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quickjs/libregexp.c
bellard b1f67dfc1a 2020-11-08 release
2020-11-08 14:30:56 +01:00

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/*
* Regular Expression Engine
*
* Copyright (c) 2017-2018 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <inttypes.h>
#include <string.h>
#include <assert.h>
#include "cutils.h"
#include "libregexp.h"
/*
TODO:
- Add full unicode canonicalize rules for character ranges (not
really useful but needed for exact "ignorecase" compatibility).
- Add a lock step execution mode (=linear time execution guaranteed)
when the regular expression is "simple" i.e. no backreference nor
complicated lookahead. The opcodes are designed for this execution
model.
*/
#if defined(TEST)
#define DUMP_REOP
#endif
typedef enum {
#define DEF(id, size) REOP_ ## id,
#include "libregexp-opcode.h"
#undef DEF
REOP_COUNT,
} REOPCodeEnum;
#define CAPTURE_COUNT_MAX 255
#define STACK_SIZE_MAX 255
/* unicode code points */
#define CP_LS 0x2028
#define CP_PS 0x2029
#define TMP_BUF_SIZE 128
typedef struct {
DynBuf byte_code;
const uint8_t *buf_ptr;
const uint8_t *buf_end;
const uint8_t *buf_start;
int re_flags;
BOOL is_utf16;
BOOL ignore_case;
BOOL dotall;
int capture_count;
int total_capture_count; /* -1 = not computed yet */
int has_named_captures; /* -1 = don't know, 0 = no, 1 = yes */
void *opaque;
DynBuf group_names;
union {
char error_msg[TMP_BUF_SIZE];
char tmp_buf[TMP_BUF_SIZE];
} u;
} REParseState;
typedef struct {
#ifdef DUMP_REOP
const char *name;
#endif
uint8_t size;
} REOpCode;
static const REOpCode reopcode_info[REOP_COUNT] = {
#ifdef DUMP_REOP
#define DEF(id, size) { #id, size },
#else
#define DEF(id, size) { size },
#endif
#include "libregexp-opcode.h"
#undef DEF
};
#define RE_HEADER_FLAGS 0
#define RE_HEADER_CAPTURE_COUNT 1
#define RE_HEADER_STACK_SIZE 2
#define RE_HEADER_LEN 7
static inline int is_digit(int c) {
return c >= '0' && c <= '9';
}
/* insert 'len' bytes at position 'pos'. Return < 0 if error. */
static int dbuf_insert(DynBuf *s, int pos, int len)
{
if (dbuf_realloc(s, s->size + len))
return -1;
memmove(s->buf + pos + len, s->buf + pos, s->size - pos);
s->size += len;
return 0;
}
/* canonicalize with the specific JS regexp rules */
static uint32_t lre_canonicalize(uint32_t c, BOOL is_utf16)
{
uint32_t res[LRE_CC_RES_LEN_MAX];
int len;
if (is_utf16) {
if (likely(c < 128)) {
if (c >= 'A' && c <= 'Z')
c = c - 'A' + 'a';
} else {
lre_case_conv(res, c, 2);
c = res[0];
}
} else {
if (likely(c < 128)) {
if (c >= 'a' && c <= 'z')
c = c - 'a' + 'A';
} else {
/* legacy regexp: to upper case if single char >= 128 */
len = lre_case_conv(res, c, FALSE);
if (len == 1 && res[0] >= 128)
c = res[0];
}
}
return c;
}
static const uint16_t char_range_d[] = {
1,
0x0030, 0x0039 + 1,
};
/* code point ranges for Zs,Zl or Zp property */
static const uint16_t char_range_s[] = {
10,
0x0009, 0x000D + 1,
0x0020, 0x0020 + 1,
0x00A0, 0x00A0 + 1,
0x1680, 0x1680 + 1,
0x2000, 0x200A + 1,
/* 2028;LINE SEPARATOR;Zl;0;WS;;;;;N;;;;; */
/* 2029;PARAGRAPH SEPARATOR;Zp;0;B;;;;;N;;;;; */
0x2028, 0x2029 + 1,
0x202F, 0x202F + 1,
0x205F, 0x205F + 1,
0x3000, 0x3000 + 1,
/* FEFF;ZERO WIDTH NO-BREAK SPACE;Cf;0;BN;;;;;N;BYTE ORDER MARK;;;; */
0xFEFF, 0xFEFF + 1,
};
BOOL lre_is_space(int c)
{
int i, n, low, high;
n = (countof(char_range_s) - 1) / 2;
for(i = 0; i < n; i++) {
low = char_range_s[2 * i + 1];
if (c < low)
return FALSE;
high = char_range_s[2 * i + 2];
if (c < high)
return TRUE;
}
return FALSE;
}
uint32_t const lre_id_start_table_ascii[4] = {
/* $ A-Z _ a-z */
0x00000000, 0x00000010, 0x87FFFFFE, 0x07FFFFFE
};
uint32_t const lre_id_continue_table_ascii[4] = {
/* $ 0-9 A-Z _ a-z */
0x00000000, 0x03FF0010, 0x87FFFFFE, 0x07FFFFFE
};
static const uint16_t char_range_w[] = {
4,
0x0030, 0x0039 + 1,
0x0041, 0x005A + 1,
0x005F, 0x005F + 1,
0x0061, 0x007A + 1,
};
#define CLASS_RANGE_BASE 0x40000000
typedef enum {
CHAR_RANGE_d,
CHAR_RANGE_D,
CHAR_RANGE_s,
CHAR_RANGE_S,
CHAR_RANGE_w,
CHAR_RANGE_W,
} CharRangeEnum;
static const uint16_t *char_range_table[] = {
char_range_d,
char_range_s,
char_range_w,
};
static int cr_init_char_range(REParseState *s, CharRange *cr, uint32_t c)
{
BOOL invert;
const uint16_t *c_pt;
int len, i;
invert = c & 1;
c_pt = char_range_table[c >> 1];
len = *c_pt++;
cr_init(cr, s->opaque, lre_realloc);
for(i = 0; i < len * 2; i++) {
if (cr_add_point(cr, c_pt[i]))
goto fail;
}
if (invert) {
if (cr_invert(cr))
goto fail;
}
return 0;
fail:
cr_free(cr);
return -1;
}
static int cr_canonicalize(CharRange *cr)
{
CharRange a;
uint32_t pt[2];
int i, ret;
cr_init(&a, cr->mem_opaque, lre_realloc);
pt[0] = 'a';
pt[1] = 'z' + 1;
ret = cr_op(&a, cr->points, cr->len, pt, 2, CR_OP_INTER);
if (ret)
goto fail;
/* convert to upper case */
/* XXX: the generic unicode case would be much more complicated
and not really useful */
for(i = 0; i < a.len; i++) {
a.points[i] += 'A' - 'a';
}
/* Note: for simplicity we keep the lower case ranges */
ret = cr_union1(cr, a.points, a.len);
fail:
cr_free(&a);
return ret;
}
#ifdef DUMP_REOP
static __maybe_unused void lre_dump_bytecode(const uint8_t *buf,
int buf_len)
{
int pos, len, opcode, bc_len, re_flags, i;
uint32_t val;
assert(buf_len >= RE_HEADER_LEN);
re_flags= buf[0];
bc_len = get_u32(buf + 3);
assert(bc_len + RE_HEADER_LEN <= buf_len);
printf("flags: 0x%x capture_count=%d stack_size=%d\n",
re_flags, buf[1], buf[2]);
if (re_flags & LRE_FLAG_NAMED_GROUPS) {
const char *p;
p = (char *)buf + RE_HEADER_LEN + bc_len;
printf("named groups: ");
for(i = 1; i < buf[1]; i++) {
if (i != 1)
printf(",");
printf("<%s>", p);
p += strlen(p) + 1;
}
printf("\n");
assert(p == (char *)(buf + buf_len));
}
printf("bytecode_len=%d\n", bc_len);
buf += RE_HEADER_LEN;
pos = 0;
while (pos < bc_len) {
printf("%5u: ", pos);
opcode = buf[pos];
len = reopcode_info[opcode].size;
if (opcode >= REOP_COUNT) {
printf(" invalid opcode=0x%02x\n", opcode);
break;
}
if ((pos + len) > bc_len) {
printf(" buffer overflow (opcode=0x%02x)\n", opcode);
break;
}
printf("%s", reopcode_info[opcode].name);
switch(opcode) {
case REOP_char:
val = get_u16(buf + pos + 1);
if (val >= ' ' && val <= 126)
printf(" '%c'", val);
else
printf(" 0x%04x", val);
break;
case REOP_char32:
val = get_u32(buf + pos + 1);
if (val >= ' ' && val <= 126)
printf(" '%c'", val);
else
printf(" 0x%08x", val);
break;
case REOP_goto:
case REOP_split_goto_first:
case REOP_split_next_first:
case REOP_loop:
case REOP_lookahead:
case REOP_negative_lookahead:
case REOP_bne_char_pos:
val = get_u32(buf + pos + 1);
val += (pos + 5);
printf(" %u", val);
break;
case REOP_simple_greedy_quant:
printf(" %u %u %u %u",
get_u32(buf + pos + 1) + (pos + 17),
get_u32(buf + pos + 1 + 4),
get_u32(buf + pos + 1 + 8),
get_u32(buf + pos + 1 + 12));
break;
case REOP_save_start:
case REOP_save_end:
case REOP_back_reference:
case REOP_backward_back_reference:
printf(" %u", buf[pos + 1]);
break;
case REOP_save_reset:
printf(" %u %u", buf[pos + 1], buf[pos + 2]);
