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#ifndef _IPXE_DEFLATE_H
#define _IPXE_DEFLATE_H
/** @file
*
* DEFLATE decompression algorithm
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <string.h>
#include <ipxe/uaccess.h>
/** Compression formats */
enum deflate_format {
/** Raw DEFLATE data (no header or footer) */
DEFLATE_RAW,
/** ZLIB header and footer */
DEFLATE_ZLIB,
};
/** Block header length (in bits) */
#define DEFLATE_HEADER_BITS 3
/** Block header final block flags bit */
#define DEFLATE_HEADER_BFINAL_BIT 0
/** Block header type LSB */
#define DEFLATE_HEADER_BTYPE_LSB 1
/** Block header type mask */
#define DEFLATE_HEADER_BTYPE_MASK 0x03
/** Block header type: literal data */
#define DEFLATE_HEADER_BTYPE_LITERAL 0
/** Block header type: static Huffman alphabet */
#define DEFLATE_HEADER_BTYPE_STATIC 1
/** Block header type: dynamic Huffman alphabet */
#define DEFLATE_HEADER_BTYPE_DYNAMIC 2
/** Literal header LEN/NLEN field length (in bits) */
#define DEFLATE_LITERAL_LEN_BITS 16
/** Dynamic header length (in bits) */
#define DEFLATE_DYNAMIC_BITS 14
/** Dynamic header HLIT field LSB */
#define DEFLATE_DYNAMIC_HLIT_LSB 0
/** Dynamic header HLIT field mask */
#define DEFLATE_DYNAMIC_HLIT_MASK 0x1f
/** Dynamic header HDIST field LSB */
#define DEFLATE_DYNAMIC_HDIST_LSB 5
/** Dynamic header HDIST field mask */
#define DEFLATE_DYNAMIC_HDIST_MASK 0x1f
/** Dynamic header HCLEN field LSB */
#define DEFLATE_DYNAMIC_HCLEN_LSB 10
/** Dynamic header HCLEN field mask */
#define DEFLATE_DYNAMIC_HCLEN_MASK 0x0f
/** Dynamic header code length length (in bits) */
#define DEFLATE_CODELEN_BITS 3
/** Maximum length of a Huffman symbol (in bits) */
#define DEFLATE_HUFFMAN_BITS 15
/** Quick lookup length for a Huffman symbol (in bits)
*
* This is a policy decision.
*/
#define DEFLATE_HUFFMAN_QL_BITS 7
/** Quick lookup shift */
#define DEFLATE_HUFFMAN_QL_SHIFT ( 16 - DEFLATE_HUFFMAN_QL_BITS )
/** Literal/length end of block code */
#define DEFLATE_LITLEN_END 256
/** Maximum value of a literal/length code */
#define DEFLATE_LITLEN_MAX_CODE 287
/** Maximum value of a distance code */
#define DEFLATE_DISTANCE_MAX_CODE 31
/** Maximum value of a code length code */
#define DEFLATE_CODELEN_MAX_CODE 18
/** ZLIB header length (in bits) */
#define ZLIB_HEADER_BITS 16
/** ZLIB header compression method LSB */
#define ZLIB_HEADER_CM_LSB 0
/** ZLIB header compression method mask */
#define ZLIB_HEADER_CM_MASK 0x0f
/** ZLIB header compression method: DEFLATE */
#define ZLIB_HEADER_CM_DEFLATE 8
/** ZLIB header preset dictionary flag bit */
#define ZLIB_HEADER_FDICT_BIT 13
/** ZLIB ADLER32 length (in bits) */
#define ZLIB_ADLER32_BITS 32
/** A Huffman-coded set of symbols of a given length */
struct deflate_huf_symbols {
/** Length of Huffman-coded symbols */
uint8_t bits;
/** Shift to normalise symbols of this length to 16 bits */
uint8_t shift;
/** Number of Huffman-coded symbols having this length */
uint16_t freq;
/** First symbol of this length (normalised to 16 bits)
*
* Stored as a 32-bit value to allow the value 0x10000 to be
* used for empty sets of symbols longer than the maximum
* utilised length.
