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phorge/externals/figlet/utf8.c
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utf8.c
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#ifdef TLF_FONTS
/*
* Copyright (c) 2007 Alexey Vatchenko <av@bsdua.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <wchar.h>
#include <arpa/inet.h> /* for htonl() */
#include "utf8.h"
#define _NXT 0x80
#define _SEQ2 0xc0
#define _SEQ3 0xe0
#define _SEQ4 0xf0
#define _SEQ5 0xf8
#define _SEQ6 0xfc
#define _BOM 0xfeff
static int __wchar_forbitten(wchar_t sym);
static int __utf8_forbitten(u_char octet);
static int
__wchar_forbitten(wchar_t sym)
{
/* Surrogate pairs */
if (sym >= 0xd800 && sym <= 0xdfff)
return (-1);
return (0);
}
static int
__utf8_forbitten(u_char octet)
{
switch (octet) {
case 0xc0:
case 0xc1:
case 0xf5:
case 0xff:
return (-1);
}
return (0);
}
/*
* DESCRIPTION
* This function translates UTF-8 string into UCS-4 string (all symbols
* will be in local machine byte order).
*
* It takes the following arguments:
* in - input UTF-8 string. It can be null-terminated.
* insize - size of input string in bytes.
* out - result buffer for UCS-4 string. If out is NULL,
* function returns size of result buffer.
* outsize - size of out buffer in wide characters.
*
* RETURN VALUES
* The function returns size of result buffer (in wide characters).
* Zero is returned in case of error.
*
* CAVEATS
* 1. If UTF-8 string contains zero symbols, they will be translated
* as regular symbols.
* 2. If UTF8_IGNORE_ERROR or UTF8_SKIP_BOM flag is set, sizes may vary
* when `out' is NULL and not NULL. It's because of special UTF-8
* sequences which may result in forbitten (by RFC3629) UNICODE
* characters. So, the caller must check return value every time and
* not prepare buffer in advance (\0 terminate) but after calling this
* function.
*/
size_t
utf8_to_wchar(const char *in, size_t insize, wchar_t *out, size_t outsize,
int flags)
{
u_char *p, *lim;
wchar_t *wlim, high;
size_t n, total, i, n_bits;
if (in == NULL || insize == 0 || (outsize == 0 && out != NULL))
return (0);
total = 0;
p = (u_char *)in;
lim = p + insize;
wlim = out + outsize;
for (; p < lim; p += n) {
if (__utf8_forbitten(*p) != 0 &&
(flags & UTF8_IGNORE_ERROR) == 0)
return (0);
/*
* Get number of bytes for one wide character.
*/
n = 1; /* default: 1 byte. Used when skipping bytes. */
if ((*p & 0x80) == 0)
high = (wchar_t)*p;
else if ((*p & 0xe0) == _SEQ2) {
n = 2;
high = (wchar_t)(*p & 0x1f);
} else if ((*p & 0xf0) == _SEQ3) {
n = 3;
high = (wchar_t)(*p & 0x0f);
} else if ((*p & 0xf8) == _SEQ4) {
n = 4;
high = (wchar_t)(*p & 0x07);
} else if ((*p & 0xfc) == _SEQ5) {
n = 5;
high = (wchar_t)(*p & 0x03);
} else if ((*p & 0xfe) == _SEQ6) {
n = 6;
high = (wchar_t)(*p & 0x01);
} else {
if ((flags & UTF8_IGNORE_ERROR) == 0)
return (0);
continue;
}
/* does the sequence header tell us truth about length? */
if (lim - p <= n - 1) {
if ((flags & UTF8_IGNORE_ERROR) == 0)
return (0);
n = 1;
continue; /* skip */
}
/*
* Validate sequence.
* All symbols must have higher bits set to 10xxxxxx
*/
if (n > 1) {
for (i = 1; i < n; i++) {
if ((p[i] & 0xc0) != _NXT)
break;
}
if (i != n) {
if ((flags & UTF8_IGNORE_ERROR) == 0)
return (0);
n = 1;
continue; /* skip */
}
}
total++;
if (out == NULL)
continue;
if (out >= wlim)
return (0); /* no space left */
*out = 0;
n_bits = 0;
for (i = 1; i < n; i++) {
*out |= (wchar_t)(p[n - i] & 0x3f) << n_bits;
n_bits += 6; /* 6 low bits in every byte */
}
*out |= high << n_bits;
if (*out == 0) /* return at end of string */
break;
if (__wchar_forbitten(*out) != 0) {
if ((flags & UTF8_IGNORE_ERROR) == 0)
return (0); /* forbitten character */
else {
total--;
out--;
}
} else if (*out == _BOM && (flags & UTF8_SKIP_BOM) != 0) {
total--;
out--;
}
out++;
}
return (total);
}
/*
* DESCRIPTION
* This function translates UCS-4 symbols (given in local machine
* byte order) into UTF-8 string.