break;
case REOP_push_i32:
val = get_u32(buf + pos + 1);
printf(" %d", val);
break;
case REOP_range:
{
int n, i;
n = get_u16(buf + pos + 1);
len += n * 4;
for(i = 0; i < n * 2; i++) {
val = get_u16(buf + pos + 3 + i * 2);
printf(" 0x%04x", val);
}
}
break;
case REOP_range32:
{
int n, i;
n = get_u16(buf + pos + 1);
len += n * 8;
for(i = 0; i < n * 2; i++) {
val = get_u32(buf + pos + 3 + i * 4);
printf(" 0x%08x", val);
}
}
break;
default:
break;
}
printf("\n");
pos += len;
}
}
#endif
static void re_emit_op(REParseState *s, int op)
{
dbuf_putc(&s->byte_code, op);
}
/* return the offset of the u32 value */
static int re_emit_op_u32(REParseState *s, int op, uint32_t val)
{
int pos;
dbuf_putc(&s->byte_code, op);
pos = s->byte_code.size;
dbuf_put_u32(&s->byte_code, val);
return pos;
}
static int re_emit_goto(REParseState *s, int op, uint32_t val)
{
int pos;
dbuf_putc(&s->byte_code, op);
pos = s->byte_code.size;
dbuf_put_u32(&s->byte_code, val - (pos + 4));
return pos;
}
static void re_emit_op_u8(REParseState *s, int op, uint32_t val)
{
dbuf_putc(&s->byte_code, op);
dbuf_putc(&s->byte_code, val);
}
static void re_emit_op_u16(REParseState *s, int op, uint32_t val)
{
dbuf_putc(&s->byte_code, op);
dbuf_put_u16(&s->byte_code, val);
}
static int __attribute__((format(printf, 2, 3))) re_parse_error(REParseState *s, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vsnprintf(s->u.error_msg, sizeof(s->u.error_msg), fmt, ap);
va_end(ap);
return -1;
}
static int re_parse_out_of_memory(REParseState *s)
{
return re_parse_error(s, "out of memory");
}
/* If allow_overflow is false, return -1 in case of
overflow. Otherwise return INT32_MAX. */
static int parse_digits(const uint8_t **pp, BOOL allow_overflow)
{
const uint8_t *p;
uint64_t v;
int c;
p = *pp;
v = 0;
for(;;) {
c = *p;
if (c < '0' || c > '9')
break;
v = v * 10 + c - '0';
if (v >= INT32_MAX) {
if (allow_overflow)
v = INT32_MAX;
else
return -1;
}
p++;
}
*pp = p;
return v;
}
static int re_parse_expect(REParseState *s, const uint8_t **pp, int c)
{
const uint8_t *p;
p = *pp;
if (*p != c)
return re_parse_error(s, "expecting '%c'", c);
p++;
*pp = p;
return 0;
}
/* Parse an escape sequence, *pp points after the '\':
allow_utf16 value:
0 : no UTF-16 escapes allowed
1 : UTF-16 escapes allowed
2 : UTF-16 escapes allowed and escapes of surrogate pairs are
converted to a unicode character (unicode regexp case).
Return the unicode char and update *pp if recognized,
return -1 if malformed escape,
return -2 otherwise. */
int lre_parse_escape(const uint8_t **pp, int allow_utf16)
{
const uint8_t *p;
uint32_t c;
p = *pp;
c = *p++;
switch(c) {
case 'b':
c = '\b';
break;
case 'f':
c = '\f';
break;
case 'n':
c = '\n';
break;
case 'r':
c = '\r';
break;
case 't':
c = '\t';
break;
case 'v':
c = '\v';
break;
case 'x':
case 'u':
{
int h, n, i;
uint32_t c1;
if (*p == '{' && allow_utf16) {
p++;
c = 0;
for(;;) {
h = from_hex(*p++);
if (h < 0)
return -1;
c = (c << 4) | h;
if (c > 0x10FFFF)
return -1;
if (*p == '}')
break;
}
p++;
} else {
if (c == 'x') {
n = 2;
} else {
n = 4;
}
c = 0;
for(i = 0; i < n; i++) {
h = from_hex(*p++);
if (h < 0) {
return -1;
}
c = (c << 4) | h;
}
if (c >= 0xd800 && c < 0xdc00 &&
allow_utf16 == 2 && p[0] == '\\' && p[1] == 'u') {
/* convert an escaped surrogate pair into a
unicode char */
c1 = 0;
for(i = 0; i < 4; i++) {
h = from_hex(p[2 + i]);
if (h < 0)
break;
c1 = (c1 << 4) | h;
}
if (i == 4 && c1 >= 0xdc00 && c1 < 0xe000) {
p += 6;
c = (((c & 0x3ff) << 10) | (c1 & 0x3ff)) + 0x10000;
}
}
}
}
break;
case '0': case '1': case '2': case '3':
case '4': case '5': case '6': case '7':
c -= '0';
if (allow_utf16 == 2) {
/* only accept \0 not followed by digit */
if (c != 0 || is_digit(*p))
return -1;
} else {
/* parse a legacy octal sequence */
uint32_t v;
v = *p - '0';
if (v > 7)
break;
c = (c << 3) | v;
p++;
if (c >= 32)
break;
v = *p - '0';
if (v > 7)
break;
c = (c << 3) | v;
p++;
}
break;
default:
return -2;
}
*pp = p;
return c;
}
#ifdef CONFIG_ALL_UNICODE
/* XXX: we use the same chars for name and value */
static BOOL is_unicode_char(int c)
{
return ((c >= '0' && c <= '9') ||
(c >= 'A' && c <= 'Z') ||
(c >= 'a' && c <= 'z') ||
(c == '_'));
}
static int parse_unicode_property(REParseState *s, CharRange *cr,
const uint8_t **pp, BOOL is_inv)
{
const uint8_t *p;
char name[64], value[64];
char *q;
BOOL script_ext;
int ret;
p = *pp;
if (*p != '{')
return re_parse_error(s, "expecting '{' after \\p");
p++;
q = name;
while (is_unicode_char(*p)) {
if ((q - name) >= sizeof(name) - 1)
goto unknown_property_name;
*q++ = *p++;
}
*q = '\0';
q = value;
if (*p == '=') {
p++;
while (is_unicode_char(*p)) {
if ((q - value) >= sizeof(value) - 1)
return re_parse_error(s, "unknown unicode property value");
*q++ = *p++;
}
}
*q = '\0';
if (*p != '}')
return re_parse_error(s, "expecting '}'");
p++;
// printf("name=%s value=%s\n", name, value);
if (!strcmp(name, "Script") || !strcmp(name, "sc")) {
script_ext = FALSE;
goto do_script;
} else if (!strcmp(name, "Script_Extensions") || !strcmp(name, "scx")) {
script_ext = TRUE;
do_script:
cr_init(cr, s->opaque, lre_realloc);
ret = unicode_script(cr, value, script_ext);
if (ret) {
cr_free(cr);
if (ret == -2)
return re_parse_error(s, "unknown unicode script");
else
goto out_of_memory;
}
} else if (!strcmp(name, "General_Category") || !strcmp(name, "gc")) {
cr_init(cr, s->opaque, lre_realloc);
ret = unicode_general_category(cr, value);
if (ret) {
cr_free(cr);
if (ret == -2)
return re_parse_error(s, "unknown unicode general category");
else
goto out_of_memory;
}
} else if (value[0] == '\0') {
cr_init(cr, s->opaque, lre_realloc);
ret = unicode_general_category(cr, name);
if (ret == -1) {
cr_free(cr);
goto out_of_memory;
}
if (ret < 0) {
ret = unicode_prop(cr, name);
if (ret) {
cr_free(cr);
if (ret == -2)
goto unknown_property_name;
else
goto out_of_memory;
}
}
} else {
unknown_property_name:
return re_parse_error(s, "unknown unicode property name");
}
if (is_inv) {
if (cr_invert(cr)) {
cr_free(cr);
return -1;
}
}
*pp = p;
return 0;
out_of_memory:
return re_parse_out_of_memory(s);
}
#endif /* CONFIG_ALL_UNICODE */
/* return -1 if error otherwise the character or a class range
(CLASS_RANGE_BASE). In case of class range, 'cr' is
initialized. Otherwise, it is ignored. */
static int get_class_atom(REParseState *s, CharRange *cr,
const uint8_t **pp, BOOL inclass)
{
const uint8_t *p;
uint32_t c;
int ret;
p = *pp;
c = *p;
switch(c) {
case '\\':
p++;
if (p >= s->buf_end)
goto unexpected_end;
c = *p++;
switch(c) {
case 'd':
c = CHAR_RANGE_d;
goto class_range;
case 'D':
c = CHAR_RANGE_D;
goto class_range;
case 's':
c = CHAR_RANGE_s;
goto class_range;
case 'S':
c = CHAR_RANGE_S;
goto class_range;
case 'w':
c = CHAR_RANGE_w;
goto class_range;
case 'W':
c = CHAR_RANGE_W;
class_range:
if (cr_init_char_range(s, cr, c))
return -1;
c = CLASS_RANGE_BASE;
break;
case 'c':
c = *p;
if ((c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(((c >= '0' && c <= '9') || c == '_') &&
