1 files changed, 318 insertions, 0 deletions
diff --git a/src/liblzma/lzma/lzma2_decoder.c b/src/liblzma/lzma/lzma2_decoder.c
new file mode 100644
index 00000000..b16c40ce
--- /dev/null
+++ b/src/liblzma/lzma/lzma2_decoder.c
@@ -0,0 +1,318 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       lzma2_decoder.c
+/// \brief      LZMA2 decoder
+//
+//  Copyright (C) 1999-2008 Igor Pavlov
+//  Copyright (C) 2008 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 "lzma2_decoder.h"
+#include "lz_decoder.h"
+#include "lzma_decoder.h"
+
+
+struct lzma_coder_s {
+	enum sequence {
+		SEQ_CONTROL,
+		SEQ_UNCOMPRESSED_1,
+		SEQ_UNCOMPRESSED_2,
+		SEQ_COMPRESSED_0,
+		SEQ_COMPRESSED_1,
+		SEQ_PROPERTIES,
+		SEQ_LZMA,
+		SEQ_COPY,
+	} sequence;
+
+	/// Sequence after the size fields have been decoded.
+	enum sequence next_sequence;
+
+	/// LZMA decoder
+	lzma_lz_decoder lzma;
+
+	/// Uncompressed size of LZMA chunk
+	size_t uncompressed_size;
+
+	/// Compressed size of the chunk (naturally equals to uncompressed
+	/// size of uncompressed chunk)
+	size_t compressed_size;
+
+	/// True if properties are needed. This is false before the
+	/// first LZMA chunk.
+	bool need_properties;
+
+	/// True if dictionary reset is needed. This is false before the
+	/// first chunk (LZMA or uncompressed).
+	bool need_dictionary_reset;
+
+	lzma_options_lzma options;
+};
+
+
+static lzma_ret
+lzma2_decode(lzma_coder *restrict coder, lzma_dict *restrict dict,
+		const uint8_t *restrict in, size_t *restrict in_pos,
+		size_t in_size)
+{
+	// With SEQ_LZMA it is possible that no new input is needed to do
+	// some progress. The rest of the sequences assume that there is
+	// at least one byte of input.
+	while (*in_pos < in_size || coder->sequence == SEQ_LZMA)
+	switch (coder->sequence) {
+	case SEQ_CONTROL:
+		if (in[*in_pos] & 0x80) {
+			// Get the highest five bits of uncompressed size.
+			coder->uncompressed_size
+					= (uint32_t)(in[*in_pos] & 0x1F) << 16;
+			coder->sequence = SEQ_UNCOMPRESSED_1;
+
+			// See if we need to reset dictionary or state.
+			switch ((in[(*in_pos)++] >> 5) & 3) {
+			case 3:
+				dict_reset(dict);
+				coder->need_dictionary_reset = false;
+
+			// Fall through
+
+			case 2:
+				if (coder->need_dictionary_reset)
+					return LZMA_DATA_ERROR;
+
+				coder->need_properties = false;
+				coder->next_sequence = SEQ_PROPERTIES;
+				break;
+
+			case 1:
+				if (coder->need_properties)
+					return LZMA_DATA_ERROR;
+
+				coder->lzma.reset(coder->lzma.coder,
+						&coder->options);
+
+				coder->next_sequence = SEQ_LZMA;
+				break;
+
+			case 0:
+				if (coder->need_properties)
+					return LZMA_DATA_ERROR;
+
+				coder->next_sequence = SEQ_LZMA;
+				break;
+			}
+
+		} else {
+			switch (in[(*in_pos)++]) {
+			case 0:
+				// End of payload marker
+				return LZMA_STREAM_END;
+
+			case 1:
+				// Dictionary reset
+				dict_reset(dict);
+				coder->need_dictionary_reset = false;
+
+			// Fall through
+
+			case 2:
+				if (coder->need_dictionary_reset)
+					return LZMA_DATA_ERROR;
+
+				// Uncompressed chunk; we need to read total
+				// size first.
+				coder->sequence = SEQ_COMPRESSED_0;
+				coder->next_sequence = SEQ_COPY;
+				break;
+
+			default:
+				return LZMA_DATA_ERROR;
+			}
+		}
+
+		break;
+
+	case SEQ_UNCOMPRESSED_1:
+		coder->uncompressed_size += (uint32_t)(in[(*in_pos)++]) << 8;
+		coder->sequence = SEQ_UNCOMPRESSED_2;
+		break;
+
+	case SEQ_UNCOMPRESSED_2:
+		coder->uncompressed_size += in[(*in_pos)++] + 1;
+		coder->sequence = SEQ_COMPRESSED_0;
+		coder->lzma.set_uncompressed(coder->lzma.coder,
+				coder->uncompressed_size);
+		break;
+
+	case SEQ_COMPRESSED_0:
+		coder->compressed_size = (uint32_t)(in[(*in_pos)++]) << 8;
+		coder->sequence = SEQ_COMPRESSED_1;
+		break;
+
+	case SEQ_COMPRESSED_1:
+		coder->compressed_size += in[(*in_pos)++] + 1;
+		coder->sequence = coder->next_sequence;
+		break;
+
+	case SEQ_PROPERTIES:
+		if (lzma_lzma_lclppb_decode(&coder->options, in[(*in_pos)++]))
+			return LZMA_DATA_ERROR;
+
+		coder->lzma.reset(coder->lzma.coder, &coder->options);
+
+		coder->sequence = SEQ_LZMA;
+		break;
+
+	case SEQ_LZMA: {
+		// Store the start offset so that we can update
+		// coder->compressed_size later.
