/*

** string.c - String class

**

** See Copyright Notice in mruby.h

*/

#ifdef _MSC_VER

# define _CRT_NONSTDC_NO_DEPRECATE

# define WIN32_LEAN_AND_MEAN

#endif

#include <mruby.h>

#include <mruby/array.h>

#include <mruby/class.h>

#include <mruby/range.h>

#include <mruby/string.h>

#include <mruby/numeric.h>

#include <mruby/internal.h>

#include <mruby/presym.h>

#include <string.h>

typedef struct mrb_shared_string {

int refcnt;

mrb_int capa;

char *ptr;

} mrb_shared_string;

const char mrb_digitmap[] = "0123456789abcdefghijklmnopqrstuvwxyz";

#define mrb_obj_alloc_string(mrb) MRB_OBJ_ALLOC((mrb), MRB_TT_STRING, (mrb)->string_class)

#ifndef MRB_STR_LENGTH_MAX

#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || defined(__OpenBSD__)

#define MRB_STR_LENGTH_MAX 0

#else

#define MRB_STR_LENGTH_MAX 1048576

#endif

#endif

static void

str_check_length(mrb_state *mrb, mrb_int len)

{

if (len < 0) {

mrb_raise(mrb, E_ARGUMENT_ERROR, "negative (or overflowed) string size");

}

#if MRB_STR_LENGTH_MAX != 0

if (len > MRB_STR_LENGTH_MAX-1) {

mrb_raisef(mrb, E_ARGUMENT_ERROR, "string too long (len=%i max=" MRB_STRINGIZE(MRB_STR_LENGTH_MAX) ")", len);

}

#endif

}

static struct RString*

str_init_normal_capa(mrb_state *mrb, struct RString *s,

const char *p, mrb_int len, mrb_int capa)

{

str_check_length(mrb, capa);

char *dst = (char*)mrb_malloc(mrb, capa + 1);

if (p) memcpy(dst, p, len);

dst[len] = '\0';

s->as.heap.ptr = dst;

s->as.heap.len = len;

s->as.heap.aux.capa = capa;

RSTR_SET_TYPE(s, NORMAL);

return s;

}

static struct RString*

str_init_normal(mrb_state *mrb, struct RString *s, const char *p, mrb_int len)

{

return str_init_normal_capa(mrb, s, p, len, len);

}

static struct RString*

str_init_embed(struct RString *s, const char *p, mrb_int len)

{

mrb_assert(len >= 0);

if (p) memcpy(RSTR_EMBED_PTR(s), p, len);

RSTR_EMBED_PTR(s)[len] = '\0';

RSTR_SET_TYPE(s, EMBED);

RSTR_SET_EMBED_LEN(s, len);

return s;

}

static struct RString*

str_init_nofree(struct RString *s, const char *p, mrb_int len)

{

s->as.heap.ptr = (char*)p;

s->as.heap.len = len;

s->as.heap.aux.capa = 0; /* nofree */

RSTR_SET_TYPE(s, NOFREE);

return s;

}

static struct RString*

str_init_shared(mrb_state *mrb, const struct RString *orig, struct RString *s, mrb_shared_string *shared)

{

if (shared) {

shared->refcnt++;

}

else {

shared = (mrb_shared_string*)mrb_malloc(mrb, sizeof(mrb_shared_string));

shared->refcnt = 1;

shared->ptr = orig->as.heap.ptr;

shared->capa = orig->as.heap.aux.capa;

}

s->as.heap.ptr = orig->as.heap.ptr;

s->as.heap.len = orig->as.heap.len;

s->as.heap.aux.shared = shared;

RSTR_SET_TYPE(s, SHARED);

return s;

}

static struct RString*

str_init_fshared(const struct RString *orig, struct RString *s, struct RString *fshared)

{

s->as.heap.ptr = orig->as.heap.ptr;

s->as.heap.len = orig->as.heap.len;

s->as.heap.aux.fshared = fshared;

