1 files changed, 380 insertions, 0 deletions
diff --git a/src/input/filter.c b/src/input/filter.c
new file mode 100644
index 0000000..5ac5391
--- /dev/null
+++ b/src/input/filter.c
@@ -0,0 +1,380 @@
+/*
+ * This file is part of Hubbub.
+ * Licensed under the MIT License,
+ *                http://www.opensource.org/licenses/mit-license.php
+ * Copyright 2007 John-Mark Bell <jmb@netsurf-browser.org>
+ */
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "charset/aliases.h"
+#include "charset/codec.h"
+#include "utils/utils.h"
+
+#include "input/filter.h"
+
+
+/** Input filter */
+struct hubbub_filter {
+	hubbub_charsetcodec *read_codec;	/**< Read codec */
+	hubbub_charsetcodec *write_codec;	/**< Write codec */
+
+	uint32_t filter_output[2];	/**< Filter output buffer */
+	uint32_t last_filter_char;	/**< Last filtered character */
+
+	uint32_t pivot_buf[64];		/**< Conversion pivot buffer */
+
+	bool leftover;			/**< Data remains from last call */
+	uint8_t *pivot_left;		/**< Remaining pivot to write */
+	size_t pivot_len;		/**< Length of pivot remaining */
+
+	struct {
+		uint16_t encoding;	/**< Input encoding */
+	} settings;			/**< Filter settings */
+
+	hubbub_alloc alloc;		/**< Memory (de)allocation function */
+	void *pw;			/**< Client private data */
+};
+
+static hubbub_error hubbub_filter_set_defaults(hubbub_filter *input);
+static hubbub_error hubbub_filter_set_encoding(hubbub_filter *input,
+		const char *enc);
+static hubbub_error read_character_filter(uint32_t c,
+		uint32_t **output, size_t *outputlen, void *pw);
+
+/**
+ * Create an input filter
+ *
+ * \param int_enc  Desired encoding of document
+ * \param alloc    Function used to (de)allocate data
+ * \param pw       Pointer to client-specific private data (may be NULL)
+ * \return Pointer to filter instance, or NULL on failure
+ */
+hubbub_filter *hubbub_filter_create(const char *int_enc,
+		hubbub_alloc alloc, void *pw)
+{
+	hubbub_filter *filter;
+
+	if (alloc == NULL)
+		return NULL;
+
+	filter = alloc(NULL, sizeof(*filter), pw);
+	if (!filter)
+		return NULL;
+
+	filter->last_filter_char = 0;
+
+	filter->leftover = false;
+	filter->pivot_left = NULL;
+	filter->pivot_len = 0;
+
+	filter->alloc = alloc;
+	filter->pw = pw;
+
+	if (hubbub_filter_set_defaults(filter) != HUBBUB_OK) {
+		filter->alloc(filter, 0, pw);
+		return NULL;
+	}
+
+	filter->write_codec = hubbub_charsetcodec_create(int_enc, alloc, pw);
+	if (filter->write_codec == NULL) {
+		if (filter->read_codec != NULL)
+			hubbub_charsetcodec_destroy(filter->read_codec);
+		filter->alloc(filter, 0, pw);
+		return NULL;
+	}
+
+	return filter;
+}
+
+/**
+ * Destroy an input filter
+ *
+ * \param input  Pointer to filter instance
+ */
+void hubbub_filter_destroy(hubbub_filter *input)
+{
+	if (input == NULL)
+		return;
+
+	if (input->read_codec != NULL)
+		hubbub_charsetcodec_destroy(input->read_codec);
+
+	if (input->write_codec != NULL)
+		hubbub_charsetcodec_destroy(input->write_codec);
+
+	input->alloc(input, 0, input->pw);
+
+	return;
+}
+
+/**
+ * Configure an input filter
+ *
+ * \param input   Pointer to filter instance
+ * \param type    Input option type to configure
+ * \param params  Option-specific parameters
+ * \return HUBBUB_OK on success, appropriate error otherwise
+ */
+hubbub_error hubbub_filter_setopt(hubbub_filter *input,
+		hubbub_filter_opttype type,
+		hubbub_filter_optparams *params)
+{
+	hubbub_error error = HUBBUB_OK;
+
+	if (input == NULL || params == NULL)
+		return HUBBUB_BADPARM;
+
+	switch (type) {
+	case HUBBUB_FILTER_SET_ENCODING:
+		error = hubbub_filter_set_encoding(input,
+				params->encoding.name);
+		break;
+	}
+
+	return error;
+}
+
+/**
+ * Process a chunk of data
+ *
+ * \param input   Pointer to filter instance
+ * \param data    Pointer to pointer to input buffer
+ * \param len     Pointer to length of input buffer
+ * \param output  Pointer to pointer to output buffer
+ * \param outlen  Pointer to length of output buffer
+ * \return HUBBUB_OK on success, appropriate error otherwise
+ *
+ * Call this with an input buffer length of 0 to flush any buffers.
