1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
/*
* Copyright 2013 MongoDB, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string.h>
#include "encoding_helpers.h"
static void
get_utf8_sequence (const char *utf8,
unsigned char *seq_length,
unsigned char *first_mask)
{
unsigned char c = *(const unsigned char *)utf8;
unsigned char m;
unsigned char n;
/*
* See the following[1] for a description of what the given multi-byte
* sequences will be based on the bits set of the first byte. We also need
* to mask the first byte based on that. All subsequent bytes are masked
* against 0x3F.
*
* [1] http://www.joelonsoftware.com/articles/Unicode.html
*/
if ((c & 0x80) == 0) {
n = 1;
m = 0x7F;
} else if ((c & 0xE0) == 0xC0) {
n = 2;
m = 0x1F;
} else if ((c & 0xF0) == 0xE0) {
n = 3;
m = 0x0F;
} else if ((c & 0xF8) == 0xF0) {
n = 4;
m = 0x07;
} else if ((c & 0xFC) == 0xF8) {
n = 5;
m = 0x03;
} else if ((c & 0xFE) == 0xFC) {
n = 6;
m = 0x01;
} else {
n = 0;
m = 0;
}
*seq_length = n;
*first_mask = m;
}
result_t
validate_utf8_encoding (const char *utf8,
size_t utf8_len,
int allow_null)
{
unsigned char first_mask;
unsigned char seq_length;
unsigned i;
unsigned j;
for (i = 0; i < utf8_len; i += seq_length) {
get_utf8_sequence(&utf8[i], &seq_length, &first_mask);
if (!seq_length) {
return INVALID_UTF8;
}
for (j = i + 1; j < (i + seq_length); j++) {
if ((utf8[j] & 0xC0) != 0x80) {
return INVALID_UTF8;
}
}
if (!allow_null) {
for (j = 0; j < seq_length; j++) {
if (((i + j) > utf8_len) || !utf8[i + j]) {
return HAS_NULL;
}
}
}
}
return VALID_UTF8;
}
|
