src/liblzma/common/stream_encoder.c - xz - Git at Google

 ///////////////////////////////////////////////////////////////////////////////
 //
 /// \file       stream_encoder.c
 /// \brief      Encodes .xz Streams
 //
 //  Author:     Lasse Collin
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.
 //
 ///////////////////////////////////////////////////////////////////////////////

 #include "block_encoder.h"
 #include "index_encoder.h"


 struct lzma_coder_s {
 	enum {
 		SEQ_STREAM_HEADER,
 		SEQ_BLOCK_INIT,
 		SEQ_BLOCK_HEADER,
 		SEQ_BLOCK_ENCODE,
 		SEQ_INDEX_ENCODE,
 		SEQ_STREAM_FOOTER,
 	} sequence;

 	/// True if Block encoder has been initialized by
 	/// stream_encoder_init() or stream_encoder_update()
 	/// and thus doesn't need to be initialized in stream_encode().
 	bool block_encoder_is_initialized;

 	/// Block
 	lzma_next_coder block_encoder;

 	/// Options for the Block encoder
 	lzma_block block_options;

 	/// The filter chain currently in use
 	lzma_filter filters[LZMA_FILTERS_MAX + 1];

 	/// Index encoder. This is separate from Block encoder, because this
 	/// doesn't take much memory, and when encoding multiple Streams
 	/// with the same encoding options we avoid reallocating memory.
 	lzma_next_coder index_encoder;

 	/// Index to hold sizes of the Blocks
 	lzma_index *index;

 	/// Read position in buffer[]
 	size_t buffer_pos;

 	/// Total number of bytes in buffer[]
 	size_t buffer_size;

 	/// Buffer to hold Stream Header, Block Header, and Stream Footer.
 	/// Block Header has biggest maximum size.
 	uint8_t buffer[LZMA_BLOCK_HEADER_SIZE_MAX];
 };


 static lzma_ret
 block_encoder_init(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	// Prepare the Block options. Even though Block encoder doesn't need
 	// compressed_size, uncompressed_size, and header_size to be
 	// initialized, it is a good idea to do it here, because this way
 	// we catch if someone gave us Filter ID that cannot be used in
 	// Blocks/Streams.
 	coder->block_options.compressed_size = LZMA_VLI_UNKNOWN;
 	coder->block_options.uncompressed_size = LZMA_VLI_UNKNOWN;

 	return_if_error(lzma_block_header_size(&coder->block_options));

 	// Initialize the actual Block encoder.
 	return lzma_block_encoder_init(&coder->block_encoder, allocator,
 			&coder->block_options);
 }


 static lzma_ret
 stream_encode(lzma_coder *coder, const lzma_allocator *allocator,
 		const uint8_t *restrict in, size_t *restrict in_pos,
 		size_t in_size, uint8_t *restrict out,
 		size_t *restrict out_pos, size_t out_size, lzma_action action)
 {
 	// Main loop
 	while (*out_pos < out_size)
 	switch (coder->sequence) {
 	case SEQ_STREAM_HEADER:
 	case SEQ_BLOCK_HEADER:
 	case SEQ_STREAM_FOOTER:
 		lzma_bufcpy(coder->buffer, &coder->buffer_pos,
 				coder->buffer_size, out, out_pos, out_size);
 		if (coder->buffer_pos < coder->buffer_size)
 			return LZMA_OK;

 		if (coder->sequence == SEQ_STREAM_FOOTER)
 			return LZMA_STREAM_END;

 		coder->buffer_pos = 0;
 		++coder->sequence;
 		break;

 	case SEQ_BLOCK_INIT: {
 		if (*in_pos == in_size) {
 			// If we are requested to flush or finish the current
 			// Block, return LZMA_STREAM_END immediately since
 			// there's nothing to do.
 			if (action != LZMA_FINISH)
 				return action == LZMA_RUN
 						? LZMA_OK : LZMA_STREAM_END;

 			// The application had used LZMA_FULL_FLUSH to finish
 			// the previous Block, but now wants to finish without
 			// encoding new data, or it is simply creating an
 			// empty Stream with no Blocks.
 			//
 			// Initialize the Index encoder, and continue to
 			// actually encoding the Index.
 			return_if_error(lzma_index_encoder_init(
 					&coder->index_encoder, allocator,
 					coder->index));
 			coder->sequence = SEQ_INDEX_ENCODE;
 			break;
 		}

