString, "dup", str_dup, 0);
+    rb_define_method(cString, "<=>", str_cmp_method, 1);
+    rb_define_method(cString, "==", str_equal, 1);
+    rb_define_method(cString, "===", str_equal, 1);
+    rb_define_method(cString, "eql?", str_equal, 1);
+    rb_define_method(cString, "hash", str_hash_method, 0);
+    rb_define_method(cString, "+", str_plus, 1);
+    rb_define_method(cString, "*", str_times, 1);
+    rb_define_method(cString, "[]", str_aref_method, -1);
+    rb_define_method(cString, "[]=", str_aset_method, -1);
+    rb_define_method(cString, "length", str_length, 0);
+    rb_define_alias(cString,  "size", "length");
+    rb_define_method(cString, "=~", str_match, 1);
+    rb_define_method(cString, "~", str_match2, 0);
+    rb_define_method(cString, "succ", str_succ, 0);
+    rb_define_method(cString, "upto", str_upto, 1);
+    rb_define_method(cString, "index", str_index_method, -1);
+    rb_define_method(cString, "rindex", str_rindex, -1);
+
+    rb_define_method(cString, "freeze", str_freeze, 0);
+    rb_define_method(cString, "frozen?", str_frozen_p, 0);
+
+    rb_define_method(cString, "taint", str_taint, 0);
+    rb_define_method(cString, "tainted?", str_tainted, 0);
+
+    rb_define_method(cString, "to_i", str_to_i, 0);
+    rb_define_method(cString, "to_f", str_to_f, 0);
+    rb_define_method(cString, "to_s", str_to_s, 0);
+    rb_define_method(cString, "inspect", str_inspect, 0);
+
+    rb_define_method(cString, "upcase", str_upcase, 0);
+    rb_define_method(cString, "downcase", str_downcase, 0);
+    rb_define_method(cString, "capitalize", str_capitalize, 0);
+    rb_define_method(cString, "swapcase", str_swapcase, 0);
+
+    rb_define_method(cString, "upcase!", str_upcase_bang, 0);
+    rb_define_method(cString, "downcase!", str_downcase_bang, 0);
+    rb_define_method(cString, "capitalize!", str_capitalize_bang, 0);
+    rb_define_method(cString, "swapcase!", str_swapcase_bang, 0);
+
+    rb_define_method(cString, "hex", str_hex, 0);
+    rb_define_method(cString, "oct", str_oct, 0);
+    rb_define_method(cString, "split", str_split_method, -1);
+    rb_define_method(cString, "reverse", str_reverse, 0);
+    rb_define_method(cString, "reverse!", str_reverse_bang, 0);
+    rb_define_method(cString, "concat", str_concat, 1);
+    rb_define_method(cString, "<<", str_concat, 1);
+    rb_define_method(cString, "crypt", str_crypt, 1);
+    rb_define_method(cString, "intern", str_intern, 0);
+
+    rb_define_method(cString, "scan", str_scan, 1);
+
+    rb_define_method(cString, "ljust", str_ljust, 1);
+    rb_define_method(cString, "rjust", str_rjust, 1);
+    rb_define_method(cString, "center", str_center, 1);
+
+    rb_define_method(cString, "sub", str_sub, -1);
+    rb_define_method(cString, "gsub", str_gsub, -1);
+    rb_define_method(cString, "chop", str_chop, 0);
+    rb_define_method(cString, "strip", str_strip, 0);
+
+    rb_define_method(cString, "sub!", str_sub_bang, -1);
+    rb_define_method(cString, "gsub!", str_gsub_bang, -1);
+    rb_define_method(cString, "strip!", str_strip_bang, 0);
+    rb_define_method(cString, "chop!", str_chop_bang, 0);
+
+    rb_define_method(cString, "tr", str_tr, 2);
+    rb_define_method(cString, "tr_s", str_tr_s, 2);
+    rb_define_method(cString, "delete", str_delete, 1);
+    rb_define_method(cString, "squeeze", str_squeeze, -1);
+
+    rb_define_method(cString, "tr!", str_tr_bang, 2);
+    rb_define_method(cString, "tr_s!", str_tr_s_bang, 2);
+    rb_define_method(cString, "delete!", str_delete_bang, 1);
+    rb_define_method(cString, "squeeze!", str_squeeze_bang, -1);
+
+    rb_define_method(cString, "each_line", str_each_line, -1);
+    rb_define_method(cString, "each", str_each_line, -1);
+    rb_define_method(cString, "each_byte", str_each_byte, 0);
+
+    rb_define_method(cString, "sum", str_sum, -1);
+
+    rb_define_global_function("sub", f_sub, -1);
+    rb_define_global_function("gsub", f_gsub, -1);
+
+    rb_define_global_function("sub!", f_sub_bang, -1);
+    rb_define_global_function("gsub!", f_gsub_bang, -1);
+
+    rb_define_global_function("chop", f_chop, 0);
+    rb_define_global_function("chop!", f_chop_bang, 0);
+
+    rb_define_global_function("split", f_split, -1);
+
+    pr_str = rb_intern("to_s");
+}