1#include <assert.h>
2#include <stdio.h>
3#include <string.h>
4
5#include "buffer.h"
6#include "houdini.h"
7#include "utf8.h"
8#include "entities.inc"
9
10/* Binary tree lookup code for entities added by JGM */
11
12static const unsigned char *S_lookup(int i, int low, int hi,
13 const unsigned char *s, int len) {
14 int j;
15 int cmp =
16 strncmp((const char *)s, (const char *)cmark_entities[i].entity, len);
17 if (cmp == 0 && cmark_entities[i].entity[len] == 0) {
18 return (const unsigned char *)cmark_entities[i].bytes;
19 } else if (cmp <= 0 && i > low) {
20 j = i - ((i - low) / 2);
21 if (j == i)
22 j -= 1;
23 return S_lookup(j, low, i - 1, s, len);
24 } else if (cmp > 0 && i < hi) {
25 j = i + ((hi - i) / 2);
26 if (j == i)
27 j += 1;
28 return S_lookup(j, i + 1, hi, s, len);
29 } else {
30 return NULL;
31 }
32}
33
34static const unsigned char *S_lookup_entity(const unsigned char *s, int len) {
35 return S_lookup(CMARK_NUM_ENTITIES / 2, 0, CMARK_NUM_ENTITIES - 1, s, len);
36}
37
38bufsize_t houdini_unescape_ent(cmark_strbuf *ob, const uint8_t *src,
39 bufsize_t size) {
40 bufsize_t i = 0;
41
42 if (size >= 3 && src[0] == '#') {
43 int codepoint = 0;
44 int num_digits = 0;
45 int max_digits = 7;
46
47 if (_isdigit(src[1])) {
48 for (i = 1; i < size && _isdigit(src[i]); ++i) {
49 codepoint = (codepoint * 10) + (src[i] - '0');
50
51 if (codepoint >= 0x110000) {
52 // Keep counting digits but
53 // avoid integer overflow.
54 codepoint = 0x110000;
55 }
56 }
57
58 num_digits = i - 1;
59 max_digits = 7;
60 }
61
62 else if (src[1] == 'x' || src[1] == 'X') {
63 for (i = 2; i < size && _isxdigit(src[i]); ++i) {
64 codepoint = (codepoint * 16) + ((src[i] | 32) % 39 - 9);
65
66 if (codepoint >= 0x110000) {
67 // Keep counting digits but
68 // avoid integer overflow.
69 codepoint = 0x110000;
70 }
71 }
72
73 num_digits = i - 2;
74 max_digits = 6;
75 }
76
77 if (num_digits >= 1 && num_digits <= max_digits &&
78 i < size && src[i] == ';') {
79 if (codepoint == 0 || (codepoint >= 0xD800 && codepoint < 0xE000) ||
80 codepoint >= 0x110000) {
81 codepoint = 0xFFFD;
82 }
83 cmark_utf8proc_encode_char(codepoint, ob);
84 return i + 1;
85 }
86 }
87
88 else {
89 if (size > CMARK_ENTITY_MAX_LENGTH)
90 size = CMARK_ENTITY_MAX_LENGTH;
91
92 for (i = CMARK_ENTITY_MIN_LENGTH; i < size; ++i) {
93 if (src[i] == ' ')
94 break;
95
96 if (src[i] == ';') {
97 const unsigned char *entity = S_lookup_entity(src, i);
98
99 if (entity != NULL) {
100 cmark_strbuf_puts(ob, (const char *)entity);
101 return i + 1;
102 }
103
104 break;
105 }
106 }
107 }
108
109 return 0;
110}
111
112int houdini_unescape_html(cmark_strbuf *ob, const uint8_t *src,
113 bufsize_t size) {
114 bufsize_t i = 0, org, ent;
115
116 while (i < size) {
117 org = i;
118 while (i < size && src[i] != '&')
119 i++;
120
121 if (likely(i > org)) {
122 if (unlikely(org == 0)) {
123 if (i >= size)
124 return 0;
125
126 cmark_strbuf_grow(ob, HOUDINI_UNESCAPED_SIZE(size));
127 }
128
129 cmark_strbuf_put(ob, src + org, i - org);
130 }
131
132 /* escaping */
133 if (i >= size)
134 break;
135
136 i++;
137
138 ent = houdini_unescape_ent(ob, src + i, size - i);
139 i += ent;
140
141 /* not really an entity */
142 if (ent == 0)
143 cmark_strbuf_putc(ob, '&');
144 }
145
146 return 1;
147}
148
149void houdini_unescape_html_f(cmark_strbuf *ob, const uint8_t *src,
150 bufsize_t size) {
151 if (!houdini_unescape_html(ob, src, size))
152 cmark_strbuf_put(ob, src, size);
153}
154