#include <assert.h>

#include <stdio.h>

#include <string.h>

#include "buffer.h"

#include "houdini.h"

#include "utf8.h"

#include "entities.inc"

#if !defined(__has_builtin)

# define __has_builtin(b) 0

#if !__has_builtin(__builtin_expect)

# define __builtin_expect(e, v) (e)

#define likely(e) __builtin_expect((e), 1)

#define unlikely(e) __builtin_expect((e), 0)

static const unsigned char *S_lookup(int i, int low, int hi,

const unsigned char *s, int len,

bufsize_t *size_out) {

int j;

uint32_t value = cmark_entities[i];

const unsigned char *ent_name = cmark_entity_text + ENT_TEXT_IDX(value);

int ent_len = ENT_NAME_SIZE(value);

int min_len = len < ent_len ? len : ent_len;

int cmp =

strncmp((const char *)s, (const char *)ent_name, min_len);

if (cmp == 0)

cmp = len - ent_len;

if (cmp == 0) {

*size_out = ENT_REPL_SIZE(value);

return ent_name + ent_len;

} else if (cmp <= 0 && i > low) {

j = i - ((i - low) / 2);

if (j == i)

j -= 1;

return S_lookup(j, low, i - 1, s, len, size_out);

} else if (cmp > 0 && i < hi) {

j = i + ((hi - i) / 2);

if (j == i)

j += 1;

return S_lookup(j, i + 1, hi, s, len, size_out);

} else {

return NULL;

}

}

static const unsigned char *S_lookup_entity(const unsigned char *s, int len,

bufsize_t *size_out) {

return S_lookup(ENT_TABLE_SIZE / 2, 0, ENT_TABLE_SIZE - 1, s, len, size_out);

}

bufsize_t houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src,

bufsize_t size) {

bufsize_t i = 0;

if (size >= 3 && src[0] == '#') {

int codepoint = 0;

int num_digits = 0;

int max_digits = 7;

if (_isdigit(src[1])) {

for (i = 1; i < size && _isdigit(src[i]); ++i) {

codepoint = (codepoint * 10) + (src[i] - '0');

if (codepoint >= 0x110000) {

// Keep counting digits but

// avoid integer overflow.

codepoint = 0x110000;

}

}

num_digits = i - 1;

max_digits = 7;

}

else if (src[1] == 'x' || src[1] == 'X') {

for (i = 2; i < size && _isxdigit(src[i]); ++i) {

codepoint = (codepoint * 16) + ((src[i] | 32) % 39 - 9);

if (codepoint >= 0x110000) {

// Keep counting digits but

// avoid integer overflow.

codepoint = 0x110000;

}

}

num_digits = i - 2;

max_digits = 6;

}

if (num_digits >= 1 && num_digits <= max_digits &&

i < size && src[i] == ';') {

if (codepoint == 0 || (codepoint >= 0xD800 && codepoint < 0xE000) ||

codepoint >= 0x110000) {

codepoint = 0xFFFD;

}

cmark_utf8proc_encode_char(codepoint, ob);

return i + 1;

}

}

else {

if (size > ENT_MAX_LENGTH)

size = ENT_MAX_LENGTH;

for (i = ENT_MIN_LENGTH; i < size; ++i) {

if (src[i] == ' ')

break;

if (src[i] == ';') {

bufsize_t size;

const unsigned char *entity = S_lookup_entity(src, i, &size);

if (entity != NULL) {

cmark_strbuf_put(ob, entity, size);

return i + 1;

}

break;

}

}

}

return 0;

}

int houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src,

bufsize_t size) {

bufsize_t i = 0, org, ent;

while (i < size) {

org = i;

while (i < size && src[i] != '&')

i++;

if (likely(i > org)) {

if (unlikely(org == 0)) {

if (i >= size)

return 0;

cmark_strbuf_grow(ob, HOUDINI_UNESCAPED_SIZE(size));

}

cmark_strbuf_put(ob, src + org, i - org);

}

/* escaping */

if (i >= size)

break;

i++;

ent = houdini_unescape_ent(ob, src + i, size - i);

i += ent;

/* not really an entity */

if (ent == 0)

cmark_strbuf_putc(ob, '&');

}

return 1;

}

void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src,

bufsize_t size) {

if (!houdini_unescape_html(ob, src, size))

cmark_strbuf_put(ob, src, size);

}