/*
* This file is part of LibParserUtils.
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
* Copyright 2008 John-Mark Bell <jmb@netsurf-browser.org>
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <parserutils/charset/mibenum.h>
#include "charset/codecs/codec_impl.h"
#include "utils/endian.h"
#include "utils/utils.h"
/**
* US-ASCII charset codec
*/
typedef struct charset_ascii_codec {
parserutils_charset_codec base; /**< Base class */
#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 */
} charset_ascii_codec;
static bool charset_ascii_codec_handles_charset(const char *charset);
static parserutils_error charset_ascii_codec_create(
const char *charset, parserutils_alloc alloc, void *pw,
parserutils_charset_codec **codec);
static parserutils_error charset_ascii_codec_destroy(
parserutils_charset_codec *codec);
static parserutils_error charset_ascii_codec_encode(
parserutils_charset_codec *codec,
const uint8_t **source, size_t *sourcelen,
uint8_t **dest, size_t *destlen);
static parserutils_error charset_ascii_codec_decode(
parserutils_charset_codec *codec,
const uint8_t **source, size_t *sourcelen,
uint8_t **dest, size_t *destlen);
static parserutils_error charset_ascii_codec_reset(
parserutils_charset_codec *codec);
static inline parserutils_error charset_ascii_codec_read_char(
charset_ascii_codec *c,
const uint8_t **source, size_t *sourcelen,
uint8_t **dest, size_t *destlen);
static inline parserutils_error charset_ascii_codec_output_decoded_char(
charset_ascii_codec *c,
uint32_t ucs4, uint8_t **dest, size_t *destlen);
static inline parserutils_error charset_ascii_from_ucs4(charset_ascii_codec *c,
uint32_t ucs4, uint8_t **s, size_t *len);
static inline parserutils_error charset_ascii_to_ucs4(charset_ascii_codec *c,
const uint8_t *s, size_t len, uint32_t *ucs4);
/**
* Determine whether this codec handles a specific charset
*
* \param charset Charset to test
* \return true if handleable, false otherwise
*/
bool charset_ascii_codec_handles_charset(const char *charset)
{
static uint16_t ascii;
uint16_t match = parserutils_charset_mibenum_from_name(charset,
if (ascii == 0) {
ascii = parserutils_charset_mibenum_from_name(
"US-ASCII", SLEN("US-ASCII"));
}
if (ascii != 0 && ascii == match)
return true;
return false;
}
/**
* Create a US-ASCII 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)
* \param codec Pointer to location to receive codec
* \return PARSERUTILS_OK on success,
* PARSERUTILS_BADPARM on bad parameters,
* PARSERUTILS_NOMEM on memory exhausion
*/
parserutils_error charset_ascii_codec_create(const char *charset,
parserutils_alloc alloc, void *pw,
parserutils_charset_codec **codec)
{
charset_ascii_codec *c;
UNUSED(charset);
c = alloc(NULL, sizeof(charset_ascii_codec), pw);
if (c == NULL)
return PARSERUTILS_NOMEM;
c->read_buf[0] = 0;
c->read_len = 0;
c->write_buf[0] = 0;
c->write_len = 0;
/* Finally, populate vtable */
c->base.handler.destroy = charset_ascii_codec_destroy;
c->base.handler.encode = charset_ascii_codec_encode;
c->base.handler.decode = charset_ascii_codec_decode;
c->base.handler.reset = charset_ascii_codec_reset;
*codec = (parserutils_charset_codec *) c;
return PARSERUTILS_OK;
}
/**
* Destroy a US-ASCII codec
*
* \param codec The codec to destroy
* \return PARSERUTILS_OK on success, appropriate error otherwise
*/
parserutils_error charset_ascii_codec_destroy (parserutils_charset_codec *codec)
{
UNUSED(codec);
return PARSERUTILS_OK;
}
/**
* Encode a chunk of UCS-4 (big endian) data into US-ASCII
*
* \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 PARSERUTILS_OK on success,
* PARSERUTILS_NOMEM if output buffer is too small,
* PARSERUTILS_INVALID if a character cannot be represented and the
* codec's error handling mode is set to STRICT,
*
* 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.
