block_encoder.h revision 213700
1/////////////////////////////////////////////////////////////////////////////// 2// 3/// \file block_encoder.h 4/// \brief Encodes .xz Blocks 5// 6// Author: Lasse Collin 7// 8// This file has been put into the public domain. 9// You can do whatever you want with this file. 10// 11/////////////////////////////////////////////////////////////////////////////// 12 13#ifndef LZMA_BLOCK_ENCODER_H 14#define LZMA_BLOCK_ENCODER_H 15 16#include "common.h" 17 18 19/// \brief Biggest Compressed Size value that the Block encoder supports 20/// 21/// The maximum size of a single Block is limited by the maximum size of 22/// a Stream, which in theory is 2^63 - 3 bytes (i.e. LZMA_VLI_MAX - 3). 23/// While the size is really big and no one should hit it in practice, we 24/// take it into account in some places anyway to catch some errors e.g. if 25/// application passes insanely big value to some function. 26/// 27/// We could take into account the headers etc. to determine the exact 28/// maximum size of the Compressed Data field, but the complexity would give 29/// us nothing useful. Instead, limit the size of Compressed Data so that 30/// even with biggest possible Block Header and Check fields the total 31/// encoded size of the Block stays as a valid VLI. This doesn't guarantee 32/// that the size of the Stream doesn't grow too big, but that problem is 33/// taken care outside the Block handling code. 34/// 35/// ~LZMA_VLI_C(3) is to guarantee that if we need padding at the end of 36/// the Compressed Data field, it will still stay in the proper limit. 37/// 38/// This constant is in this file because it is needed in both 39/// block_encoder.c and block_buffer_encoder.c. 40#define COMPRESSED_SIZE_MAX ((LZMA_VLI_MAX - LZMA_BLOCK_HEADER_SIZE_MAX \ 41 - LZMA_CHECK_SIZE_MAX) & ~LZMA_VLI_C(3)) 42 43 44extern lzma_ret lzma_block_encoder_init(lzma_next_coder *next, 45 lzma_allocator *allocator, lzma_block *block); 46 47#endif 48