inclass && !s->is_utf16)) { /* Annex B.1.4 */
c &= 0x1f;
p++;
} else if (s->is_utf16) {
goto invalid_escape;
} else {
/* otherwise return '\' and 'c' */
p--;
c = '\\';
}
break;
#ifdef CONFIG_ALL_UNICODE
case 'p':
case 'P':
if (s->is_utf16) {
if (parse_unicode_property(s, cr, &p, (c == 'P')))
return -1;
c = CLASS_RANGE_BASE;
break;
}
/* fall thru */
#endif
default:
p--;
ret = lre_parse_escape(&p, s->is_utf16 * 2);
if (ret >= 0) {
c = ret;
} else {
if (ret == -2 && *p != '\0' && strchr("^$\\.*+?()[]{}|/", *p)) {
/* always valid to escape these characters */
goto normal_char;
} else if (s->is_utf16) {
invalid_escape:
return re_parse_error(s, "invalid escape sequence in regular expression");
} else {
/* just ignore the '\' */
goto normal_char;
}
}
break;
}
break;
case '\0':
if (p >= s->buf_end) {
unexpected_end:
return re_parse_error(s, "unexpected end");
}
/* fall thru */
default:
normal_char:
/* normal char */
if (c >= 128) {
c = unicode_from_utf8(p, UTF8_CHAR_LEN_MAX, &p);
if ((unsigned)c > 0xffff && !s->is_utf16) {
/* XXX: should handle non BMP-1 code points */
return re_parse_error(s, "malformed unicode char");
}
} else {
p++;
}
break;
}
*pp = p;
return c;
}
static int re_emit_range(REParseState *s, const CharRange *cr)
{
int len, i;
uint32_t high;
len = (unsigned)cr->len / 2;
if (len >= 65535)
return re_parse_error(s, "too many ranges");
if (len == 0) {
/* not sure it can really happen. Emit a match that is always
false */
re_emit_op_u32(s, REOP_char32, -1);
} else {
high = cr->points[cr->len - 1];
if (high == UINT32_MAX)
high = cr->points[cr->len - 2];
if (high <= 0xffff) {
/* can use 16 bit ranges with the conversion that 0xffff =
infinity */
re_emit_op_u16(s, REOP_range, len);
for(i = 0; i < cr->len; i += 2) {
dbuf_put_u16(&s->byte_code, cr->points[i]);
high = cr->points[i + 1] - 1;
if (high == UINT32_MAX - 1)
high = 0xffff;
dbuf_put_u16(&s->byte_code, high);
}
} else {
re_emit_op_u16(s, REOP_range32, len);
for(i = 0; i < cr->len; i += 2) {
dbuf_put_u32(&s->byte_code, cr->points[i]);
dbuf_put_u32(&s->byte_code, cr->points[i + 1] - 1);
}
}
}
return 0;
}
static int re_parse_char_class(REParseState *s, const uint8_t **pp)
{
const uint8_t *p;
uint32_t c1, c2;
CharRange cr_s, *cr = &cr_s;
CharRange cr1_s, *cr1 = &cr1_s;
BOOL invert;
cr_init(cr, s->opaque, lre_realloc);
p = *pp;
p++; /* skip '[' */
invert = FALSE;
if (*p == '^') {
p++;
invert = TRUE;
}
for(;;) {
if (*p == ']')
break;
c1 = get_class_atom(s, cr1, &p, TRUE);
if ((int)c1 < 0)
goto fail;
if (*p == '-' && p[1] != ']') {
const uint8_t *p0 = p + 1;
if (c1 >= CLASS_RANGE_BASE) {
if (s->is_utf16) {
cr_free(cr1);
goto invalid_class_range;
}
/* Annex B: match '-' character */
goto class_atom;
}
c2 = get_class_atom(s, cr1, &p0, TRUE);
if ((int)c2 < 0)
goto fail;
if (c2 >= CLASS_RANGE_BASE) {
cr_free(cr1);
if (s->is_utf16) {
goto invalid_class_range;
}
/* Annex B: match '-' character */
goto class_atom;
}
p = p0;
if (c2 < c1) {
invalid_class_range:
re_parse_error(s, "invalid class range");
goto fail;
}
if (cr_union_interval(cr, c1, c2))
goto memory_error;
} else {
class_atom:
if (c1 >= CLASS_RANGE_BASE) {
int ret;
ret = cr_union1(cr, cr1->points, cr1->len);
cr_free(cr1);
if (ret)
goto memory_error;
} else {
if (cr_union_interval(cr, c1, c1))
goto memory_error;
}
}
}
if (s->ignore_case) {
if (cr_canonicalize(cr))
goto memory_error;
}
if (invert) {
if (cr_invert(cr))
goto memory_error;
}
if (re_emit_range(s, cr))
goto fail;
cr_free(cr);
p++; /* skip ']' */
*pp = p;
return 0;
memory_error:
re_parse_out_of_memory(s);
fail:
cr_free(cr);
return -1;
}
/* Return:
1 if the opcodes in bc_buf[] always advance the character pointer.
0 if the character pointer may not be advanced.
-1 if the code may depend on side effects of its previous execution (backreference)
*/
static int re_check_advance(const uint8_t *bc_buf, int bc_buf_len)
{
int pos, opcode, ret, len, i;
uint32_t val, last;
BOOL has_back_reference;
uint8_t capture_bitmap[CAPTURE_COUNT_MAX];
ret = -2; /* not known yet */
pos = 0;
has_back_reference = FALSE;
memset(capture_bitmap, 0, sizeof(capture_bitmap));
while (pos < bc_buf_len) {
opcode = bc_buf[pos];
len = reopcode_info[opcode].size;
switch(opcode) {
case REOP_range:
val = get_u16(bc_buf + pos + 1);
len += val * 4;
goto simple_char;
case REOP_range32:
val = get_u16(bc_buf + pos + 1);
len += val * 8;
goto simple_char;
case REOP_char:
case REOP_char32:
case REOP_dot:
case REOP_any:
simple_char:
if (ret == -2)
ret = 1;
break;
case REOP_line_start:
case REOP_line_end:
case REOP_push_i32:
case REOP_push_char_pos:
case REOP_drop:
case REOP_word_boundary:
case REOP_not_word_boundary:
case REOP_prev:
/* no effect */
break;
case REOP_save_start:
case REOP_save_end:
val = bc_buf[pos + 1];
capture_bitmap[val] |= 1;
break;
case REOP_save_reset:
{
val = bc_buf[pos + 1];
last = bc_buf[pos + 2];
while (val < last)
capture_bitmap[val++] |= 1;
}
break;
case REOP_back_reference:
case REOP_backward_back_reference:
val = bc_buf[pos + 1];
capture_bitmap[val] |= 2;
has_back_reference = TRUE;
break;
default:
/* safe behvior: we cannot predict the outcome */
if (ret == -2)
ret = 0;
break;
}
pos += len;
}
if (has_back_reference) {
/* check if there is back reference which references a capture
made in the some code */
for(i = 0; i < CAPTURE_COUNT_MAX; i++) {
if (capture_bitmap[i] == 3)
return -1;
}
}
if (ret == -2)
ret = 0;
return ret;
}
/* return -1 if a simple quantifier cannot be used. Otherwise return
the number of characters in the atom. */
static int re_is_simple_quantifier(const uint8_t *bc_buf, int bc_buf_len)
{
int pos, opcode, len, count;
uint32_t val;
count = 0;
pos = 0;
while (pos < bc_buf_len) {
opcode = bc_buf[pos];
len = reopcode_info[opcode].size;
switch(opcode) {
case REOP_range:
val = get_u16(bc_buf + pos + 1);
len += val * 4;
goto simple_char;
case REOP_range32:
val = get_u16(bc_buf + pos + 1);
len += val * 8;
goto simple_char;
case REOP_char:
case REOP_char32:
case REOP_dot:
case REOP_any:
simple_char:
count++;
break;
case REOP_line_start:
case REOP_line_end:
case REOP_word_boundary:
case REOP_not_word_boundary:
break;
default:
return -1;
}
pos += len;
}
return count;
}
/* '*pp' is the first char after '<' */
static int re_parse_group_name(char *buf, int buf_size,
const uint8_t **pp, BOOL is_utf16)
{
const uint8_t *p;
uint32_t c;
char *q;
p = *pp;
q = buf;
for(;;) {
c = *p;
if (c == '\\') {
p++;
if (*p != 'u')
return -1;
c = lre_parse_escape(&p, is_utf16 * 2);
} else if (c == '>') {
break;
} else if (c >= 128) {
c = unicode_from_utf8(p, UTF8_CHAR_LEN_MAX, &p);
} else {
p++;
}
if (c > 0x10FFFF)
return -1;
if (q == buf) {
if (!lre_js_is_ident_first(c))
return -1;
} else {
if (!lre_js_is_ident_next(c))
return -1;
}
if ((q - buf + UTF8_CHAR_LEN_MAX + 1) > buf_size)
return -1;
if (c < 128) {
*q++ = c;
} else {
q += unicode_to_utf8((uint8_t*)q, c);
}
}
if (q == buf)
return -1;
*q = '\0';
p++;
*pp = p;
return 0;
}
/* if capture_name = NULL: return the number of captures + 1.
