1 files changed, 405 insertions, 0 deletions

diff --git a/src/liblzma/common/block_decoder.c b/src/liblzma/common/block_decoder.c
new file mode 100644
index 00000000..b9dcde49
--- /dev/null
+++ b/src/liblzma/common/block_decoder.c
@@ -0,0 +1,405 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       block_decoder.c
+/// \brief      Decodes .lzma Blocks
+//
+//  Copyright (C) 2007 Lasse Collin
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Lesser General Public
+//  License as published by the Free Software Foundation; either
+//  version 2.1 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Lesser General Public License for more details.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "block_decoder.h"
+#include "block_private.h"
+#include "raw_decoder.h"
+#include "check.h"
+
+
+struct lzma_coder_s {
+	enum {
+		SEQ_CODE,
+		SEQ_CHECK,
+		SEQ_UNCOMPRESSED_SIZE,
+		SEQ_BACKWARD_SIZE,
+		SEQ_PADDING,
+		SEQ_END,
+	} sequence;
+
+	/// The filters in the chain; initialized with lzma_raw_decoder_init().
+	lzma_next_coder next;
+
+	/// Decoding options; we also write Total Size, Compressed Size, and
+	/// Uncompressed Size back to this structure when the encoding has
+	/// been finished.
+	lzma_options_block *options;
+
+	/// Position in variable-length integers (and in some other places).
+	size_t pos;
+
+	/// Check of the uncompressed data
+	lzma_check check;
+
+	/// Total Size calculated while encoding
+	lzma_vli total_size;
+
+	/// Compressed Size calculated while encoding
+	lzma_vli compressed_size;
+
+	/// Uncompressed Size calculated while encoding
+	lzma_vli uncompressed_size;
+
+	/// Maximum allowed total_size
+	lzma_vli total_limit;
+
+	/// Maximum allowed uncompressed_size
+	lzma_vli uncompressed_limit;
+
+	/// Temporary location for the Uncompressed Size and Backward Size
+	/// fields in Block Footer.
+	lzma_vli tmp;
+
+	/// Size of the Backward Size field - This is needed so that we
+	/// can verify the Backward Size and still keep updating total_size.
+	size_t size_of_backward_size;
+};
+
+
+static lzma_ret
+update_sequence(lzma_coder *coder)
+{
+	switch (coder->sequence) {
+	case SEQ_CODE:
+		if (coder->options->check != LZMA_CHECK_NONE) {
+			lzma_check_finish(&coder->check,
+					coder->options->check);
+			coder->sequence = SEQ_CHECK;
+			break;
+		}
+
+	// Fall through
+
+	case SEQ_CHECK:
+		if (coder->options->has_uncompressed_size_in_footer) {
+			coder->sequence = SEQ_UNCOMPRESSED_SIZE;
+			break;
+		}
+
+	// Fall through
+
+	case SEQ_UNCOMPRESSED_SIZE:
+		if (coder->options->has_backward_size) {
+			coder->sequence = SEQ_BACKWARD_SIZE;
+			break;
+		}
+
+	// Fall through
+
+	case SEQ_BACKWARD_SIZE:
+		if (coder->options->handle_padding) {
+			coder->sequence = SEQ_PADDING;
+			break;
+		}
+
+	case SEQ_PADDING:
+		if (!is_size_valid(coder->total_size,
+					coder->options->total_size)
+				|| !is_size_valid(coder->compressed_size,
+					coder->options->compressed_size)
+				|| !is_size_valid(coder->uncompressed_size,
+					coder->options->uncompressed_size))
+			return LZMA_DATA_ERROR;
+
+		// Copy the values into coder->options. The caller
+		// may use this information to construct Index.
+		coder->options->total_size = coder->total_size;
+		coder->options->compressed_size = coder->compressed_size;
+		coder->options->uncompressed_size = coder->uncompressed_size;
+
+		return LZMA_STREAM_END;
+
+	default:
+		assert(0);
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static lzma_ret
+block_decode(lzma_coder *coder, 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)
+{
+	// Special case when the Block has only Block Header.