RSTR_SET_TYPE(s, FSHARED);

return s;

}

static struct RString*

str_init_modifiable(mrb_state *mrb, struct RString *s, const char *p, mrb_int len)

{

if (RSTR_EMBEDDABLE_P(len)) {

return str_init_embed(s, p, len);

}

return str_init_normal(mrb, s, p, len);

}

static struct RString*

str_new_static(mrb_state *mrb, const char *p, mrb_int len)

{

if (RSTR_EMBEDDABLE_P(len)) {

return str_init_embed(mrb_obj_alloc_string(mrb), p, len);

}

return str_init_nofree(mrb_obj_alloc_string(mrb), p, len);

}

static struct RString*

str_new(mrb_state *mrb, const char *p, mrb_int len)

{

str_check_length(mrb, len);

if (RSTR_EMBEDDABLE_P(len)) {

return str_init_embed(mrb_obj_alloc_string(mrb), p, len);

}

if (p && mrb_ro_data_p(p)) {

return str_init_nofree(mrb_obj_alloc_string(mrb), p, len);

}

return str_init_normal(mrb, mrb_obj_alloc_string(mrb), p, len);

}

MRB_API mrb_value

mrb_str_new_capa(mrb_state *mrb, mrb_int capa)

{

struct RString *s = mrb_obj_alloc_string(mrb);

if (RSTR_EMBEDDABLE_P(capa)) {

s = str_init_embed(s, NULL, 0);

}

else {

s = str_init_normal_capa(mrb, s, NULL, 0, capa);

}

return mrb_obj_value(s);

}

static void

resize_capa(mrb_state *mrb, struct RString *s, mrb_int capacity)

{

if (RSTR_EMBED_P(s)) {

if (!RSTR_EMBEDDABLE_P(capacity)) {

str_init_normal_capa(mrb, s, RSTR_EMBED_PTR(s), RSTR_EMBED_LEN(s), capacity);

}

}

else {

str_check_length(mrb, capacity);

s->as.heap.ptr = (char*)mrb_realloc(mrb, RSTR_PTR(s), capacity+1);

s->as.heap.aux.capa = (mrb_ssize)capacity;

}

}

MRB_API mrb_value

mrb_str_new(mrb_state *mrb, const char *p, mrb_int len)

{

return mrb_obj_value(str_new(mrb, p, len));

}

MRB_API mrb_value

mrb_str_new_cstr(mrb_state *mrb, const char *p)

{

struct RString *s;

mrb_int len;

if (p) {

len = strlen(p);

}

else {

len = 0;

}

s = str_new(mrb, p, len);

return mrb_obj_value(s);

}

MRB_API mrb_value

mrb_str_new_static(mrb_state *mrb, const char *p, mrb_int len)

{

struct RString *s = str_new_static(mrb, p, len);

return mrb_obj_value(s);

}

static void

str_decref(mrb_state *mrb, mrb_shared_string *shared)

{

shared->refcnt--;

if (shared->refcnt == 0) {

mrb_free(mrb, shared->ptr);

mrb_free(mrb, shared);

}

}

static void

str_unshare_buffer(mrb_state *mrb, struct RString *s)

{

if (RSTR_SHARED_P(s)) {

mrb_shared_string *shared = s->as.heap.aux.shared;

if (shared->refcnt == 1 && s->as.heap.ptr == shared->ptr) {

s->as.heap.aux.capa = shared->capa;

s->as.heap.ptr[s->as.heap.len] = '\0';

RSTR_SET_TYPE(s, NORMAL);

mrb_free(mrb, shared);

}

else {

str_init_modifiable(mrb, s, s->as.heap.ptr, s->as.heap.len);

str_decref(mrb, shared);

}

}

else if (RSTR_NOFREE_P(s) || RSTR_FSHARED_P(s)) {

str_init_modifiable(mrb, s, s->as.heap.ptr, s->as.heap.len);