 		// Initialize the Block encoder unless it was already
 		// initialized by stream_encoder_init() or
 		// stream_encoder_update().
 		if (!coder->block_encoder_is_initialized)
 			return_if_error(block_encoder_init(coder, allocator));

 		// Make it false so that we don't skip the initialization
 		// with the next Block.
 		coder->block_encoder_is_initialized = false;

 		// Encode the Block Header. This shouldn't fail since we have
 		// already initialized the Block encoder.
 		if (lzma_block_header_encode(&coder->block_options,
 				coder->buffer) != LZMA_OK)
 			return LZMA_PROG_ERROR;

 		coder->buffer_size = coder->block_options.header_size;
 		coder->sequence = SEQ_BLOCK_HEADER;
 		break;
 	}

 	case SEQ_BLOCK_ENCODE: {
 		static const lzma_action convert[LZMA_ACTION_MAX + 1] = {
 			LZMA_RUN,
 			LZMA_SYNC_FLUSH,
 			LZMA_FINISH,
 			LZMA_FINISH,
 			LZMA_FINISH,
 		};

 		const lzma_ret ret = coder->block_encoder.code(
 				coder->block_encoder.coder, allocator,
 				in, in_pos, in_size,
 				out, out_pos, out_size, convert[action]);
 		if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
 			return ret;

 		// Add a new Index Record.
 		const lzma_vli unpadded_size = lzma_block_unpadded_size(
 				&coder->block_options);
 		assert(unpadded_size != 0);
 		return_if_error(lzma_index_append(coder->index, allocator,
 				unpadded_size,
 				coder->block_options.uncompressed_size));

 		coder->sequence = SEQ_BLOCK_INIT;
 		break;
 	}

 	case SEQ_INDEX_ENCODE: {
 		// Call the Index encoder. It doesn't take any input, so
 		// those pointers can be NULL.
 		const lzma_ret ret = coder->index_encoder.code(
 				coder->index_encoder.coder, allocator,
 				NULL, NULL, 0,
 				out, out_pos, out_size, LZMA_RUN);
 		if (ret != LZMA_STREAM_END)
 			return ret;

 		// Encode the Stream Footer into coder->buffer.
 		const lzma_stream_flags stream_flags = {
 			.version = 0,
 			.backward_size = lzma_index_size(coder->index),
 			.check = coder->block_options.check,
 		};

 		if (lzma_stream_footer_encode(&stream_flags, coder->buffer)
 				!= LZMA_OK)
 			return LZMA_PROG_ERROR;

 		coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
 		coder->sequence = SEQ_STREAM_FOOTER;
 		break;
 	}

 	default:
 		assert(0);
 		return LZMA_PROG_ERROR;
 	}

 	return LZMA_OK;
 }


 static void
 stream_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->block_encoder, allocator);
 	lzma_next_end(&coder->index_encoder, allocator);
 	lzma_index_end(coder->index, allocator);

 	for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
 		lzma_free(coder->filters[i].options, allocator);

 	lzma_free(coder, allocator);
 	return;
 }


 static lzma_ret
 stream_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
 		const lzma_filter *filters,
 		const lzma_filter *reversed_filters)
 {
 	if (coder->sequence <= SEQ_BLOCK_INIT) {
 		// There is no incomplete Block waiting to be finished,
 		// thus we can change the whole filter chain. Start by
 		// trying to initialize the Block encoder with the new
 		// chain. This way we detect if the chain is valid.
 		coder->block_encoder_is_initialized = false;
 		coder->block_options.filters = (lzma_filter *)(filters);
 		const lzma_ret ret = block_encoder_init(coder, allocator);
 		coder->block_options.filters = coder->filters;
 		if (ret != LZMA_OK)
 			return ret;

 		coder->block_encoder_is_initialized = true;

 	} else if (coder->sequence <= SEQ_BLOCK_ENCODE) {
 		// We are in the middle of a Block. Try to update only
 		// the filter-specific options.
 		return_if_error(coder->block_encoder.update(
 				coder->block_encoder.coder, allocator,
 				filters, reversed_filters));
 	} else {
 		// Trying to update the filter chain when we are already
 		// encoding Index or Stream Footer.
 		return LZMA_PROG_ERROR;
 	}

