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/* LZ4frame API example : compress a file
* Modified from an example code by 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 <getopt.h>
#include <lz4frame.h>
#include <lz4frame_static.h>
#define IN_CHUNK_SIZE (16*1024)
static const LZ4F_preferences_t kPrefs = {
{ LZ4F_max256KB, LZ4F_blockLinked, LZ4F_noContentChecksum, LZ4F_frame,
0 /* unknown content size */, 0 /* no dictID */ , LZ4F_noBlockChecksum },
0, /* compression level; 0 == default */
0, /* autoflush */
0, /* favor decompression speed */
{ 0, 0, 0 }, /* reserved, must be set to 0 */
};
/* 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;
if (nbElt>0) assert(expectedSize / nbElt == eltSize); /* check overflow */
if (writtenSize < expectedSize) {
if (ferror(f)) /* note : ferror() must follow fwrite */
fprintf(stderr, "Write failed \n");
else
fprintf(stderr, "Write too short \n");
exit(1);
}
}
/* ================================================= */
/* Streaming Compression example */
/* ================================================= */
typedef struct {
int error;
unsigned long long size_in;
unsigned long long size_out;
} compressResult_t;
static compressResult_t
compress_file_internal(FILE* f_in, FILE* f_out,
LZ4F_compressionContext_t ctx,
void* inBuff, size_t inChunkSize,
void* outBuff, size_t outCapacity,
FILE* f_unc, long uncOffset)
{
compressResult_t result = { 1, 0, 0 }; /* result for an error */
long long count_in = 0, count_out, bytesToOffset = -1;
assert(f_in != NULL); assert(f_out != NULL);
assert(ctx != NULL);
assert(outCapacity >= LZ4F_HEADER_SIZE_MAX);
assert(outCapacity >= LZ4F_compressBound(inChunkSize, &kPrefs));
/* write frame header */
{ size_t const headerSize = LZ4F_compressBegin(ctx, outBuff, outCapacity, &kPrefs);
if (LZ4F_isError(headerSize)) {
printf("Failed to start compression: error %u \n", (unsigned)headerSize);
return result;
}
count_out = headerSize;
printf("Buffer size is %u bytes, header size %u bytes \n",
(unsigned)outCapacity, (unsigned)headerSize);
safe_fwrite(outBuff, 1, headerSize, f_out);
}
/* stream file */
for (;;) {
size_t compressedSize;
long long inSize = IN_CHUNK_SIZE;
if (uncOffset >= 0) {
bytesToOffset = uncOffset - count_in;
/* read only remaining bytes to offset position */
if (bytesToOffset < IN_CHUNK_SIZE && bytesToOffset > 0) {
inSize = bytesToOffset;
}
}
/* input data is at uncompressed data offset */
if (bytesToOffset <= 0 && uncOffset >= 0 && f_unc) {
size_t const readSize = fread(inBuff, 1, inSize, f_unc);
if (readSize == 0) {
uncOffset = -1;
continue;
}
count_in += readSize;
compressedSize = LZ4F_uncompressedUpdate(ctx,
outBuff, outCapacity,
inBuff, readSize,
NULL);
} else {
size_t const readSize = fread(inBuff, 1, inSize, f_in);
if (readSize == 0) break; /* nothing left to read from input file */
count_in += readSize;
compressedSize = LZ4F_compressUpdate(ctx,
outBuff, outCapacity,
inBuff, readSize,
NULL);
}
if (LZ4F_isError(compressedSize)) {
printf("Compression failed: error %u \n", (unsigned)compressedSize);
return result;
}
printf("Writing %u bytes\n", (unsigned)compressedSize);
safe_fwrite(outBuff, 1, compressedSize, f_out);
count_out += compressedSize;
}
/* flush whatever remains within internal buffers */
{ size_t const compressedSize = LZ4F_compressEnd(ctx,
outBuff, outCapacity,
NULL);
if (LZ4F_isError(compressedSize)) {
printf("Failed to end compression: error %u \n", (unsigned)compressedSize);
return result;
}
printf("Writing %u bytes \n", (unsigned)compressedSize);
safe_fwrite(outBuff, 1, compressedSize, f_out);
count_out += compressedSize;
}
result.size_in = count_in;
result.size_out = count_out;
result.error = 0;
return result;
}
static compressResult_t
compress_file(FILE* f_in, FILE* f_out,
FILE* f_unc, int uncOffset)
{
assert(f_in != NULL);
assert(f_out != NULL);
/* resource allocation */
LZ4F_compressionContext_t ctx;
size_t const ctxCreation = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
void* const src = malloc(IN_CHUNK_SIZE);