}

}

static void

check_null_byte(mrb_state *mrb, struct RString *str)

{

const char *p = RSTR_PTR(str);

if (p && memchr(p, '\0', RSTR_LEN(str))) {

mrb_raise(mrb, E_ARGUMENT_ERROR, "string contains null byte");

}

}

void

mrb_gc_free_str(mrb_state *mrb, struct RString *str)

{

if (RSTR_EMBED_P(str))

/* no code */;

else if (RSTR_SHARED_P(str))

str_decref(mrb, str->as.heap.aux.shared);

else if (!RSTR_NOFREE_P(str) && !RSTR_FSHARED_P(str))

mrb_free(mrb, str->as.heap.ptr);

}

#if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \

defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64) || \

defined(__powerpc64__) || defined(__POWERPC__) || defined(__aarch64__) || \

defined(__mc68020__)

# define ALIGNED_WORD_ACCESS 0

#else

# define ALIGNED_WORD_ACCESS 1

#endif

#ifdef MRB_64BIT

#define bitint uint64_t

#define MASK01 0x0101010101010101ull

#else

#define bitint uint32_t

#define MASK01 0x01010101ul

#endif

#ifdef MRB_UTF8_STRING

#define NOASCII(c) ((c) & 0x80)

#ifdef SIMPLE_SEARCH_NONASCII

/* the naive implementation. define SIMPLE_SEARCH_NONASCII, */

/* if you need it for any constraint (e.g. code size). */

static const char*

search_nonascii(const char* p, const char *e)

{

for (; p < e; ++p) {

if (NOASCII(*p)) return p;

}

return e;

}

#elif defined(__SSE2__)

# include <emmintrin.h>

static inline const char *

search_nonascii(const char *p, const char *e)

{

if (sizeof(__m128i) < (size_t)(e - p)) {

if (!_mm_movemask_epi8(_mm_loadu_si128((__m128i const*)p))) {

const intptr_t lowbits = sizeof(__m128i) - 1;

const __m128i *s, *t;

s = (const __m128i*)(~lowbits & ((intptr_t)p + lowbits));

t = (const __m128i*)(~lowbits & (intptr_t)e);

for (; s < t; ++s) {

if (_mm_movemask_epi8(_mm_load_si128(s))) break;

}

p = (const char *)s;

}

}

switch (e - p) {

default:

case 15: if (NOASCII(*p)) return p; ++p;

case 14: if (NOASCII(*p)) return p; ++p;

case 13: if (NOASCII(*p)) return p; ++p;

case 12: if (NOASCII(*p)) return p; ++p;

case 11: if (NOASCII(*p)) return p; ++p;

case 10: if (NOASCII(*p)) return p; ++p;

case 9: if (NOASCII(*p)) return p; ++p;

case 8: if (NOASCII(*p)) return p; ++p;

case 7: if (NOASCII(*p)) return p; ++p;

case 6: if (NOASCII(*p)) return p; ++p;

case 5: if (NOASCII(*p)) return p; ++p;

case 4: if (NOASCII(*p)) return p; ++p;

case 3: if (NOASCII(*p)) return p; ++p;

case 2: if (NOASCII(*p)) return p; ++p;

case 1: if (NOASCII(*p)) return p; ++p;

if (NOASCII(*p)) return p;

case 0: break;

}

return e;

}

#else

static const char*

search_nonascii(const char *p, const char *e)

{

ptrdiff_t byte_len = e - p;

const char *be = p + sizeof(bitint) * (byte_len / sizeof(bitint));

for (; p < be; p+=sizeof(bitint)) {

bitint t0;

memcpy(&t0, p, sizeof(bitint));

const bitint t1 = t0 & (MASK01*0x80);

if (t1) {

e = p + sizeof(bitint)-1;

byte_len = sizeof(bitint)-1;

break;