+		const size_t in_start = *in_pos;
+
+		// Decode from in[] to *dict.
+		const lzma_ret ret = coder->lzma.code(coder->lzma.coder,
+				dict, in, in_pos, in_size);
+
+		// Validate and update coder->compressed_size.
+		const size_t in_used = *in_pos - in_start;
+		if (in_used > coder->compressed_size)
+			return LZMA_DATA_ERROR;
+
+		coder->compressed_size -= in_used;
+
+		// Return if we didn't finish the chunk, or an error occurred.
+		if (ret != LZMA_STREAM_END)
+			return ret;
+
+		// The LZMA decoder must have consumed the whole chunk now.
+		// We don't need to worry about uncompressed size since it
+		// is checked by the LZMA decoder.
+		if (coder->compressed_size != 0)
+			return LZMA_DATA_ERROR;
+
+		coder->sequence = SEQ_CONTROL;
+		break;
+	}
+
+	case SEQ_COPY: {
+		// Copy from input to the dictionary as is.
+		// FIXME Can copy too much?
+		dict_write(dict, in, in_pos, in_size, &coder->compressed_size);
+		if (coder->compressed_size != 0)
+			return LZMA_OK;
+
+		coder->sequence = SEQ_CONTROL;
+		break;
+	}
+
+	default:
+		assert(0);
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static void
+lzma2_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+	assert(coder->lzma.end == NULL);
+	lzma_free(coder->lzma.coder, allocator);
+
+	lzma_free(coder, allocator);
+
+	return;
+}
+
+
+static lzma_ret
+lzma2_decoder_init(lzma_lz_decoder *lz, lzma_allocator *allocator,
+		const void *options, size_t *dict_size)
+{
+	if (lz->coder == NULL) {
+		lz->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+		if (lz->coder == NULL)
+			return LZMA_MEM_ERROR;
+
+		lz->code = &lzma2_decode;
+		lz->end = &lzma2_decoder_end;
+
+		lz->coder->lzma = LZMA_LZ_DECODER_INIT;
+	}
+
+	lz->coder->sequence = SEQ_CONTROL;
+	lz->coder->need_properties = true;
+	lz->coder->need_dictionary_reset = true;
+
+	return lzma_lzma_decoder_create(&lz->coder->lzma,
+			allocator, options, dict_size);
+}
+
+
+extern lzma_ret
+lzma_lzma2_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+		const lzma_filter_info *filters)
+{
+	// LZMA2 can only be the last filter in the chain. This is enforced
+	// by the raw_decoder initialization.
+	assert(filters[1].init == NULL);
+
+	return lzma_lz_decoder_init(next, allocator, filters,
+			&lzma2_decoder_init);
+}
+
+
+extern uint64_t
+lzma_lzma2_decoder_memusage(const void *options)
+{
+	const uint64_t lzma_memusage = lzma_lzma_decoder_memusage(options);
+	if (lzma_memusage == UINT64_MAX)
+		return UINT64_MAX;
+
+	return sizeof(lzma_coder) + lzma_memusage;
+}
+
+
+extern lzma_ret
+lzma_lzma2_props_decode(void **options, lzma_allocator *allocator,
+		const uint8_t *props, size_t props_size)
+{
+	if (props_size != 1)
+		return LZMA_HEADER_ERROR;
+
+	// Check that reserved bits are unset.
+	if (props[0] & 0xC0)
+		return LZMA_HEADER_ERROR;
+
+	// Decode the dictionary size.
+	if (props[0] > 40)
+		return LZMA_HEADER_ERROR;
+
+	lzma_options_lzma *opt = lzma_alloc(
+			sizeof(lzma_options_lzma), allocator);
+	if (opt == NULL)
+		return LZMA_MEM_ERROR;
+
+	if (props[0] == 40) {
+		opt->dictionary_size = UINT32_MAX;
+	} else {
+		opt->dictionary_size = 2 | (props[0] & 1);
+		opt->dictionary_size <<= props[0] / 2 + 11;
+	}
+
+	opt->preset_dictionary = NULL;
+	opt->preset_dictionary_size = 0;
+
+	*options = opt;
+
+	return LZMA_OK;
+}