diff options
| -rw-r--r-- | Makefile | 3 | ||||
| -rw-r--r-- | doc/lz4_manual.html | 4 | ||||
| -rw-r--r-- | doc/lz4frame_manual.html | 44 | ||||
| -rw-r--r-- | examples/frameCompress.c | 150 | ||||
| -rw-r--r-- | lib/lz4frame.c | 3 | ||||
| -rw-r--r-- | lib/lz4frame.h | 12 |
6 files changed, 120 insertions, 96 deletions
@@ -70,7 +70,7 @@ lz4 lz4-release : .PHONY: examples examples: lib lz4 - $(MAKE) -C $(EXDIR) test + $(MAKE) -C $(EXDIR) all .PHONY: manuals manuals: @@ -125,6 +125,7 @@ list: .PHONY: test test: $(MAKE) -C $(TESTDIR) $@ + $(MAKE) -C $(EXDIR) $@ clangtest: clean clang -v diff --git a/doc/lz4_manual.html b/doc/lz4_manual.html index 6b7935d..46e6c3d 100644 --- a/doc/lz4_manual.html +++ b/doc/lz4_manual.html @@ -176,8 +176,8 @@ int LZ4_freeStream (LZ4_stream_t* streamPtr); If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster. Important : Up to 64KB of previously compressed data is assumed to remain present and unmodified in memory ! - Special 1 : If input buffer is a double-buffer, it can have any size, including < 64 KB. - Special 2 : If input buffer is a ring-buffer, it can have any size, including < 64 KB. + Special 1 : If input buffer is a double-buffer, it can have any size, including < 64 KB. + Special 2 : If input buffer is a ring-buffer, it can have any size, including < 64 KB. @return : size of compressed block or 0 if there is an error (typically, compressed data cannot fit into 'dst') diff --git a/doc/lz4frame_manual.html b/doc/lz4frame_manual.html index 590c632..1ddf6d8 100644 --- a/doc/lz4frame_manual.html +++ b/doc/lz4frame_manual.html @@ -101,8 +101,10 @@ <a name="Chapter5"></a><h2>Simple compression function</h2><pre></pre> <pre><b>size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr); -</b><p> Returns the maximum possible size of a frame compressed with LZ4F_compressFrame() given srcSize content and preferences. - Note : this result is only usable with LZ4F_compressFrame(), not with multi-segments compression. +</b><p> Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences. + `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences. + Note : this result is only usable with LZ4F_compressFrame(). + It may also be used with LZ4F_compressUpdate() _if no flush() operation_ is performed. </p></pre><BR> @@ -151,19 +153,21 @@ LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx); </p></pre><BR> <pre><b>size_t LZ4F_compressBound(size_t srcSize, const LZ4F_preferences_t* prefsPtr); -</b><p> Provides dstCapacity given a srcSize to guarantee operation success in worst case situations. - prefsPtr is optional : you can provide NULL as argument, preferences will be set to cover worst case scenario. - Result is always the same for a srcSize and prefsPtr, so it can be trusted to size reusable buffers. - When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() operations. +</b><p> Provides minimum dstCapacity for a given srcSize to guarantee operation success in worst case scenarios. + Estimation includes frame footer, which would be generated by LZ4F_compressEnd(). + Estimation doesn't include frame header, already generated by LZ4F_compressBegin(). + prefsPtr is optional : when NULL is provided, preferences will be set to cover worst case scenario. + Result is always the same for a srcSize and prefsPtr, so it can be trusted to size reusable buffers. + When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() operations. </p></pre><BR> <pre><b>size_t LZ4F_compressUpdate(LZ4F_cctx* cctx, void* dstBuffer, size_t dstCapacity, const void* srcBuffer, size_t srcSize, const LZ4F_compressOptions_t* cOptPtr); -</b><p> LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary. - An important rule is that dstCapacity MUST be large enough to ensure operation success even in worst case situations. - This value is provided by LZ4F_compressBound(). - If this condition is not respected, LZ4F_compress() will fail (result is an errorCode). - LZ4F_compressUpdate() doesn't guarantee error recovery. When an error occurs, compression context must be freed or resized. +</b><p> LZ4F_compressUpdate() can be called repetitively to compress as much data as necessary. + An important rule is that dstCapacity MUST be large enough to ensure operation success even in worst case situations. + This value is provided by LZ4F_compressBound(). + If this