}

}

switch (byte_len % sizeof(bitint)) {

#ifdef MRB_64BIT

case 7: if (e[-7]&0x80) return e-7;

case 6: if (e[-6]&0x80) return e-6;

case 5: if (e[-5]&0x80) return e-5;

case 4: if (e[-4]&0x80) return e-4;

#endif

case 3: if (e[-3]&0x80) return e-3;

case 2: if (e[-2]&0x80) return e-2;

case 1: if (e[-1]&0x80) return e-1;

}

return e;

}

#endif /* SIMPLE_SEARCH_NONASCII */

#define utf8_islead(c) ((unsigned char)((c)&0xc0) != 0x80)

extern const char mrb_utf8len_table[];

const char mrb_utf8len_table[] = {

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,

0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 3, 3, 4, 0

};

mrb_int

mrb_utf8len(const char* p, const char* e)

{

mrb_int len = mrb_utf8len_table[(unsigned char)p[0] >> 3];

if (len > e - p) return 1;

switch (len) {

case 0:

return 1;

case 4:

if (utf8_islead(p[3])) return 1;

case 3:

if (utf8_islead(p[2])) return 1;

case 2:

if (utf8_islead(p[1])) return 1;

}

return len;

}

#if defined(__GNUC__) || __has_builtin(__builtin_popcount)

# ifdef MRB_64BIT

# define popcount(x) __builtin_popcountll(x)

# else

# define popcount(x) __builtin_popcountl(x)

# endif

#else

static inline uint32_t popcount(bitint x)

{

x = (x & (MASK01*0x55)) + ((x >> 1) & (MASK01*0x55));

x = (x & (MASK01*0x33)) + ((x >> 2) & (MASK01*0x33));

x = (x & (MASK01*0x0F)) + ((x >> 4) & (MASK01*0x0F));

return (x * MASK01) >> 56;

}

#endif

mrb_int

mrb_utf8_strlen(const char *str, mrb_int byte_len)

{

const char *p = str;

const char *e = str + byte_len;

mrb_int len = 0;

while (p < e) {

const char *np = search_nonascii(p, e);

len += np - p;

if (np == e) break;

p = np;

while (NOASCII(*p)) {

p += mrb_utf8len(p, e);

len++;

}

}

return len;

}

static mrb_int

utf8_strlen(mrb_value str)

{

struct RString *s = mrb_str_ptr(str);

mrb_int byte_len = RSTR_LEN(s);

if (RSTR_SINGLE_BYTE_P(s)) {

return byte_len;

}

else {

mrb_int utf8_len = mrb_utf8_strlen(RSTR_PTR(s), byte_len);

mrb_assert(utf8_len <= byte_len);

if (byte_len == utf8_len) RSTR_SET_SINGLE_BYTE_FLAG(s);

return utf8_len;

}

}

#define RSTRING_CHAR_LEN(s) utf8_strlen(s)

/* map character index to byte offset index */

static mrb_int

chars2bytes(mrb_value str, mrb_int off, mrb_int idx)

{

struct RString *s = mrb_str_ptr(str);

if (RSTR_SINGLE_BYTE_P(s) || RSTR_BINARY_P(s)) {

return idx;

}

const char *o = RSTR_PTR(s);

const char *p0 = o + off;

const char *p = p0;

const char *e = o + RSTR_LEN(s);

mrb_int i = 0;

while (p<e && i<idx) {

if ((*p & 0x80) == 0) {

const char *np = search_nonascii(p, e);

ptrdiff_t alen = np - p;

if (idx < i+alen) {

p += idx-i;

i=idx;

}

else {

p = np;

i += alen;

}

}

else {

p += mrb_utf8len(p, e);

i++;

}

}

mrb_int len = (mrb_int)(p-p0);

if (i<idx) len++;

return len;

}

/* map byte offset to character index */

static mrb_int

bytes2chars(mrb_value str, mrb_int bi)

{

struct RString *s = mrb_str_ptr(str);

if (RSTR_SINGLE_BYTE_P(s) || RSTR_BINARY_P(s)) {

return bi;

