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Diffstat (limited to 'src/charset/encodings/utf8impl.h')
-rw-r--r-- | src/charset/encodings/utf8impl.h | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/src/charset/encodings/utf8impl.h b/src/charset/encodings/utf8impl.h new file mode 100644 index 0000000..1ca9de7 --- /dev/null +++ b/src/charset/encodings/utf8impl.h @@ -0,0 +1,339 @@ +/* + * This file is part of LibParserUtils. + * Licensed under the MIT License, + * http://www.opensource.org/licenses/mit-license.php + * Copyright 2007 John-Mark Bell <jmb@netsurf-browser.org> + */ + +#ifndef parserutils_charset_encodings_utf8impl_h_ +#define parserutils_charset_encodings_utf8impl_h_ + +/** \file + * UTF-8 manipulation macros (implementation). + */ + +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> + +/** Number of continuation bytes for a given start byte */ +extern const uint8_t numContinuations[256]; + +/** + * Convert a UTF-8 multibyte sequence into a single UCS4 character + * + * Encoding of UCS values outside the UTF-16 plane has been removed from + * RFC3629. This macro conforms to RFC2279, however. + * + * \param s The sequence to process + * \param len Length of sequence + * \param ucs4 Pointer to location to receive UCS4 character (host endian) + * \param clen Pointer to location to receive byte length of UTF-8 sequence + * \param error Location to receive error code + */ +#define UTF8_TO_UCS4(s, len, ucs4, clen, error) \ +do { \ + uint32_t c, min; \ + uint8_t n; \ + \ + error = PARSERUTILS_OK; \ + \ + if (s == NULL || ucs4 == NULL || clen == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + if (len == 0) { \ + error = PARSERUTILS_NEEDDATA; \ + break; \ + } \ + \ + c = s[0]; \ + \ + if (c < 0x80) { \ + n = 1; \ + min = 0; \ + } else if ((c & 0xE0) == 0xC0) { \ + c &= 0x1F; \ + n = 2; \ + min = 0x80; \ + } else if ((c & 0xF0) == 0xE0) { \ + c &= 0x0F; \ + n = 3; \ + min = 0x800; \ + } else if ((c & 0xF8) == 0xF0) { \ + c &= 0x07; \ + n = 4; \ + min = 0x10000; \ + } else if ((c & 0xFC) == 0xF8) { \ + c &= 0x03; \ + n = 5; \ + min = 0x200000; \ + } else if ((c & 0xFE) == 0xFC) { \ + c &= 0x01; \ + n = 6; \ + min = 0x4000000; \ + } else { \ + error = PARSERUTILS_INVALID; \ + break; \ + } \ + \ + if (len < n) { \ + error = PARSERUTILS_NEEDDATA; \ + break; \ + } \ + \ + for (uint8_t i = 1; i < n; i++) { \ + uint32_t t = s[i]; \ + \ + if ((t & 0xC0) != 0x80) { \ + error = PARSERUTILS_INVALID; \ + break; \ + } \ + \ + c <<= 6; \ + c |= t & 0x3F; \ + } \ + \ + if (error == PARSERUTILS_OK) { \ + /* Detect overlong sequences, surrogates and fffe/ffff */ \ + if (c < min || (c >= 0xD800 && c <= 0xDFFF) || \ + c == 0xFFFE || c == 0xFFFF) { \ + error = PARSERUTILS_INVALID; \ + break; \ + } \ + \ + *ucs4 = c; \ + *clen = n; \ + } \ +} while(0) + +/** + * Convert a single UCS4 character into a UTF-8 multibyte sequence + * + * Encoding of UCS values outside the UTF-16 plane has been removed from + * RFC3629. This macro conforms to RFC2279, however. + * + * \param ucs4 The character to process (0 <= c <= 0x7FFFFFFF) (host endian) + * \param s Pointer to pointer to output buffer, updated on exit + * \param len Pointer to length, in bytes, of output buffer, updated on exit + * \param error Location to receive error code + */ +#define UTF8_FROM_UCS4(ucs4, s, len, error) \ +do { \ + uint8_t *buf; \ + uint8_t l = 0; \ + \ + error = PARSERUTILS_OK; \ + \ + if (s == NULL || *s == NULL || len == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + if (ucs4 < 0x80) { \ + l = 1; \ + } else if (ucs4 < 0x800) { \ + l = 2; \ + } else if (ucs4 < 0x10000) { \ + l = 3; \ + } else if (ucs4 < 0x200000) { \ + l = 4; \ + } else if (ucs4 < 0x4000000) { \ + l = 5; \ + } else if (ucs4 <= 0x7FFFFFFF) { \ + l = 6; \ + } else { \ + error = PARSERUTILS_INVALID; \ + break; \ + } \ + \ + if (l > *len) { \ + error = PARSERUTILS_NOMEM; \ + break; \ + } \ + \ + buf = *s; \ + \ + if (l == 1) { \ + buf[0] = (uint8_t) ucs4; \ + } else { \ + for (uint8_t i = l; i > 1; i--) { \ + buf[i - 1] = 0x80 | (ucs4 & 0x3F); \ + ucs4 >>= 6; \ + } \ + buf[0] = ~((1 << (8 - l)) - 1) | ucs4; \ + } \ + \ + *s += l; \ + *len -= l; \ +} while(0) + +/** + * Calculate the length (in characters) of a bounded UTF-8 string + * + * \param s The string + * \param max Maximum length + * \param len Pointer to location to receive length of string + * \param error Location to receive error code + */ +#define UTF8_LENGTH(s, max, len, error) \ +do { \ + const uint8_t *end = s + max; \ + int l = 0; \ + \ + error = PARSERUTILS_OK; \ + \ + if (s == NULL || len == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + while (s < end) { \ + uint32_t c = s[0]; \ + \ + if ((c & 0x80) == 0x00) \ + s += 1; \ + else if ((c & 0xE0) == 0xC0) \ + s += 2; \ + else if ((c & 0xF0) == 0xE0) \ + s += 3; \ + else if ((c & 0xF8) == 0xF0) \ + s += 4; \ + else if ((c & 0xFC) == 0xF8) \ + s += 5; \ + else if ((c & 0xFE) == 0xFC) \ + s += 6; \ + else { \ + error = PARSERUTILS_INVALID; \ + break; \ + } \ + \ + l++; \ + } \ + \ + if (error == PARSERUTILS_OK) \ + *len = l; \ +} while(0) + +/** + * Calculate the length (in bytes) of a UTF-8 character + * + * \param s Pointer to start of character + * \param len Pointer to location to receive length + * \param error Location to receive error code + */ +#define UTF8_CHAR_BYTE_LENGTH(s, len, error) \ +do { \ + if (s == NULL || len == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + *len = numContinuations[s[0]] + 1 /* Start byte */; \ + \ + error = PARSERUTILS_OK; \ +} while(0) + +/** + * Find previous legal UTF-8 char in string + * + * \param s The string + * \param off Offset in the string to start at + * \param prevoff Pointer to location to receive offset of first byte of + * previous legal character + * \param error Location to receive error code + */ +#define UTF8_PREV(s, off, prevoff, error) \ +do { \ + if (s == NULL || prevoff == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + while (off != 0 && (s[--off] & 0xC0) == 0x80) \ + /* do nothing */; \ + \ + *prevoff = off; \ + \ + error = PARSERUTILS_OK; \ +} while(0) + +/** + * Find next legal UTF-8 char in string + * + * \param s The string (assumed valid) + * \param len Maximum offset in string + * \param off Offset in the string to start at + * \param nextoff Pointer to location to receive offset of first byte of + * next legal character + * \param error Location to receive error code + */ +#define UTF8_NEXT(s, len, off, nextoff, error) \ +do { \ + if (s == NULL || off >= len || nextoff == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + /* Skip current start byte (if present - may be mid-sequence) */\ + if (s[off] < 0x80 || (s[off] & 0xC0) == 0xC0) \ + off++; \ + \ + while (off < len && (s[off] & 0xC0) == 0x80) \ + off++; \ + \ + *nextoff = off; \ + \ + error = PARSERUTILS_OK; \ +} while(0) + +/** + * Skip to start of next sequence in UTF-8 input + * + * \param s The string (assumed to be of dubious validity) + * \param len Maximum offset in string + * \param off Offset in the string to start at + * \param nextoff Pointer to location to receive offset of first byte of + * next legal character + * \param error Location to receive error code + */ +#define UTF8_NEXT_PARANOID(s, len, off, nextoff, error) \ +do { \ + uint8_t c; \ + \ + error = PARSERUTILS_OK; \ + \ + if (s == NULL || off >= len || nextoff == NULL) { \ + error = PARSERUTILS_BADPARM; \ + break; \ + } \ + \ + c = s[off]; \ + \ + /* If we're mid-sequence, simply advance to next byte */ \ + if (!(c < 0x80 || (c & 0xC0) == 0xC0)) { \ + off++; \ + } else { \ + uint32_t nCont = numContinuations[c]; \ + uint32_t nToSkip; \ + \ + if (off + nCont + 1 >= len) { \ + error = PARSERUTILS_NEEDDATA; \ + break; \ + } \ + \ + /* Verify continuation bytes */ \ + for (nToSkip = 1; nToSkip <= nCont; nToSkip++) { \ + if ((s[off + nToSkip] & 0xC0) != 0x80) \ + break; \ + } \ + \ + /* Skip over the valid bytes */ \ + off += nToSkip; \ + } \ + \ + *nextoff = off; \ +} while(0) + +#endif |