 	// Free the copy of the old chain and make a copy of the new chain.
 	for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
 		lzma_free(coder->filters[i].options, allocator);

 	return lzma_filters_copy(filters, coder->filters, allocator);
 }


 static lzma_ret
 stream_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *filters, lzma_check check)
 {
 	lzma_next_coder_init(&stream_encoder_init, next, allocator);

 	if (filters == NULL)
 		return LZMA_PROG_ERROR;

 	if (next->coder == NULL) {
 		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
 		if (next->coder == NULL)
 			return LZMA_MEM_ERROR;

 		next->code = &stream_encode;
 		next->end = &stream_encoder_end;
 		next->update = &stream_encoder_update;

 		next->coder->filters[0].id = LZMA_VLI_UNKNOWN;
 		next->coder->block_encoder = LZMA_NEXT_CODER_INIT;
 		next->coder->index_encoder = LZMA_NEXT_CODER_INIT;
 		next->coder->index = NULL;
 	}

 	// Basic initializations
 	next->coder->sequence = SEQ_STREAM_HEADER;
 	next->coder->block_options.version = 0;
 	next->coder->block_options.check = check;

 	// Initialize the Index
 	lzma_index_end(next->coder->index, allocator);
 	next->coder->index = lzma_index_init(allocator);
 	if (next->coder->index == NULL)
 		return LZMA_MEM_ERROR;

 	// Encode the Stream Header
 	lzma_stream_flags stream_flags = {
 		.version = 0,
 		.check = check,
 	};
 	return_if_error(lzma_stream_header_encode(
 			&stream_flags, next->coder->buffer));

 	next->coder->buffer_pos = 0;
 	next->coder->buffer_size = LZMA_STREAM_HEADER_SIZE;

 	// Initialize the Block encoder. This way we detect unsupported
 	// filter chains when initializing the Stream encoder instead of
 	// giving an error after Stream Header has already written out.
 	return stream_encoder_update(
 			next->coder, allocator, filters, NULL);
 }


 extern LZMA_API(lzma_ret)
 lzma_stream_encoder(lzma_stream *strm,
 		const lzma_filter *filters, lzma_check check)
 {
 	lzma_next_strm_init(stream_encoder_init, strm, filters, check);

 	strm->internal->supported_actions[LZMA_RUN] = true;
 	strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
 	strm->internal->supported_actions[LZMA_FULL_FLUSH] = true;
 	strm->internal->supported_actions[LZMA_FULL_BARRIER] = true;
 	strm->internal->supported_actions[LZMA_FINISH] = true;

 	return LZMA_OK;
 }
	///////////////////////////////////////////////////////////////////////////////
	//
	/// \file stream_encoder.c
	/// \brief Encodes .xz Streams
	//
	// Author: Lasse Collin
	//
	// This file has been put into the public domain.
	// You can do whatever you want with this file.
	//
	///////////////////////////////////////////////////////////////////////////////

	#include "block_encoder.h"
	#include "index_encoder.h"


	struct lzma_coder_s {
	enum {
	SEQ_STREAM_HEADER,
	SEQ_BLOCK_INIT,
	SEQ_BLOCK_HEADER,
	SEQ_BLOCK_ENCODE,
	SEQ_INDEX_ENCODE,
	SEQ_STREAM_FOOTER,
	} sequence;

	/// True if Block encoder has been initialized by
	/// stream_encoder_init() or stream_encoder_update()
	/// and thus doesn't need to be initialized in stream_encode().
	bool block_encoder_is_initialized;

	/// Block
	lzma_next_coder block_encoder;

	/// Options for the Block encoder
	lzma_block block_options;

	/// The filter chain currently in use
	lzma_filter filters[LZMA_FILTERS_MAX + 1];

	/// Index encoder. This is separate from Block encoder, because this
	/// doesn't take much memory, and when encoding multiple Streams
	/// with the same encoding options we avoid reallocating memory.
	lzma_next_coder index_encoder;

	/// Index to hold sizes of the Blocks
	lzma_index *index;

	/// Read position in buffer[]
	size_t buffer_pos;

	/// Total number of bytes in buffer[]
	size_t buffer_size;

	/// Buffer to hold Stream Header, Block Header, and Stream Footer.
	/// Block Header has biggest maximum size.
	uint8_t buffer[LZMA_BLOCK_HEADER_SIZE_MAX];
	};


	static lzma_ret
	block_encoder_init(lzma_coder coder, const lzma_allocator allocator)
	{
	// Prepare the Block options. Even though Block encoder doesn't need
	// compressed_size, uncompressed_size, and header_size to be
	// initialized, it is a good idea to do it here, because this way
	// we catch if someone gave us Filter ID that cannot be used in
	// Blocks/Streams.
	coder->block_options.compressed_size = LZMA_VLI_UNKNOWN;
	coder->block_options.uncompressed_size = LZMA_VLI_UNKNOWN;

	return_if_error(lzma_block_header_size(&coder->block_options));