}

const char *p = RSTR_PTR(s);

const char *e = p + RSTR_LEN(s);

const char *pivot = p + bi;

mrb_int i = 0;

if (e < pivot) return -1;

while (p < pivot) {

if ((*p & 0x80) == 0) {

const char *np = search_nonascii(p, pivot);

i += np - p;

p = np;

}

else {

p += mrb_utf8len(p, e);

i++;

}

}

if (p != pivot) return -1;

return i;

}

static const char*

char_adjust(const char *ptr, const char *end)

{

ptrdiff_t len = end - ptr;

if (len < 1 || utf8_islead(ptr[0])) return ptr;

if (len > 1 && utf8_islead(ptr[1])) return ptr+1;

if (len > 2 && utf8_islead(ptr[2])) return ptr+2;

if (len > 3 && utf8_islead(ptr[3])) return ptr+3;

return ptr;

}

static const char*

char_backtrack(const char *ptr, const char *end)

{

ptrdiff_t len = end - ptr;

if (len < 1 || utf8_islead(end[-1])) return end-1;

if (len > 1 && utf8_islead(end[-2])) return end-2;

if (len > 2 && utf8_islead(end[-3])) return end-3;

if (len > 3 && utf8_islead(end[-4])) return end-4;

return end - 1;

}

static mrb_int

str_index_str_by_char(mrb_state *mrb, mrb_value str, mrb_value sub, mrb_int pos)

{

const char *ptr = RSTRING_PTR(sub);

mrb_int len = RSTRING_LEN(sub);

if (pos > 0) {

pos = chars2bytes(str, 0, pos);

}

pos = mrb_str_index(mrb, str, ptr, len, pos);

if (pos > 0) {

pos = bytes2chars(str, pos);

}

return pos;

}

#else

#define RSTRING_CHAR_LEN(s) RSTRING_LEN(s)

#define chars2bytes(s, off, ci) (ci)

#define bytes2chars(s, bi) (bi)

#define char_adjust(ptr, end) (ptr)

#define char_backtrack(ptr, end) ((end) - 1)

#define str_index_str_by_char(mrb, str, sub, pos) str_index_str((mrb), (str), (sub), (pos))

#endif

/* memsearch_swar (SWAR stands for SIMD within a register) */

/* See https://en.wikipedia.org/wiki/SWAR */

/* The function is taken from http://0x80.pl/articles/simd-strfind.html */

/* The original source code is under 2-clause BSD license; see LEGAL file. */

/* The modifications:

* port from C++ to C

* returns mrb_int

* remove alignment issue

* support bigendian CPU

* fixed potential buffer overflow

*/

static inline mrb_int

memsearch_swar(const char *xs, mrb_int m, const char *ys, mrb_int n)

{

#define MASK7f (MASK01*0x7f)

#define MASK80 (MASK01*0x80)

#if defined(MRB_ENDIAN_BIG)

#ifdef MRB_64BIT

#define MASKtop 0x8000000000000000ull

#else

#define MASKtop 0x80000000ul

#endif

#else

#define MASKtop 0x80

#endif

const bitint first = MASK01 * (uint8_t)xs[0];

const bitint last = MASK01 * (uint8_t)xs[m-1];

const char *s0 = ys;

const char *s1 = ys+m-1;

const mrb_int lim = n - m - (mrb_int)sizeof(bitint);

mrb_int i;

for (i=0; i < lim; i+=sizeof(bitint)) {

bitint t0, t1;

memcpy(&t0, s0+i, sizeof(bitint));

memcpy(&t1, s1+i, sizeof(bitint));

const bitint eq = (t0 ^ first) | (t1 ^ last);

bitint zeros = ((~eq & MASK7f) + MASK01) & (~eq & MASK80);

for (size_t j = 0; zeros; j++) {

if (zeros & MASKtop) {

const mrb_int idx = i + j;

const char* p = s0 + idx + 1;

if (memcmp(p, xs + 1, m - 2) == 0) {

return idx;

