720 lines
18 KiB
C
720 lines
18 KiB
C
/*
|
|
Basic UTF-8 manipulation routines
|
|
by Jeff Bezanson
|
|
placed in the public domain Fall 2005
|
|
|
|
This code is designed to provide the utilities you need to manipulate
|
|
UTF-8 as an internal string encoding. These functions do not perform the
|
|
error checking normally needed when handling UTF-8 data, so if you happen
|
|
to be from the Unicode Consortium you will want to flay me alive.
|
|
I do this because error checking can be performed at the boundaries (I/O),
|
|
with these routines reserved for higher performance on data known to be
|
|
valid.
|
|
A UTF-8 validation routine is included.
|
|
*/
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdarg.h>
|
|
#include <wchar.h>
|
|
#include <wctype.h>
|
|
#ifdef WIN32
|
|
#include <malloc.h>
|
|
#define snprintf _snprintf
|
|
#else
|
|
#include <alloca.h>
|
|
#endif
|
|
#include <assert.h>
|
|
|
|
#include "utf8.h"
|
|
|
|
static const u_int32_t offsetsFromUTF8[6] = {
|
|
0x00000000UL, 0x00003080UL, 0x000E2080UL,
|
|
0x03C82080UL, 0xFA082080UL, 0x82082080UL
|
|
};
|
|
|
|
static const char trailingBytesForUTF8[256] = {
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
|
|
1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
|
|
2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3,4,4,4,4,5,5,5,5
|
|
};
|
|
|
|
/* returns length of next utf-8 sequence */
|
|
size_t u8_seqlen(const char *s)
|
|
{
|
|
return trailingBytesForUTF8[(unsigned int)(unsigned char)s[0]] + 1;
|
|
}
|
|
|
|
/* returns the # of bytes needed to encode a certain character
|
|
0 means the character cannot (or should not) be encoded. */
|
|
size_t u8_charlen(u_int32_t ch)
|
|
{
|
|
if (ch < 0x80)
|
|
return 1;
|
|
else if (ch < 0x800)
|
|
return 2;
|
|
else if (ch < 0x10000)
|
|
return 3;
|
|
else if (ch < 0x110000)
|
|
return 4;
|
|
return 0;
|
|
}
|
|
|
|
size_t u8_codingsize(u_int32_t *wcstr, size_t n)
|
|
{
|
|
size_t i, c=0;
|
|
|
|
for(i=0; i < n; i++)
|
|
c += u8_charlen(wcstr[i]);
|
|
return c;
|
|
}
|
|
|
|
/* conversions without error checking
|
|
only works for valid UTF-8, i.e. no 5- or 6-byte sequences
|
|
srcsz = source size in bytes
|
|
sz = dest size in # of wide characters
|
|
|
|
returns # characters converted
|
|
if sz == srcsz+1 (i.e. 4*srcsz+4 bytes), there will always be enough space.
|
|
*/
|
|
size_t u8_toucs(u_int32_t *dest, size_t sz, const char *src, size_t srcsz)
|
|
{
|
|
u_int32_t ch;
|
|
const char *src_end = src + srcsz;
|
|
size_t nb;
|
|
size_t i=0;
|
|
|
|
if (sz == 0 || srcsz == 0)
|
|
return 0;
|
|
|
|
while (i < sz) {
|
|
if (!isutf(*src)) { // invalid sequence
|
|
dest[i++] = 0xFFFD;
|
|
src++;
|
|
if (src >= src_end) break;
|
|
continue;
|
|
}
|
|
nb = trailingBytesForUTF8[(unsigned char)*src];
|
|
if (src + nb >= src_end)
|
|
break;
|
|
ch = 0;
|
|
switch (nb) {
|
|
/* these fall through deliberately */
|
|
case 5: ch += (unsigned char)*src++; ch <<= 6;
|
|
case 4: ch += (unsigned char)*src++; ch <<= 6;
|
|
case 3: ch += (unsigned char)*src++; ch <<= 6;
|
|
case 2: ch += (unsigned char)*src++; ch <<= 6;
|
|
case 1: ch += (unsigned char)*src++; ch <<= 6;
|
|
case 0: ch += (unsigned char)*src++;
|
|
}
|
|
ch -= offsetsFromUTF8[nb];
|
|
dest[i++] = ch;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
/* srcsz = number of source characters
|
|
sz = size of dest buffer in bytes
|
|
|
|
returns # bytes stored in dest
|
|
the destination string will never be bigger than the source string.