	// Initialize the actual Block encoder.
	return lzma_block_encoder_init(&coder->block_encoder, allocator,
	&coder->block_options);
	}


	static lzma_ret
	stream_encode(lzma_coder coder, const lzma_allocator allocator,
	const uint8_t restrict in, size_t restrict in_pos,
	size_t in_size, uint8_t *restrict out,
	size_t *restrict out_pos, size_t out_size, lzma_action action)
	{
	// Main loop
	while (*out_pos < out_size)
	switch (coder->sequence) {
	case SEQ_STREAM_HEADER:
	case SEQ_BLOCK_HEADER:
	case SEQ_STREAM_FOOTER:
	lzma_bufcpy(coder->buffer, &coder->buffer_pos,
	coder->buffer_size, out, out_pos, out_size);
	if (coder->buffer_pos < coder->buffer_size)
	return LZMA_OK;

	if (coder->sequence == SEQ_STREAM_FOOTER)
	return LZMA_STREAM_END;

	coder->buffer_pos = 0;
	++coder->sequence;
	break;

	case SEQ_BLOCK_INIT: {
	if (*in_pos == in_size) {
	// If we are requested to flush or finish the current
	// Block, return LZMA_STREAM_END immediately since
	// there's nothing to do.
	if (action != LZMA_FINISH)
	return action == LZMA_RUN
	? LZMA_OK : LZMA_STREAM_END;

	// The application had used LZMA_FULL_FLUSH to finish
	// the previous Block, but now wants to finish without
	// encoding new data, or it is simply creating an
	// empty Stream with no Blocks.
	//
	// Initialize the Index encoder, and continue to
	// actually encoding the Index.
	return_if_error(lzma_index_encoder_init(
	&coder->index_encoder, allocator,
	coder->index));
	coder->sequence = SEQ_INDEX_ENCODE;
	break;
	}

	// Initialize the Block encoder unless it was already
	// initialized by stream_encoder_init() or
	// stream_encoder_update().
	if (!coder->block_encoder_is_initialized)
	return_if_error(block_encoder_init(coder, allocator));

	// Make it false so that we don't skip the initialization
	// with the next Block.
	coder->block_encoder_is_initialized = false;

	// Encode the Block Header. This shouldn't fail since we have
	// already initialized the Block encoder.
	if (lzma_block_header_encode(&coder->block_options,
	coder->buffer) != LZMA_OK)
	return LZMA_PROG_ERROR;

	coder->buffer_size = coder->block_options.header_size;
	coder->sequence = SEQ_BLOCK_HEADER;
	break;
	}

	case SEQ_BLOCK_ENCODE: {
	static const lzma_action convert[LZMA_ACTION_MAX + 1] = {
	LZMA_RUN,
	LZMA_SYNC_FLUSH,
	LZMA_FINISH,
	LZMA_FINISH,
	LZMA_FINISH,
	};

	const lzma_ret ret = coder->block_encoder.code(
	coder->block_encoder.coder, allocator,
	in, in_pos, in_size,
	out, out_pos, out_size, convert[action]);
	if (ret != LZMA_STREAM_END \|\| action == LZMA_SYNC_FLUSH)
	return ret;

	// Add a new Index Record.
	const lzma_vli unpadded_size = lzma_block_unpadded_size(
	&coder->block_options);
	assert(unpadded_size != 0);
	return_if_error(lzma_index_append(coder->index, allocator,
	unpadded_size,
	coder->block_options.uncompressed_size));

	coder->sequence = SEQ_BLOCK_INIT;
	break;
	}

	case SEQ_INDEX_ENCODE: {
	// Call the Index encoder. It doesn't take any input, so
	// those pointers can be NULL.
	const lzma_ret ret = coder->index_encoder.code(
	coder->index_encoder.coder, allocator,
	NULL, NULL, 0,
	out, out_pos, out_size, LZMA_RUN);
	if (ret != LZMA_STREAM_END)
	return ret;

