174 lines
6.9 KiB
C
174 lines
6.9 KiB
C
/*
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* Copyright (C) 2013-2015 Willy Tarreau <w@1wt.eu>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#ifndef _SLZ_H
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#define _SLZ_H
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#include <inttypes.h>
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/* We have two macros UNALIGNED_LE_OK and UNALIGNED_FASTER. The latter indicates
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* that using unaligned data is faster than a simple shift. On x86 32-bit at
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* least it is not the case as the per-byte access is 30% faster. A core2-duo on
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* x86_64 is 7% faster to read one byte + shifting by 8 than to read one word,
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* but a core i5 is 7% faster doing the unaligned read, so we privilege more
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* recent implementations here.
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*/
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#if defined(__x86_64__)
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#define UNALIGNED_LE_OK
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#define UNALIGNED_FASTER
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#define USE_64BIT_QUEUE
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#elif defined(__i386__) || defined(__i486__) || defined(__i586__) || defined(__i686__)
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#define UNALIGNED_LE_OK
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//#define UNALIGNED_FASTER
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#elif defined(__ARMEL__) && defined(__ARM_ARCH_7A__)
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#define UNALIGNED_LE_OK
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#define UNALIGNED_FASTER
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#elif defined(__ARM_ARCH_8A) || defined(__ARM_FEATURE_UNALIGNED)
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#define UNALIGNED_LE_OK
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#define UNALIGNED_FASTER
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#endif
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/* Log2 of the size of the hash table used for the references table. */
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#define HASH_BITS 13
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enum slz_state {
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SLZ_ST_INIT, /* stream initialized */
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SLZ_ST_EOB, /* header or end of block already sent */
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SLZ_ST_FIXED, /* inside a fixed huffman sequence */
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SLZ_ST_LAST, /* last block, BFINAL sent */
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SLZ_ST_DONE, /* BFINAL+EOB sent BFINAL */
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SLZ_ST_END /* end sent (BFINAL, EOB, CRC + len) */
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};
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enum {
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SLZ_FMT_GZIP, /* RFC1952: gzip envelope and crc32 for CRC */
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SLZ_FMT_ZLIB, /* RFC1950: zlib envelope and adler-32 for CRC */
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SLZ_FMT_DEFLATE, /* RFC1951: raw deflate, and no crc */
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};
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struct slz_stream {
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#ifdef USE_64BIT_QUEUE
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uint64_t queue; /* last pending bits, LSB first */
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#else
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uint32_t queue; /* last pending bits, LSB first */
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#endif
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uint32_t qbits; /* number of bits in queue, < 8 on 32-bit, < 32 on 64-bit */
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unsigned char *outbuf; /* set by encode() */
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uint16_t state; /* one of slz_state */
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uint8_t level:1; /* 0 = no compression, 1 = compression */
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uint8_t format:2; /* SLZ_FMT_* */
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uint8_t unused1; /* unused for now */
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uint32_t crc32;
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uint32_t ilen;
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};
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/* Functions specific to rfc1951 (deflate) */
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long slz_rfc1951_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
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int slz_rfc1951_init(struct slz_stream *strm, int level);
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int slz_rfc1951_finish(struct slz_stream *strm, unsigned char *buf);
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/* Functions specific to rfc1952 (gzip) */
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uint32_t slz_crc32_by1(uint32_t crc, const unsigned char *buf, int len);
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uint32_t slz_crc32_by4(uint32_t crc, const unsigned char *buf, int len);
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long slz_rfc1952_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
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int slz_rfc1952_send_header(struct slz_stream *strm, unsigned char *buf);
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int slz_rfc1952_init(struct slz_stream *strm, int level);
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int slz_rfc1952_finish(struct slz_stream *strm, unsigned char *buf);
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/* Functions specific to rfc1950 (zlib) */
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uint32_t slz_adler32_by1(uint32_t crc, const unsigned char *buf, int len);
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uint32_t slz_adler32_block(uint32_t crc, const unsigned char *buf, long len);
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long slz_rfc1950_encode(struct slz_stream *strm, unsigned char *out, const unsigned char *in, long ilen, int more);
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int slz_rfc1950_send_header(struct slz_stream *strm, unsigned char *buf);
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int slz_rfc1950_init(struct slz_stream *strm, int level);
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int slz_rfc1950_finish(struct slz_stream *strm, unsigned char *buf);
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/* generic functions */
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/* Initializes stream <strm>. It will configure the stream to use format
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* <format> for the data, which must be one of SLZ_FMT_*. The compression level
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* passed in <level> is set. This value can only be 0 (no compression) or 1
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* (compression) and other values will lead to unpredictable behaviour. The
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* function should always return 0.
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*/
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static inline int slz_init(struct slz_stream *strm, int level, int format)
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{
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int ret;
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if (format == SLZ_FMT_GZIP)
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ret = slz_rfc1952_init(strm, level);
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else if (format == SLZ_FMT_ZLIB)
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ret = slz_rfc1950_init(strm, level);
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else { /* deflate for anything else */
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ret = slz_rfc1951_init(strm, level);
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strm->format = format;
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}
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return ret;
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}
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/* Encodes the block according to the format used by the stream. This means
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* that the CRC of the input block may be computed according to the CRC32 or
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* adler-32 algorithms. The number of output bytes is returned.
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*/
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static inline long slz_encode(struct slz_stream *strm, void *out,
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const void *in, long ilen, int more)
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{
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long ret;
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if (strm->format == SLZ_FMT_GZIP)
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ret = slz_rfc1952_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
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else if (strm->format == SLZ_FMT_ZLIB)
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ret = slz_rfc1950_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
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else /* deflate for other ones */
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ret = slz_rfc1951_encode(strm, (unsigned char *) out, (const unsigned char *) in, ilen, more);
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return ret;
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}
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/* Flushes pending bits and sends the trailer for stream <strm> into buffer
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* <buf> if needed. When it's done, the stream state is updated to SLZ_ST_END.
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* It returns the number of bytes emitted. The trailer consists in flushing the
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* possibly pending bits from the queue (up to 24 bits), rounding to the next
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* byte, then 4 bytes for the CRC when doing zlib/gzip, then another 4 bytes
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* for the input length for gzip. That may about to 4+4+4 = 12 bytes, that the
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* caller must ensure are available before calling the function. Note that if
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* the initial header was never sent, it will be sent first as well (up to 10
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* extra bytes).
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*/
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static inline int slz_finish(struct slz_stream *strm, void *buf)
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{
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int ret;
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if (strm->format == SLZ_FMT_GZIP)
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ret = slz_rfc1952_finish(strm, (unsigned char *) buf);
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else if (strm->format == SLZ_FMT_ZLIB)
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ret = slz_rfc1950_finish(strm, (unsigned char *) buf);
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else /* deflate for other ones */
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ret = slz_rfc1951_finish(strm, (unsigned char *) buf);
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return ret;
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}
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#endif
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