*
* 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).
*
* ::sourcelen will be reduced appropriately on exit.
*
* ::dest will point immediately _after_ the last character written.
*
* ::destlen will be reduced appropriately on exit.
*/
parserutils_error charset_ascii_codec_encode(parserutils_charset_codec *codec,
const uint8_t **source, size_t *sourcelen,
uint8_t **dest, size_t *destlen)
{
charset_ascii_codec *c = (charset_ascii_codec *) codec;
uint32_t ucs4;
uint32_t *towrite;
size_t towritelen;
parserutils_error error;
/* Process any outstanding characters from the previous call */
if (c->write_len > 0) {
uint32_t *pwrite = c->write_buf;
while (c->write_len > 0) {
error = charset_ascii_from_ucs4(c, pwrite[0],
dest, destlen);
if (error != PARSERUTILS_OK) {
uint32_t len;
assert(error
== PARSERUTILS_NOMEM
);
for (len = 0; len < c->write_len; len++) {
c->write_buf[len] = pwrite[len];
}
return error;
}
pwrite++;
c->write_len--;
}
}
/* Now process the characters for this call */
while (*sourcelen > 0) {
ucs4 = endian_big_to_host(*((uint32_t *) (void *) *source));
towrite = &ucs4;
towritelen = 1;
/* Output current characters */
while (towritelen > 0) {
error = charset_ascii_from_ucs4(c, towrite[0], dest,
destlen);
if (error != PARSERUTILS_OK) {
uint32_t len;
if (error != PARSERUTILS_NOMEM) {
return error;
}
/* Insufficient output space */
if (towritelen >= WRITE_BUFSIZE)
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 PARSERUTILS_NOMEM;
}
towrite++;
towritelen--;
}
*source += 4;
*sourcelen -= 4;
}
return PARSERUTILS_OK;
}
/**
* Decode a chunk of US-ASCII data into UCS-4 (big endian)
*
* \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 PARSERUTILS_OK on success,
* PARSERUTILS_NOMEM if output buffer is too small,
* PARSERUTILS_INVALID if a character cannot be represented and the
* codec's error handling mode is set to STRICT,
*
* 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.
*
* In the case of the result being _INVALID, ::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).
*
* 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.
*/
parserutils_error charset_ascii_codec_decode(parserutils_charset_codec *codec,
const uint8_t **source, size_t *sourcelen,
uint8_t **dest, size_t *destlen)
{
charset_ascii_codec *c = (charset_ascii_codec *) codec;
parserutils_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) =
endian_host_to_big(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 PARSERUTILS_NOMEM;
}
}
/* Finally, the "normal" case; process all outstanding characters */
while (*sourcelen > 0) {
error = charset_ascii_codec_read_char(c,
source, sourcelen, dest, destlen);
if (error != PARSERUTILS_OK) {
return error;
}
}
return PARSERUTILS_OK;
}
/**
* Clear a US-ASCII codec's encoding state
*
* \param codec The codec to reset
* \return PARSERUTILS_OK on success, appropriate error otherwise
*/
parserutils_error charset_ascii_codec_reset(parserutils_charset_codec *codec)
{
charset_ascii_codec *c = (charset_ascii_codec *) codec;
c->read_buf[0] = 0;
c->read_len = 0;
c->write_buf[0] = 0;
c->write_len = 0;
return PARSERUTILS_OK;
}
/**
* Read a character from US-ASCII to UCS-4 (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 PARSERUTILS_OK on success,
* PARSERUTILS_NOMEM if output buffer is too small,
* PARSERUTILS_INVALID if a character cannot be represented and the
* codec's error handling mode is set to STRICT,
*
* 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.
*
* In the case of the result being _INVALID, ::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.
