1 // SPDX-License-Identifier: 0BSD 2 3 /////////////////////////////////////////////////////////////////////////////// 4 // 5 /// \file block_encoder.h 6 /// \brief Encodes .xz Blocks 7 // 8 // Author: Lasse Collin 9 // 10 /////////////////////////////////////////////////////////////////////////////// 11 12 #ifndef LZMA_BLOCK_ENCODER_H 13 #define LZMA_BLOCK_ENCODER_H 14 15 #include "common.h" 16 17 18 /// \brief Biggest Compressed Size value that the Block encoder supports 19 /// 20 /// The maximum size of a single Block is limited by the maximum size of 21 /// a Stream, which in theory is 2^63 - 3 bytes (i.e. LZMA_VLI_MAX - 3). 22 /// While the size is really big and no one should hit it in practice, we 23 /// take it into account in some places anyway to catch some errors e.g. if 24 /// application passes insanely big value to some function. 25 /// 26 /// We could take into account the headers etc. to determine the exact 27 /// maximum size of the Compressed Data field, but the complexity would give 28 /// us nothing useful. Instead, limit the size of Compressed Data so that 29 /// even with biggest possible Block Header and Check fields the total 30 /// encoded size of the Block stays as a valid VLI. This doesn't guarantee 31 /// that the size of the Stream doesn't grow too big, but that problem is 32 /// taken care outside the Block handling code. 33 /// 34 /// ~LZMA_VLI_C(3) is to guarantee that if we need padding at the end of 35 /// the Compressed Data field, it will still stay in the proper limit. 36 /// 37 /// This constant is in this file because it is needed in both 38 /// block_encoder.c and block_buffer_encoder.c. 39 #define COMPRESSED_SIZE_MAX ((LZMA_VLI_MAX - LZMA_BLOCK_HEADER_SIZE_MAX \ 40 - LZMA_CHECK_SIZE_MAX) & ~LZMA_VLI_C(3)) 41 42 43 extern lzma_ret lzma_block_encoder_init(lzma_next_coder *next, 44 const lzma_allocator *allocator, lzma_block *block); 45 46 #endif 47