Otherwise, return the capture index corresponding to capture_name
or -1 if none */
static int re_parse_captures(REParseState *s, int *phas_named_captures,
const char *capture_name)
{
const uint8_t *p;
int capture_index;
char name[TMP_BUF_SIZE];
capture_index = 1;
*phas_named_captures = 0;
for (p = s->buf_start; p < s->buf_end; p++) {
switch (*p) {
case '(':
if (p[1] == '?') {
if (p[2] == '<' && p[3] != '=' && p[3] != '!') {
*phas_named_captures = 1;
/* potential named capture */
if (capture_name) {
p += 3;
if (re_parse_group_name(name, sizeof(name), &p,
s->is_utf16) == 0) {
if (!strcmp(name, capture_name))
return capture_index;
}
}
capture_index++;
if (capture_index >= CAPTURE_COUNT_MAX)
goto done;
}
} else {
capture_index++;
if (capture_index >= CAPTURE_COUNT_MAX)
goto done;
}
break;
case '\\':
p++;
break;
case '[':
for (p += 1 + (*p == ']'); p < s->buf_end && *p != ']'; p++) {
if (*p == '\\')
p++;
}
break;
}
}
done:
if (capture_name)
return -1;
else
return capture_index;
}
static int re_count_captures(REParseState *s)
{
if (s->total_capture_count < 0) {
s->total_capture_count = re_parse_captures(s, &s->has_named_captures,
NULL);
}
return s->total_capture_count;
}
static BOOL re_has_named_captures(REParseState *s)
{
if (s->has_named_captures < 0)
re_count_captures(s);
return s->has_named_captures;
}
static int find_group_name(REParseState *s, const char *name)
{
const char *p, *buf_end;
size_t len, name_len;
int capture_index;
name_len = strlen(name);
p = (char *)s->group_names.buf;
buf_end = (char *)s->group_names.buf + s->group_names.size;
capture_index = 1;
while (p < buf_end) {
len = strlen(p);
if (len == name_len && memcmp(name, p, name_len) == 0)
return capture_index;
p += len + 1;
capture_index++;
}
return -1;
}
static int re_parse_disjunction(REParseState *s, BOOL is_backward_dir);
static int re_parse_term(REParseState *s, BOOL is_backward_dir)
{
const uint8_t *p;
int c, last_atom_start, quant_min, quant_max, last_capture_count;
BOOL greedy, add_zero_advance_check, is_neg, is_backward_lookahead;
CharRange cr_s, *cr = &cr_s;
last_atom_start = -1;
last_capture_count = 0;
p = s->buf_ptr;
c = *p;
switch(c) {
case '^':
p++;
re_emit_op(s, REOP_line_start);
break;
case '$':
p++;
re_emit_op(s, REOP_line_end);
break;
case '.':
p++;
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
if (is_backward_dir)
re_emit_op(s, REOP_prev);
re_emit_op(s, s->dotall ? REOP_any : REOP_dot);
if (is_backward_dir)
re_emit_op(s, REOP_prev);
break;
case '{':
if (s->is_utf16) {
return re_parse_error(s, "syntax error");
} else if (!is_digit(p[1])) {
/* Annex B: we accept '{' not followed by digits as a
normal atom */
goto parse_class_atom;
} else {
const uint8_t *p1 = p + 1;
/* Annex B: error if it is like a repetition count */
parse_digits(&p1, TRUE);
if (*p1 == ',') {
p1++;
if (is_digit(*p1)) {
parse_digits(&p1, TRUE);
}
}
if (*p1 != '}') {
goto parse_class_atom;
}
}
/* fall thru */
case '*':
case '+':
case '?':
return re_parse_error(s, "nothing to repeat");
case '(':
if (p[1] == '?') {
if (p[2] == ':') {
p += 3;
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
s->buf_ptr = p;
if (re_parse_disjunction(s, is_backward_dir))
return -1;
p = s->buf_ptr;
if (re_parse_expect(s, &p, ')'))
return -1;
} else if ((p[2] == '=' || p[2] == '!')) {
is_neg = (p[2] == '!');
is_backward_lookahead = FALSE;
p += 3;
goto lookahead;
} else if (p[2] == '<' &&
(p[3] == '=' || p[3] == '!')) {
int pos;
is_neg = (p[3] == '!');
is_backward_lookahead = TRUE;
p += 4;
/* lookahead */
lookahead:
/* Annex B allows lookahead to be used as an atom for
the quantifiers */
if (!s->is_utf16 && !is_backward_lookahead) {
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
}
pos = re_emit_op_u32(s, REOP_lookahead + is_neg, 0);
s->buf_ptr = p;
if (re_parse_disjunction(s, is_backward_lookahead))
return -1;
p = s->buf_ptr;
if (re_parse_expect(s, &p, ')'))
return -1;
re_emit_op(s, REOP_match);
/* jump after the 'match' after the lookahead is successful */
if (dbuf_error(&s->byte_code))
return -1;
put_u32(s->byte_code.buf + pos, s->byte_code.size - (pos + 4));
} else if (p[2] == '<') {
p += 3;
if (re_parse_group_name(s->u.tmp_buf, sizeof(s->u.tmp_buf),
&p, s->is_utf16)) {
return re_parse_error(s, "invalid group name");
}
if (find_group_name(s, s->u.tmp_buf) > 0) {
return re_parse_error(s, "duplicate group name");
}
/* group name with a trailing zero */
dbuf_put(&s->group_names, (uint8_t *)s->u.tmp_buf,
strlen(s->u.tmp_buf) + 1);
s->has_named_captures = 1;
goto parse_capture;
} else {
return re_parse_error(s, "invalid group");
}
} else {
int capture_index;
p++;
/* capture without group name */
dbuf_putc(&s->group_names, 0);
parse_capture:
if (s->capture_count >= CAPTURE_COUNT_MAX)
return re_parse_error(s, "too many captures");
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
capture_index = s->capture_count++;
re_emit_op_u8(s, REOP_save_start + is_backward_dir,
capture_index);
s->buf_ptr = p;
if (re_parse_disjunction(s, is_backward_dir))
return -1;
p = s->buf_ptr;
re_emit_op_u8(s, REOP_save_start + 1 - is_backward_dir,
capture_index);
if (re_parse_expect(s, &p, ')'))
return -1;
}
break;
case '\\':
switch(p[1]) {
case 'b':
case 'B':
re_emit_op(s, REOP_word_boundary + (p[1] != 'b'));
p += 2;
break;
case 'k':
{
const uint8_t *p1;
int dummy_res;
p1 = p;
if (p1[2] != '<') {
/* annex B: we tolerate invalid group names in non
unicode mode if there is no named capture
definition */
if (s->is_utf16 || re_has_named_captures(s))
return re_parse_error(s, "expecting group name");
else
goto parse_class_atom;
}
p1 += 3;
if (re_parse_group_name(s->u.tmp_buf, sizeof(s->u.tmp_buf),
&p1, s->is_utf16)) {
if (s->is_utf16 || re_has_named_captures(s))
return re_parse_error(s, "invalid group name");
else
goto parse_class_atom;
}
c = find_group_name(s, s->u.tmp_buf);
if (c < 0) {
/* no capture name parsed before, try to look
after (inefficient, but hopefully not common */
c = re_parse_captures(s, &dummy_res, s->u.tmp_buf);
if (c < 0) {
if (s->is_utf16 || re_has_named_captures(s))
return re_parse_error(s, "group name not defined");
else
goto parse_class_atom;
}
}
p = p1;
}
goto emit_back_reference;
case '0':
p += 2;
c = 0;
if (s->is_utf16) {
if (is_digit(*p)) {
return re_parse_error(s, "invalid decimal escape in regular expression");
}
} else {
/* Annex B.1.4: accept legacy octal */
if (*p >= '0' && *p <= '7') {
c = *p++ - '0';
if (*p >= '0' && *p <= '7') {
c = (c << 3) + *p++ - '0';
}
}
}
goto normal_char;
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8':
case '9':
{
const uint8_t *q = ++p;
c = parse_digits(&p, FALSE);
if (c < 0 || (c >= s->capture_count && c >= re_count_captures(s))) {
if (!s->is_utf16) {
/* Annex B.1.4: accept legacy octal */
p = q;
if (*p <= '7') {
c = 0;
if (*p <= '3')
c = *p++ - '0';
if (*p >= '0' && *p <= '7') {
c = (c << 3) + *p++ - '0';
if (*p >= '0' && *p <= '7') {
c = (c << 3) + *p++ - '0';
}
}
} else {
c = *p++;
}
goto normal_char;
}
return re_parse_error(s, "back reference out of range in regular expression");
}
emit_back_reference:
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
re_emit_op_u8(s, REOP_back_reference + is_backward_dir, c);
}
break;
default:
goto parse_class_atom;
}
break;
case '[':
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
if (is_backward_dir)
re_emit_op(s, REOP_prev);
if (re_parse_char_class(s, &p))
return -1;
if (is_backward_dir)
re_emit_op(s, REOP_prev);
break;
case ']':
case '}':
if (s->is_utf16)
return re_parse_error(s, "syntax error");
goto parse_class_atom;
default:
parse_class_atom:
c = get_class_atom(s, cr, &p, FALSE);
if ((int)c < 0)
return -1;
normal_char:
last_atom_start = s->byte_code.size;
last_capture_count = s->capture_count;
if (is_backward_dir)
re_emit_op(s, REOP_prev);
if (c >= CLASS_RANGE_BASE) {
int ret;
/* Note: canonicalization is not needed */