size_t const outbufCapacity = LZ4F_compressBound(IN_CHUNK_SIZE, &kPrefs); /* large enough for any input <= IN_CHUNK_SIZE */
void* const outbuff = malloc(outbufCapacity);
compressResult_t result = { 1, 0, 0 }; /* == error (default) */
if (!LZ4F_isError(ctxCreation) && src && outbuff) {
result = compress_file_internal(f_in, f_out,
ctx,
src, IN_CHUNK_SIZE,
outbuff, outbufCapacity,
f_unc, uncOffset);
} else {
printf("error : resource allocation failed \n");
}
LZ4F_freeCompressionContext(ctx); /* supports free on NULL */
free(src);
free(outbuff);
return result;
}
/* ================================================= */
/* Streaming decompression example */
/* ================================================= */
static size_t get_block_size(const LZ4F_frameInfo_t* info) {
switch (info->blockSizeID) {
case LZ4F_default:
case LZ4F_max64KB: return 1 << 16;
case LZ4F_max256KB: return 1 << 18;
case LZ4F_max1MB: return 1 << 20;
case LZ4F_max4MB: return 1 << 22;
default:
printf("Impossible with expected frame specification (<=v1.6.1)\n");
exit(1);
}
}
/* @return : 1==error, 0==success */
static int
decompress_file_internal(FILE* f_in, FILE* f_out,
LZ4F_dctx* dctx,
void* src, size_t srcCapacity, size_t filled, size_t alreadyConsumed,
void* dst, size_t dstCapacity)
{
int firstChunk = 1;
size_t ret = 1;
assert(f_in != NULL); assert(f_out != NULL);
assert(dctx != NULL);
assert(src != NULL); assert(srcCapacity > 0); assert(filled <= srcCapacity); assert(alreadyConsumed <= filled);
assert(dst != NULL); assert(dstCapacity > 0);
/* Decompression */
while (ret != 0) {
/* Load more input */
size_t readSize = firstChunk ? filled : fread(src, 1, srcCapacity, f_in); firstChunk=0;
const void* srcPtr = (const char*)src + alreadyConsumed; alreadyConsumed=0;
const void* const srcEnd = (const char*)srcPtr + readSize;
if (readSize == 0 || ferror(f_in)) {
printf("Decompress: not enough input or error reading file\n");
return 1;
}
/* Decompress:
* Continue while there is more input to read (srcPtr != srcEnd)
* and the frame isn't over (ret != 0)
*/
while (srcPtr < srcEnd && ret != 0) {
/* Any data within dst has been flushed at this stage */
size_t dstSize = dstCapacity;
size_t srcSize = (const char*)srcEnd - (const char*)srcPtr;
ret = LZ4F_decompress(dctx, dst, &dstSize, srcPtr, &srcSize, /* LZ4F_decompressOptions_t */ NULL);
if (LZ4F_isError(ret)) {
printf("Decompression error: %s\n", LZ4F_getErrorName(ret));
return 1;
}
/* Flush output */
if (dstSize != 0) safe_fwrite(dst, 1, dstSize, f_out);
/* Update input */
srcPtr = (const char*)srcPtr + srcSize;
}
assert(srcPtr <= srcEnd);
/* Ensure all input data has been consumed.
* It is valid to have multiple frames in the same file,
* but this example only supports one frame.
*/
if (srcPtr < srcEnd) {
printf("Decompress: Trailing data left in file after frame\n");
return 1;
}
}
/* Check that there isn't trailing data in the file after the frame.
* It is valid to have multiple frames in the same file,
* but this example only supports one frame.
*/
{ size_t const readSize = fread(src, 1, 1, f_in);
if (readSize != 0 || !feof(f_in)) {
printf("Decompress: Trailing data left in file after frame\n");
return 1;
} }
return 0;
}
/* @return : 1==error, 0==completed */
static int
decompress_file_allocDst(FILE* f_in, FILE* f_out,
LZ4F_dctx* dctx,
void* src, size_t srcCapacity)
{
assert(f_in != NULL); assert(f_out != NULL);
assert(dctx != NULL);
assert(src != NULL);
assert(srcCapacity >= LZ4F_HEADER_SIZE_MAX); /* ensure LZ4F_getFrameInfo() can read enough data */
/* Read Frame header */
size_t const readSize = fread(src, 1, srcCapacity, f_in);
if (readSize == 0 || ferror(f_in)) {
printf("Decompress: not enough input or error reading file\n");
return 1;
}
LZ4F_frameInfo_t info;
size_t consumedSize = readSize;
{ size_t const fires = LZ4F_getFrameInfo(dctx, &info, src, &consumedSize);
if (LZ4F_isError(fires)) {
printf("LZ4F_getFrameInfo error: %s\n", LZ4F_getErrorName(fires));
return 1;
} }
/* Allocating enough space for an entire block isn't necessary for
* correctness, but it allows some memcpy's to be elided.