condition is not respected, LZ4F_compress() will fail (result is an errorCode). + LZ4F_compressUpdate() doesn't guarantee error recovery. When an error occurs, compression context must be freed or resized. `cOptPtr` is optional : NULL can be provided, in which case all options are set to default. @return : number of bytes written into `dstBuffer` (it can be zero, meaning input data was just buffered). or an error code if it fails (which can be tested using LZ4F_isError()) @@ -171,8 +175,8 @@ LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx); </p></pre><BR> <pre><b>size_t LZ4F_flush(LZ4F_cctx* cctx, void* dstBuffer, size_t dstCapacity, const LZ4F_compressOptions_t* cOptPtr); -</b><p> When data must be generated and sent immediately, without waiting for a block to be completely filled, - it's possible to call LZ4_flush(). It will immediately compress any data buffered within cctx. +</b><p> When data must be generated and sent immediately, without waiting for a block to be completely filled, + it's possible to call LZ4_flush(). It will immediately compress any data buffered within cctx. `dstCapacity` must be large enough to ensure the operation will be successful. `cOptPtr` is optional : it's possible to provide NULL, all options will be set to default. @return : number of bytes written into dstBuffer (it can be zero, which means there was no data stored within cctx) @@ -200,13 +204,13 @@ LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx); </b></pre><BR> <pre><b>LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** dctxPtr, unsigned version); LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx); -</b><p> Create an LZ4F_dctx object, to track all decompression operations. - The version provided MUST be LZ4F_VERSION. - The function provides a pointer to an allocated and initialized LZ4F_dctx object. - The result is an errorCode, which can be tested using LZ4F_isError(). - dctx memory can be released using LZ4F_freeDecompressionContext(); - The result of LZ4F_freeDecompressionContext() is indicative of the current state of decompressionContext when being released. - That is, it should be == 0 if decompression has been completed fully and correctly. +</b><p> Create an LZ4F_dctx object, to track all decompression operations. + The version provided MUST be LZ4F_VERSION. + The function provides a pointer to an allocated and initialized LZ4F_dctx object. + The result is an errorCode, which can be tested using LZ4F_isError(). + dctx memory can be released using LZ4F_freeDecompressionContext(); + The result of LZ4F_freeDecompressionContext() is indicative of the current state of decompressionContext when being released. + That is, it should be == 0 if decompression has been completed fully and correctly. </p></pre><BR> diff --git a/examples/frameCompress.c b/examples/frameCompress.c index d66a8dc..35dbde2 100644 --- a/examples/frameCompress.c +++ b/examples/frameCompress.c @@ -1,122 +1,133 @@ -// LZ4frame API example : compress a file -// Based on sample code from Zbigniew Jędrzejewski-Szmek +/* LZ4frame API example : compress a file + * Based on sample code from Zbigniew Jędrzejewski-Szmek + * + * This example streams an input file into an output file + * using a bounded memory budget. + * Input is read in chunks of IN_CHUNK_SIZE */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <errno.h> +#include <assert.h> #include <lz4frame.h> -#define BUF_SIZE 16*1024 -#define LZ4_HEADER_SIZE 19 -#define LZ4_FOOTER_SIZE 4 + +#define IN_CHUNK_SIZE (16*1024) static const LZ4F_preferences_t lz4_preferences = { { LZ4F_max256KB, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame, - 0 /* content size unknown */, 0 /* no dictID */ , LZ4F_noBlockChecksum }, - 0, /* compression level */ + 0 /* unknown content size */, 0 /* no dictID */ , LZ4F_noBlockChecksum }, + 0, /* compression level; 0 == default */ 0, /* autoflush */ { 0, 0, 0, 0 }, /* reserved, must be set to 0 */ }; -static size_t compress_file(FILE *in, FILE *out, size_t *size_in, size_t *size_out) { - size_t r=1; /* function result; 1 == error, default (early exit) */ - LZ4F_compressionContext_t ctx; - char *src, *buf = NULL; - size_t size, count_in = 0, count_out, offset = 0, frame_size; +/* safe_fwrite() : + * performs fwrite(), ensure operation success, or immediately exit() */ +static void