ret = re_emit_range(s, cr);
cr_free(cr);
if (ret)
return -1;
} else {
if (s->ignore_case)
c = lre_canonicalize(c, s->is_utf16);
if (c <= 0xffff)
re_emit_op_u16(s, REOP_char, c);
else
re_emit_op_u32(s, REOP_char32, c);
}
if (is_backward_dir)
re_emit_op(s, REOP_prev);
break;
}
/* quantifier */
if (last_atom_start >= 0) {
c = *p;
switch(c) {
case '*':
p++;
quant_min = 0;
quant_max = INT32_MAX;
goto quantifier;
case '+':
p++;
quant_min = 1;
quant_max = INT32_MAX;
goto quantifier;
case '?':
p++;
quant_min = 0;
quant_max = 1;
goto quantifier;
case '{':
{
const uint8_t *p1 = p;
/* As an extension (see ES6 annex B), we accept '{' not
followed by digits as a normal atom */
if (!is_digit(p[1])) {
if (s->is_utf16)
goto invalid_quant_count;
break;
}
p++;
quant_min = parse_digits(&p, TRUE);
quant_max = quant_min;
if (*p == ',') {
p++;
if (is_digit(*p)) {
quant_max = parse_digits(&p, TRUE);
if (quant_max < quant_min) {
invalid_quant_count:
return re_parse_error(s, "invalid repetition count");
}
} else {
quant_max = INT32_MAX; /* infinity */
}
}
if (*p != '}' && !s->is_utf16) {
/* Annex B: normal atom if invalid '{' syntax */
p = p1;
break;
}
if (re_parse_expect(s, &p, '}'))
return -1;
}
quantifier:
greedy = TRUE;
if (*p == '?') {
p++;
greedy = FALSE;
}
if (last_atom_start < 0) {
return re_parse_error(s, "nothing to repeat");
}
if (greedy) {
int len, pos;
if (quant_max > 0) {
/* specific optimization for simple quantifiers */
if (dbuf_error(&s->byte_code))
goto out_of_memory;
len = re_is_simple_quantifier(s->byte_code.buf + last_atom_start,
s->byte_code.size - last_atom_start);
if (len > 0) {
re_emit_op(s, REOP_match);
if (dbuf_insert(&s->byte_code, last_atom_start, 17))
goto out_of_memory;
pos = last_atom_start;
s->byte_code.buf[pos++] = REOP_simple_greedy_quant;
put_u32(&s->byte_code.buf[pos],
s->byte_code.size - last_atom_start - 17);
pos += 4;
put_u32(&s->byte_code.buf[pos], quant_min);
pos += 4;
put_u32(&s->byte_code.buf[pos], quant_max);
pos += 4;
put_u32(&s->byte_code.buf[pos], len);
pos += 4;
goto done;
}
}
if (dbuf_error(&s->byte_code))
goto out_of_memory;
add_zero_advance_check = (re_check_advance(s->byte_code.buf + last_atom_start,
s->byte_code.size - last_atom_start) == 0);
} else {
add_zero_advance_check = FALSE;
}
{
int len, pos;
len = s->byte_code.size - last_atom_start;
if (quant_min == 0) {
/* need to reset the capture in case the atom is
not executed */
if (last_capture_count != s->capture_count) {
if (dbuf_insert(&s->byte_code, last_atom_start, 3))
goto out_of_memory;
s->byte_code.buf[last_atom_start++] = REOP_save_reset;
s->byte_code.buf[last_atom_start++] = last_capture_count;
s->byte_code.buf[last_atom_start++] = s->capture_count - 1;
}
if (quant_max == 0) {
s->byte_code.size = last_atom_start;
} else if (quant_max == 1) {
if (dbuf_insert(&s->byte_code, last_atom_start, 5))
goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_split_goto_first +
greedy;
put_u32(s->byte_code.buf + last_atom_start + 1, len);
} else if (quant_max == INT32_MAX) {
if (dbuf_insert(&s->byte_code, last_atom_start, 5 + add_zero_advance_check))
goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_split_goto_first +
greedy;
put_u32(s->byte_code.buf + last_atom_start + 1,
len + 5 + add_zero_advance_check);
if (add_zero_advance_check) {
/* avoid infinite loop by stoping the
recursion if no advance was made in the
atom (only works if the atom has no
side effect) */
s->byte_code.buf[last_atom_start + 1 + 4] = REOP_push_char_pos;
re_emit_goto(s, REOP_bne_char_pos, last_atom_start);
} else {
re_emit_goto(s, REOP_goto, last_atom_start);
}
} else {
if (dbuf_insert(&s->byte_code, last_atom_start, 10))
goto out_of_memory;
pos = last_atom_start;
s->byte_code.buf[pos++] = REOP_push_i32;
put_u32(s->byte_code.buf + pos, quant_max);
pos += 4;
s->byte_code.buf[pos++] = REOP_split_goto_first + greedy;
put_u32(s->byte_code.buf + pos, len + 5);
re_emit_goto(s, REOP_loop, last_atom_start + 5);
re_emit_op(s, REOP_drop);
}
} else if (quant_min == 1 && quant_max == INT32_MAX &&
!add_zero_advance_check) {
re_emit_goto(s, REOP_split_next_first - greedy,
last_atom_start);
} else {
if (quant_min == 1) {
/* nothing to add */
} else {
if (dbuf_insert(&s->byte_code, last_atom_start, 5))
goto out_of_memory;
s->byte_code.buf[last_atom_start] = REOP_push_i32;
put_u32(s->byte_code.buf + last_atom_start + 1,
quant_min);
last_atom_start += 5;
re_emit_goto(s, REOP_loop, last_atom_start);
re_emit_op(s, REOP_drop);
}
if (quant_max == INT32_MAX) {
pos = s->byte_code.size;
re_emit_op_u32(s, REOP_split_goto_first + greedy,
len + 5 + add_zero_advance_check);
if (add_zero_advance_check)
re_emit_op(s, REOP_push_char_pos);
/* copy the atom */
dbuf_put_self(&s->byte_code, last_atom_start, len);
if (add_zero_advance_check)
re_emit_goto(s, REOP_bne_char_pos, pos);
else
re_emit_goto(s, REOP_goto, pos);
} else if (quant_max > quant_min) {
re_emit_op_u32(s, REOP_push_i32, quant_max - quant_min);
pos = s->byte_code.size;
re_emit_op_u32(s, REOP_split_goto_first + greedy, len + 5);
/* copy the atom */
dbuf_put_self(&s->byte_code, last_atom_start, len);
re_emit_goto(s, REOP_loop, pos);
re_emit_op(s, REOP_drop);
}
}
last_atom_start = -1;
}
break;
default:
break;
}
}
done:
s->buf_ptr = p;
return 0;
out_of_memory:
return re_parse_out_of_memory(s);
}
static int re_parse_alternative(REParseState *s, BOOL is_backward_dir)
{
const uint8_t *p;
int ret;
size_t start, term_start, end, term_size;
start = s->byte_code.size;
for(;;) {
p = s->buf_ptr;
if (p >= s->buf_end)
break;
if (*p == '|' || *p == ')')
break;
term_start = s->byte_code.size;
ret = re_parse_term(s, is_backward_dir);
if (ret)
return ret;
if (is_backward_dir) {
/* reverse the order of the terms (XXX: inefficient, but
speed is not really critical here) */
end = s->byte_code.size;
term_size = end - term_start;
if (dbuf_realloc(&s->byte_code, end + term_size))
return -1;
memmove(s->byte_code.buf + start + term_size,
s->byte_code.buf + start,
end - start);
memcpy(s->byte_code.buf + start, s->byte_code.buf + end,
term_size);
}
}
return 0;
}
static int re_parse_disjunction(REParseState *s, BOOL is_backward_dir)
{
int start, len, pos;
if (lre_check_stack_overflow(s->opaque, 0))
return re_parse_error(s, "stack overflow");
start = s->byte_code.size;
if (re_parse_alternative(s, is_backward_dir))
return -1;
while (*s->buf_ptr == '|') {
s->buf_ptr++;
len = s->byte_code.size - start;
/* insert a split before the first alternative */
if (dbuf_insert(&s->byte_code, start, 5)) {
return re_parse_out_of_memory(s);
}
s->byte_code.buf[start] = REOP_split_next_first;
put_u32(s->byte_code.buf + start + 1, len + 5);
pos = re_emit_op_u32(s, REOP_goto, 0);
if (re_parse_alternative(s, is_backward_dir))
return -1;
/* patch the goto */
len = s->byte_code.size - (pos + 4);
put_u32(s->byte_code.buf + pos, len);
}
return 0;
}
/* the control flow is recursive so the analysis can be linear */
static int compute_stack_size(const uint8_t *bc_buf, int bc_buf_len)
{
int stack_size, stack_size_max, pos, opcode, len;
uint32_t val;
stack_size = 0;
stack_size_max = 0;
bc_buf += RE_HEADER_LEN;
bc_buf_len -= RE_HEADER_LEN;
pos = 0;
while (pos < bc_buf_len) {
opcode = bc_buf[pos];
len = reopcode_info[opcode].size;
assert(opcode < REOP_COUNT);
assert((pos + len) <= bc_buf_len);
switch(opcode) {
case REOP_push_i32:
case REOP_push_char_pos:
stack_size++;
if (stack_size > stack_size_max) {
if (stack_size > STACK_SIZE_MAX)
return -1;
stack_size_max = stack_size;
}
break;
case REOP_drop:
case REOP_bne_char_pos:
assert(stack_size > 0);
stack_size--;
break;
case REOP_range:
val = get_u16(bc_buf + pos + 1);
len += val * 4;
break;
case REOP_range32:
val = get_u16(bc_buf + pos + 1);
len += val * 8;
break;
}
pos += len;
}
return stack_size_max;
}
/* 'buf' must be a zero terminated UTF-8 string of length buf_len.
