From 2ee4edeffc8d9734bf68230df31b20ac6a94c9b5 Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Mon, 11 Apr 2011 13:59:50 +0300 Subject: [PATCH] liblzma: Don't create an empty Block in lzma_stream_buffer_encode(). Empty Block was created if the input buffer was empty. Empty Block wastes a few bytes of space, but more importantly it triggers a bug in XZ Utils 5.0.1 and older when trying to decompress such a file. 5.0.1 and older consider such files to be corrupt. I thought that no encoder creates empty Blocks when releasing 5.0.2 but I was wrong. --- src/liblzma/common/stream_buffer_encoder.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/src/liblzma/common/stream_buffer_encoder.c b/src/liblzma/common/stream_buffer_encoder.c index dd23c9af..2450ee2e 100644 --- a/src/liblzma/common/stream_buffer_encoder.c +++ b/src/liblzma/common/stream_buffer_encoder.c @@ -84,26 +84,32 @@ lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check, out_pos += LZMA_STREAM_HEADER_SIZE; - // Block + // Encode a Block but only if there is at least one byte of input. lzma_block block = { .version = 0, .check = check, .filters = filters, }; - return_if_error(lzma_block_buffer_encode(&block, allocator, - in, in_size, out, &out_pos, out_size)); + if (in_size > 0) + return_if_error(lzma_block_buffer_encode(&block, allocator, + in, in_size, out, &out_pos, out_size)); // Index { - // Create an Index with one Record. + // Create an Index. It will have one Record if there was + // at least one byte of input to encode. Otherwise the + // Index will be empty. lzma_index *i = lzma_index_init(allocator); if (i == NULL) return LZMA_MEM_ERROR; - lzma_ret ret = lzma_index_append(i, allocator, - lzma_block_unpadded_size(&block), - block.uncompressed_size); + lzma_ret ret = LZMA_OK; + + if (in_size > 0) + ret = lzma_index_append(i, allocator, + lzma_block_unpadded_size(&block), + block.uncompressed_size); // If adding the Record was successful, encode the Index // and get its size which will be stored into Stream Footer.