*/
uint32_t start;
/** Raw symbols having this length */
uint16_t *raw;
};
/** A Huffman-coded alphabet */
struct deflate_alphabet {
/** Huffman-coded symbol set for each length */
struct deflate_huf_symbols huf[DEFLATE_HUFFMAN_BITS];
/** Quick lookup table */
uint8_t lookup[ 1 << DEFLATE_HUFFMAN_QL_BITS ];
/** Raw symbols
*
* Ordered by Huffman-coded symbol length, then by symbol
* value. This field has a variable length.
*/
uint16_t raw[0];
};
/** A static Huffman alphabet length pattern */
struct deflate_static_length_pattern {
/** Length pair */
uint8_t fill;
/** Repetition count */
uint8_t count;
} __attribute__ (( packed ));
/** Decompressor */
struct deflate {
/** Resume point
*
* Used as the target of a computed goto to jump to the
* appropriate point within the state machine.
*/
void *resume;
/** Format */
enum deflate_format format;
/** Accumulator */
uint32_t accumulator;
/** Bit-reversed accumulator
*
* Don't ask.
*/
uint32_t rotalumucca;
/** Number of bits within the accumulator */
unsigned int bits;
/** Current block header */
unsigned int header;
/** Remaining length of data (e.g. within a literal block) */
size_t remaining;
/** Current length index within a set of code lengths */
unsigned int length_index;
/** Target length index within a set of code lengths */
unsigned int length_target;
/** Current length within a set of code lengths */
unsigned int length;
/** Number of extra bits required */
unsigned int extra_bits;
/** Length of a duplicated string */
size_t dup_len;
/** Distance of a duplicated string */
size_t dup_distance;
/** Literal/length Huffman alphabet */
struct deflate_alphabet litlen;
/** Literal/length raw symbols
*
* Must immediately follow the literal/length Huffman alphabet.
*/
uint16_t litlen_raw[ DEFLATE_LITLEN_MAX_CODE + 1 ];
/** Number of symbols in the literal/length Huffman alphabet */
unsigned int litlen_count;
/** Distance and code length Huffman alphabet
*
* The code length Huffman alphabet has a maximum Huffman
* symbol length of 7 and a maximum code value of 18, and is
* thus strictly smaller than the distance Huffman alphabet.
* Since we never need both alphabets simultaneously, we can
* reuse the storage space for the distance alphabet to
* temporarily hold the code length alphabet.
*/
struct deflate_alphabet distance_codelen;
/** Distance and code length raw symbols
*
* Must immediately follow the distance and code length
* Huffman alphabet.
*/
uint16_t distance_codelen_raw[ DEFLATE_DISTANCE_MAX_CODE + 1 ];
/** Number of symbols in the distance Huffman alphabet */
unsigned int distance_count;
/** Huffman code lengths
*
* The literal/length and distance code lengths are
* constructed as a single set of lengths.
*
* The code length Huffman alphabet has a maximum code value
* of 18 and the set of lengths is thus strictly smaller than
* the combined literal/length and distance set of lengths.
* Since we never need both alphabets simultaneously, we can
* reuse the storage space for the literal/length and distance
* code lengths to temporarily hold the code length code
* lengths.
*/
uint8_t lengths[ ( ( DEFLATE_LITLEN_MAX_CODE + 1 ) +
( DEFLATE_DISTANCE_MAX_CODE + 1 ) +
1 /* round up */ ) / 2 ];
};
/** A chunk of data */
struct deflate_chunk {
/** Data */
userptr_t data;
/** Current offset */
size_t offset;
/** Length of data */
size_t len;
};
/**
* Initialise chunk of data
*
* @v chunk Chunk of data to initialise
* @v data Data
* @v offset Starting offset
* @v len Length
*/
static inline __attribute__ (( always_inline )) void
deflate_chunk_init ( struct deflate_chunk *chunk, userptr_t data,
size_t offset, size_t len ) {
chunk->data = data;
chunk->offset = offset;
chunk->len = len;
}
/**
* Check if decompression has finished
*
* @v deflate Decompressor
* @ret finished Decompression has finished
*/
static inline int deflate_finished ( struct deflate *deflate ) {
return ( deflate->resume == NULL );
}
extern void deflate_init ( struct deflate *deflate,
enum deflate_format format );
extern int deflate_inflate ( struct deflate *deflate,
struct deflate_chunk *in,
struct deflate_chunk *out );
#endif /* _IPXE_DEFLATE_H */
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