|
|
*/
|
|
size_t u8_toutf8(char *dest, size_t sz, const u_int32_t *src, size_t srcsz)
|
|
{
|
|
u_int32_t ch;
|
|
size_t i = 0;
|
|
char *dest0 = dest;
|
|
char *dest_end = dest + sz;
|
|
|
|
while (i < srcsz) {
|
|
ch = src[i];
|
|
if (ch < 0x80) {
|
|
if (dest >= dest_end)
|
|
break;
|
|
*dest++ = (char)ch;
|
|
}
|
|
else if (ch < 0x800) {
|
|
if (dest >= dest_end-1)
|
|
break;
|
|
*dest++ = (ch>>6) | 0xC0;
|
|
*dest++ = (ch & 0x3F) | 0x80;
|
|
}
|
|
else if (ch < 0x10000) {
|
|
if (dest >= dest_end-2)
|
|
break;
|
|
*dest++ = (ch>>12) | 0xE0;
|
|
*dest++ = ((ch>>6) & 0x3F) | 0x80;
|
|
*dest++ = (ch & 0x3F) | 0x80;
|
|
}
|
|
else if (ch < 0x110000) {
|
|
if (dest >= dest_end-3)
|
|
break;
|
|
*dest++ = (ch>>18) | 0xF0;
|
|
*dest++ = ((ch>>12) & 0x3F) | 0x80;
|
|
*dest++ = ((ch>>6) & 0x3F) | 0x80;
|
|
*dest++ = (ch & 0x3F) | 0x80;
|
|
}
|
|
i++;
|
|
}
|
|
return (dest-dest0);
|
|
}
|
|
|
|
size_t u8_wc_toutf8(char *dest, u_int32_t ch)
|
|
{
|
|
if (ch < 0x80) {
|
|
dest[0] = (char)ch;
|
|
return 1;
|
|
}
|
|
if (ch < 0x800) {
|
|
dest[0] = (ch>>6) | 0xC0;
|
|
dest[1] = (ch & 0x3F) | 0x80;
|
|
return 2;
|
|
}
|
|
if (ch < 0x10000) {
|
|
dest[0] = (ch>>12) | 0xE0;
|
|
dest[1] = ((ch>>6) & 0x3F) | 0x80;
|
|
dest[2] = (ch & 0x3F) | 0x80;
|
|
return 3;
|
|
}
|
|
if (ch < 0x110000) {
|
|
dest[0] = (ch>>18) | 0xF0;
|
|
dest[1] = ((ch>>12) & 0x3F) | 0x80;
|
|
dest[2] = ((ch>>6) & 0x3F) | 0x80;
|
|
dest[3] = (ch & 0x3F) | 0x80;
|
|
return 4;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* charnum => byte offset */
|
|
size_t u8_offset(const char *s, size_t charnum)
|
|
{
|
|
size_t i=0;
|
|
|
|
while (charnum > 0) {
|
|
if (s[i++] & 0x80) {
|
|
(void)(isutf(s[++i]) || isutf(s[++i]) || ++i);
|
|
}
|
|
charnum--;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
/* byte offset => charnum */
|
|
size_t u8_charnum(const char *s, size_t offset)
|
|
{
|
|
size_t charnum = 0, i=0;
|
|
|
|
while (i < offset) {
|
|
if (s[i++] & 0x80) {
|
|
(void)(isutf(s[++i]) || isutf(s[++i]) || ++i);
|
|
}
|
|
charnum++;
|
|
}
|
|
return charnum;
|
|
}
|
|
|
|
/* number of characters in NUL-terminated string */
|
|
size_t u8_strlen(const char *s)
|
|
{
|
|
size_t count = 0;
|
|
size_t i = 0, lasti;
|
|
|
|
while (1) {
|
|
lasti = i;
|
|
while (s[i] > 0)
|
|
i++;
|
|
count += (i-lasti);
|
|
if (s[i++]==0) break;
|
|
(void)(isutf(s[++i]) || isutf(s[++i]) || ++i);
|
|
count++;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
size_t u8_strwidth(const char *s)
|
|
{
|
|
u_int32_t ch;
|
|
size_t nb, tot=0;
|
|
int w;
|
|
signed char sc;
|
|
|
|
while ((sc = (signed char)*s) != 0) {
|
|
if (sc >= 0) {
|
|
s++;
|
|
if (sc) tot++;
|
|
}
|
|
else {
|
|
