Imported to git.

1 files changed, 197 insertions, 0 deletions

diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c
new file mode 100644
index 00000000..092047b4
--- /dev/null
+++ b/src/liblzma/common/alone_decoder.c
@@ -0,0 +1,197 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       alone_decoder.c
+/// \brief      Decoder for LZMA_Alone files
+//
+//  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 "alone_decoder.h"
+#include "lzma_decoder.h"
+
+
+struct lzma_coder_s {
+	lzma_next_coder next;
+
+	enum {
+		SEQ_PROPERTIES,
+		SEQ_DICTIONARY_SIZE,
+		SEQ_UNCOMPRESSED_SIZE,
+		SEQ_CODER_INIT,
+		SEQ_CODE,
+	} sequence;
+
+	size_t pos;
+
+	lzma_options_alone options;
+};
+
+
+static lzma_ret
+alone_decode(lzma_coder *coder,
+		lzma_allocator *allocator lzma_attribute((unused)),
+		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)
+{
+	while (*out_pos < out_size
+			&& (coder->sequence == SEQ_CODE || *in_pos < in_size))
+	switch (coder->sequence) {
+	case SEQ_PROPERTIES:
+		if (lzma_lzma_decode_properties(
+				&coder->options.lzma, in[*in_pos]))
+			return LZMA_DATA_ERROR;
+
+		coder->sequence = SEQ_DICTIONARY_SIZE;
+		++*in_pos;
+		break;
+
+	case SEQ_DICTIONARY_SIZE:
+		coder->options.lzma.dictionary_size
+				|= (size_t)(in[*in_pos]) << (coder->pos * 8);
+
+		if (++coder->pos == 4) {
+			// A hack to ditch tons of false positives: We allow
+			// only dictionary sizes that are a power of two.
+			// LZMA_Alone didn't create other kinds of files,
+			// although it's not impossible that files with
+			// other dictionary sizes exist. Well, if someone
+			// complains, this will be reconsidered.
+			size_t count = 0;
+			for (size_t i = 0; i < 32; ++i)
+				if (coder->options.lzma.dictionary_size
+						& (UINT32_C(1) << i))
+					++count;
+
+			if (count > 1)
+				return LZMA_DATA_ERROR;
+
+			coder->pos = 0;
+			coder->sequence = SEQ_UNCOMPRESSED_SIZE;
+		}
+
+		++*in_pos;
+		break;
+
+	case SEQ_UNCOMPRESSED_SIZE:
+		coder->options.uncompressed_size
+				|= (lzma_vli)(in[*in_pos]) << (coder->pos * 8);
+
+		if (++coder->pos == 8) {
+			// Another hack to ditch false positives: Assume that
+			// if the uncompressed size is known, it must be less
+			// than 256 GiB. Again, if someone complains, this
+			// will be reconsidered.
+			if (coder->options.uncompressed_size
+						!= LZMA_VLI_VALUE_UNKNOWN
+					&& coder->options.uncompressed_size
+						>= (LZMA_VLI_C(1) << 38))
+				return LZMA_DATA_ERROR;
+
+			coder->pos = 0;
+			coder->sequence = SEQ_CODER_INIT;
+		}
+
+		++*in_pos;
+		break;
+
+	case SEQ_CODER_INIT: {
+		// Two is enough because there won't be implicit filters.
+		lzma_filter_info filters[2] = {
+			{
+				.init = &lzma_lzma_decoder_init,
+				.options = &coder->options.lzma,
+				.uncompressed_size = coder->options
+						.uncompressed_size,
+			}, {
+				.init = NULL,
+			}
+		};
+
+		const lzma_ret ret = lzma_next_filter_init(&coder->next,
+				allocator, filters);
+		if (ret != LZMA_OK)
+			return ret;
+
+		coder->sequence = SEQ_CODE;
+	}
+
+	// Fall through
+
+	case SEQ_CODE: {
+		return coder->next.code(coder->next.coder,
+				allocator, in, in_pos, in_size,
+				out, out_pos, out_size, action);
+	}
+
+	default:
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static void
+alone_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+	lzma_next_coder_end(&coder->next, allocator);
+	lzma_free(coder, allocator);
+	return;
+}
+
+
+static lzma_ret
+alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator)
+{
+	if (next->coder == NULL) {
+		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+		if (next->coder == NULL)
+			return LZMA_MEM_ERROR;
+
+		next->code = &alone_decode;
+		next->end = &alone_decoder_end;
+		next->coder->next = LZMA_NEXT_CODER_INIT;
+	}
+
+	next->coder->sequence = SEQ_PROPERTIES;
+	next->coder->pos = 0;
+	next->coder->options.lzma.dictionary_size = 0;
+	next->coder->options.uncompressed_size = 0;
+
+	return LZMA_OK;
+}
+
+
+extern lzma_ret
+lzma_alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator)
+{
+	// We need to use _init2 because we don't pass any varadic args.
+	lzma_next_coder_init2(next, allocator, alone_decoder_init,
+			alone_decoder_init, allocator);
+}
+
+
+extern LZMA_API lzma_ret
+lzma_alone_decoder(lzma_stream *strm)
+{
+	lzma_next_strm_init2(strm, alone_decoder_init,
+			alone_decoder_init, strm->allocator);
+
+	strm->internal->supported_actions[LZMA_RUN] = true;
+	strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
+
+	return LZMA_OK;
+}