	// Encode the Stream Footer into coder->buffer.
	const lzma_stream_flags stream_flags = {
	.version = 0,
	.backward_size = lzma_index_size(coder->index),
	.check = coder->block_options.check,
	};

	if (lzma_stream_footer_encode(&stream_flags, coder->buffer)
	!= LZMA_OK)
	return LZMA_PROG_ERROR;

	coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
	coder->sequence = SEQ_STREAM_FOOTER;
	break;
	}

	default:
	assert(0);
	return LZMA_PROG_ERROR;
	}

	return LZMA_OK;
	}


	static void
	stream_encoder_end(lzma_coder coder, const lzma_allocator allocator)
	{
	lzma_next_end(&coder->block_encoder, allocator);
	lzma_next_end(&coder->index_encoder, allocator);
	lzma_index_end(coder->index, allocator);

	for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
	lzma_free(coder->filters[i].options, allocator);

	lzma_free(coder, allocator);
	return;
	}


	static lzma_ret
	stream_encoder_update(lzma_coder coder, const lzma_allocator allocator,
	const lzma_filter *filters,
	const lzma_filter *reversed_filters)
	{
	if (coder->sequence <= SEQ_BLOCK_INIT) {
	// There is no incomplete Block waiting to be finished,
	// thus we can change the whole filter chain. Start by
	// trying to initialize the Block encoder with the new
	// chain. This way we detect if the chain is valid.
	coder->block_encoder_is_initialized = false;
	coder->block_options.filters = (lzma_filter *)(filters);
	const lzma_ret ret = block_encoder_init(coder, allocator);
	coder->block_options.filters = coder->filters;
	if (ret != LZMA_OK)
	return ret;

	coder->block_encoder_is_initialized = true;

	} else if (coder->sequence <= SEQ_BLOCK_ENCODE) {
	// We are in the middle of a Block. Try to update only
	// the filter-specific options.
	return_if_error(coder->block_encoder.update(
	coder->block_encoder.coder, allocator,
	filters, reversed_filters));
	} else {
	// Trying to update the filter chain when we are already
	// encoding Index or Stream Footer.
	return LZMA_PROG_ERROR;
	}

	// Free the copy of the old chain and make a copy of the new chain.
	for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
	lzma_free(coder->filters[i].options, allocator);

	return lzma_filters_copy(filters, coder->filters, allocator);
	}


	static lzma_ret
	stream_encoder_init(lzma_next_coder next, const lzma_allocator allocator,
	const lzma_filter *filters, lzma_check check)
	{
	lzma_next_coder_init(&stream_encoder_init, next, allocator);

	if (filters == NULL)
	return LZMA_PROG_ERROR;

	if (next->coder == NULL) {
	next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
	if (next->coder == NULL)
	return LZMA_MEM_ERROR;

	next->code = &stream_encode;
	next->end = &stream_encoder_end;
	next->update = &stream_encoder_update;

	next->coder->filters[0].id = LZMA_VLI_UNKNOWN;
	next->coder->block_encoder = LZMA_NEXT_CODER_INIT;
	next->coder->index_encoder = LZMA_NEXT_CODER_INIT;
	next->coder->index = NULL;
	}

	// Basic initializations
	next->coder->sequence = SEQ_STREAM_HEADER;
	next->coder->block_options.version = 0;
	next->coder->block_options.check = check;

	// Initialize the Index
	lzma_index_end(next->coder->index, allocator);
	next->coder->index = lzma_index_init(allocator);
	if (next->coder->index == NULL)
	return LZMA_MEM_ERROR;

	// Encode the Stream Header
	lzma_stream_flags stream_flags = {
	.version = 0,
	.check = check,
	};
	return_if_error(lzma_stream_header_encode(
	&stream_flags, next->coder->buffer));

	next->coder->buffer_pos = 0;
	next->coder->buffer_size = LZMA_STREAM_HEADER_SIZE;

	// Initialize the Block encoder. This way we detect unsupported
	// filter chains when initializing the Stream encoder instead of
	// giving an error after Stream Header has already written out.
	return stream_encoder_update(
	next->coder, allocator, filters, NULL);
	}


	extern LZMA_API(lzma_ret)
	lzma_stream_encoder(lzma_stream *strm,
	const lzma_filter *filters, lzma_check check)
	{
	lzma_next_strm_init(stream_encoder_init, strm, filters, check);

	strm->internal->supported_actions[LZMA_RUN] = true;
	strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
	strm->internal->supported_actions[LZMA_FULL_FLUSH] = true;
	strm->internal->supported_actions[LZMA_FULL_BARRIER] = true;
	strm->internal->supported_actions[LZMA_FINISH] = true;

	return LZMA_OK;
	}