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thodg/libiconv/lib/utf7.h
Bruno Haible
- lib/utf7.h
-
/* * Copyright (C) 1999-2001, 2008, 2016 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, see <http://www.gnu.org/licenses/>. */ /* * 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, size_t 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, size_t 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, size_t 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; }