/*
* Copyright (C) 1999-2001, 2008 Free Software Foundation, Inc.
* This file is part of the GNU LIBICONV Library.
*
* The GNU LIBICONV Library is free software; you can redistribute it
* and/or modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* The GNU LIBICONV Library is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with the GNU LIBICONV Library; see the file COPYING.LIB.
* If not, write to the Free Software Foundation, Inc., 51 Franklin Street,
* Fifth Floor, Boston, MA 02110-1301, USA.
*/
/*
* UTF-7
*/
/* Specification: RFC 2152 (and old RFC 1641, RFC 1642) */
/* The original Base64 encoding is defined in RFC 2045. */
/* Set of direct characters:
* A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
*/
static const unsigned char direct_tab[128/8] = {
0x00, 0x26, 0x00, 0x00, 0x81, 0xf3, 0xff, 0x87,
0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07,
};
#define isdirect(ch) ((ch) < 128 && ((direct_tab[(ch)>>3] >> (ch & 7)) & 1))
/* Set of direct and optional direct characters:
* A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
* ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
*/
static const unsigned char xdirect_tab[128/8] = {
0x00, 0x26, 0x00, 0x00, 0xff, 0xf7, 0xff, 0xff,
0xff, 0xff, 0xff, 0xef, 0xff, 0xff, 0xff, 0x3f,
};
#define isxdirect(ch) ((ch) < 128 && ((xdirect_tab[(ch)>>3] >> (ch & 7)) & 1))
/* Set of base64 characters, extended:
* A-Z a-z 0-9 + / -
*/
static const unsigned char xbase64_tab[128/8] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0xa8, 0xff, 0x03,
0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07,
};
#define isxbase64(ch) ((ch) < 128 && ((xbase64_tab[(ch)>>3] >> (ch & 7)) & 1))
/*
* The state is structured as follows:
* bit 1..0: shift
* bit 7..2: data
* Precise meaning:
* shift data
* 0 0 not inside base64 encoding
* 1 0 inside base64, no pending bits
* 2 XXXX00 inside base64, 4 bits remain from 2nd byte
* 3 XX0000 inside base64, 2 bits remain from 3rd byte
*/
static int
utf7_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, int n)
{
state_t state = conv->istate;
int count = 0; /* number of input bytes already read */
if (state & 3)
goto active;
else
goto inactive;
inactive:
{
/* Here (state & 3) == 0 */
if (n < count+1)
goto none;
{
unsigned char c = *s;
if (isxdirect(c)) {
*pwc = (ucs4_t) c;
conv->istate = state;
return count+1;
}
if (c == '+') {
if (n < count+2)
goto none;
if (s[1] == '-') {
*pwc = (ucs4_t) '+';
conv->istate = state;
return count+2;
}
s++; count++;
state = 1;
goto active;
}
goto ilseq;
}
}
active:
{
/* base64 encoding active */
unsigned int wc = 0;
state_t base64state = state;
unsigned int kmax = 2; /* number of payload bytes to read */
unsigned int k = 0; /* number of payload bytes already read */
unsigned int base64count = 0; /* number of base64 bytes already read */
for (;;) {
unsigned char c = *s;
unsigned int i;
if (c >= 'A' && c <= 'Z')
i = c-'A';
else if (c >= 'a' && c <= 'z')
i = c-'a'+26;
else if (c >= '0' && c <= '9')
i = c-'0'+52;
else if (c == '+')
i = 62;
else if (c == '/')
i = 63;
else {
/* c terminates base64 encoding */
if (base64state & -4)
goto ilseq; /* data must be 0, otherwise illegal */
if (base64count)
goto ilseq; /* partial UTF-16 characters are invalid */
if (c == '-') {
s++; count++;
}
state = 0;
goto inactive;
}
s++; base64count++;
/* read 6 bits: 0 <= i < 64 */
switch (base64state & 3) {
case 1: /* inside base64, no pending bits */
base64state = (i << 2) | 0; break;
case 0: /* inside base64, 6 bits remain from 1st byte */
wc = (wc << 8) | (base64state & -4) | (i >> 4); k++;
base64state = ((i & 15) << 4) | 2; break;
case 2: /* inside base64, 4 bits remain from 2nd byte */
wc = (wc << 8) | (base64state & -4) | (i >> 2); k++;
base64state = ((i & 3) << 6) | 3; break;
case 3: /* inside base64, 2 bits remain from 3rd byte */
wc = (wc << 8) | (base64state & -4) | i; k++;
base64state = 1; break;
}
if (k == kmax) {
/* UTF-16: When we see a High Surrogate, we must also decode
the following Low Surrogate. */
if (kmax == 2 && (wc >= 0xd800 && wc < 0xdc00))
kmax = 4;
else
break;
}
if (n < count+base64count+1)
goto none;
}
/* Here k = kmax > 0, hence base64count > 0. */
if ((base64state & 3) == 0) abort();
if (kmax == 4) {
ucs4_t wc1 = wc >> 16;
ucs4_t wc2 = wc & 0xffff;
if (!(wc1 >= 0xd800 && wc1 < 0xdc00)) abort();
if (!(wc2 >= 0xdc00 && wc2 < 0xe000)) goto ilseq;
*pwc = 0x10000 + ((wc1 - 0xd800) << 10) + (wc2 - 0xdc00);
} else {
*pwc = wc;
}
conv->istate = base64state;
return count+base64count;
}
none:
conv->istate = state;
return RET_TOOFEW(count);
ilseq:
conv->istate = state;
return RET_SHIFT_ILSEQ(count);
}
/*
* The state is structured as follows:
* bit 1..0: shift
* bit 7..2: data
* Precise meaning:
* shift data
* 0 0 not inside base64 encoding
* 1 0 inside base64, no pending bits
* 2 XX00 inside base64, 2 bits known for 2nd byte
* 3 XXXX inside base64, 4 bits known for 3rd byte
*/
/* Define this to 1 if you want the so-called "optional direct" characters
! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
to be encoded. Define to 0 if you want them to be passed straight through,
like the so-called "direct" characters.