*
* It takes the following arguments:
* in - input unicode string. It can be null-terminated.
* insize - size of input string in wide characters.
* out - result buffer for utf8 string. If out is NULL,
* function returns size of result buffer.
* outsize - size of result buffer.
*
* RETURN VALUES
* The function returns size of result buffer (in bytes). Zero is returned
* in case of error.
*
* CAVEATS
* If UCS-4 string contains zero symbols, they will be translated
* as regular symbols.
*/
size_t
wchar_to_utf8(const wchar_t *in, size_t insize, char *out, size_t outsize,
int flags)
{
wchar_t *w, *wlim, ch;
u_char *p, *lim, *oc;
size_t total, n;
if (in == NULL || insize == 0 || (outsize == 0 && out != NULL))
return (0);
w = (wchar_t *)in;
wlim = w + insize;
p = (u_char *)out;
lim = p + outsize;
total = 0;
for (; w < wlim; w++) {
if (__wchar_forbitten(*w) != 0) {
if ((flags & UTF8_IGNORE_ERROR) == 0)
return (0);
else
continue;
}
if (*w == _BOM && (flags & UTF8_SKIP_BOM) != 0)
continue;
if (*w < 0) {
if ((flags & UTF8_IGNORE_ERROR) == 0)
return (0);
continue;
} else if (*w <= 0x0000007f)
n = 1;
else if (*w <= 0x000007ff)
n = 2;
else if (*w <= 0x0000ffff)
n = 3;
else if (*w <= 0x001fffff)
n = 4;
else if (*w <= 0x03ffffff)
n = 5;
else /* if (*w <= 0x7fffffff) */
n = 6;
total += n;
if (out == NULL)
continue;
if (lim - p <= n - 1)
return (0); /* no space left */
/* make it work under different endians */
ch = htonl(*w);
oc = (u_char *)&ch;
switch (n) {
case 1:
*p = oc[3];
break;
case 2:
p[1] = _NXT | (oc[3] & 0x3f);
p[0] = _SEQ2 | (oc[3] >> 6) | ((oc[2] & 0x07) << 2);
break;
case 3:
p[2] = _NXT | (oc[3] & 0x3f);
p[1] = _NXT | (oc[3] >> 6) | ((oc[2] & 0x0f) << 2);
p[0] = _SEQ3 | ((oc[2] & 0xf0) >> 4);
break;
case 4:
p[3] = _NXT | (oc[3] & 0x3f);
p[2] = _NXT | (oc[3] >> 6) | ((oc[2] & 0x0f) << 2);
p[1] = _NXT | ((oc[2] & 0xf0) >> 4) |
((oc[1] & 0x03) << 4);
p[0] = _SEQ4 | ((oc[1] & 0x1f) >> 2);
break;
case 5:
p[4] = _NXT | (oc[3] & 0x3f);
p[3] = _NXT | (oc[3] >> 6) | ((oc[2] & 0x0f) << 2);
p[2] = _NXT | ((oc[2] & 0xf0) >> 4) |
((oc[1] & 0x03) << 4);
p[1] = _NXT | (oc[1] >> 2);
p[0] = _SEQ5 | (oc[0] & 0x03);
break;
case 6:
p[5] = _NXT | (oc[3] & 0x3f);
p[4] = _NXT | (oc[3] >> 6) | ((oc[2] & 0x0f) << 2);
p[3] = _NXT | (oc[2] >> 4) | ((oc[1] & 0x03) << 4);
p[2] = _NXT | (oc[1] >> 2);
p[1] = _NXT | (oc[0] & 0x3f);
p[0] = _SEQ6 | ((oc[0] & 0x40) >> 6);
break;
}
/*
* NOTE: do not check here for forbitten UTF-8 characters.
* They cannot appear here because we do proper convertion.
*/
p += n;
}
return (total);
}
#endif /* TLF_FONTS */

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