upscheme/c/utf8.c

785 lines
19 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 <assert.h>
#include <math.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>
#ifdef _WIN32
#include <malloc.h>
#define snprintf _snprintf
#endif
#include "scheme.h"
static const uint32_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(uint32_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(uint32_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(uint32_t *dest, size_t sz, const char *src, size_t srcsz)
{
uint32_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) {
case 5:
ch += (unsigned char)*src++;
ch <<= 6;
// fallthrough
case 4:
ch += (unsigned char)*src++;
ch <<= 6;
// fallthrough
case 3:
ch += (unsigned char)*src++;
ch <<= 6;
// fallthrough
case 2:
ch += (unsigned char)*src++;
ch <<= 6;
// fallthrough
case 1:
ch += (unsigned char)*src++;
ch <<= 6;
// fallthrough
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 uint32_t *src, size_t srcsz)
{
uint32_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, uint32_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;
}
#ifdef _WIN32
#include "wcwidth.h"
#endif
size_t u8_strwidth(const char *s)
{
uint32_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) {
case 5:
ch += (unsigned char)*s++;
ch <<= 6;
// fallthrough
case 4:
ch += (unsigned char)*s++;
ch <<= 6;
// fallthrough
case 3:
ch += (unsigned char)*s++;
ch <<= 6;
// fallthrough
case 2:
ch += (unsigned char)*s++;
ch <<= 6;
// fallthrough
case 1:
ch += (unsigned char)*s++;
ch <<= 6;
// fallthrough
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 */
uint32_t u8_nextchar(const char *s, size_t *i)
{
uint32_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 */
uint32_t u8_nextmemchar(const char *s, size_t *i)
{
uint32_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 == 'e')
return '\e';
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, uint32_t *dest)
{
uint32_t ch;
char digs[10];
int dno, ndig;
size_t i;
char c0;
assert(ssz > 0);
dno = 0;
i = 1;
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);
*dest = ch;
return i;
}
if (c0 == 'x') {
ndig = 2;
} else if (c0 == 'u') {
ndig = 4;
} else if (c0 == 'U') {
ndig = 8;
} else {
ndig = 0;
}
if (ndig) {
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 = (uint32_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;
uint32_t ch;
char temp[4];
while (*src && c < sz) {
if (*src == '\\') {
src++;
amt = u8_read_escape_sequence(src, 1000, &ch);
} else {
ch = (uint32_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 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, uint32_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'\e')
return buf_put2c(buf, "\\e");
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", (uint32_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;
uint32_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, uint32_t ch, size_t *charn)
{
size_t i = 0, lasti = 0;
uint32_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, uint32_t ch, size_t sz, size_t *charn)
{
size_t i = 0, lasti = 0;
uint32_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, uint32_t ch, size_t sz)
{
size_t i = sz - 1, tempi = 0;
uint32_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)
{
const char *cp;
if (locale == NULL)
return 0;
/* this code based on libutf8 */
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 nc;
char *buf;
uint32_t *wcs;
int cnt;
if ((cnt = vsnprintf(0, 0, fmt, ap)) < 0) {
return 0;
}
if (!(buf = calloc(cnt + 1, 1))) {
return 0;
}
vsnprintf(buf, cnt + 1, fmt, ap);
if (!(wcs = calloc(cnt + 1, sizeof(uint32_t)))) {
free(buf);
return 0;
}
nc = u8_toucs(wcs, cnt + 1, buf, cnt);
wcs[nc] = 0;
printf("%ls", (wchar_t *)wcs);
free(wcs);
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;
}