*/
size_t const dstCapacity = get_block_size(&info);
void* const dst = malloc(dstCapacity);
if (!dst) { perror("decompress_file(dst)"); return 1; }
int const decompressionResult = decompress_file_internal(
f_in, f_out,
dctx,
src, srcCapacity, readSize-consumedSize, consumedSize,
dst, dstCapacity);
free(dst);
return decompressionResult;
}
/* @result : 1==error, 0==success */
static int decompress_file(FILE* f_in, FILE* f_out)
{
assert(f_in != NULL); assert(f_out != NULL);
/* Resource allocation */
void* const src = malloc(IN_CHUNK_SIZE);
if (!src) { perror("decompress_file(src)"); return 1; }
LZ4F_dctx* dctx;
{ size_t const dctxStatus = LZ4F_createDecompressionContext(&dctx, LZ4F_VERSION);
if (LZ4F_isError(dctxStatus)) {
printf("LZ4F_dctx creation error: %s\n", LZ4F_getErrorName(dctxStatus));
} }
int const result = !dctx ? 1 /* error */ :
decompress_file_allocDst(f_in, f_out, dctx, src, IN_CHUNK_SIZE);
free(src);
LZ4F_freeDecompressionContext(dctx); /* note : free works on NULL */
return result;
}
int compareFiles(FILE* fp0, FILE* fp1, FILE* fpUnc, long uncOffset)
{
int result = 0;
long bytesRead = 0;
long bytesToOffset = -1;
long b1Size = 1024;
while (result==0) {
char b1[b1Size];
size_t r1;
size_t bytesToRead = sizeof b1;
if (uncOffset >= 0) {
bytesToOffset = uncOffset - bytesRead;
/* read remainder to offset */
if (bytesToOffset < b1Size) {
bytesToRead = bytesToOffset;
}
}
char b0[1024];
size_t r0;
if (bytesToOffset <= 0 && fpUnc) {
bytesToRead = sizeof b1;
r0 = fread(b0, 1,bytesToRead, fpUnc);
} else {
r0 = fread(b0, 1, bytesToRead, fp0);
}
r1 = fread(b1, 1, r0, fp1);
result = (r0 != r1);
if (!r0 || !r1) break;
if (!result) result = memcmp(b0, b1, r0);
bytesRead += r1;
}
return result;
}
int main(int argc, char **argv) {
char inpFilename[256] = { 0 };
char lz4Filename[256] = { 0 };
char decFilename[256] = { 0 };
int uncOffset = -1;
char uncFilename[256] = { 0 };
int opt;
if (argc < 2) {
printf("Please specify input filename\n");
return EXIT_FAILURE;
}
snprintf(inpFilename, 256, "%s", argv[1]);
snprintf(lz4Filename, 256, "%s.lz4", argv[1]);
snprintf(decFilename, 256, "%s.lz4.dec", argv[1]);
while ((opt = getopt(argc, argv, "o:d:")) != -1) {
switch (opt) {
case 'd':
snprintf(uncFilename, 256, "%s", optarg);
break;
case 'o':
uncOffset = atoi(optarg);
break;
default:
printf("usage: %s <input file> [-o <offset> -d <file>]\n", argv[0]);
printf("-o uncompressed data offset\n");
printf(" inject uncompressed data at this offset into the lz4 file\n");
printf("-d uncompressed file\n");
printf(" file to inject without compression into the lz4 file\n");
return EXIT_FAILURE;
}
}
printf("inp = [%s]\n", inpFilename);
printf("lz4 = [%s]\n", lz4Filename);
printf("dec = [%s]\n", decFilename);
if (uncOffset > 0) {
printf("unc = [%s]\n", uncFilename);
printf("ofs = [%i]\n", uncOffset);
}
/* compress */
{ FILE* const inpFp = fopen(inpFilename, "rb");
FILE* const outFp = fopen(lz4Filename, "wb");
FILE* const uncFp = fopen(uncFilename, "rb");
printf("compress : %s -> %s\n", inpFilename, lz4Filename);
compressResult_t const ret = compress_file(
inpFp, outFp,
uncFp, uncOffset);
fclose(outFp);
fclose(inpFp);
if (uncFp)
fclose(uncFp);
if (ret.error) {
printf("compress : failed with code %i\n", ret.error);
return ret.error;
}
printf("%s: %zu → %zu bytes, %.1f%%\n",
inpFilename,
(size_t)ret.size_in, (size_t)ret.size_out, /* might overflow is size_t is 32 bits and size_{in,out} > 4 GB */
(double)ret.size_out / ret.size_in * 100);
printf("compress : done\n");
}
/* decompress */
{ FILE* const inpFp = fopen(lz4Filename, "rb");
FILE* const outFp = fopen(decFilename, "wb");
printf("decompress : %s -> %s\n", lz4Filename, decFilename);
int const ret = decompress_file(inpFp, outFp);
fclose(outFp);
fclose(inpFp);
if (ret) {
printf("decompress : failed with code %i\n", ret);
return ret;
}
printf("decompress : done\n");
}
/* verify */
{ FILE* const inpFp = fopen(inpFilename, "rb");
FILE* const decFp = fopen(decFilename, "rb");
FILE* const uncFp = fopen(uncFilename, "rb");
printf("verify : %s <-> %s\n", inpFilename, decFilename);
int const cmp = compareFiles(inpFp, decFp,
uncFp, uncOffset);
fclose(decFp);
fclose(inpFp);
if (uncFp)
fclose(uncFp);
if (cmp) {
printf("corruption detected : decompressed file differs from original\n");
return cmp;
}
printf("verify : OK\n");
}
return 0;
}