if (!isutf(sc)) { tot++; s++; continue; }
|
|
nb = trailingBytesForUTF8[(unsigned char)sc];
|
|
ch = 0;
|
|
switch (nb) {
|
|
/* these fall through deliberately */
|
|
case 5: ch += (unsigned char)*s++; ch <<= 6;
|
|
case 4: ch += (unsigned char)*s++; ch <<= 6;
|
|
case 3: ch += (unsigned char)*s++; ch <<= 6;
|
|
case 2: ch += (unsigned char)*s++; ch <<= 6;
|
|
case 1: ch += (unsigned char)*s++; ch <<= 6;
|
|
case 0: ch += (unsigned char)*s++;
|
|
}
|
|
ch -= offsetsFromUTF8[nb];
|
|
w = wcwidth(ch); // might return -1
|
|
if (w > 0) tot += w;
|
|
}
|
|
}
|
|
return tot;
|
|
}
|
|
|
|
/* reads the next utf-8 sequence out of a string, updating an index */
|
|
u_int32_t u8_nextchar(const char *s, size_t *i)
|
|
{
|
|
u_int32_t ch = 0;
|
|
size_t sz = 0;
|
|
|
|
do {
|
|
ch <<= 6;
|
|
ch += (unsigned char)s[(*i)];
|
|
sz++;
|
|
} while (s[*i] && (++(*i)) && !isutf(s[*i]));
|
|
ch -= offsetsFromUTF8[sz-1];
|
|
|
|
return ch;
|
|
}
|
|
|
|
/* next character without NUL character terminator */
|
|
u_int32_t u8_nextmemchar(const char *s, size_t *i)
|
|
{
|
|
u_int32_t ch = 0;
|
|
size_t sz = 0;
|
|
|
|
do {
|
|
ch <<= 6;
|
|
ch += (unsigned char)s[(*i)++];
|
|
sz++;
|
|
} while (!isutf(s[*i]));
|
|
ch -= offsetsFromUTF8[sz-1];
|
|
|
|
return ch;
|
|
}
|
|
|
|
void u8_inc(const char *s, size_t *i)
|
|
{
|
|
(void)(isutf(s[++(*i)]) || isutf(s[++(*i)]) || isutf(s[++(*i)]) || ++(*i));
|
|
}
|
|
|
|
void u8_dec(const char *s, size_t *i)
|
|
{
|
|
(void)(isutf(s[--(*i)]) || isutf(s[--(*i)]) || isutf(s[--(*i)]) || --(*i));
|
|
}
|
|
|
|
int octal_digit(char c)
|
|
{
|
|
return (c >= '0' && c <= '7');
|
|
}
|
|
|
|
int hex_digit(char c)
|
|
{
|
|
return ((c >= '0' && c <= '9') ||
|
|
(c >= 'A' && c <= 'F') ||
|
|
(c >= 'a' && c <= 'f'));
|
|
}
|
|
|
|
char read_escape_control_char(char c)
|
|
{
|
|
if (c == 'n')
|
|
return '\n';
|
|
else if (c == 't')
|
|
return '\t';
|
|
else if (c == 'r')
|
|
return '\r';
|
|
else if (c == 'b')
|
|
return '\b';
|
|
else if (c == 'f')
|
|
return '\f';
|
|
else if (c == 'v')
|
|
return '\v';
|
|
else if (c == 'a')
|
|
return '\a';
|
|
return c;
|
|
}
|
|
|
|
/* assumes that src points to the character after a backslash
|
|
returns number of input characters processed, 0 if error */
|
|
size_t u8_read_escape_sequence(const char *str, size_t ssz, u_int32_t *dest)
|
|
{
|
|
assert(ssz > 0);
|
|
u_int32_t ch;
|
|
char digs[10];
|
|
int dno=0, ndig;
|
|
size_t i=1;
|
|
char c0 = str[0];
|
|
|
|
if (octal_digit(c0)) {
|
|
i = 0;
|
|
do {
|
|
digs[dno++] = str[i++];
|
|
} while (i<ssz && octal_digit(str[i]) && dno<3);
|
|
digs[dno] = '\0';
|
|
ch = strtol(digs, NULL, 8);
|
|
}
|
|
else if ((c0=='x' && (ndig=2)) ||
|
|
(c0=='u' && (ndig=4)) ||
|
|