+	if (coder->sequence == SEQ_END)
+		return LZMA_STREAM_END;
+
+	// FIXME: Termination condition should work but could be cleaner.
+	while (*out_pos < out_size && (*in_pos < in_size
+			|| coder->sequence == SEQ_CODE))
+	switch (coder->sequence) {
+	case SEQ_CODE: {
+		const size_t in_start = *in_pos;
+		const size_t out_start = *out_pos;
+
+		lzma_ret ret = coder->next.code(coder->next.coder,
+				allocator, in, in_pos, in_size,
+				out, out_pos, out_size, action);
+
+		const size_t in_used = *in_pos - in_start;
+		const size_t out_used = *out_pos - out_start;
+
+		if (update_size(&coder->total_size, in_used,
+					coder->total_limit)
+				|| update_size(&coder->compressed_size,
+					in_used,
+					coder->options->compressed_size)
+				|| update_size(&coder->uncompressed_size,
+					out_used, coder->uncompressed_limit))
+			return LZMA_DATA_ERROR;
+
+		lzma_check_update(&coder->check, coder->options->check,
+				out + out_start, out_used);
+
+		if (ret != LZMA_STREAM_END)
+			return ret;
+
+		ret = update_sequence(coder);
+		if (ret != LZMA_OK)
+			return ret;
+
+		break;
+	}
+
+	case SEQ_CHECK:
+		switch (coder->options->check) {
+		case LZMA_CHECK_CRC32:
+			if (((coder->check.crc32 >> (coder->pos * 8))
+					& 0xFF) != in[*in_pos])
+				return LZMA_DATA_ERROR;
+			break;
+
+		case LZMA_CHECK_CRC64:
+			if (((coder->check.crc64 >> (coder->pos * 8))
+					& 0xFF) != in[*in_pos])
+				return LZMA_DATA_ERROR;
+			break;
+
+		case LZMA_CHECK_SHA256:
+			if (coder->check.sha256.buffer[coder->pos]
+					!= in[*in_pos])
+				return LZMA_DATA_ERROR;
+			break;
+
+		default:
+			assert(coder->options->check != LZMA_CHECK_NONE);
+			assert(coder->options->check <= LZMA_CHECK_ID_MAX);
+			break;
+		}
+
+		if (update_size(&coder->total_size, 1, coder->total_limit))
+			return LZMA_DATA_ERROR;
+
+		++*in_pos;
+
+		if (++coder->pos == lzma_check_sizes[coder->options->check]) {
+			const lzma_ret ret = update_sequence(coder);
+			if (ret != LZMA_OK)
+				return ret;
+
+			coder->pos = 0;
+		}
+
+		break;
+
+	case SEQ_UNCOMPRESSED_SIZE: {
+		const size_t in_start = *in_pos;
+
+		lzma_ret ret = lzma_vli_decode(&coder->tmp,
+				&coder->pos, in, in_pos, in_size);
+
+		if (update_size(&coder->total_size, *in_pos - in_start,
+				coder->total_limit))
+			return LZMA_DATA_ERROR;
+
+		if (ret != LZMA_STREAM_END)
+			return ret;
+
+		if (coder->tmp != coder->uncompressed_size)
+			return LZMA_DATA_ERROR;
+
+		coder->pos = 0;
+		coder->tmp = 0;
+
+		ret = update_sequence(coder);
+		if (ret != LZMA_OK)
+			return ret;
+
+		break;
+	}
+
+	case SEQ_BACKWARD_SIZE: {
+		const size_t in_start = *in_pos;
+
+		lzma_ret ret = lzma_vli_decode(&coder->tmp,
+				&coder->pos, in, in_pos, in_size);
+
+		const size_t in_used = *in_pos - in_start;
+
+		if (update_size(&coder->total_size, in_used,
+				coder->total_limit))
+			return LZMA_DATA_ERROR;
+
+		coder->size_of_backward_size += in_used;
+
+		if (ret != LZMA_STREAM_END)
+			return ret;
+
+		if (coder->tmp != coder->total_size
+				- coder->size_of_backward_size)
+			return LZMA_DATA_ERROR;
+
+		ret = update_sequence(coder);
+		if (ret != LZMA_OK)
+			return ret;
+
+		break;
+	}
+
+	case SEQ_PADDING:
+		if (in[*in_pos] == 0x00) {
+			if (update_size(&coder->total_size, 1,
+					coder->total_limit))
+				return LZMA_DATA_ERROR;
+
+			++*in_pos;
+			break;
+		}
+
+		return update_sequence(coder);
+
+	default:
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static void
+block_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+	lzma_next_coder_end(&coder->next, allocator);
+	lzma_free(coder, allocator);
+	return;
+}
+
+
+extern lzma_ret
+lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+		lzma_options_block *options)
+{
+	// This is pretty similar to lzma_block_encoder_init().