}

}

#if defined(MRB_ENDIAN_BIG)

zeros <<= 8;

#else

zeros >>= 8;

#endif

}

}

if (i+m < n) {

const char *p = s0;

const char *e = ys + n;

while (p<e) {

p = (const char*)memchr(p, *xs, e - p);

if (p == NULL || (e - p) < m) break;

if (memcmp(p+1, xs+1, m-1) == 0) return (mrb_int)(p - ys);

p++;

}

}

return -1;

}

static mrb_int

mrb_memsearch(const char *x, mrb_int m, const char *y, mrb_int n)

{

if (m > n) return -1;

else if (m == n) {

return memcmp(x, y, m) == 0 ? 0 : -1;

}

else if (m < 1) {

return 0;

}

else if (m == 1) {

const char *p = (const char*)memchr(y, *x, n);

if (p) return (mrb_int)(p - y);

return -1;

}

return memsearch_swar(x, m, y, n);

}

static void

str_share(mrb_state *mrb, struct RString *orig, struct RString *s)

{

size_t len = (size_t)orig->as.heap.len;

mrb_assert(!RSTR_EMBED_P(orig));

if (RSTR_NOFREE_P(orig)) {

str_init_nofree(s, orig->as.heap.ptr, len);

}

else if (RSTR_SHARED_P(orig)) {

str_init_shared(mrb, orig, s, orig->as.heap.aux.shared);

}

else if (RSTR_FSHARED_P(orig)) {

str_init_fshared(orig, s, orig->as.heap.aux.fshared);

}

else {

if (orig->as.heap.aux.capa > orig->as.heap.len) {

orig->as.heap.ptr = (char*)mrb_realloc(mrb, orig->as.heap.ptr, len+1);

orig->as.heap.aux.capa = (mrb_ssize)len;

}

str_init_shared(mrb, orig, s, NULL);

str_init_shared(mrb, orig, orig, s->as.heap.aux.shared);

}

}

mrb_value

mrb_str_byte_subseq(mrb_state *mrb, mrb_value str, mrb_int beg, mrb_int len)

{

struct RString *orig = mrb_str_ptr(str);

struct RString *s = mrb_obj_alloc_string(mrb);

if (RSTR_EMBEDDABLE_P(len)) {

str_init_embed(s, RSTR_PTR(orig)+beg, len);

}

else {

str_share(mrb, orig, s);

s->as.heap.ptr += (mrb_ssize)beg;

s->as.heap.len = (mrb_ssize)len;

}

RSTR_COPY_SINGLE_BYTE_FLAG(s, orig);

return mrb_obj_value(s);

}

#ifdef MRB_UTF8_STRING

static inline mrb_value

str_subseq(mrb_state *mrb, mrb_value str, mrb_int beg, mrb_int len)

{

beg = chars2bytes(str, 0, beg);

len = chars2bytes(str, beg, len);

return mrb_str_byte_subseq(mrb, str, beg, len);

}

#else

#define str_subseq(mrb, str, beg, len) mrb_str_byte_subseq(mrb, str, beg, len)

#endif

mrb_bool

mrb_str_beg_len(mrb_int str_len, mrb_int *begp, mrb_int *lenp)

{

if (str_len < *begp || *lenp < 0) return FALSE;

if (*begp < 0) {

*begp += str_len;

if (*begp < 0) return FALSE;

}

if (*lenp > str_len - *begp)

*lenp = str_len - *begp;

if (*lenp <= 0) {

*lenp = 0;

}

return TRUE;

}

static mrb_value

str_substr(mrb_state *mrb, mrb_value str, mrb_int beg, mrb_int len)

{

return mrb_str_beg_len(RSTRING_CHAR_LEN(str), &beg, &len) ?

str_subseq(mrb, str, beg, len) : mrb_nil_value();

