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88 lines
2.7 KiB
C
88 lines
2.7 KiB
C
/* -*- mode: C; c-basic-offset: 4 -*- */
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#ident "Copyright (c) 2011 Tokutek Inc. All rights reserved."
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#ident "$Id$"
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#include <zlib.h>
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#include "compress.h"
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#include "memory.h"
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#include "quicklz.h"
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#include "toku_assert.h"
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size_t toku_compress_bound (enum toku_compression_method a, size_t size)
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// See compress.h for the specification of this function.
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{
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switch (a) {
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case TOKU_QUICKLZ_METHOD:
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return size+400 + 1; // quicklz manual says 400 bytes is enough. We need one more byte for the rfc1950-style header byte. bits 0-3 are 9, bits 4-7 are the QLZ_COMPRESSION_LEVEL.
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case TOKU_ZLIB_METHOD:
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return compressBound (size);
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}
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// fall through for bad enum (thus compiler can warn us if we didn't use all the enums
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assert(0); return 0;
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}
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static const int zlib_compression_level = 5;
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void toku_compress (enum toku_compression_method a,
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// the following types and naming conventions come from zlib.h
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Bytef *dest, uLongf *destLen,
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const Bytef *source, uLong sourceLen)
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// See compress.h for the specification of this function.
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{
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assert(sourceLen < (1LL << 32));
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switch (a) {
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case TOKU_ZLIB_METHOD: {
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int r = compress2(dest, destLen, source, sourceLen, zlib_compression_level);
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assert(r == Z_OK);
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assert((dest[0]&0xF) == TOKU_ZLIB_METHOD);
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return;
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}
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case TOKU_QUICKLZ_METHOD: {
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if (sourceLen==0) {
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// quicklz requires at least one byte, so we handle this ourselves
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assert(1 <= *destLen);
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*destLen = 1;
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} else {
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qlz_state_compress *XMALLOC(qsc);
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size_t actual_destlen = qlz_compress(source, (char*)(dest+1), sourceLen, qsc);
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assert(actual_destlen +1 <= *destLen);
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*destLen = actual_destlen+1; // add one for the rfc1950-style header byte.
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toku_free(qsc);
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}
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// Fill in that first byte
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dest[0] = TOKU_QUICKLZ_METHOD + (QLZ_COMPRESSION_LEVEL << 4);
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return;
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}}
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// default fall through to error.
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assert(0);
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}
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void toku_decompress (Bytef *dest, uLongf destLen,
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const Bytef *source, uLongf sourceLen)
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// See compress.h for the specification of this function.
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{
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assert(sourceLen>=1); // need at least one byte for the RFC header.
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switch (source[0] & 0xF) {
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case TOKU_ZLIB_METHOD: {
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uLongf actual_destlen = destLen;
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int r = uncompress(dest, &actual_destlen, source, sourceLen);
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assert(r == Z_OK);
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assert(actual_destlen == destLen);
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return;
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}
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case TOKU_QUICKLZ_METHOD:
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if (sourceLen>1) {
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qlz_state_decompress *XMALLOC(qsd);
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uLongf actual_destlen = qlz_decompress((char*)source+1, dest, qsd);
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assert(actual_destlen == destLen);
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toku_free(qsd);
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} else {
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// length 1 means there is no data, so do nothing.
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assert(destLen==0);
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}
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return;
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}
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// default fall through to error.
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assert(0);
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}
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