93 lines
3.9 KiB
C
93 lines
3.9 KiB
C
|
#include <stdio.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* http://www.unicode.org/versions/Unicode6.0.0/ch03.pdf - page 94
|
||
|
|
*
|
||
|
|
* Table 3-7. Well-Formed UTF-8 Byte Sequences
|
||
|
|
*
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | Code Points | First Byte | Second Byte | Third Byte | Fourth Byte |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+0000..U+007F | 00..7F | | | |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+0080..U+07FF | C2..DF | 80..BF | | |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+0800..U+0FFF | E0 | A0..BF | 80..BF | |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+1000..U+CFFF | E1..EC | 80..BF | 80..BF | |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+D000..U+D7FF | ED | 80..9F | 80..BF | |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+E000..U+FFFF | EE..EF | 80..BF | 80..BF | |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+10000..U+3FFFF | F0 | 90..BF | 80..BF | 80..BF |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+40000..U+FFFFF | F1..F3 | 80..BF | 80..BF | 80..BF |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
* | U+100000..U+10FFFF | F4 | 80..8F | 80..BF | 80..BF |
|
||
|
|
* +--------------------+------------+-------------+------------+-------------+
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Return 0 - success, >0 - index(1 based) of first error char */
|
||
|
|
int utf8_naive(const unsigned char *data, int len)
|
||
|
|
{
|
||
|
|
int err_pos = 1;
|
||
|
|
|
||
|
|
while (len) {
|
||
|
|
int bytes;
|
||
|
|
const unsigned char byte1 = data[0];
|
||
|
|
|
||
|
|
/* 00..7F */
|
||
|
|
if (byte1 <= 0x7F) {
|
||
|
|
bytes = 1;
|
||
|
|
/* C2..DF, 80..BF */
|
||
|
|
} else if (len >= 2 && byte1 >= 0xC2 && byte1 <= 0xDF &&
|
||
|
|
(signed char)data[1] <= (signed char)0xBF) {
|
||
|
|
bytes = 2;
|
||
|
|
} else if (len >= 3) {
|
||
|
|
const unsigned char byte2 = data[1];
|
||
|
|
|
||
|
|
/* Is byte2, byte3 between 0x80 ~ 0xBF */
|
||
|
|
const int byte2_ok = (signed char)byte2 <= (signed char)0xBF;
|
||
|
|
const int byte3_ok = (signed char)data[2] <= (signed char)0xBF;
|
||
|
|
|
||
|
|
if (byte2_ok && byte3_ok &&
|
||
|
|
/* E0, A0..BF, 80..BF */
|
||
|
|
((byte1 == 0xE0 && byte2 >= 0xA0) ||
|
||
|
|
/* E1..EC, 80..BF, 80..BF */
|
||
|
|
(byte1 >= 0xE1 && byte1 <= 0xEC) ||
|
||
|
|
/* ED, 80..9F, 80..BF */
|
||
|
|
(byte1 == 0xED && byte2 <= 0x9F) ||
|
||
|
|
/* EE..EF, 80..BF, 80..BF */
|
||
|
|
(byte1 >= 0xEE && byte1 <= 0xEF))) {
|
||
|
|
bytes = 3;
|
||
|
|
} else if (len >= 4) {
|
||
|
|
/* Is byte4 between 0x80 ~ 0xBF */
|
||
|
|
const int byte4_ok = (signed char)data[3] <= (signed char)0xBF;
|
||
|
|
|
||
|
|
if (byte2_ok && byte3_ok && byte4_ok &&
|
||
|
|
/* F0, 90..BF, 80..BF, 80..BF */
|
||
|
|
((byte1 == 0xF0 && byte2 >= 0x90) ||
|
||
|
|
/* F1..F3, 80..BF, 80..BF, 80..BF */
|
||
|
|
(byte1 >= 0xF1 && byte1 <= 0xF3) ||
|
||
|
|
/* F4, 80..8F, 80..BF, 80..BF */
|
||
|
|
(byte1 == 0xF4 && byte2 <= 0x8F))) {
|
||
|
|
bytes = 4;
|
||
|
|
} else {
|
||
|
|
return err_pos;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
return err_pos;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
return err_pos;
|
||
|
|
}
|
||
|
|
|
||
|
|
len -= bytes;
|
||
|
|
err_pos += bytes;
|
||
|
|
data += bytes;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|