}

MRB_API mrb_int

mrb_str_index(mrb_state *mrb, mrb_value str, const char *sptr, mrb_int slen, mrb_int offset)

{

mrb_int len = RSTRING_LEN(str);

if (offset < 0) {

offset += len;

if (offset < 0) return -1;

}

if (len - offset < slen) return -1;

char *s = RSTRING_PTR(str);

if (offset) {

s += offset;

}

if (slen == 0) return offset;

/* need proceed one character at a time */

len = RSTRING_LEN(str) - offset;

mrb_int pos = mrb_memsearch(sptr, slen, s, len);

if (pos < 0) return pos;

return pos + offset;

}

static mrb_int

str_index_str(mrb_state *mrb, mrb_value str, mrb_value str2, mrb_int offset)

{

const char *ptr = RSTRING_PTR(str2);

mrb_int len = RSTRING_LEN(str2);

return mrb_str_index(mrb, str, ptr, len, offset);

}

static mrb_value

str_replace(mrb_state *mrb, struct RString *s1, struct RString *s2)

{

mrb_check_frozen(mrb, s1);

if (s1 == s2) return mrb_obj_value(s1);

RSTR_COPY_SINGLE_BYTE_FLAG(s1, s2);

if (RSTR_SHARED_P(s1)) {

str_decref(mrb, s1->as.heap.aux.shared);

}

else if (!RSTR_EMBED_P(s1) && !RSTR_NOFREE_P(s1) && !RSTR_FSHARED_P(s1)) {

mrb_free(mrb, s1->as.heap.ptr);

}

size_t len = (size_t)RSTR_LEN(s2);

if (RSTR_EMBEDDABLE_P(len)) {

str_init_embed(s1, RSTR_PTR(s2), len);

}

else {

str_share(mrb, s2, s1);

}

return mrb_obj_value(s1);

}

static mrb_int

str_rindex(mrb_state *mrb, mrb_value str, mrb_value sub, mrb_int pos)

{

const char *s, *sbeg, *send, *t;

struct RString *ps = mrb_str_ptr(str);

mrb_int len = RSTRING_LEN(sub);

mrb_int slen = RSTR_LEN(ps);

/* substring longer than string */

if (slen < len) return -1;

if (slen - pos < len) {

pos = slen - len;

}

sbeg = RSTR_PTR(ps);

send = sbeg + slen;

s = sbeg + pos;

t = RSTRING_PTR(sub);

if (len) {

s = char_adjust(s, send);

while (sbeg <= s) {

if ((mrb_int)(send - s) >= len && memcmp(s, t, len) == 0) {

return (mrb_int)(s - sbeg);

}

s = char_backtrack(sbeg, s);

}

return -1;

}

else {

return pos;

}

}

#ifdef _WIN32

#include <stdlib.h>

#include <malloc.h>

#include <windows.h>

char*

mrb_utf8_from_locale(const char *str, int len)

{

wchar_t* wcsp;

char* mbsp;

int mbssize, wcssize;

if (len == 0)

return strdup("");

if (len == -1)

len = (int)strlen(str);

wcssize = MultiByteToWideChar(GetACP(), 0, str, len, NULL, 0);

wcsp = (wchar_t*) malloc((wcssize + 1) * sizeof(wchar_t));

if (!wcsp)

return NULL;

wcssize = MultiByteToWideChar(GetACP(), 0, str, len, wcsp, wcssize + 1);

wcsp[wcssize] = 0;

mbssize = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR) wcsp, -1, NULL, 0, NULL, NULL);

mbsp = (char*) malloc((mbssize + 1));

if (!mbsp) {

free(wcsp);

return NULL;

}

mbssize = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR) wcsp, -1, mbsp, mbssize, NULL, NULL);

mbsp[mbssize] = 0;

free(wcsp);

return mbsp;

}

char*

mrb_locale_from_utf8(const char *utf8, int len)

