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