(c0=='U' && (ndig=8))) {
|
|
while (i<ssz && hex_digit(str[i]) && dno<ndig) {
|
|
digs[dno++] = str[i++];
|
|
}
|
|
if (dno == 0) return 0;
|
|
digs[dno] = '\0';
|
|
ch = strtol(digs, NULL, 16);
|
|
}
|
|
else {
|
|
ch = (u_int32_t)read_escape_control_char(c0);
|
|
}
|
|
*dest = ch;
|
|
|
|
return i;
|
|
}
|
|
|
|
/* convert a string with literal \uxxxx or \Uxxxxxxxx characters to UTF-8
|
|
example: u8_unescape(mybuf, 256, "hello\\u220e")
|
|
note the double backslash is needed if called on a C string literal */
|
|
size_t u8_unescape(char *buf, size_t sz, const char *src)
|
|
{
|
|
size_t c=0, amt;
|
|
u_int32_t ch;
|
|
char temp[4];
|
|
|
|
while (*src && c < sz) {
|
|
if (*src == '\\') {
|
|
src++;
|
|
amt = u8_read_escape_sequence(src, 1000, &ch);
|
|
}
|
|
else {
|
|
ch = (u_int32_t)*src;
|
|
amt = 1;
|
|
}
|
|
src += amt;
|
|
amt = u8_wc_toutf8(temp, ch);
|
|
if (amt > sz-c)
|
|
break;
|
|
memcpy(&buf[c], temp, amt);
|
|
c += amt;
|
|
}
|
|
if (c < sz)
|
|
buf[c] = '\0';
|
|
return c;
|
|
}
|
|
|
|
static inline int buf_put2c(char *buf, const char *src)
|
|
{
|
|
buf[0] = src[0];
|
|
buf[1] = src[1];
|
|
buf[2] = '\0';
|
|
return 2;
|
|
}
|
|
|
|
int u8_escape_wchar(char *buf, size_t sz, u_int32_t ch)
|
|
{
|
|
assert(sz > 2);
|
|
if (ch == L'\n')
|
|
return buf_put2c(buf, "\\n");
|
|
else if (ch == L'\t')
|
|
return buf_put2c(buf, "\\t");
|
|
else if (ch == L'\r')
|
|
return buf_put2c(buf, "\\r");
|
|
else if (ch == L'\b')
|
|
return buf_put2c(buf, "\\b");
|
|
else if (ch == L'\f')
|
|
return buf_put2c(buf, "\\f");
|
|
else if (ch == L'\v')
|
|
return buf_put2c(buf, "\\v");
|
|
else if (ch == L'\a')
|
|
return buf_put2c(buf, "\\a");
|
|
else if (ch == L'\\')
|
|
return buf_put2c(buf, "\\\\");
|
|
else if (ch < 32 || ch == 0x7f)
|
|
return snprintf(buf, sz, "\\x%.2hhx", (unsigned char)ch);
|
|
else if (ch > 0xFFFF)
|
|
return snprintf(buf, sz, "\\U%.8x", (u_int32_t)ch);
|
|
else if (ch >= 0x80)
|
|
return snprintf(buf, sz, "\\u%.4hx", (unsigned short)ch);
|
|
|
|
buf[0] = (char)ch;
|
|
buf[1] = '\0';
|
|
return 1;
|
|
}
|
|
|
|
size_t u8_escape(char *buf, size_t sz, const char *src, size_t *pi, size_t end,
|
|
int escape_quotes, int ascii)
|
|
{
|
|
size_t i = *pi, i0;
|
|
u_int32_t ch;
|
|
char *start = buf;
|
|
char *blim = start + sz-11;
|
|
assert(sz > 11);
|
|
|
|
while (i<end && buf<blim) {
|
|
// sz-11: leaves room for longest escape sequence
|
|
if (escape_quotes && src[i] == '"') {
|
|
buf += buf_put2c(buf, "\\\"");
|
|
i++;
|
|
}
|
|
else if (src[i] == '\\') {
|
|
buf += buf_put2c(buf, "\\\\");
|
|
i++;
|
|
}
|
|
else {
|
|
i0 = i;
|
|
ch = u8_nextmemchar(src, &i);
|
|
if (ascii || !iswprint((wint_t)ch)) {
|
|