{

wchar_t* wcsp;

char* mbsp;

int mbssize, wcssize;

if (len == 0)

return strdup("");

if (len == -1)

len = (int)strlen(utf8);

wcssize = MultiByteToWideChar(CP_UTF8, 0, utf8, len, NULL, 0);

wcsp = (wchar_t*) malloc((wcssize + 1) * sizeof(wchar_t));

if (!wcsp)

return NULL;

wcssize = MultiByteToWideChar(CP_UTF8, 0, utf8, len, wcsp, wcssize + 1);

wcsp[wcssize] = 0;

mbssize = WideCharToMultiByte(GetACP(), 0, (LPCWSTR) wcsp, -1, NULL, 0, NULL, NULL);

mbsp = (char*) malloc((mbssize + 1));

if (!mbsp) {

free(wcsp);

return NULL;

}

mbssize = WideCharToMultiByte(GetACP(), 0, (LPCWSTR) wcsp, -1, mbsp, mbssize, NULL, NULL);

mbsp[mbssize] = 0;

free(wcsp);

return mbsp;

}

#endif

MRB_API void

mrb_str_modify_keep_ascii(mrb_state *mrb, struct RString *s)

{

mrb_check_frozen(mrb, s);

str_unshare_buffer(mrb, s);

}

MRB_API void

mrb_str_modify(mrb_state *mrb, struct RString *s)

{

mrb_str_modify_keep_ascii(mrb, s);

RSTR_UNSET_SINGLE_BYTE_FLAG(s);

}

MRB_API mrb_value

mrb_str_resize(mrb_state *mrb, mrb_value str, mrb_int len)

{

mrb_int slen;

struct RString *s = mrb_str_ptr(str);

str_check_length(mrb, len);

mrb_str_modify(mrb, s);

slen = RSTR_LEN(s);

if (len != slen) {

if (slen < len || slen - len > 256) {

resize_capa(mrb, s, len);

}

RSTR_SET_LEN(s, len);

RSTR_PTR(s)[len] = '\0'; /* sentinel */

}

return str;

}

MRB_API char*

mrb_str_to_cstr(mrb_state *mrb, mrb_value str0)

{

struct RString *s;

const char *p = RSTRING_PTR(str0);

mrb_int len = RSTRING_LEN(str0);

check_null_byte(mrb, RSTRING(str0));

s = str_init_modifiable(mrb, mrb_obj_alloc_string(mrb), p, len);

return RSTR_PTR(s);

}

MRB_API void

mrb_str_concat(mrb_state *mrb, mrb_value self, mrb_value other)

{

other = mrb_obj_as_string(mrb, other);

mrb_str_cat_str(mrb, self, other);

}

MRB_API mrb_value

mrb_str_plus(mrb_state *mrb, mrb_value a, mrb_value b)

{

struct RString *s = mrb_str_ptr(a);

struct RString *s2 = mrb_str_ptr(b);

struct RString *t;

mrb_int slen = RSTR_LEN(s);

mrb_int s2len = RSTR_LEN(s2);

const char *p = RSTR_PTR(s);

const char *p2 = RSTR_PTR(s2);

t = str_new(mrb, 0, slen + s2len);

char *pt = RSTR_PTR(t);

memcpy(pt, p, slen);

memcpy(pt + slen, p2, s2len);

return mrb_obj_value(t);

}

/* 15.2.10.5.2 */

/*

* call-seq:

* str + other_str -> new_str

*

* Concatenation---Returns a new <code>String</code> containing

* <i>other_str</i> concatenated to <i>str</i>.

*

* "Hello from " + self.to_s #=> "Hello from main"

*/

static mrb_value

mrb_str_plus_m(mrb_state *mrb, mrb_value self)

{

mrb_value str;

mrb_get_args(mrb, "S", &str);

return mrb_str_plus(mrb, self, str);

}

/* 15.2.10.5.26 */

/* 15.2.10.5.33 */

/*

* call-seq:

* "abcd".size => int

*

* Returns the length of string.