safe_fwrite(void* buf, size_t eltSize, size_t nbElt, FILE* f) +{ + size_t const writtenSize = fwrite(buf, eltSize, nbElt, f); + size_t const expectedSize = eltSize * nbElt; /* note : should check for overflow */ + if (writtenSize < expectedSize) { + if (ferror(f)) /* note : ferror() must follow fwrite */ + printf("Write failed\n"); + else + printf("Short write\n"); + exit(1); + } +} + + +static size_t +compress_file(FILE* in, FILE* out, + unsigned long long* size_in, + unsigned long long* size_out) +{ + size_t result = 1; /* function result; 1 == error, default (early exit) */ + unsigned long long count_in = 0, count_out; + + /* init */ + LZ4F_compressionContext_t ctx; if (LZ4F_isError( LZ4F_createCompressionContext(&ctx, LZ4F_VERSION) )) { - printf("Failed to create context: error %zu\n", r); - return 1; + printf("error: failed to create context \n"); + return result; } - src = malloc(BUF_SIZE); + char* outbuff = NULL; + void* const src = malloc(IN_CHUNK_SIZE); if (!src) { printf("Not enough memory\n"); goto cleanup; } - frame_size = LZ4F_compressBound(BUF_SIZE, &lz4_preferences); - size = frame_size + LZ4_HEADER_SIZE + LZ4_FOOTER_SIZE; - buf = malloc(size); - if (!buf) { + size_t const outbufCapacity = LZ4F_compressBound(IN_CHUNK_SIZE, &lz4_preferences); /* large enough for any input <= IN_CHUNK_SIZE */ + outbuff = malloc(outbufCapacity); + if (!outbuff) { printf("Not enough memory\n"); goto cleanup; } - { size_t const headerSize = LZ4F_compressBegin(ctx, buf, size, &lz4_preferences); + /* write frame header */ + assert(outbufCapacity >= LZ4F_HEADER_SIZE_MAX); + { size_t const headerSize = LZ4F_compressBegin(ctx, outbuff, outbufCapacity, &lz4_preferences); if (LZ4F_isError(headerSize)) { printf("Failed to start compression: error %zu\n", headerSize); goto cleanup; } - offset = count_out = headerSize; - printf("Buffer size is %zu bytes, header size %zu bytes\n", size, headerSize); + count_out = headerSize; + printf("Buffer size is %zu bytes, header size %zu bytes\n", outbufCapacity, headerSize); + safe_fwrite(outbuff, 1, headerSize, out); } - + /* stream file */ for (;;) { - size_t const readSize = fread(src, 1, BUF_SIZE, in); - if (readSize == 0) - break; + size_t const readSize = fread(src, 1, outbufCapacity, in); + if (readSize == 0) break; count_in += readSize; - { size_t const compressedSize = LZ4F_compressUpdate(ctx, buf + offset, size - offset, src, readSize, NULL); - if (LZ4F_isError(compressedSize)) { - printf("Compression failed: error %zu\n", compressedSize); - goto cleanup; - } - offset += compressedSize; - count_out += compressedSize; + size_t const compressedSize = LZ4F_compressUpdate(ctx, + outbuff, outbufCapacity, + src, readSize, + NULL); + if (LZ4F_isError(compressedSize)) { + printf("Compression failed: error %zu\n", compressedSize); + goto cleanup; } - if (size - offset < frame_size + LZ4_FOOTER_SIZE) { - size_t writtenSize; - printf("Writing %zu bytes\n", offset); - - writtenSize = fwrite(buf, 1, offset, out); - if (writtenSize < offset) { - if (ferror(out)) /* note : ferror() must follow fwrite */ - printf("Write failed\n"); - else - printf("Short write\n"); - goto cleanup; - } - - offset = 0; - } + printf("Writing %zu bytes\n", compressedSize); + safe_fwrite(outbuff, 1, compressedSize, out); + count_out += compressedSize; } - { size_t const compressedSize = LZ4F_compressEnd(ctx, buf + offset, size - offset, NULL); + /* flush whatever remains within internal buffers */ + { size_t const compressedSize = LZ4F_compressEnd(ctx, + outbuff, outbufCapacity, + NULL); if (LZ4F_isError(compressedSize)) { printf("Failed to end compression: error %zu\n", compressedSize); goto cleanup; } - offset += compressedSize; + + printf("Writing %zu bytes\n", compressedSize); + safe_fwrite(outbuff, 1, compressedSize, out); count_out += compressedSize; } - printf("Writing %zu bytes\n", offset); - { size_t const writtenSize = fwrite(buf, 1, offset, out); - if (writtenSize < offset) { - if (ferror(out)) - printf("Write failed\n"); - else - printf("Short write\n"); - goto cleanup; - } } - *size_in = count_in; *size_out = count_out; - r = 0; /* success */ + result = 0; /* success */ cleanup: LZ4F_freeCompressionContext(ctx); /* supports free on NULL */ free(src); - free(buf); - return r; + free(outbuff); + return result; } + static size_t get_block_size(const LZ4F_frameInfo_t* info) { switch (info->blockSizeID) { case LZ4F_default: @@ -131,7 +142,7 @@ static size_t get_block_size(const LZ4F_frameInfo_t* info) { } static size_t decompress_file(FILE* in, FILE* out) { - void* const src = malloc(BUF_SIZE); + void* const src = malloc(IN_CHUNK_SIZE); void* dst = NULL; size_t dstCapacity = 0; LZ4F_dctx* dctx = NULL; @@ -148,7 +159,7 @@ static size_t decompress_file(FILE* in, FILE* out) { /* Decompression */ while (ret != 0) { /* Load more input */ - size_t srcSize = fread(src, 1, BUF_SIZE, in); + size_t srcSize = fread(src, 1, IN_CHUNK_SIZE, in); const void* srcPtr = src; const void* const srcEnd = srcPtr + srcSize; if (srcSize == 0 || ferror(in)) { @@ -215,6 +226,7 @@ cleanup: return LZ4F_freeDecompressionContext(dctx); /* note : free works on NULL */ } + int compare(FILE* fp0, FILE* fp1) { int result = 0; @@ -238,6 +250,7 @@ int compare(FILE* fp0, FILE* fp1) return result; } + int main(int argc, const char **argv) { char inpFilename[256] = { 0 }; char lz4Filename[256] = { 0 }; @@ -259,8 +272,8 @@ int main(int argc, const char **argv) { /* compress */ { FILE* const inpFp = fopen(inpFilename, "rb"); FILE* const outFp = fopen(lz4Filename, "wb"); - size_t sizeIn = 0; - size_t sizeOut = 0; + unsigned long long sizeIn = 0; + unsigned long long sizeOut = 0; size_t ret; printf("compress : %s -> %s\n", inpFilename, lz4Filename); @@ -270,7 +283,8 @@ int main(int argc, const char **argv) { return (int)ret; } printf("%s: %zu → %zu bytes, %.1f%%\n", - inpFilename, sizeIn, sizeOut, + inpFilename, + (size_t)sizeIn, (size_t)sizeOut, /* might overflow */ (double)sizeOut / sizeIn * 100); printf("compress : done\n"); diff --git a/lib/lz4frame.c b/lib/lz4frame.c index 0b26f75..a394d1f 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -726,7 +726,8 @@ size_t LZ4F_compressUpdate(LZ4F_cctx* cctxPtr, if (cctxPtr->cStage != 1) return err0r(LZ4F_ERROR_GENERIC); - if (dstCapacity < LZ4F_compressBound_internal(srcSize, &(cctxPtr->prefs), cctxPtr->tmpInSize)) return err0r(LZ4F_ERROR_dstMaxSize_tooSmall); + if (dstCapacity < LZ4F_compressBound_internal(srcSize, &(cctxPtr->prefs), cctxPtr->tmpInSize)) + return err0r(LZ4F_ERROR_dstMaxSize_tooSmall); memset(&cOptionsNull, 0, sizeof(cOptionsNull)); if (compressOptionsPtr == NULL) compressOptionsPtr = &cOptionsNull; diff --git a/lib/lz4frame.h b/lib/lz4frame.h index eb55e45..15484d7 100644 --- a/lib/lz4frame.h +++ b/lib/lz4frame.h @@ -189,8 +189,10 @@ LZ4FLIB_API int LZ4F_compressionLevel_max(void); * Simple compression function ***********************************/ /*! LZ4F_compressFrameBound() : - * Returns the maximum possible size of a frame compressed with LZ4F_compressFrame() given srcSize content and preferences. - * Note : this result is only usable with LZ4F_compressFrame(), not with multi-segments compression. + * Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences. + * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences. + * Note : this result is only usable with LZ4F_compressFrame(). + * It may also be used with LZ4F_compressUpdate() _if no flush() operation_ is performed. */ LZ4FLIB_API size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr); @@ -235,7 +237,7 @@ LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx); /*---- Compression ----*/ -#define LZ4F_HEADER_SIZE_MAX 19 +#define LZ4F_HEADER_SIZE_MAX 19 /* LZ4 Frame header size can vary from 7 to 19 bytes */ /*! LZ4F_compressBegin() : * will write the frame header into dstBuffer. * dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes. @@ -248,7 +250,9 @@ LZ4FLIB_API size_t LZ4F_compressBegin(LZ4F_cctx* cctx, const LZ4F_preferences_t* prefsPtr); /*! LZ4F_compressBound() : - * Provides minimum dstCapacity for a given srcSize to guarantee operation success in worst case situations. + * Provides minimum dstCapacity for a given srcSize to guarantee operation success in worst case scenarios. + * Estimation includes frame footer, which would be generated by LZ4F_compressEnd(). + * Estimation doesn't include frame header, already generated by LZ4F_compressBegin(). * prefsPtr is optional : when NULL is provided, preferences will be set to cover worst case scenario. * Result is always the same for a srcSize and prefsPtr, so it can be trusted to size reusable buffers. * When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() operations. |