buf += u8_escape_wchar(buf, sz - (buf-start), ch);
|
|
}
|
|
else {
|
|
i = i0;
|
|
do {
|
|
*buf++ = src[i++];
|
|
} while (!isutf(src[i]));
|
|
}
|
|
}
|
|
}
|
|
*buf++ = '\0';
|
|
*pi = i;
|
|
return (buf-start);
|
|
}
|
|
|
|
char *u8_strchr(const char *s, u_int32_t ch, size_t *charn)
|
|
{
|
|
size_t i = 0, lasti=0;
|
|
u_int32_t c;
|
|
|
|
*charn = 0;
|
|
while (s[i]) {
|
|
c = u8_nextchar(s, &i);
|
|
if (c == ch) {
|
|
/* it's const for us, but not necessarily the caller */
|
|
return (char*)&s[lasti];
|
|
}
|
|
lasti = i;
|
|
(*charn)++;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
char *u8_memchr(const char *s, u_int32_t ch, size_t sz, size_t *charn)
|
|
{
|
|
size_t i = 0, lasti=0;
|
|
u_int32_t c;
|
|
int csz;
|
|
|
|
*charn = 0;
|
|
while (i < sz) {
|
|
c = csz = 0;
|
|
do {
|
|
c <<= 6;
|
|
c += (unsigned char)s[i++];
|
|
csz++;
|
|
} while (i < sz && !isutf(s[i]));
|
|
c -= offsetsFromUTF8[csz-1];
|
|
|
|
if (c == ch) {
|
|
return (char*)&s[lasti];
|
|
}
|
|
lasti = i;
|
|
(*charn)++;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
char *u8_memrchr(const char *s, u_int32_t ch, size_t sz)
|
|
{
|
|
size_t i = sz-1, tempi=0;
|
|
u_int32_t c;
|
|
|
|
if (sz == 0) return NULL;
|
|
|
|
while (i && !isutf(s[i])) i--;
|
|
|
|
while (1) {
|
|
tempi = i;
|
|
c = u8_nextmemchar(s, &tempi);
|
|
if (c == ch) {
|
|
return (char*)&s[i];
|
|
}
|
|
if (i == 0)
|
|
break;
|
|
tempi = i;
|
|
u8_dec(s, &i);
|
|
if (i > tempi)
|
|
break;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
int u8_is_locale_utf8(const char *locale)
|
|
{
|
|
if (locale == NULL) return 0;
|
|
|
|
/* this code based on libutf8 */
|
|
const char* cp = locale;
|
|
|
|
for (; *cp != '\0' && *cp != '@' && *cp != '+' && *cp != ','; cp++) {
|
|
if (*cp == '.') {
|
|
const char* encoding = ++cp;
|
|
for (; *cp != '\0' && *cp != '@' && *cp != '+' && *cp != ','; cp++)
|
|
;
|
|
if ((cp-encoding == 5 && !strncmp(encoding, "UTF-8", 5))
|
|
|| (cp-encoding == 4 && !strncmp(encoding, "utf8", 4)))
|
|
return 1; /* it's UTF-8 */
|
|
break;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
size_t u8_vprintf(const char *fmt, va_list ap)
|
|
{
|
|
size_t cnt, sz=0, nc, needfree=0;
|
|
char *buf;
|
|
u_int32_t *wcs;
|
|
|
|
sz = 512;
|
|
buf = (char*)alloca(sz);
|
|
cnt = vsnprintf(buf, sz, fmt, ap);
|
|
if ((ssize_t)cnt < 0)
|
|
return 0;
|
|
if (cnt >= sz) {
|
|
buf = (char*)malloc(cnt + 1);
|
|
needfree = 1;
|
|
vsnprintf(buf, cnt+1, fmt, ap);
|
|
}
|
|
wcs = (u_int32_t*)alloca((cnt+1) * sizeof(u_int32_t));
|
|
nc = u8_toucs(wcs, cnt+1, buf, cnt);
|
|
wcs[nc] = 0;
|
|
printf("%ls", (wchar_t*)wcs);
|
|
if (needfree) free(buf);
|
|
return nc;
|
|
}
|
|
|
|
size_t u8_printf(const char *fmt, ...)
