From 7b30a5520cfb56e651f0eb4da85a3e07747da7dc Mon Sep 17 00:00:00 2001 From: John Mark Bell Date: Sat, 23 Jun 2007 22:40:25 +0000 Subject: Import hubbub -- an HTML parsing library. Plenty of work still to do (like tree generation ;) svn path=/trunk/hubbub/; revision=3359 --- src/charset/codec_utf8.c | 620 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 620 insertions(+) create mode 100644 src/charset/codec_utf8.c (limited to 'src/charset/codec_utf8.c') diff --git a/src/charset/codec_utf8.c b/src/charset/codec_utf8.c new file mode 100644 index 0000000..86d667f --- /dev/null +++ b/src/charset/codec_utf8.c @@ -0,0 +1,620 @@ +/* + * This file is part of Hubbub. + * Licensed under the MIT License, + * http://www.opensource.org/licenses/mit-license.php + * Copyright 2007 John-Mark Bell + */ + +#include +#include + +/* These two are for htonl / ntohl */ +#include +#include + +#include "charset/aliases.h" +#include "utils/utf8.h" +#include "utils/utils.h" + +#include "codec_impl.h" + +/** + * UTF-8 charset codec + */ +typedef struct hubbub_utf8_codec { + hubbub_charsetcodec base; /**< Base class */ + +#define INVAL_BUFSIZE (32) + uint8_t inval_buf[INVAL_BUFSIZE]; /**< Buffer for fixing up + * incomplete input + * sequences */ + size_t inval_len; /*< Byte length of inval_buf **/ + +#define READ_BUFSIZE (8) + uint32_t read_buf[READ_BUFSIZE]; /**< Buffer for partial + * output sequences (decode) + * (host-endian) */ + size_t read_len; /**< Character length of read_buf */ + +#define WRITE_BUFSIZE (8) + uint32_t write_buf[WRITE_BUFSIZE]; /**< Buffer for partial + * output sequences (encode) + * (host-endian) */ + size_t write_len; /**< Character length of write_buf */ + +} hubbub_utf8_codec; + +static bool hubbub_utf8_codec_handles_charset(const char *charset); +static hubbub_charsetcodec *hubbub_utf8_codec_create(const char *charset, + hubbub_alloc alloc, void *pw); +static void hubbub_utf8_codec_destroy (hubbub_charsetcodec *codec); +static hubbub_error hubbub_utf8_codec_encode(hubbub_charsetcodec *codec, + const uint8_t **source, size_t *sourcelen, + uint8_t **dest, size_t *destlen); +static hubbub_error hubbub_utf8_codec_decode(hubbub_charsetcodec *codec, + const uint8_t **source, size_t *sourcelen, + uint8_t **dest, size_t *destlen); +static hubbub_error hubbub_utf8_codec_reset(hubbub_charsetcodec *codec); +static hubbub_error hubbub_utf8_codec_read_char(hubbub_utf8_codec *c, + const uint8_t **source, size_t *sourcelen, + uint8_t **dest, size_t *destlen); +static hubbub_error hubbub_utf8_codec_filter_decoded_char( + hubbub_utf8_codec *c, + uint32_t ucs4, uint8_t **dest, size_t *destlen); + +/** + * Determine whether this codec handles a specific charset + * + * \param charset Charset to test + * \return true if handleable, false otherwise + */ +bool hubbub_utf8_codec_handles_charset(const char *charset) +{ + return hubbub_mibenum_from_name(charset, strlen(charset)) == + hubbub_mibenum_from_name("UTF-8", SLEN("UTF-8")); +} + +/** + * Create a utf8 codec + * + * \param charset The charset to read from / write to + * \param alloc Memory (de)allocation function + * \param pw Pointer to client-specific private data (may be NULL) + * \return Pointer to codec, or NULL on failure + */ +hubbub_charsetcodec *hubbub_utf8_codec_create(const char *charset, + hubbub_alloc alloc, void *pw) +{ + hubbub_utf8_codec *codec; + + UNUSED(charset); + + codec = alloc(NULL, sizeof(hubbub_utf8_codec), pw); + if (codec == NULL) + return NULL; + + codec->inval_buf[0] = '\0'; + codec->inval_len = 0; + + codec->read_buf[0] = 0; + codec->read_len = 0; + + codec->write_buf[0] = 0; + codec->write_len = 0; + + /* Finally, populate vtable */ + codec->base.handler.destroy = hubbub_utf8_codec_destroy; + codec->base.handler.encode = hubbub_utf8_codec_encode; + codec->base.handler.decode = hubbub_utf8_codec_decode; + codec->base.handler.reset = hubbub_utf8_codec_reset; + + return (hubbub_charsetcodec *) codec; +} + +/** + * Destroy a utf8 codec + * + * \param codec The codec to destroy + */ +void hubbub_utf8_codec_destroy (hubbub_charsetcodec *codec) +{ + UNUSED(codec); +} + +/** + * Encode a chunk of UCS4 data into utf8 + * + * \param codec The codec to use + * \param source Pointer to pointer to source data + * \param sourcelen Pointer to length (in bytes) of source data + * \param dest Pointer to pointer to output buffer + * \param destlen Pointer to length (in bytes) of output buffer + * \return HUBBUB_OK on success, + * HUBBUB_NOMEM if output buffer is too small, + * HUBBUB_INVALID if a character cannot be represented and the + * codec's error handling mode is set to STRICT, + * as a result of the failure of the + * client-provided filter function. + * + * On exit, ::source will point immediately _after_ the last input character + * read. Any remaining output for the character will be buffered by the + * codec for writing on the next call. This buffered data is post-filtering, + * so will not be refiltered on the next call. + * + * In the case of the filter function failing, ::source will point _at_ the + * last input character read; nothing will be written or buffered for the + * failed character. It is up to the client to fix the cause of the failure + * and retry the encoding process. + * + * Note that, if failure occurs whilst attempting to write any output + * buffered by the last call, then ::source and ::sourcelen will remain + * unchanged (as nothing more has been read). + * + * There is no way to determine the output character which caused a + * failure (as it may be one in a filter-injected replacement sequence). + * It is, however, possible to determine which source character caused it + * (this being the character immediately before the location pointed to by + * ::source on exit). + * + * [I.e. the process of filtering results in a potential one-to-many mapping + * between source characters and output characters, and identification of + * individual output characters is impossible.] + * + * ::sourcelen will be reduced appropriately on exit. + * + * ::dest will point immediately _after_ the last character written. + * + * ::destlen will be reduced appropriately on exit. + */ +hubbub_error hubbub_utf8_codec_encode(hubbub_charsetcodec *codec, + const uint8_t **source, size_t *sourcelen, + uint8_t **dest, size_t *destlen) +{ + hubbub_utf8_codec *c = (hubbub_utf8_codec *) codec; + uint32_t ucs4; + uint32_t *towrite; + size_t towritelen; + hubbub_error error; + + /* Process any outstanding characters from the previous call */ + if (c->write_len > 0) { + uint32_t *pwrite = c->write_buf; + uint8_t buf[6]; + size_t len; + + while (c->write_len > 0) { + error = hubbub_utf8_from_ucs4(pwrite[0], buf, &len); + if (error != HUBBUB_OK) + abort(); + + if (*destlen < len) { + /* Insufficient output buffer space */ + for (len = 0; len < c->write_len; len++) + c->write_buf[len] = pwrite[len]; + + return HUBBUB_NOMEM; + } + + memcpy(*dest, buf, len); + + *dest += len; + *destlen -= len; + + pwrite++; + c->write_len--; + } + } + + /* Now process the characters for this call */ + while (*sourcelen > 0) { + ucs4 = ntohl(*((uint32_t *) (void *) *source)); + towrite = &ucs4; + towritelen = 1; + + /* Run character we're about to output through the + * registered filter, so it can replace it. */ + if (c->base.filter != NULL) { + error = c->base.filter(ucs4, + &towrite, &towritelen, + c->base.filter_pw); + if (error != HUBBUB_OK) + return error; + } + + /* Output current characters */ + while (towritelen > 0) { + uint8_t buf[6]; + size_t len; + + error = hubbub_utf8_from_ucs4(towrite[0], buf, &len); + if (error != HUBBUB_OK) + abort(); + + if (*destlen < len) { + /* Insufficient output space */ + if (towritelen >= WRITE_BUFSIZE) + abort(); + + c->write_len = towritelen; + + /* Copy pending chars to save area, for + * processing next call. */ + for (len = 0; len < towritelen; len++) + c->write_buf[len] = towrite[len]; + + /* Claim character we've just buffered, + * so it's not reprocessed */ + *source += 4; + *sourcelen -= 4; + + return HUBBUB_NOMEM; + } + + memcpy(*dest, buf, len); + + *dest += len; + *destlen -= len; + + towrite++; + towritelen--; + } + + *source += 4; + *sourcelen -= 4; + } + + return HUBBUB_OK; +} + +/** + * Decode a chunk of utf8 data into UCS4 + * + * \param codec The codec to use + * \param source Pointer to pointer to source data + * \param sourcelen Pointer to length (in bytes) of source data + * \param dest Pointer to pointer to output buffer + * \param destlen Pointer to length (in bytes) of output buffer + * \return HUBBUB_OK on success, + * HUBBUB_NOMEM if output buffer is too small, + * HUBBUB_INVALID if a character cannot be represented and the + * codec's error handling mode is set to STRICT, + * as a result of the failure of the + * client-provided filter function. + * + * On exit, ::source will point immediately _after_ the last input character + * read, if the result is _OK or _NOMEM. Any remaining output for the + * character will be buffered by the codec for writing on the next call. + * This buffered data is post-filtering, so will not be refiltered on the + * next call. + * + * In the case of the result being _INVALID or the filter function failing, + * ::source will point _at_ the last input character read; nothing will be + * written or buffered for the failed character. It is up to the client to + * fix the cause of the failure and retry the decoding process. + * + * Note that, if failure occurs whilst attempting to write any output + * buffered by the last call, then ::source and ::sourcelen will remain + * unchanged (as nothing more has been read). + * + * There is no way to determine the output character which caused a + * failure (as it may be one in a filter-injected replacement sequence). + * It is, however, possible to determine which source character caused it + * (this being the character immediately at or before the location pointed + * to by ::source on exit). + * + * [I.e. the process of filtering results in a potential one-to-many mapping + * between source characters and output characters, and identification of + * individual output characters is impossible.] + * + * If STRICT error handling is configured and an illegal sequence is split + * over two calls, then _INVALID will be returned from the second call, + * but ::source will point mid-way through the invalid sequence (i.e. it + * will be unmodified over the second call). In addition, the internal + * incomplete-sequence buffer will be emptied, such that subsequent calls + * will progress, rather than re-evaluating the same invalid sequence. + * + * ::sourcelen will be reduced appropriately on exit. + * + * ::dest will point immediately _after_ the last character written. + * + * ::destlen will be reduced appropriately on exit. + * + * Call this with a source length of 0 to flush the output buffer. + */ +hubbub_error hubbub_utf8_codec_decode(hubbub_charsetcodec *codec, + const uint8_t **source, size_t *sourcelen, + uint8_t **dest, size_t *destlen) +{ + hubbub_utf8_codec *c = (hubbub_utf8_codec *) codec; + hubbub_error error; + + if (c->read_len > 0) { + /* Output left over from last decode */ + uint32_t *pread = c->read_buf; + + while (c->read_len > 0 && *destlen >= c->read_len * 4) { + *((uint32_t *) (void *) *dest) = htonl(pread[0]); + + *dest += 4; + *destlen -= 4; + + pread++; + c->read_len--; + } + + if (*destlen < c->read_len * 4) { + /* Ran out of output buffer */ + size_t i; + + /* Shuffle remaining output down */ + for (i = 0; i < c->read_len; i++) + c->read_buf[i] = pread[i]; + + return HUBBUB_NOMEM; + } + } + + if (c->inval_len > 0) { + /* The last decode ended in an incomplete sequence. + * Fill up inval_buf with data from the start of the + * new chunk and process it. */ + uint8_t *in = c->inval_buf; + size_t ol = c->inval_len; + size_t l = min(INVAL_BUFSIZE - ol - 1, *sourcelen); + size_t orig_l = l; + + memcpy(c->inval_buf + ol, *source, l); + + l += c->inval_len; + + error = hubbub_utf8_codec_read_char(c, + (const uint8_t **) &in, &l, dest, destlen); + if (error != HUBBUB_OK && error != HUBBUB_NOMEM) { + return error; + } + + /* And now, fix up source pointers */ + *source += max((signed) (orig_l - l), 0); + *sourcelen -= max((signed) (orig_l - l), 0); + + /* Failed to resolve an incomplete character and + * ran out of buffer space. No recovery strategy + * possible, so explode everywhere. */ + if ((orig_l + ol) - l == 0) + abort(); + + /* Report memory exhaustion case from above */ + if (error != HUBBUB_OK) + return error; + } + + /* Finally, the "normal" case; process all outstanding characters */ + while (*sourcelen > 0) { + error = hubbub_utf8_codec_read_char(c, + source, sourcelen, dest, destlen); + if (error != HUBBUB_OK) { + return error; + } + } + + return HUBBUB_OK; +} + +/** + * Clear a utf8 codec's encoding state + * + * \param codec The codec to reset + * \return HUBBUB_OK on success, appropriate error otherwise + */ +hubbub_error hubbub_utf8_codec_reset(hubbub_charsetcodec *codec) +{ + hubbub_utf8_codec *c = (hubbub_utf8_codec *) codec; + + c->inval_buf[0] = '\0'; + c->inval_len = 0; + + c->read_buf[0] = 0; + c->read_len = 0; + + c->write_buf[0] = 0; + c->write_len = 0; + + return HUBBUB_OK; +} + + +/** + * Read a character from the UTF-8 to UCS4 (big endian) + * + * \param c The codec + * \param source Pointer to pointer to source buffer (updated on exit) + * \param sourcelen Pointer to length of source buffer (updated on exit) + * \param dest Pointer to pointer to output buffer (updated on exit) + * \param destlen Pointer to length of output buffer (updated on exit) + * \return HUBBUB_OK on success, + * HUBBUB_NOMEM if output buffer is too small, + * HUBBUB_INVALID if a character cannot be represented and the + * codec's error handling mode is set to STRICT, + * as a result of the failure of the + * client-provided filter function. + * + * On exit, ::source will point immediately _after_ the last input character + * read, if the result is _OK or _NOMEM. Any remaining output for the + * character will be buffered by the codec for writing on the next call. + * This buffered data is post-filtering, so will not be refiltered on the + * next call. + * + * In the case of the result being _INVALID or the filter function failing, + * ::source will point _at_ the last input character read; nothing will be + * written or buffered for the failed character. It is up to the client to + * fix the cause of the failure and retry the decoding process. + * + * ::sourcelen will be reduced appropriately on exit. + * + * ::dest will point immediately _after_ the last character written. + * + * ::destlen will be reduced appropriately on exit. + */ +hubbub_error hubbub_utf8_codec_read_char(hubbub_utf8_codec *c, + const uint8_t **source, size_t *sourcelen, + uint8_t **dest, size_t *destlen) +{ + uint32_t ucs4; + size_t sucs4; + hubbub_error error; + + /* Convert a single character */ + error = hubbub_utf8_to_ucs4(*source, *sourcelen, &ucs4, &sucs4); + if (error == HUBBUB_OK) { + /* Read a character */ + error = hubbub_utf8_codec_filter_decoded_char(c, + ucs4, dest, destlen); + if (error == HUBBUB_OK || error == HUBBUB_NOMEM) { + /* filter function succeeded; update source pointers */ + *source += sucs4; + *sourcelen -= sucs4; + } + + /* Clear inval buffer */ + c->inval_buf[0] = '\0'; + c->inval_len = 0; + + return error; + } else if (error == HUBBUB_NEEDDATA) { + /* Incomplete input sequence */ + if (*sourcelen > INVAL_BUFSIZE) + abort(); + + memmove(c->inval_buf, (char *) *source, *sourcelen); + c->inval_buf[*sourcelen] = '\0'; + c->inval_len = *sourcelen; + + *source += *sourcelen; + *sourcelen = 0; + + return HUBBUB_OK; + } else if (error == HUBBUB_INVALID) { + /* Illegal input sequence */ + uint32_t nextchar; + + /* Clear inval buffer */ + c->inval_buf[0] = '\0'; + c->inval_len = 0; + + /* Strict errormode; simply flag invalid character */ + if (c->base.errormode == HUBBUB_CHARSETCODEC_ERROR_STRICT) { + return HUBBUB_INVALID; + } + + /* Find next valid UTF-8 sequence. + * We're processing client-provided data, so let's + * be paranoid about its validity. */ + error = hubbub_utf8_next_paranoid(*source, *sourcelen, + 0, &nextchar); + if (error != HUBBUB_OK) { + if (error == HUBBUB_NEEDDATA) { + /* Need more data to be sure */ + if (*sourcelen > INVAL_BUFSIZE) + abort(); + + memmove(c->inval_buf, (char *) *source, + *sourcelen); + c->inval_buf[*sourcelen] = '\0'; + c->inval_len = *sourcelen; + + *source += *sourcelen; + *sourcelen = 0; + + nextchar = 0; + } else { + return error; + } + } + + /* output U+FFFD and continue processing. */ + error = hubbub_utf8_codec_filter_decoded_char(c, + 0xFFFD, dest, destlen); + if (error == HUBBUB_OK || error == HUBBUB_NOMEM) { + /* filter function succeeded; update source pointers */ + *source += nextchar; + *sourcelen -= nextchar; + } + + return error; + } + + return HUBBUB_OK; +} + +/** + * Feed a UCS4 character through the registered filter and output the result + * + * \param c Codec to use + * \param ucs4 UCS4 character (host endian) + * \param dest Pointer to pointer to output buffer + * \param destlen Pointer to output buffer length + * \return HUBBUB_OK on success, + * HUBBUB_NOMEM if output buffer is too small, + * as a result of the failure of the + * client-provided filter function. + */ +hubbub_error hubbub_utf8_codec_filter_decoded_char(hubbub_utf8_codec *c, + uint32_t ucs4, uint8_t **dest, size_t *destlen) +{ + if (c->base.filter != NULL) { + uint32_t *rep; + size_t replen; + hubbub_error error; + + error = c->base.filter(ucs4, &rep, &replen, + c->base.filter_pw); + if (error != HUBBUB_OK) { + return error; + } + + while (replen > 0 && *destlen >= replen * 4) { + *((uint32_t *) (void *) *dest) = htonl(*rep); + + *dest += 4; + *destlen -= 4; + + rep++; + replen--; + } + + if (*destlen < replen * 4) { + /* Run out of output buffer */ + size_t i; + + /* Buffer remaining output */ + c->read_len = replen; + + for (i = 0; i < replen; i++) { + c->read_buf[i] = rep[i]; + } + + return HUBBUB_NOMEM; + } + + } else { + if (*destlen < 4) { + /* Run out of output buffer */ + c->read_len = 1; + c->read_buf[0] = ucs4; + + return HUBBUB_NOMEM; + } + + *((uint32_t *) (void *) *dest) = htonl(ucs4); + *dest += 4; + *destlen -= 4; + } + + return HUBBUB_OK; +} + + +const hubbub_charsethandler hubbub_utf8_codec_handler = { + hubbub_utf8_codec_handles_charset, + hubbub_utf8_codec_create +}; -- cgit v1.2.3