X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=include%2Fwimlib%2Flzx.h;h=da0c55143c4bc9a569bdc5550b51c0e16c16d80b;hb=1ba2a3422b48935899b8cd406d6976a5997e81ea;hp=50d80f620de6333510004947cefc2c42eb77c9a7;hpb=b7071062542143113ad654d89ee6b0603b23b524;p=wimlib diff --git a/include/wimlib/lzx.h b/include/wimlib/lzx.h index 50d80f62..da0c5514 100644 --- a/include/wimlib/lzx.h +++ b/include/wimlib/lzx.h @@ -1,152 +1,59 @@ +/* + * lzx.h + * + * Declarations shared between LZX compression and decompression. + */ + #ifndef _WIMLIB_LZX_H #define _WIMLIB_LZX_H -/* Constants for the LZX data compression format. See the comments in - * lzx-compress.c and lzx-decompress.c for more information about this format. - * */ - #include "wimlib/assert.h" +#include "wimlib/compiler.h" +#include "wimlib/lzx_constants.h" #include "wimlib/util.h" #include "wimlib/types.h" //#define ENABLE_LZX_DEBUG #ifdef ENABLE_LZX_DEBUG -# define LZX_DEBUG DEBUG # define LZX_ASSERT wimlib_assert #else -# define LZX_DEBUG(format, ...) # define LZX_ASSERT(...) #endif -/* Constants, most of which are defined by the LZX specification: */ - -/* The smallest and largest allowed match lengths. */ -#define LZX_MIN_MATCH_LEN 2 -#define LZX_MAX_MATCH_LEN 257 - -/* Number of values an uncompressed literal byte can represent. */ -#define LZX_NUM_CHARS 256 - -/* Each LZX block begins with 3 bits that determines the block type. Below are - * the valid block types. Values 0, and 4 through 7, are invalid. */ -#define LZX_BLOCKTYPE_VERBATIM 1 -#define LZX_BLOCKTYPE_ALIGNED 2 -#define LZX_BLOCKTYPE_UNCOMPRESSED 3 - -#define LZX_NUM_PRIMARY_LENS 7 - -/* The number of position slots varies from 30 to 51 depending on the window - * size (see comment in lzx-decompress.c). */ -#define LZX_MAX_POSITION_SLOTS 51 - -#define LZX_MIN_WINDOW_ORDER 15 -#define LZX_MAX_WINDOW_ORDER 21 -#define LZX_MIN_WINDOW_SIZE (1U << LZX_MIN_WINDOW_ORDER) /* 32768 */ -#define LZX_MAX_WINDOW_SIZE (1U << LZX_MAX_WINDOW_ORDER) /* 2097152 */ - -/* Read the LZX specification for information about the Huffman trees used in - * the LZX compression format. Basically there are 4 of them: The main tree, - * the length tree, the pre tree, and the aligned tree. The main tree and - * length tree are given at the beginning of VERBATIM and ALIGNED blocks as a - * list of *_NUM_SYMBOLS code length values. They are read using the - * read_code_lens() function and built using the make_decode_table() function. - * The decode table is not a real tree but rather a table that we can index by - * some number of bits (*_TABLEBITS) of the input to quickly look up the symbol - * corresponding to a Huffman code. - * - * The ALIGNED tree is only present on ALIGNED blocks. - * - * A PRECODE is used to encode the code lengths for the main tree and the length - * tree. There is a separate pretree for each half of the main tree. */ - -#define LZX_MAINCODE_MAX_NUM_SYMBOLS (LZX_NUM_CHARS + (LZX_MAX_POSITION_SLOTS << 3)) -#define LZX_MAINCODE_TABLEBITS 11 - -#define LZX_LENCODE_NUM_SYMBOLS 249 -#define LZX_LENCODE_TABLEBITS 10 - -#define LZX_PRECODE_NUM_SYMBOLS 20 -#define LZX_PRECODE_TABLEBITS 6 -#define LZX_PRECODE_ELEMENT_SIZE 4 - -#define LZX_ALIGNEDCODE_NUM_SYMBOLS 8 -#define LZX_ALIGNEDCODE_TABLEBITS 7 -#define LZX_ALIGNEDCODE_ELEMENT_SIZE 3 - -/* Maximum allowed length of Huffman codewords. */ -#define LZX_MAX_MAIN_CODEWORD_LEN 16 -#define LZX_MAX_LEN_CODEWORD_LEN 16 -#define LZX_MAX_PRE_CODEWORD_LEN 16 -#define LZX_MAX_ALIGNED_CODEWORD_LEN 8 - -/* For the LZX-compressed blocks in WIM files, this