|
|
{
|
|
size_t cnt;
|
|
va_list args;
|
|
|
|
va_start(args, fmt);
|
|
|
|
cnt = u8_vprintf(fmt, args);
|
|
|
|
va_end(args);
|
|
return cnt;
|
|
}
|
|
|
|
/* based on the valid_utf8 routine from the PCRE library by Philip Hazel
|
|
|
|
length is in bytes, since without knowing whether the string is valid
|
|
it's hard to know how many characters there are! */
|
|
int u8_isvalid(const char *str, int length)
|
|
{
|
|
const unsigned char *p, *pend = (unsigned char*)str + length;
|
|
unsigned char c;
|
|
int ab;
|
|
|
|
for (p = (unsigned char*)str; p < pend; p++) {
|
|
c = *p;
|
|
if (c < 128)
|
|
continue;
|
|
if ((c & 0xc0) != 0xc0)
|
|
return 0;
|
|
ab = trailingBytesForUTF8[c];
|
|
if (length < ab)
|
|
return 0;
|
|
length -= ab;
|
|
|
|
p++;
|
|
/* Check top bits in the second byte */
|
|
if ((*p & 0xc0) != 0x80)
|
|
return 0;
|
|
|
|
/* Check for overlong sequences for each different length */
|
|
switch (ab) {
|
|
/* Check for xx00 000x */
|
|
case 1:
|
|
if ((c & 0x3e) == 0) return 0;
|
|
continue; /* We know there aren't any more bytes to check */
|
|
|
|
/* Check for 1110 0000, xx0x xxxx */
|
|
case 2:
|
|
if (c == 0xe0 && (*p & 0x20) == 0) return 0;
|
|
break;
|
|
|
|
/* Check for 1111 0000, xx00 xxxx */
|
|
case 3:
|
|
if (c == 0xf0 && (*p & 0x30) == 0) return 0;
|
|
break;
|
|
|
|
/* Check for 1111 1000, xx00 0xxx */
|
|
case 4:
|
|
if (c == 0xf8 && (*p & 0x38) == 0) return 0;
|
|
break;
|
|
|
|
/* Check for leading 0xfe or 0xff,
|
|
and then for 1111 1100, xx00 00xx */
|
|
case 5:
|
|
if (c == 0xfe || c == 0xff ||
|
|
(c == 0xfc && (*p & 0x3c) == 0)) return 0;
|
|
break;
|
|
}
|
|
|
|
/* Check for valid bytes after the 2nd, if any; all must start 10 */
|
|
while (--ab > 0) {
|
|
if ((*(++p) & 0xc0) != 0x80) return 0;
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
int u8_reverse(char *dest, char * src, size_t len)
|
|
{
|
|
size_t si=0, di=len;
|
|
unsigned char c;
|
|
|
|
dest[di] = '\0';
|
|
while (si < len) {
|
|
c = (unsigned char)src[si];
|
|
if ((~c) & 0x80) {
|
|
di--;
|
|
dest[di] = c;
|
|
si++;
|
|
}
|
|
else {
|
|
switch (c>>4) {
|
|
case 0xC:
|
|
case 0xD:
|
|
di -= 2;
|
|
*((int16_t*)&dest[di]) = *((int16_t*)&src[si]);
|
|
si += 2;
|
|
break;
|
|
case 0xE:
|
|
di -= 3;
|
|
dest[di] = src[si];
|
|
*((int16_t*)&dest[di+1]) = *((int16_t*)&src[si+1]);
|
|
si += 3;
|
|
break;
|
|
case 0xF:
|
|
di -= 4;
|
|
*((int32_t*)&dest[di]) = *((int32_t*)&src[si]);
|
|
si += 4;
|
|
break;
|
|
default:
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|