*/
parserutils_error charset_ascii_codec_read_char(charset_ascii_codec *c,
const uint8_t **source, size_t *sourcelen,
uint8_t **dest, size_t *destlen)
{
uint32_t ucs4;
parserutils_error error;
/* Convert a single character */
error = charset_ascii_to_ucs4(c, *source, *sourcelen, &ucs4);
if (error == PARSERUTILS_OK) {
/* Read a character */
error = charset_ascii_codec_output_decoded_char(c,
ucs4, dest, destlen);
if (error == PARSERUTILS_OK || error == PARSERUTILS_NOMEM) {
/* output succeeded; update source pointers */
*source += 1;
*sourcelen -= 1;
}
return error;
} else if (error == PARSERUTILS_NEEDDATA) {
/* Can only happen if sourcelen == 0 */
return error;
} else if (error == PARSERUTILS_INVALID) {
/* Illegal input sequence */
/* Strict errormode; simply flag invalid character */
if (c->base.errormode ==
PARSERUTILS_CHARSET_CODEC_ERROR_STRICT) {
return PARSERUTILS_INVALID;
}
/* output U+FFFD and continue processing. */
error = charset_ascii_codec_output_decoded_char(c,
0xFFFD, dest, destlen);
if (error == PARSERUTILS_OK || error == PARSERUTILS_NOMEM) {
/* output succeeded; update source pointers */
*source += 1;
*sourcelen -= 1;
}
return error;
}
return PARSERUTILS_OK;
}
/**
* Output a UCS-4 character (big endian)
*
* \param c Codec to use
* \param ucs4 UCS-4 character (host endian)
* \param dest Pointer to pointer to output buffer
* \param destlen Pointer to output buffer length
* \return PARSERUTILS_OK on success,
* PARSERUTILS_NOMEM if output buffer is too small,
*/
parserutils_error charset_ascii_codec_output_decoded_char(
charset_ascii_codec *c,
uint32_t ucs4, uint8_t **dest, size_t *destlen)
{
if (*destlen < 4) {
/* Run out of output buffer */
c->read_len = 1;
c->read_buf[0] = ucs4;
return PARSERUTILS_NOMEM;
}
*((uint32_t *) (void *) *dest) = endian_host_to_big(ucs4);
*dest += 4;
*destlen -= 4;
return PARSERUTILS_OK;
}
/**
* Convert a UCS4 (host endian) character to US-ASCII
*
* \param c The codec instance
* \param ucs4 The UCS4 character to convert
* \param s Pointer to pointer to destination buffer
* \param len Pointer to destination buffer length
* \return PARSERUTILS_OK on success,
* PARSERUTILS_NOMEM if there's insufficient space in the output buffer,
* PARSERUTILS_INVALID if the character cannot be represented
*
* _INVALID will only be returned if the codec's conversion mode is STRICT.
* Otherwise, '?' will be output.
*
* On successful conversion, *s and *len will be updated.
*/
parserutils_error charset_ascii_from_ucs4(charset_ascii_codec *c,
uint32_t ucs4, uint8_t **s, size_t *len)
{
uint8_t out = 0;
if (*len < 1)
return PARSERUTILS_NOMEM;
if (ucs4 < 0x80) {
/* ASCII */
out = ucs4;
} else {
if (c->base.errormode == PARSERUTILS_CHARSET_CODEC_ERROR_STRICT)
return PARSERUTILS_INVALID;
else
out = '?';
}
*(*s) = out;
(*s)++;
(*len)--;
return PARSERUTILS_OK;
}
/**
* Convert a US-ASCII character to UCS4 (host endian)
*
* \param c The codec instance
* \param s Pointer to source buffer
* \param len Source buffer length
* \param ucs4 Pointer to destination buffer
* \return PARSERUTILS_OK on success,
* PARSERUTILS_NEEDDATA if there's insufficient input data
* PARSERUTILS_INVALID if the character cannot be represented
*/
parserutils_error charset_ascii_to_ucs4(charset_ascii_codec *c,
const uint8_t *s, size_t len, uint32_t *ucs4)
{
uint32_t out;
UNUSED(c);
if (len < 1)
return PARSERUTILS_NEEDDATA;
if (*s < 0x80) {
out = *s;
} else {
return PARSERUTILS_INVALID;
}
*ucs4 = out;
return PARSERUTILS_OK;
}
const parserutils_charset_handler charset_ascii_codec_handler = {
charset_ascii_codec_handles_charset,
charset_ascii_codec_create
};