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/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
#include <stdio.h> // printf
#include <stdlib.h> // free
#include <string.h> // memset, strcat, strlen
#include <zstd.h> // presumes zstd library is installed
#include "common.h" // Helper functions, CHECK(), and CHECK_ZSTD()
static void compressFile_orDie(const char* fname, const char* outName, int cLevel,
int nbThreads)
{
fprintf (stderr, "Starting compression of %s with level %d, using %d threads\n",
fname, cLevel, nbThreads);
/* Open the input and output files. */
FILE* const fin = fopen_orDie(fname, "rb");
FILE* const fout = fopen_orDie(outName, "wb");
/* Create the input and output buffers.
* They may be any size, but we recommend using these functions to size them.
* Performance will only suffer significantly for very tiny buffers.
*/
size_t const buffInSize = ZSTD_CStreamInSize();
void* const buffIn = malloc_orDie(buffInSize);
size_t const buffOutSize = ZSTD_CStreamOutSize();
void* const buffOut = malloc_orDie(buffOutSize);
/* Create the context. */
ZSTD_CCtx* const cctx = ZSTD_createCCtx();
CHECK(cctx != NULL, "ZSTD_createCCtx() failed!");
/* Set any parameters you want.
* Here we set the compression level, and enable the checksum.
*/
CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, cLevel) );
CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1) );
ZSTD_CCtx_setParameter(cctx, ZSTD_c_nbWorkers, nbThreads);
/* This loop read from the input file, compresses that entire chunk,
* and writes all output produced to the output file.
*/
size_t const toRead = buffInSize;
for (;;) {
size_t read = fread_orDie(buffIn, toRead, fin);
/* Select the flush mode.
* If the read may not be finished (read == toRead) we use
* ZSTD_e_continue. If this is the last chunk, we use ZSTD_e_end.
* Zstd optimizes the case where the first flush mode is ZSTD_e_end,
* since it knows it is compressing the entire source in one pass.
*/
int const lastChunk = (read < toRead);
ZSTD_EndDirective const mode = lastChunk ? ZSTD_e_end : ZSTD_e_continue;
/* Set the input buffer to what we just read.
* We compress until the input buffer is empty, each time flushing the
* output.
*/
ZSTD_inBuffer input = { buffIn, read, 0 };
int finished;
do {
/* Compress into the output buffer and write all of the output to
* the file so we can reuse the buffer next iteration.
*/
ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
size_t const remaining = ZSTD_compressStream2(cctx, &output , &input, mode);
CHECK_ZSTD(remaining);
fwrite_orDie(buffOut, output.pos, fout);
/* If we're on the last chunk we're finished when zstd returns 0,
* which means its consumed all the input AND finished the frame.
* Otherwise, we're finished when we've consumed all the input.
*/
finished = lastChunk ? (remaining == 0) : (input.pos == input.size);
} while (!finished);
CHECK(input.pos == input.size,
"Impossible: zstd only returns 0 when the input is completely consumed!");
if (lastChunk) {
break;
}
}
ZSTD_freeCCtx(cctx);
fclose_orDie(fout);
fclose_orDie(fin);
free(buffIn);
free(buffOut);
}
static char* createOutFilename_orDie(const char* filename)
{
size_t const inL = strlen(filename);
size_t const outL = inL + 5;
void* const outSpace = malloc_orDie(outL);
memset(outSpace, 0, outL);
strcat(outSpace, filename);
strcat(outSpace, ".zst");
return (char*)outSpace;
}
int main(int argc, const char** argv)
{
const char* const exeName = argv[0];
if (argc < 2) {
printf("wrong arguments\n");
printf("usage:\n");
printf("%s FILE [LEVEL] [THREADS]\n", exeName);
return 1;
}
int cLevel = 1;
int nbThreads = 4;
if (argc >= 3) {
cLevel = atoi (argv[2]);
CHECK(cLevel != 0, "can't parse LEVEL!");
}
if (argc >= 4) {
nbThreads = atoi (argv[3]);
CHECK(nbThreads != 0, "can't parse THREADS!");
}
const char* const inFilename = argv[1];
char* const outFilename = createOutFilename_orDie(inFilename);
compressFile_orDie(inFilename, outFilename, cLevel, nbThreads);
free(outFilename); /* not strictly required, since program execution stops there,
* but some static analyzer may complain otherwise */
return 0;
}
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