r5429 jmb - in /trunk/libparserutils/src/charset: codec.c codecs/Makefile codecs/codec_ascii.c

netsurf at semichrome.net netsurf at semichrome.net
Wed Sep 24 02:47:13 BST 2008


Author: jmb
Date: Tue Sep 23 20:47:13 2008
New Revision: 5429

URL: http://source.netsurf-browser.org?rev=5429&view=rev
Log:
ASCII charset codec.

Added:
    trunk/libparserutils/src/charset/codecs/codec_ascii.c
Modified:
    trunk/libparserutils/src/charset/codec.c
    trunk/libparserutils/src/charset/codecs/Makefile

Modified: trunk/libparserutils/src/charset/codec.c
URL: http://source.netsurf-browser.org/trunk/libparserutils/src/charset/codec.c?rev=5429&r1=5428&r2=5429&view=diff
==============================================================================
--- trunk/libparserutils/src/charset/codec.c (original)
+++ trunk/libparserutils/src/charset/codec.c Tue Sep 23 20:47:13 2008
@@ -10,6 +10,7 @@
 #include "charset/aliases.h"
 #include "charset/codecs/codec_impl.h"
 
+extern parserutils_charset_handler charset_ascii_codec_handler;
 extern parserutils_charset_handler charset_8859_codec_handler;
 extern parserutils_charset_handler charset_ext8_codec_handler;
 extern parserutils_charset_handler charset_utf8_codec_handler;
@@ -20,6 +21,7 @@
 	&charset_utf16_codec_handler,
 	&charset_8859_codec_handler,
 	&charset_ext8_codec_handler,
+	&charset_ascii_codec_handler,
 	NULL,
 };
 

Modified: trunk/libparserutils/src/charset/codecs/Makefile
URL: http://source.netsurf-browser.org/trunk/libparserutils/src/charset/codecs/Makefile?rev=5429&r1=5428&r2=5429&view=diff
==============================================================================
--- trunk/libparserutils/src/charset/codecs/Makefile (original)
+++ trunk/libparserutils/src/charset/codecs/Makefile Tue Sep 23 20:47:13 2008
@@ -32,7 +32,7 @@
 d              := $(DIR)
 
 # Sources
-SRCS_$(d) := codec_8859.c codec_ext8.c codec_utf8.c codec_utf16.c
+SRCS_$(d) := codec_ascii.c codec_8859.c codec_ext8.c codec_utf8.c codec_utf16.c
 
 # Append to sources for component
 SOURCES += $(addprefix $(d), $(SRCS_$(d)))

Added: trunk/libparserutils/src/charset/codecs/codec_ascii.c
URL: http://source.netsurf-browser.org/trunk/libparserutils/src/charset/codecs/codec_ascii.c?rev=5429&view=auto
==============================================================================
--- trunk/libparserutils/src/charset/codecs/codec_ascii.c (added)
+++ trunk/libparserutils/src/charset/codecs/codec_ascii.c Tue Sep 23 20:47:13 2008
@@ -1,0 +1,526 @@
+/*
+ * 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 at netsurf-browser.org>
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* These two are for htonl / ntohl */
+#include <arpa/inet.h>
+#include <netinet/in.h>
+
+#include <parserutils/charset/mibenum.h>
+
+#include "charset/codecs/codec_impl.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_charset_codec *charset_ascii_codec_create(
+		const char *charset, parserutils_alloc alloc, void *pw);
+static void 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,
+			strlen(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)
+ * \return Pointer to codec, or NULL on failure
+ */
+parserutils_charset_codec *charset_ascii_codec_create(const char *charset,
+		parserutils_alloc alloc, void *pw)
+{
+	charset_ascii_codec *codec;
+
+	UNUSED(charset);
+
+	codec = alloc(NULL, sizeof(charset_ascii_codec), pw);
+	if (codec == NULL)
+		return NULL;
+
+	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 = charset_ascii_codec_destroy;
+	codec->base.handler.encode = charset_ascii_codec_encode;
+	codec->base.handler.decode = charset_ascii_codec_decode;
+	codec->base.handler.reset = charset_ascii_codec_reset;
+
+	return (parserutils_charset_codec *) codec;
+}
+
+/**
+ * Destroy a US-ASCII codec
+ *
+ * \param codec  The codec to destroy
+ */
+void charset_ascii_codec_destroy (parserutils_charset_codec *codec)
+{
+	UNUSED(codec);
+}
+
+/**
+ * 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) {
+				assert(error == PARSERUTILS_NOMEM);
+
+				for (uint32_t 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 = ntohl(*((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) {
+				if (error != PARSERUTILS_NOMEM) {
+					return error;
+				}
+
+				/* Insufficient output space */
+				if (towritelen >= WRITE_BUFSIZE)
+					abort();
+
+				c->write_len = towritelen;
+
+				/* Copy pending chars to save area, for
+				 * processing next call. */
+				for (uint32_t 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) = 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 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) = htonl(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
+};
+




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