+ */
+hubbub_error hubbub_filter_process_chunk(hubbub_filter *input,
+		const uint8_t **data, size_t *len,
+		uint8_t **output, size_t *outlen)
+{
+	hubbub_error read_error, write_error;
+
+	if (input == NULL || data == NULL || *data == NULL || len == NULL ||
+			output == NULL || *output == NULL || outlen == NULL)
+		return HUBBUB_BADPARM;
+
+	if (input->leftover) {
+		/* Some data left to be written from last call */
+
+		/* Attempt to flush the remaining data. */
+		write_error = hubbub_charsetcodec_encode(input->write_codec,
+				(const uint8_t **) &input->pivot_left,
+				&input->pivot_len,
+				output, outlen);
+
+		if (write_error != HUBBUB_OK) {
+			return write_error;
+		}
+
+		/* And clear leftover */
+		input->pivot_left = NULL;
+		input->pivot_len = 0;
+		input->leftover = false;
+	}
+
+	while (*len > 0) {
+		size_t pivot_len = sizeof(input->pivot_buf);
+		uint8_t *pivot = (uint8_t *) input->pivot_buf;
+
+		read_error = hubbub_charsetcodec_decode(input->read_codec,
+				data, len,
+				(uint8_t **) &pivot, &pivot_len);
+
+		pivot = (uint8_t *) input->pivot_buf;
+		pivot_len = sizeof(input->pivot_buf) - pivot_len;
+
+		if (pivot_len > 0) {
+			write_error = hubbub_charsetcodec_encode(
+					input->write_codec,
+					(const uint8_t **) &pivot,
+					&pivot_len,
+					output, outlen);
+
+			if (write_error != HUBBUB_OK) {
+				input->leftover = true;
+				input->pivot_left = pivot;
+				input->pivot_len = pivot_len;
+
+				return write_error;
+			}
+		}
+
+		if (read_error != HUBBUB_OK && read_error != HUBBUB_NOMEM)
+			return read_error;
+	}
+
+	return HUBBUB_OK;
+}
+
+/**
+ * Reset an input filter's state
+ *
+ * \param input  The input filter to reset
+ * \param HUBBUB_OK on success, appropriate error otherwise
+ */
+hubbub_error hubbub_filter_reset(hubbub_filter *input)
+{
+	hubbub_error error;
+
+	if (input == NULL)
+		return HUBBUB_BADPARM;
+
+	/* Clear pivot buffer leftovers */
+	input->pivot_left = NULL;
+	input->pivot_len = 0;
+	input->leftover = false;
+
+	/* Reset read codec */
+	error = hubbub_charsetcodec_reset(input->read_codec);
+	if (error != HUBBUB_OK)
+		return error;
+
+	/* Reset write codec */
+	error = hubbub_charsetcodec_reset(input->write_codec);
+	if (error != HUBBUB_OK)
+		return error;
+
+	return HUBBUB_OK;
+}
+
+/**
+ * Set an input filter's default settings
+ *
+ * \param input  Input filter to configure
+ * \return HUBBUB_OK on success, appropriate error otherwise
+ */
+hubbub_error hubbub_filter_set_defaults(hubbub_filter *input)
+{
+	hubbub_error error;
+
+	if (input == NULL)
+		return HUBBUB_BADPARM;
+
+	input->read_codec = NULL;
+	input->write_codec = NULL;
+	input->settings.encoding = 0;
+	error = hubbub_filter_set_encoding(input, "ISO-8859-1");
+	if (error != HUBBUB_OK)
+		return error;
+
+	return HUBBUB_OK;
+}
+
+/**
+ * Set an input filter's encoding
+ *
+ * \param input  Input filter to configure