+	// See comments there.
+
+	if (next->coder == NULL) {
+		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+		if (next->coder == NULL)
+			return LZMA_MEM_ERROR;
+
+		next->code = &block_decode;
+		next->end = &block_decoder_end;
+		next->coder->next = LZMA_NEXT_CODER_INIT;
+	}
+
+	if (!lzma_vli_is_valid(options->total_size)
+			|| !lzma_vli_is_valid(options->compressed_size)
+			|| !lzma_vli_is_valid(options->uncompressed_size)
+			|| !lzma_vli_is_valid(options->total_size)
+			|| !lzma_vli_is_valid(options->total_limit)
+			|| !lzma_vli_is_valid(options->uncompressed_limit)
+			|| (options->uncompressed_size
+					!= LZMA_VLI_VALUE_UNKNOWN
+				&& options->uncompressed_size
+					> options->uncompressed_limit)
+			|| (options->total_size != LZMA_VLI_VALUE_UNKNOWN
+				&& options->total_size
+					> options->total_limit)
+			|| (!options->has_eopm && options->uncompressed_size
+				== LZMA_VLI_VALUE_UNKNOWN)
+			|| options->header_size > options->total_size
+			|| (options->handle_padding
+				&& (options->has_uncompressed_size_in_footer
+					|| options->has_backward_size)))
+		return LZMA_PROG_ERROR;
+
+	{
+		const lzma_ret ret = lzma_check_init(
+				&next->coder->check, options->check);
+		if (ret != LZMA_OK)
+			return ret;
+	}
+
+	if (!options->has_eopm && options->uncompressed_size == 0) {
+		if (!is_size_valid(0, options->compressed_size))
+			return LZMA_PROG_ERROR;
+
+		if (options->check != LZMA_CHECK_NONE) {
+			lzma_check_finish(&next->coder->check, options->check);
+			next->coder->sequence = SEQ_CHECK;
+		} else if (options->handle_padding) {
+			next->coder->sequence = SEQ_PADDING;
+		} else {
+			next->coder->sequence = SEQ_END;
+		}
+	} else {
+		next->coder->sequence = SEQ_CODE;
+	}
+
+	{
+		const lzma_ret ret = lzma_raw_decoder_init(
+				&next->coder->next, allocator,
+				options->filters, options->has_eopm
+					? LZMA_VLI_VALUE_UNKNOWN
+					: options->uncompressed_size,
+				true);
+		if (ret != LZMA_OK)
+			return ret;
+	}
+
+	next->coder->options = options;
+	next->coder->pos = 0;
+	next->coder->total_size = options->header_size;
+	next->coder->compressed_size = 0;
+	next->coder->uncompressed_size = 0;
+	next->coder->total_limit
+			= MIN(options->total_size, options->total_limit);
+	next->coder->uncompressed_limit = MIN(options->uncompressed_size,
+			options->uncompressed_limit);
+	next->coder->tmp = 0;
+	next->coder->size_of_backward_size = 0;
+
+	return LZMA_OK;
+}
+
+
+extern LZMA_API lzma_ret
+lzma_block_decoder(lzma_stream *strm, lzma_options_block *options)
+{
+	lzma_next_strm_init(strm, lzma_block_decoder_init, options);
+
+	strm->internal->supported_actions[LZMA_RUN] = true;
+	strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
+
+	return LZMA_OK;
+}