value is always used as the - * filesize parameter for the call instruction (0xe8 byte) preprocessing, even - * though the blocks themselves are not this size, and the size of the actual - * file resource in the WIM file is very likely to be something entirely - * different as well. */ -#define LZX_WIM_MAGIC_FILESIZE 12000000 - -/* Assumed LZX block size when the encoded block size begins with a 0 bit. */ -#define LZX_DEFAULT_BLOCK_SIZE 32768 - -#define USE_LZX_EXTRA_BITS_ARRAY - -#ifdef USE_LZX_EXTRA_BITS_ARRAY -extern const u8 lzx_extra_bits[LZX_MAX_POSITION_SLOTS]; -#endif - -/* Given the number of an LZX position slot, return the number of extra bits that - * are needed to encode the match offset. */ -static inline unsigned -lzx_get_num_extra_bits(unsigned position_slot) -{ -#ifdef USE_LZX_EXTRA_BITS_ARRAY - /* Use a table */ - return lzx_extra_bits[position_slot]; -#else - /* Calculate directly using a shift and subtraction. */ - LZX_ASSERT(position_slot >= 2 && position_slot <= 37); - return (position_slot >> 1) - 1; -#endif -} +extern const u32 lzx_offset_slot_base[LZX_MAX_OFFSET_SLOTS]; -extern const u32 lzx_position_base[LZX_MAX_POSITION_SLOTS]; +extern const u8 lzx_extra_offset_bits[LZX_MAX_OFFSET_SLOTS]; -/* Returns the LZX position slot that corresponds to a given formatted offset. +/* Returns the LZX offset slot that corresponds to a given adjusted offset. * * Logically, this returns the smallest i such that - * formatted_offset >= lzx_position_base[i]. + * adjusted_offset >= lzx_offset_slot_base[i]. * * The actual implementation below takes advantage of the regularity of the - * numbers in the lzx_position_base array to calculate the slot directly from - * the formatted offset without actually looking at the array. + * numbers in the lzx_offset_slot_base array to calculate the slot directly from + * the adjusted offset without actually looking at the array. */ static inline unsigned -lzx_get_position_slot_raw(u32 formatted_offset) +lzx_get_offset_slot_raw(u32 adjusted_offset) { - if (formatted_offset >= 196608) { - return (formatted_offset >> 17) + 34; + if (adjusted_offset >= 196608) { + return (adjusted_offset >> 17) + 34; } else { - LZX_ASSERT(2 <= formatted_offset && formatted_offset < 655360); - unsigned mssb_idx = bsr32(formatted_offset); + LZX_ASSERT(2 <= adjusted_offset && adjusted_offset < 655360); + unsigned mssb_idx = bsr32(adjusted_offset); return (mssb_idx << 1) | - ((formatted_offset >> (mssb_idx - 1)) & 1); + ((adjusted_offset >> (mssb_idx - 1)) & 1); } } -extern bool lzx_window_size_valid(size_t window_size); -extern unsigned lzx_get_num_main_syms(u32 window_size); +extern unsigned lzx_get_window_order(size_t max_block_size); -#define LZX_NUM_RECENT_OFFSETS 3 +extern unsigned lzx_get_num_main_syms(unsigned window_order); /* Least-recently used queue for match offsets. */ struct lzx_lru_queue { u32 R[LZX_NUM_RECENT_OFFSETS]; -}; - -/* In the LZX format, an offset of n bytes is actually encoded - * as (n + LZX_OFFSET_OFFSET). */ -#define LZX_OFFSET_OFFSET (LZX_NUM_RECENT_OFFSETS - 1) +} _aligned_attribute(sizeof(unsigned long)); /* Initialize the LZX least-recently-used match offset queue at the beginning of * a new window for either decompression or compression. */ @@ -158,9 +65,9 @@ lzx_lru_queue_init(struct lzx_lru_queue *queue) } extern void -lzx_do_e8_preprocessing(u8 *data, s32 size); +lzx_do_e8_preprocessing(u8 *data, u32 size); extern void -lzx_undo_e8_preprocessing(u8 *data, s32 size); +lzx_undo_e8_preprocessing(u8 *data, u32 size); #endif /* _WIMLIB_LZX_H */