+ * \param enc    Encoding name
+ * \return HUBBUB_OK on success, appropriate error otherwise
+ */
+hubbub_error hubbub_filter_set_encoding(hubbub_filter *input,
+		const char *enc)
+{
+	const char *old_enc;
+	uint16_t mibenum;
+	hubbub_error error;
+	hubbub_charsetcodec_optparams params;
+
+	if (input == NULL || enc == NULL)
+		return HUBBUB_BADPARM;
+
+	mibenum = hubbub_mibenum_from_name(enc, strlen(enc));
+	if (mibenum == 0)
+		return HUBBUB_INVALID;
+
+	/* Exit early if we're already using this encoding */
+	if (input->settings.encoding == mibenum)
+		return HUBBUB_OK;
+
+	old_enc = hubbub_mibenum_to_name(input->settings.encoding);
+	if (old_enc == NULL)
+		old_enc = "ISO-8859-1";
+
+	if (input->read_codec != NULL)
+		hubbub_charsetcodec_destroy(input->read_codec);
+
+	input->read_codec = hubbub_charsetcodec_create(enc, input->alloc,
+			input->pw);
+	if (input->read_codec == NULL)
+		return HUBBUB_NOMEM;
+
+	/* Register filter function */
+	params.filter_func.filter = read_character_filter;
+	params.filter_func.pw = (void *) input;
+	error = hubbub_charsetcodec_setopt(input->read_codec,
+			HUBBUB_CHARSETCODEC_FILTER_FUNC,
+			(hubbub_charsetcodec_optparams *) &params);
+	if (error != HUBBUB_OK)
+		return error;
+
+	input->settings.encoding = mibenum;
+
+	return HUBBUB_OK;
+}
+
+/**
+ * Character filter function for read characters
+ *
+ * \param c          The read character (UCS4 - host byte order)
+ * \param output     Pointer to pointer to output buffer (filled on exit)
+ * \param outputlen  Pointer to output buffer length (filled on exit)
+ * \param pw         Pointer to client-specific private data.
+ * \return HUBBUB_OK on success, appropriate error otherwise
+ */
+hubbub_error read_character_filter(uint32_t c, uint32_t **output,
+		size_t *outputlen, void *pw)
+{
+	hubbub_filter *input = (hubbub_filter *) pw;
+	size_t len;
+
+	if (output == NULL || outputlen == NULL || pw == NULL)
+		return HUBBUB_BADPARM;
+
+	/* Line ending normalisation:
+	 *   CRLF -> LF  (trap CR and let LF through unmodified)
+	 *   CR   -> LF  (trap CR and convert to LF if not CRLF)
+	 *   LF   -> LF  (leave LF alone)
+	 */
+
+#define NUL (0x00000000)
+#define CR  (0x0000000D)
+#define LF  (0x0000000A)
+#define REP (0x0000FFFD)
+
+	if (c == NUL) {
+		/* Replace NUL (U+0000) characters in input with U+FFFD */
+		input->filter_output[0] = REP;
+		len = 1;
+	} else if (c == CR) {
+		/* Trap CR characters */
+		len = 0;
+	} else if (input->last_filter_char == CR && c != LF) {
+		/* Last char was CR and this isn't LF => CR -> LF */
+		input->filter_output[0] = LF;
+		input->filter_output[1] = c;
+		len = 2;
+	} else {
+		/* Let character through unchanged */
+		input->filter_output[0] = c;
+		len = 1;
+	}
+
+#undef NUL
+#undef CR
+#undef LF
+#undef REP
+
+	input->last_filter_char = c;
+
+	*output = input->filter_output;
+	*outputlen = len;
+
+	return HUBBUB_OK;
+}