Return NULL if error and allocate an error message in *perror_msg,
otherwise the compiled bytecode and its length in plen.
*/
uint8_t *lre_compile(int *plen, char *error_msg, int error_msg_size,
const char *buf, size_t buf_len, int re_flags,
void *opaque)
{
REParseState s_s, *s = &s_s;
int stack_size;
BOOL is_sticky;
memset(s, 0, sizeof(*s));
s->opaque = opaque;
s->buf_ptr = (const uint8_t *)buf;
s->buf_end = s->buf_ptr + buf_len;
s->buf_start = s->buf_ptr;
s->re_flags = re_flags;
s->is_utf16 = ((re_flags & LRE_FLAG_UTF16) != 0);
is_sticky = ((re_flags & LRE_FLAG_STICKY) != 0);
s->ignore_case = ((re_flags & LRE_FLAG_IGNORECASE) != 0);
s->dotall = ((re_flags & LRE_FLAG_DOTALL) != 0);
s->capture_count = 1;
s->total_capture_count = -1;
s->has_named_captures = -1;
dbuf_init2(&s->byte_code, opaque, lre_realloc);
dbuf_init2(&s->group_names, opaque, lre_realloc);
dbuf_putc(&s->byte_code, re_flags); /* first element is the flags */
dbuf_putc(&s->byte_code, 0); /* second element is the number of captures */
dbuf_putc(&s->byte_code, 0); /* stack size */
dbuf_put_u32(&s->byte_code, 0); /* bytecode length */
if (!is_sticky) {
/* iterate thru all positions (about the same as .*?( ... ) )
. We do it without an explicit loop so that lock step
thread execution will be possible in an optimized
implementation */
re_emit_op_u32(s, REOP_split_goto_first, 1 + 5);
re_emit_op(s, REOP_any);
re_emit_op_u32(s, REOP_goto, -(5 + 1 + 5));
}
re_emit_op_u8(s, REOP_save_start, 0);
if (re_parse_disjunction(s, FALSE)) {
error:
dbuf_free(&s->byte_code);
dbuf_free(&s->group_names);
pstrcpy(error_msg, error_msg_size, s->u.error_msg);
*plen = 0;
return NULL;
}
re_emit_op_u8(s, REOP_save_end, 0);
re_emit_op(s, REOP_match);
if (*s->buf_ptr != '\0') {
re_parse_error(s, "extraneous characters at the end");
goto error;
}
if (dbuf_error(&s->byte_code)) {
re_parse_out_of_memory(s);
goto error;
}
stack_size = compute_stack_size(s->byte_code.buf, s->byte_code.size);
if (stack_size < 0) {
re_parse_error(s, "too many imbricated quantifiers");
goto error;
}
s->byte_code.buf[RE_HEADER_CAPTURE_COUNT] = s->capture_count;
s->byte_code.buf[RE_HEADER_STACK_SIZE] = stack_size;
put_u32(s->byte_code.buf + 3, s->byte_code.size - RE_HEADER_LEN);
/* add the named groups if needed */
if (s->group_names.size > (s->capture_count - 1)) {
dbuf_put(&s->byte_code, s->group_names.buf, s->group_names.size);
s->byte_code.buf[RE_HEADER_FLAGS] |= LRE_FLAG_NAMED_GROUPS;
}
dbuf_free(&s->group_names);
#ifdef DUMP_REOP
lre_dump_bytecode(s->byte_code.buf, s->byte_code.size);
#endif
error_msg[0] = '\0';
*plen = s->byte_code.size;
return s->byte_code.buf;
}
static BOOL is_line_terminator(uint32_t c)
{
return (c == '\n' || c == '\r' || c == CP_LS || c == CP_PS);
}
static BOOL is_word_char(uint32_t c)
{
return ((c >= '0' && c <= '9') ||
(c >= 'a' && c <= 'z') ||
(c >= 'A' && c <= 'Z') ||
(c == '_'));
}
#define GET_CHAR(c, cptr, cbuf_end) \
do { \
if (cbuf_type == 0) { \
c = *cptr++; \
} else { \
uint32_t __c1; \
c = *(uint16_t *)cptr; \
cptr += 2; \
if (c >= 0xd800 && c < 0xdc00 && \
cbuf_type == 2 && cptr < cbuf_end) { \
__c1 = *(uint16_t *)cptr; \
if (__c1 >= 0xdc00 && __c1 < 0xe000) { \
c = (((c & 0x3ff) << 10) | (__c1 & 0x3ff)) + 0x10000; \
cptr += 2; \
} \
} \
} \
} while (0)
#define PEEK_CHAR(c, cptr, cbuf_end) \
do { \
if (cbuf_type == 0) { \
c = cptr[0]; \
} else { \
uint32_t __c1; \
c = ((uint16_t *)cptr)[0]; \
if (c >= 0xd800 && c < 0xdc00 && \
cbuf_type == 2 && (cptr + 2) < cbuf_end) { \
__c1 = ((uint16_t *)cptr)[1]; \
if (__c1 >= 0xdc00 && __c1 < 0xe000) { \
c = (((c & 0x3ff) << 10) | (__c1 & 0x3ff)) + 0x10000; \
} \
} \
} \
} while (0)
#define PEEK_PREV_CHAR(c, cptr, cbuf_start) \
do { \
if (cbuf_type == 0) { \
c = cptr[-1]; \
} else { \
uint32_t __c1; \
c = ((uint16_t *)cptr)[-1]; \
if (c >= 0xdc00 && c < 0xe000 && \
cbuf_type == 2 && (cptr - 4) >= cbuf_start) { \
__c1 = ((uint16_t *)cptr)[-2]; \
if (__c1 >= 0xd800 && __c1 < 0xdc00 ) { \
c = (((__c1 & 0x3ff) << 10) | (c & 0x3ff)) + 0x10000; \
} \
} \
} \
} while (0)
#define GET_PREV_CHAR(c, cptr, cbuf_start) \
do { \
if (cbuf_type == 0) { \
cptr--; \
c = cptr[0]; \
} else { \
uint32_t __c1; \
cptr -= 2; \
c = ((uint16_t *)cptr)[0]; \
if (c >= 0xdc00 && c < 0xe000 && \
cbuf_type == 2 && cptr > cbuf_start) { \
__c1 = ((uint16_t *)cptr)[-1]; \
if (__c1 >= 0xd800 && __c1 < 0xdc00 ) { \
cptr -= 2; \
c = (((__c1 & 0x3ff) << 10) | (c & 0x3ff)) + 0x10000; \
} \
} \
} \
} while (0)
#define PREV_CHAR(cptr, cbuf_start) \
do { \
if (cbuf_type == 0) { \
cptr--; \
} else { \
cptr -= 2; \
if (cbuf_type == 2) { \
c = ((uint16_t *)cptr)[0]; \
if (c >= 0xdc00 && c < 0xe000 && cptr > cbuf_start) { \
c = ((uint16_t *)cptr)[-1]; \
if (c >= 0xd800 && c < 0xdc00) \
cptr -= 2; \
} \
} \
} \
} while (0)
typedef uintptr_t StackInt;
typedef enum {
RE_EXEC_STATE_SPLIT,
RE_EXEC_STATE_LOOKAHEAD,
RE_EXEC_STATE_NEGATIVE_LOOKAHEAD,
RE_EXEC_STATE_GREEDY_QUANT,
} REExecStateEnum;
typedef struct REExecState {
REExecStateEnum type : 8;
uint8_t stack_len;
size_t count; /* only used for RE_EXEC_STATE_GREEDY_QUANT */
const uint8_t *cptr;
const uint8_t *pc;
void *buf[0];
} REExecState;
typedef struct {
const uint8_t *cbuf;
const uint8_t *cbuf_end;
/* 0 = 8 bit chars, 1 = 16 bit chars, 2 = 16 bit chars, UTF-16 */
int cbuf_type;
int capture_count;
int stack_size_max;
BOOL multi_line;
BOOL ignore_case;
BOOL is_utf16;
void *opaque; /* used for stack overflow check */
size_t state_size;
uint8_t *state_stack;
size_t state_stack_size;
size_t state_stack_len;
} REExecContext;
static int push_state(REExecContext *s,
uint8_t **capture,
StackInt *stack, size_t stack_len,
const uint8_t *pc, const uint8_t *cptr,
REExecStateEnum type, size_t count)
{
