1 files changed, 227 insertions, 0 deletions
diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
new file mode 100644
index 0000000..4a136ef
--- /dev/null
+++ b/src/liblzma/common/block_encoder.c
@@ -0,0 +1,227 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       block_encoder.c
+/// \brief      Encodes .xz Blocks
+//
+//  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 "filter_encoder.h"
+#include "check.h"
+
+
+typedef struct {
+	/// The filters in the chain; initialized with lzma_raw_decoder_init().
+	lzma_next_coder next;
+
+	/// Encoding options; we also write Unpadded Size, Compressed Size,
+	/// and Uncompressed Size back to this structure when the encoding
+	/// has been finished.
+	lzma_block *block;
+
+	enum {
+		SEQ_CODE,
+		SEQ_PADDING,
+		SEQ_CHECK,
+	} sequence;
+
+	/// Compressed Size calculated while encoding
+	lzma_vli compressed_size;
+
+	/// Uncompressed Size calculated while encoding
+	lzma_vli uncompressed_size;
+
+	/// Position in the Check field
+	size_t pos;
+
+	/// Check of the uncompressed data
+	lzma_check_state check;
+} lzma_block_coder;
+
+
+static lzma_ret
+block_encode(void *coder_ptr, 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)
+{
+	lzma_block_coder *coder = coder_ptr;
+
+	// Check that our amount of input stays in proper limits.
+	if (LZMA_VLI_MAX - coder->uncompressed_size < in_size - *in_pos)
+		return LZMA_DATA_ERROR;
+
+	switch (coder->sequence) {
+	case SEQ_CODE: {
+		const size_t in_start = *in_pos;
+		const size_t out_start = *out_pos;
+
+		const 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 (COMPRESSED_SIZE_MAX - coder->compressed_size < out_used)
+			return LZMA_DATA_ERROR;
+
+		coder->compressed_size += out_used;
+
+		// No need to check for overflow because we have already
+		// checked it at the beginning of this function.
+		coder->uncompressed_size += in_used;
+
+		// Call lzma_check_update() only if input was consumed. This
+		// avoids null pointer + 0 (undefined behavior) when in == 0.
+		if (in_used > 0)
+			lzma_check_update(&coder->check, coder->block->check,
+					in + in_start, in_used);
+
+		if (ret != LZMA_STREAM_END || action == LZMA_SYNC_FLUSH)
+			return ret;
+
+		assert(*in_pos == in_size);
+		assert(action == LZMA_FINISH);
+
+		// Copy the values into coder->block. The caller
+		// may use this information to construct Index.
+		coder->block->compressed_size = coder->compressed_size;
+		coder->block->uncompressed_size = coder->uncompressed_size;
+
+		coder->sequence = SEQ_PADDING;
+	}
+
+	// Fall through
+
+	case SEQ_PADDING:
+		// Pad Compressed Data to a multiple of four bytes. We can
+		// use coder->compressed_size for this since we don't need
+		// it for anything else anymore.
+		while (coder->compressed_size & 3) {
+			if (*out_pos >= out_size)
+				return LZMA_OK;
+
+			out[*out_pos] = 0x00;
+			++*out_pos;
+			++coder->compressed_size;
+		}
+
+		if (coder->block->check == LZMA_CHECK_NONE)
+			return LZMA_STREAM_END;
+
+		lzma_check_finish(&coder->check, coder->block->check);
+
+		coder->sequence = SEQ_CHECK;
+
+	// Fall through
+
+	case SEQ_CHECK: {
+		const size_t check_size = lzma_check_size(coder->block->check);
+		lzma_bufcpy(coder->check.buffer.u8, &coder->pos, check_size,
+				out, out_pos, out_size);
+		if (coder->pos < check_size)
+			return LZMA_OK;
+
+		memcpy(coder->block->raw_check, coder->check.buffer.u8,
+				check_size);
+		return LZMA_STREAM_END;
+	}
+	}
+
+	return LZMA_PROG_ERROR;
+}
+
+
+static void
+block_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
+{
+	lzma_block_coder *coder = coder_ptr;
+	lzma_next_end(&coder->next, allocator);
+	lzma_free(coder, allocator);
+	return;
+}
+
+
+static lzma_ret
+block_encoder_update(void *coder_ptr, const lzma_allocator *allocator,
+		const lzma_filter *filters lzma_attribute((__unused__)),
+		const lzma_filter *reversed_filters)
+{
+	lzma_block_coder *coder = coder_ptr;
+
+	if (coder->sequence != SEQ_CODE)
+		return LZMA_PROG_ERROR;
+
+	return lzma_next_filter_update(
+			&coder->next, allocator, reversed_filters);
+}
+
+
+extern lzma_ret
+lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
+		lzma_block *block)
+{
+	lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
+
+	if (block == NULL)
+		return LZMA_PROG_ERROR;
+
+	// The contents of the structure may depend on the version so
+	// check the version first.
+	if (block->version > 1)
+		return LZMA_OPTIONS_ERROR;
+
+	// If the Check ID is not supported, we cannot calculate the check and
+	// thus not create a proper Block.
+	if ((unsigned int)(block->check) > LZMA_CHECK_ID_MAX)
+		return LZMA_PROG_ERROR;
+
+	if (!lzma_check_is_supported(block->check))
+		return LZMA_UNSUPPORTED_CHECK;
+
+	// Allocate and initialize *next->coder if needed.
+	lzma_block_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
+		if (coder == NULL)
+			return LZMA_MEM_ERROR;
+
+		next->coder = coder;
+		next->code = &block_encode;
+		next->end = &block_encoder_end;
+		next->update = &block_encoder_update;
+		coder->next = LZMA_NEXT_CODER_INIT;
+	}
+
+	// Basic initializations
+	coder->sequence = SEQ_CODE;
+	coder->block = block;
+	coder->compressed_size = 0;
+	coder->uncompressed_size = 0;
+	coder->pos = 0;
+
+	// Initialize the check
+	lzma_check_init(&coder->check, block->check);
+
+	// Initialize the requested filters.
+	return lzma_raw_encoder_init(&coder->next, allocator, block->filters);
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_block_encoder(lzma_stream *strm, lzma_block *block)
+{
+	lzma_next_strm_init(lzma_block_encoder_init, strm, block);
+
+	strm->internal->supported_actions[LZMA_RUN] = true;
+	strm->internal->supported_actions[LZMA_SYNC_FLUSH] = true;
+	strm->internal->supported_actions[LZMA_FINISH] = true;
+
+	return LZMA_OK;
+}