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972baa3747
"UTF2" method. Although UTF-8 and the old UTF2 encoding are compatible for 16-bit characters, the new UTF-8 implementation is much more strict about rejecting malformed input and also handles the full 31 bit range of characters.
205 lines
5.0 KiB
C
205 lines
5.0 KiB
C
/*-
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* Copyright (c) 2002 Tim J. Robbins
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <rune.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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rune_t _UTF8_sgetrune(const char *, size_t, char const **);
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int _UTF8_sputrune(rune_t, char *, size_t, char **);
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int
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_UTF8_init(_RuneLocale *rl)
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{
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rl->sgetrune = _UTF8_sgetrune;
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rl->sputrune = _UTF8_sputrune;
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_CurrentRuneLocale = rl;
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__mb_cur_max = 6;
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return (0);
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}
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rune_t
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_UTF8_sgetrune(const char *string, size_t n, const char **result)
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{
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int ch, len, mask, siglen;
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rune_t lbound, wch;
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if (n < 1) {
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if (result != NULL)
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*result = string;
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return (_INVALID_RUNE);
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}
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/*
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* Determine the number of octets that make up this character from
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* the first octet, and a mask that extracts the interesting bits of
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* the first octet.
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*
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* We also specify a lower bound for the character code to detect
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* redundant, non-"shortest form" encodings. For example, the
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* sequence C0 80 is _not_ a legal representation of the null
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* character. This enforces a 1-to-1 mapping between character
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* codes and their multibyte representations.
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*/
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ch = (unsigned char)*string;
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if ((ch & 0x80) == 0) {
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mask = 0x7f;
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len = 1;
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lbound = 0;
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} else if ((ch & 0xe0) == 0xc0) {
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mask = 0x1f;
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len = 2;
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lbound = 0x80;
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} else if ((ch & 0xf0) == 0xe0) {
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mask = 0x0f;
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len = 3;
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lbound = 0x800;
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} else if ((ch & 0xf8) == 0xf0) {
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mask = 0x07;
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len = 4;
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lbound = 0x10000;
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} else if ((ch & 0xfc) == 0xf8) {
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mask = 0x03;
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len = 5;
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lbound = 0x200000;
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} else if ((ch & 0xfc) == 0xfc) {
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mask = 0x01;
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len = 6;
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lbound = 0x4000000;
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} else {
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/*
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* Malformed input; input is not UTF-8.
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*/
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if (result != NULL)
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*result = string + 1;
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return (_INVALID_RUNE);
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}
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if (n < len) {
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/*
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* Truncated or partial input.
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*/
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if (result != NULL)
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*result = string;
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return (_INVALID_RUNE);
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}
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/*
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* Decode the octet sequence representing the character in chunks
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* of 6 bits, most significant first.
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*/
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wch = (unsigned char)*string++ & mask;
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while (--len != 0) {
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if ((*string & 0xc0) != 0x80) {
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/*
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* Malformed input; bad characters in the middle
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* of a character.
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*/
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wch = _INVALID_RUNE;
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if (result != NULL)
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*result = string + 1;
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return (_INVALID_RUNE);
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}
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wch <<= 6;
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wch |= *string++ & 0x3f;
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}
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if (wch != _INVALID_RUNE && wch < lbound)
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/*
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* Malformed input; redundant encoding.
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*/
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wch = _INVALID_RUNE;
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if (result != NULL)
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*result = string;
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return (wch);
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}
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int
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_UTF8_sputrune(rune_t c, char *string, size_t n, char **result)
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{
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unsigned char lead;
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int i, len;
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/*
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* Determine the number of octets needed to represent this character.
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* We always output the shortest sequence possible. Also specify the
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* first few bits of the first octet, which contains the information
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* about the sequence length.
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*/
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if ((c & ~0x7f) == 0) {
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lead = 0;
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len = 1;
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} else if ((c & ~0x7ff) == 0) {
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lead = 0xc0;
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len = 2;
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} else if ((c & ~0xffff) == 0) {
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lead = 0xe0;
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len = 3;
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} else if ((c & ~0x1fffff) == 0) {
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lead = 0xf0;
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len = 4;
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} else if ((c & ~0x3ffffff) == 0) {
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lead = 0xf8;
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len = 5;
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} else if ((c & ~0x7fffffff) == 0) {
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lead = 0xfc;
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len = 6;
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} else {
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/*
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* Wide character code is out of range.
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*/
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if (result != NULL)
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*result = NULL;
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return (0);
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}
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if (n < len) {
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if (result != NULL)
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*result = NULL;
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} else {
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/*
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* Output the octets representing the character in chunks
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* of 6 bits, least significant last. The first octet is
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* a special case because it contains the sequence length
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* information.
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*/
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for (i = len - 1; i > 0; i--) {
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string[i] = (c & 0x3f) | 0x80;
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c >>= 6;
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}
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*string = (c & 0xff) | lead;
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if (result != NULL)
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*result = string + len;
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}
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return (len);
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}
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