REExecState *rs;
uint8_t *new_stack;
size_t new_size, i, n;
StackInt *stack_buf;
if (unlikely((s->state_stack_len + 1) > s->state_stack_size)) {
/* reallocate the stack */
new_size = s->state_stack_size * 3 / 2;
if (new_size < 8)
new_size = 8;
new_stack = lre_realloc(s->opaque, s->state_stack, new_size * s->state_size);
if (!new_stack)
return -1;
s->state_stack_size = new_size;
s->state_stack = new_stack;
}
rs = (REExecState *)(s->state_stack + s->state_stack_len * s->state_size);
s->state_stack_len++;
rs->type = type;
rs->count = count;
rs->stack_len = stack_len;
rs->cptr = cptr;
rs->pc = pc;
n = 2 * s->capture_count;
for(i = 0; i < n; i++)
rs->buf[i] = capture[i];
stack_buf = (StackInt *)(rs->buf + n);
for(i = 0; i < stack_len; i++)
stack_buf[i] = stack[i];
return 0;
}
/* return 1 if match, 0 if not match or -1 if error. */
static intptr_t lre_exec_backtrack(REExecContext *s, uint8_t **capture,
StackInt *stack, int stack_len,
const uint8_t *pc, const uint8_t *cptr,
BOOL no_recurse)
{
int opcode, ret;
int cbuf_type;
uint32_t val, c;
const uint8_t *cbuf_end;
cbuf_type = s->cbuf_type;
cbuf_end = s->cbuf_end;
for(;;) {
// printf("top=%p: pc=%d\n", th_list.top, (int)(pc - (bc_buf + RE_HEADER_LEN)));
opcode = *pc++;
switch(opcode) {
case REOP_match:
{
REExecState *rs;
if (no_recurse)
return (intptr_t)cptr;
ret = 1;
goto recurse;
no_match:
if (no_recurse)
return 0;
ret = 0;
recurse:
for(;;) {
if (s->state_stack_len == 0)
return ret;
rs = (REExecState *)(s->state_stack +
(s->state_stack_len - 1) * s->state_size);
if (rs->type == RE_EXEC_STATE_SPLIT) {
if (!ret) {
pop_state:
memcpy(capture, rs->buf,
sizeof(capture[0]) * 2 * s->capture_count);
pop_state1:
pc = rs->pc;
cptr = rs->cptr;
stack_len = rs->stack_len;
memcpy(stack, rs->buf + 2 * s->capture_count,
stack_len * sizeof(stack[0]));
s->state_stack_len--;
break;
}
} else if (rs->type == RE_EXEC_STATE_GREEDY_QUANT) {
if (!ret) {
uint32_t char_count, i;
memcpy(capture, rs->buf,
sizeof(capture[0]) * 2 * s->capture_count);
stack_len = rs->stack_len;
memcpy(stack, rs->buf + 2 * s->capture_count,
stack_len * sizeof(stack[0]));
pc = rs->pc;
cptr = rs->cptr;
/* go backward */
char_count = get_u32(pc + 12);
for(i = 0; i < char_count; i++) {
PREV_CHAR(cptr, s->cbuf);
}
pc = (pc + 16) + (int)get_u32(pc);
rs->cptr = cptr;
rs->count--;
if (rs->count == 0) {
s->state_stack_len--;
}
break;
}
} else {
ret = ((rs->type == RE_EXEC_STATE_LOOKAHEAD && ret) ||
(rs->type == RE_EXEC_STATE_NEGATIVE_LOOKAHEAD && !ret));
if (ret) {
/* keep the capture in case of positive lookahead */
if (rs->type == RE_EXEC_STATE_LOOKAHEAD)
goto pop_state1;
else
goto pop_state;
}
}
s->state_stack_len--;
}
}
break;
case REOP_char32:
val = get_u32(pc);
pc += 4;
goto test_char;
case REOP_char:
val = get_u16(pc);
pc += 2;
test_char:
if (cptr >= cbuf_end)
goto no_match;
GET_CHAR(c, cptr, cbuf_end);
if (s->ignore_case) {
c = lre_canonicalize(c, s->is_utf16);
}
if (val != c)
goto no_match;
break;
case REOP_split_goto_first:
case REOP_split_next_first:
{
const uint8_t *pc1;
val = get_u32(pc);
pc += 4;
if (opcode == REOP_split_next_first) {
pc1 = pc + (int)val;
} else {
pc1 = pc;
pc = pc + (int)val;
}
ret = push_state(s, capture, stack, stack_len,
pc1, cptr, RE_EXEC_STATE_SPLIT, 0);
if (ret < 0)
return -1;
break;
}
case REOP_lookahead:
case REOP_negative_lookahead:
val = get_u32(pc);
pc += 4;
ret = push_state(s, capture, stack, stack_len,
pc + (int)val, cptr,
RE_EXEC_STATE_LOOKAHEAD + opcode - REOP_lookahead,
0);
if (ret < 0)
return -1;
break;
case REOP_goto:
val = get_u32(pc);
pc += 4 + (int)val;
break;
case REOP_line_start:
if (cptr == s->cbuf)
break;
if (!s->multi_line)
goto no_match;
PEEK_PREV_CHAR(c, cptr, s->cbuf);
if (!is_line_terminator(c))
goto no_match;
break;
case REOP_line_end:
if (cptr == cbuf_end)
break;
if (!s->multi_line)
goto no_match;
PEEK_CHAR(c, cptr, cbuf_end);
if (!is_line_terminator(c))
goto no_match;
break;
case REOP_dot:
if (cptr == cbuf_end)
goto no_match;
GET_CHAR(c, cptr, cbuf_end);
if (is_line_terminator(c))
goto no_match;
break;
case REOP_any:
if (cptr == cbuf_end)
goto no_match;
GET_CHAR(c, cptr, cbuf_end);
break;
case REOP_save_start:
case REOP_save_end:
val = *pc++;
assert(val < s->capture_count);
capture[2 * val + opcode - REOP_save_start] = (uint8_t *)cptr;
break;
case REOP_save_reset:
{
uint32_t val2;
val = pc[0];
val2 = pc[1];
pc += 2;
assert(val2 < s->capture_count);
while (val <= val2) {
capture[2 * val] = NULL;
capture[2 * val + 1] = NULL;
val++;
}
}
break;
case REOP_push_i32:
val = get_u32(pc);
pc += 4;
stack[stack_len++] = val;
break;
case REOP_drop:
stack_len--;
break;
case REOP_loop:
val = get_u32(pc);
pc += 4;
if (--stack[stack_len - 1] != 0) {
pc += (int)val;
}
break;
case REOP_push_char_pos:
stack[stack_len++] = (uintptr_t)cptr;
break;
case REOP_bne_char_pos:
val = get_u32(pc);
pc += 4;
if (stack[--stack_len] != (uintptr_t)cptr)
pc += (int)val;
break;
case REOP_word_boundary:
case REOP_not_word_boundary:
{
BOOL v1, v2;
/* char before */
if (cptr == s->cbuf) {
v1 = FALSE;
} else {
PEEK_PREV_CHAR(c, cptr, s->cbuf);
v1 = is_word_char(c);
}
/* current char */
if (cptr >= cbuf_end) {
v2 = FALSE;
} else {
PEEK_CHAR(c, cptr, cbuf_end);
v2 = is_word_char(c);
}
if (v1 ^ v2 ^ (REOP_not_word_boundary - opcode))
goto no_match;
}
break;
case REOP_back_reference:
case REOP_backward_back_reference:
{
const uint8_t *cptr1, *cptr1_end, *cptr1_start;
uint32_t c1, c2;
val = *pc++;
if (val >= s->capture_count)
goto no_match;
cptr1_start = capture[2 * val];
cptr1_end = capture[2 * val + 1];
if (!cptr1_start || !cptr1_end)
break;
if (opcode == REOP_back_reference) {
cptr1 = cptr1_start;
while (cptr1 < cptr1_end) {
if (cptr >= cbuf_end)
goto no_match;
