Index: xz/src/liblzma/common/block_header_encoder.c |
=================================================================== |
--- xz/src/liblzma/common/block_header_encoder.c (revision 0) |
+++ xz/src/liblzma/common/block_header_encoder.c (revision 0) |
@@ -0,0 +1,132 @@ |
+/////////////////////////////////////////////////////////////////////////////// |
+// |
+/// \file block_header_encoder.c |
+/// \brief Encodes Block Header for .xz files |
+// |
+// Author: Lasse Collin |
+// |
+// This file has been put into the public domain. |
+// You can do whatever you want with this file. |
+// |
+/////////////////////////////////////////////////////////////////////////////// |
+ |
+#include "common.h" |
+#include "check.h" |
+ |
+ |
+extern LZMA_API(lzma_ret) |
+lzma_block_header_size(lzma_block *block) |
+{ |
+ if (block->version != 0) |
+ return LZMA_OPTIONS_ERROR; |
+ |
+ // Block Header Size + Block Flags + CRC32. |
+ uint32_t size = 1 + 1 + 4; |
+ |
+ // Compressed Size |
+ if (block->compressed_size != LZMA_VLI_UNKNOWN) { |
+ const uint32_t add = lzma_vli_size(block->compressed_size); |
+ if (add == 0 || block->compressed_size == 0) |
+ return LZMA_PROG_ERROR; |
+ |
+ size += add; |
+ } |
+ |
+ // Uncompressed Size |
+ if (block->uncompressed_size != LZMA_VLI_UNKNOWN) { |
+ const uint32_t add = lzma_vli_size(block->uncompressed_size); |
+ if (add == 0) |
+ return LZMA_PROG_ERROR; |
+ |
+ size += add; |
+ } |
+ |
+ // List of Filter Flags |
+ if (block->filters == NULL || block->filters[0].id == LZMA_VLI_UNKNOWN) |
+ return LZMA_PROG_ERROR; |
+ |
+ for (size_t i = 0; block->filters[i].id != LZMA_VLI_UNKNOWN; ++i) { |
+ // Don't allow too many filters. |
+ if (i == LZMA_FILTERS_MAX) |
+ return LZMA_PROG_ERROR; |
+ |
+ uint32_t add; |
+ return_if_error(lzma_filter_flags_size(&add, |
+ block->filters + i)); |
+ |
+ size += add; |
+ } |
+ |
+ // Pad to a multiple of four bytes. |
+ block->header_size = (size + 3) & ~UINT32_C(3); |
+ |
+ // NOTE: We don't verify that the encoded size of the Block stays |
+ // within limits. This is because it is possible that we are called |
+ // with exaggerated Compressed Size (e.g. LZMA_VLI_MAX) to reserve |
+ // space for Block Header, and later called again with lower, |
+ // real values. |
+ |
+ return LZMA_OK; |
+} |
+ |
+ |
+extern LZMA_API(lzma_ret) |
+lzma_block_header_encode(const lzma_block *block, uint8_t *out) |
+{ |
+ // Validate everything but filters. |
+ if (lzma_block_unpadded_size(block) == 0 |
+ || !lzma_vli_is_valid(block->uncompressed_size)) |
+ return LZMA_PROG_ERROR; |
+ |
+ // Indicate the size of the buffer _excluding_ the CRC32 field. |
+ const size_t out_size = block->header_size - 4; |
+ |
+ // Store the Block Header Size. |
+ out[0] = out_size / 4; |
+ |
+ // We write Block Flags in pieces. |
+ out[1] = 0x00; |
+ size_t out_pos = 2; |
+ |
+ // Compressed Size |
+ if (block->compressed_size != LZMA_VLI_UNKNOWN) { |
+ return_if_error(lzma_vli_encode(block->compressed_size, NULL, |
+ out, &out_pos, out_size)); |
+ |
+ out[1] |= 0x40; |
+ } |
+ |
+ // Uncompressed Size |
+ if (block->uncompressed_size != LZMA_VLI_UNKNOWN) { |
+ return_if_error(lzma_vli_encode(block->uncompressed_size, NULL, |
+ out, &out_pos, out_size)); |
+ |
+ out[1] |= 0x80; |
+ } |
+ |
+ // Filter Flags |
+ if (block->filters == NULL || block->filters[0].id == LZMA_VLI_UNKNOWN) |
+ return LZMA_PROG_ERROR; |
+ |
+ size_t filter_count = 0; |
+ do { |
+ // There can be a maximum of four filters. |
+ if (filter_count == LZMA_FILTERS_MAX) |
+ return LZMA_PROG_ERROR; |
+ |
+ return_if_error(lzma_filter_flags_encode( |
+ block->filters + filter_count, |
+ out, &out_pos, out_size)); |
+ |
+ } while (block->filters[++filter_count].id != LZMA_VLI_UNKNOWN); |
+ |
+ out[1] |= filter_count - 1; |
+ |
+ // Padding |
+ memzero(out + out_pos, out_size - out_pos); |
+ |
+ // CRC32 |
+ unaligned_write32le(out + out_size, lzma_crc32(out, out_size, 0)); |
+ |
+ return LZMA_OK; |
+} |
Property changes on: xz/src/liblzma/common/block_header_encoder.c |
___________________________________________________________________ |
Added: svn:eol-style |
+ LF |