Imported to git.

1 files changed, 258 insertions, 0 deletions

diff --git a/src/liblzma/common/stream_flags_decoder.c b/src/liblzma/common/stream_flags_decoder.c
new file mode 100644
index 00000000..d9c847ac
--- /dev/null
+++ b/src/liblzma/common/stream_flags_decoder.c
@@ -0,0 +1,258 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       stream_flags_decoder.c
+/// \brief      Decodes Stream Header and tail from .lzma 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 "stream_flags_decoder.h"
+#include "stream_common.h"
+
+
+////////////
+// Common //
+////////////
+
+struct lzma_coder_s {
+	enum {
+		SEQ_HEADER_MAGIC,
+		SEQ_HEADER_FLAGS,
+		SEQ_HEADER_CRC32,
+
+		SEQ_FOOTER_FLAGS,
+		SEQ_FOOTER_MAGIC,
+	} sequence;
+
+	size_t pos;
+	uint32_t crc32;
+
+	lzma_stream_flags *options;
+};
+
+
+static void
+stream_header_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+{
+	lzma_free(coder, allocator);
+	return;
+}
+
+
+static bool
+stream_flags_decode(const uint8_t *in, lzma_stream_flags *options)
+{
+	// Reserved bits must be unset.
+	if (*in & 0xE0)
+		return true;
+
+	options->check = *in & 0x07;
+	options->has_crc32 = (*in & 0x08) != 0;
+	options->is_multi = (*in & 0x10) != 0;
+
+	return false;
+}
+
+
+////////////
+// Header //
+////////////
+
+static lzma_ret
+stream_header_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 lzma_attribute((unused)),
+		size_t *restrict out_pos lzma_attribute((unused)),
+		size_t out_size lzma_attribute((unused)),
+		lzma_action action lzma_attribute((unused)))
+{
+	while (*in_pos < in_size)
+	switch (coder->sequence) {
+	case SEQ_HEADER_MAGIC:
+		if (in[*in_pos] != lzma_header_magic[coder->pos])
+			return LZMA_DATA_ERROR;
+
+		++*in_pos;
+
+		if (++coder->pos == sizeof(lzma_header_magic)) {
+			coder->pos = 0;
+			coder->sequence = SEQ_HEADER_FLAGS;
+		}
+
+		break;
+
+	case SEQ_HEADER_FLAGS:
+		if (stream_flags_decode(in + *in_pos, coder->options))
+			return LZMA_HEADER_ERROR;
+
+		coder->crc32 = lzma_crc32(in + *in_pos, 1, 0);
+
+		++*in_pos;
+		coder->sequence = SEQ_HEADER_CRC32;
+		break;
+
+	case SEQ_HEADER_CRC32:
+		if (in[*in_pos] != ((coder->crc32 >> (coder->pos * 8)) & 0xFF))
+			return LZMA_DATA_ERROR;
+
+		++*in_pos;
+
+		if (++coder->pos == 4)
+			return LZMA_STREAM_END;
+
+		break;
+
+	default:
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static lzma_ret
+stream_header_decoder_init(lzma_next_coder *next,
+		lzma_allocator *allocator, lzma_stream_flags *options)
+{
+	if (options == 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;
+	}
+
+	// Set the function pointers unconditionally, because they may
+	// have been pointing to footer decoder too.
+	next->code = &stream_header_decode;
+	next->end = &stream_header_decoder_end;
+
+	next->coder->sequence = SEQ_HEADER_MAGIC;
+	next->coder->pos = 0;
+	next->coder->crc32 = 0;
+	next->coder->options = options;
+
+	return LZMA_OK;
+}
+
+
+extern lzma_ret
+lzma_stream_header_decoder_init(lzma_next_coder *next,
+		lzma_allocator *allocator, lzma_stream_flags *options)
+{
+	lzma_next_coder_init(
+			stream_header_decoder_init, next, allocator, options);
+}
+
+
+extern LZMA_API lzma_ret
+lzma_stream_header_decoder(lzma_stream *strm, lzma_stream_flags *options)
+{
+	lzma_next_strm_init(strm, stream_header_decoder_init, options);
+
+	strm->internal->supported_actions[LZMA_RUN] = true;
+
+	return LZMA_OK;
+}
+
+
+//////////
+// Tail //
+//////////
+
+static lzma_ret
+stream_tail_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 lzma_attribute((unused)),
+		size_t *restrict out_pos lzma_attribute((unused)),
+		size_t out_size lzma_attribute((unused)),
+		lzma_action action lzma_attribute((unused)))
+{
+	while (*in_pos < in_size)
+	switch (coder->sequence) {
+	case SEQ_FOOTER_FLAGS:
+		if (stream_flags_decode(in + *in_pos, coder->options))
+			return LZMA_HEADER_ERROR;
+
+		++*in_pos;
+		coder->sequence = SEQ_FOOTER_MAGIC;
+		break;
+
+	case SEQ_FOOTER_MAGIC:
+		if (in[*in_pos] != lzma_footer_magic[coder->pos])
+			return LZMA_DATA_ERROR;
+
+		++*in_pos;
+
+		if (++coder->pos == sizeof(lzma_footer_magic))
+			return LZMA_STREAM_END;
+
+		break;
+
+	default:
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static lzma_ret
+stream_tail_decoder_init(lzma_next_coder *next,
+		lzma_allocator *allocator, lzma_stream_flags *options)
+{
+	if (options == 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;
+	}
+
+	// Set the function pointers unconditionally, because they may
+	// have been pointing to footer decoder too.
+	next->code = &stream_tail_decode;
+	next->end = &stream_header_decoder_end;
+
+	next->coder->sequence = SEQ_FOOTER_FLAGS;
+	next->coder->pos = 0;
+	next->coder->options = options;
+
+	return LZMA_OK;
+}
+
+
+extern lzma_ret
+lzma_stream_tail_decoder_init(lzma_next_coder *next,
+		lzma_allocator *allocator, lzma_stream_flags *options)
+{
+	lzma_next_coder_init2(next, allocator, stream_header_decoder_init,
+			stream_tail_decoder_init, allocator, options);
+}
+
+
+extern LZMA_API lzma_ret
+lzma_stream_tail_decoder(lzma_stream *strm, lzma_stream_flags *options)
+{
+	lzma_next_strm_init2(strm, stream_header_decoder_init,
+			stream_tail_decoder_init, strm->allocator, options);
+
+	strm->internal->supported_actions[LZMA_RUN] = true;
+
+	return LZMA_OK;
+}