GET_CHAR(c1, cptr1, cptr1_end);
GET_CHAR(c2, cptr, cbuf_end);
if (s->ignore_case) {
c1 = lre_canonicalize(c1, s->is_utf16);
c2 = lre_canonicalize(c2, s->is_utf16);
}
if (c1 != c2)
goto no_match;
}
} else {
cptr1 = cptr1_end;
while (cptr1 > cptr1_start) {
if (cptr == s->cbuf)
goto no_match;
GET_PREV_CHAR(c1, cptr1, cptr1_start);
GET_PREV_CHAR(c2, cptr, s->cbuf);
if (s->ignore_case) {
c1 = lre_canonicalize(c1, s->is_utf16);
c2 = lre_canonicalize(c2, s->is_utf16);
}
if (c1 != c2)
goto no_match;
}
}
}
break;
case REOP_range:
{
int n;
uint32_t low, high, idx_min, idx_max, idx;
n = get_u16(pc); /* n must be >= 1 */
pc += 2;
if (cptr >= cbuf_end)
goto no_match;
GET_CHAR(c, cptr, cbuf_end);
if (s->ignore_case) {
c = lre_canonicalize(c, s->is_utf16);
}
idx_min = 0;
low = get_u16(pc + 0 * 4);
if (c < low)
goto no_match;
idx_max = n - 1;
high = get_u16(pc + idx_max * 4 + 2);
/* 0xffff in for last value means +infinity */
if (unlikely(c >= 0xffff) && high == 0xffff)
goto range_match;
if (c > high)
goto no_match;
while (idx_min <= idx_max) {
idx = (idx_min + idx_max) / 2;
low = get_u16(pc + idx * 4);
high = get_u16(pc + idx * 4 + 2);
if (c < low)
idx_max = idx - 1;
else if (c > high)
idx_min = idx + 1;
else
goto range_match;
}
goto no_match;
range_match:
pc += 4 * n;
}
break;
case REOP_range32:
{
int n;
uint32_t low, high, idx_min, idx_max, idx;
n = get_u16(pc); /* n must be >= 1 */
pc += 2;
if (cptr >= cbuf_end)
goto no_match;
GET_CHAR(c, cptr, cbuf_end);
if (s->ignore_case) {
c = lre_canonicalize(c, s->is_utf16);
}
idx_min = 0;
low = get_u32(pc + 0 * 8);
if (c < low)
goto no_match;
idx_max = n - 1;
high = get_u32(pc + idx_max * 8 + 4);
if (c > high)
goto no_match;
while (idx_min <= idx_max) {
idx = (idx_min + idx_max) / 2;
low = get_u32(pc + idx * 8);
high = get_u32(pc + idx * 8 + 4);
if (c < low)
idx_max = idx - 1;
else if (c > high)
idx_min = idx + 1;
else
goto range32_match;
}
goto no_match;
range32_match:
pc += 8 * n;
}
break;
case REOP_prev:
/* go to the previous char */
if (cptr == s->cbuf)
goto no_match;
PREV_CHAR(cptr, s->cbuf);
break;
case REOP_simple_greedy_quant:
{
uint32_t next_pos, quant_min, quant_max;
size_t q;
intptr_t res;
const uint8_t *pc1;
next_pos = get_u32(pc);
quant_min = get_u32(pc + 4);
quant_max = get_u32(pc + 8);
pc += 16;
pc1 = pc;
pc += (int)next_pos;
q = 0;
for(;;) {
res = lre_exec_backtrack(s, capture, stack, stack_len,
pc1, cptr, TRUE);
if (res == -1)
return res;
if (!res)
break;
cptr = (uint8_t *)res;
q++;
if (q >= quant_max && quant_max != INT32_MAX)
break;
}
if (q < quant_min)
goto no_match;
if (q > quant_min) {
/* will examine all matches down to quant_min */
ret = push_state(s, capture, stack, stack_len,
pc1 - 16, cptr,
RE_EXEC_STATE_GREEDY_QUANT,
q - quant_min);
if (ret < 0)
return -1;
}
}
break;
default:
abort();
}
}
}
/* Return 1 if match, 0 if not match or -1 if error. cindex is the
starting position of the match and must be such as 0 <= cindex <=
clen. */
int lre_exec(uint8_t **capture,
const uint8_t *bc_buf, const uint8_t *cbuf, int cindex, int clen,
int cbuf_type, void *opaque)
{
REExecContext s_s, *s = &s_s;
int re_flags, i, alloca_size, ret;
StackInt *stack_buf;
re_flags = bc_buf[RE_HEADER_FLAGS];
s->multi_line = (re_flags & LRE_FLAG_MULTILINE) != 0;
s->ignore_case = (re_flags & LRE_FLAG_IGNORECASE) != 0;
s->is_utf16 = (re_flags & LRE_FLAG_UTF16) != 0;
s->capture_count = bc_buf[RE_HEADER_CAPTURE_COUNT];
s->stack_size_max = bc_buf[RE_HEADER_STACK_SIZE];
s->cbuf = cbuf;
s->cbuf_end = cbuf + (clen << cbuf_type);
s->cbuf_type = cbuf_type;
if (s->cbuf_type == 1 && s->is_utf16)
s->cbuf_type = 2;
s->opaque = opaque;
s->state_size = sizeof(REExecState) +
s->capture_count * sizeof(capture[0]) * 2 +
s->stack_size_max * sizeof(stack_buf[0]);
s->state_stack = NULL;
s->state_stack_len = 0;
s->state_stack_size = 0;
for(i = 0; i < s->capture_count * 2; i++)
capture[i] = NULL;
alloca_size = s->stack_size_max * sizeof(stack_buf[0]);
stack_buf = alloca(alloca_size);
ret = lre_exec_backtrack(s, capture, stack_buf, 0, bc_buf + RE_HEADER_LEN,
cbuf + (cindex << cbuf_type), FALSE);
lre_realloc(s->opaque, s->state_stack, 0);
return ret;
}
int lre_get_capture_count(const uint8_t *bc_buf)
{
return bc_buf[RE_HEADER_CAPTURE_COUNT];
}
int lre_get_flags(const uint8_t *bc_buf)
{
return bc_buf[RE_HEADER_FLAGS];
}
/* Return NULL if no group names. Otherwise, return a pointer to
'capture_count - 1' zero terminated UTF-8 strings. */
const char *lre_get_groupnames(const uint8_t *bc_buf)
{
uint32_t re_bytecode_len;
if ((lre_get_flags(bc_buf) & LRE_FLAG_NAMED_GROUPS) == 0)
return NULL;
re_bytecode_len = get_u32(bc_buf + 3);
return (const char *)(bc_buf + 7 + re_bytecode_len);
}
#ifdef TEST
BOOL lre_check_stack_overflow(void *opaque, size_t alloca_size)
{
return FALSE;
}
void *lre_realloc(void *opaque, void *ptr, size_t size)
{
return realloc(ptr, size);
}
int main(int argc, char **argv)
{
int len, ret, i;
uint8_t *bc;
char error_msg[64];
uint8_t *capture[CAPTURE_COUNT_MAX * 2];
const char *input;
int input_len, capture_count;
if (argc < 3) {
printf("usage: %s regexp input\n", argv[0]);
exit(1);
}
bc = lre_compile(&len, error_msg, sizeof(error_msg), argv[1],
strlen(argv[1]), 0, NULL);
if (!bc) {
fprintf(stderr, "error: %s\n", error_msg);
exit(1);
}
input = argv[2];
input_len = strlen(input);
ret = lre_exec(capture, bc, (uint8_t *)input, 0, input_len, 0, NULL);
printf("ret=%d\n", ret);
if (ret == 1) {
capture_count = lre_get_capture_count(bc);
for(i = 0; i < 2 * capture_count; i++) {
uint8_t *ptr;
ptr = capture[i];
printf("%d: ", i);
if (!ptr)
printf("<nil>");
else
printf("%u", (int)(ptr - (uint8_t *)input));
printf("\n");
}
}
return 0;
}
#endif
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