We set this to 1 because it's safer.
*/
#define UTF7_ENCODE_OPTIONAL_CHARS 1
static int
utf7_wctomb (conv_t conv, unsigned char *r, ucs4_t iwc, int n)
{
state_t state = conv->ostate;
unsigned int wc = iwc;
int count = 0;
if (state & 3)
goto active;
/*inactive:*/
{
if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect(wc) : isxdirect(wc)) {
r[0] = (unsigned char) wc;
/*conv->ostate = state;*/
return 1;
} else {
*r++ = '+';
if (wc == '+') {
if (n < 2)
return RET_TOOSMALL;
*r = '-';
/*conv->ostate = state;*/
return 2;
}
count = 1;
state = 1;
goto active;
}
}
active:
{
/* base64 encoding active */
if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect(wc) : isxdirect(wc)) {
/* deactivate base64 encoding */
count += ((state & 3) >= 2 ? 1 : 0) + (isxbase64(wc) ? 1 : 0) + 1;
if (n < count)
return RET_TOOSMALL;
if ((state & 3) >= 2) {
unsigned int i = state & -4;
unsigned char c;
if (i < 26)
c = i+'A';
else if (i < 52)
c = i-26+'a';
else if (i < 62)
c = i-52+'0';
else if (i == 62)
c = '+';
else if (i == 63)
c = '/';
else
abort();
*r++ = c;
}
if (isxbase64(wc))
*r++ = '-';
state = 0;
*r++ = (unsigned char) wc;
conv->ostate = state;
return count;
} else {
unsigned int k; /* number of payload bytes to write */
if (wc < 0x10000) {
k = 2;
count += ((state & 3) >= 2 ? 3 : 2);
} else if (wc < 0x110000) {
unsigned int wc1 = 0xd800 + ((wc - 0x10000) >> 10);
unsigned int wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
wc = (wc1 << 16) | wc2;
k = 4;
count += ((state & 3) >= 3 ? 6 : 5);
} else
return RET_ILUNI;
if (n < count)
return RET_TOOSMALL;
for (;;) {
unsigned int i;
unsigned char c;
switch (state & 3) {
case 0: /* inside base64, 6 bits known for 4th byte */
c = (state & -4) >> 2; state = 1; break;
case 1: /* inside base64, no pending bits */
i = (wc >> (8 * --k)) & 0xff;
c = i >> 2; state = ((i & 3) << 4) | 2; break;
case 2: /* inside base64, 2 bits known for 2nd byte */
i = (wc >> (8 * --k)) & 0xff;
c = (state & -4) | (i >> 4); state = ((i & 15) << 2) | 3; break;
case 3: /* inside base64, 4 bits known for 3rd byte */
i = (wc >> (8 * --k)) & 0xff;
c = (state & -4) | (i >> 6); state = ((i & 63) << 2) | 0; break;
default: abort(); /* stupid gcc */
}
if (c < 26)
c = c+'A';
else if (c < 52)
c = c-26+'a';
else if (c < 62)
c = c-52+'0';
else if (c == 62)
c = '+';
else if (c == 63)
c = '/';
else
abort();
*r++ = c;
if ((state & 3) && (k == 0))
break;
}
conv->ostate = state;
return count;
}
}
}
static int
utf7_reset (conv_t conv, unsigned char *r, int n)
{
state_t state = conv->ostate;
if (state & 3) {
/* deactivate base64 encoding */
unsigned int count = ((state & 3) >= 2 ? 1 : 0) + 1;
if (n < count)
return RET_TOOSMALL;
if ((state & 3) >= 2) {
unsigned int i = state & -4;
unsigned char c;
if (i < 26)
c = i+'A';
else if (i < 52)
c = i-26+'a';
else if (i < 62)
c = i-52+'0';
else if (i == 62)
c = '+';
else if (i == 63)
c = '/';
else
abort();
*r++ = c;
}
*r++ = '-';
/* conv->ostate = 0; will be done by the caller */
return count;
} else
return 0;
}
Submit an article or tip