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-rw-r--r--Makefile3
-rw-r--r--doc/lz4_manual.html4
-rw-r--r--doc/lz4frame_manual.html44
-rw-r--r--examples/frameCompress.c150
-rw-r--r--lib/lz4frame.c3
-rw-r--r--lib/lz4frame.h12
6 files changed, 120 insertions, 96 deletions
diff --git a/Makefile b/Makefile
index 0aa1b9d..d17b4a7 100644
--- a/Makefile
+++ b/Makefile
@@ -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.