Merge pull request #1566 from terrelln/examples
[examples] Update multiple_streaming_compression.cdev
commit
882ceb86bc
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@ -18,7 +18,7 @@
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#include <stdio.h> // fprintf, perror, feof
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#include <string.h> // strerror
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#include <errno.h> // errno
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#define ZSTD_STATIC_LINKING_ONLY // streaming API defined as "experimental" for the time being
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#define ZSTD_STATIC_LINKING_ONLY // TODO: Remove once the API is stable
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#include <zstd.h> // presumes zstd library is installed
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#include "utils.h"
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@ -27,52 +27,67 @@ typedef struct {
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void* buffOut;
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size_t buffInSize;
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size_t buffOutSize;
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ZSTD_CStream* cstream;
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} resources ;
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ZSTD_CCtx* cctx;
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} resources;
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static resources createResources_orDie()
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static resources createResources_orDie(int cLevel)
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{
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resources ress;
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ress.buffInSize = ZSTD_CStreamInSize(); /* can always read one full block */
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ress.buffOutSize= ZSTD_CStreamOutSize(); /* can always flush a full block */
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ress.buffIn = malloc_orDie(ress.buffInSize);
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ress.buffOut= malloc_orDie(ress.buffOutSize);
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ress.cstream = ZSTD_createCStream();
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if (ress.cstream==NULL) { fprintf(stderr, "ZSTD_createCStream() error \n"); exit(10); }
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ress.cctx = ZSTD_createCCtx();
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CHECK(ress.cctx != NULL, "ZSTD_createCCtx() failed!");
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/* Set any compression parameters you want here.
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* They will persist for every compression operation.
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* Here we set the compression level, and enable the checksum.
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*/
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CHECK_ZSTD( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_compressionLevel, cLevel) );
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CHECK_ZSTD( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_checksumFlag, 1) );
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return ress;
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}
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static void freeResources(resources ress)
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{
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ZSTD_freeCStream(ress.cstream);
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ZSTD_freeCCtx(ress.cctx);
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free(ress.buffIn);
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free(ress.buffOut);
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}
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static void compressFile_orDie(resources ress, const char* fname, const char* outName, int cLevel)
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static void compressFile_orDie(resources ress, const char* fname, const char* outName)
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{
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// Open the input and output files.
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FILE* const fin = fopen_orDie(fname, "rb");
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FILE* const fout = fopen_orDie(outName, "wb");
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size_t const initResult = ZSTD_initCStream(ress.cstream, cLevel);
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if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_initCStream() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
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/* Reset the context to a clean state to start a new compression operation.
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* The parameters are sticky, so we keep the compression level and extra
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* parameters that we set in createResources_orDie().
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*/
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CHECK_ZSTD( ZSTD_CCtx_reset(ress.cctx, ZSTD_reset_session_only) );
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size_t const toRead = ress.buffInSize;
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size_t read;
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while ( (read = fread_orDie(ress.buffIn, toRead, fin)) ) {
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/* This loop is the same as streaming_compression.c.
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* See that file for detailed comments.
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*/
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int const lastChunk = (read < toRead);
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ZSTD_EndDirective const mode = lastChunk ? ZSTD_e_end : ZSTD_e_continue;
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size_t read, toRead = ress.buffInSize;
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while( (read = fread_orDie(ress.buffIn, toRead, fin)) ) {
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ZSTD_inBuffer input = { ress.buffIn, read, 0 };
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while (input.pos < input.size) {
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int finished;
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do {
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ZSTD_outBuffer output = { ress.buffOut, ress.buffOutSize, 0 };
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toRead = ZSTD_compressStream(ress.cstream, &output , &input); /* toRead is guaranteed to be <= ZSTD_CStreamInSize() */
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if (ZSTD_isError(toRead)) { fprintf(stderr, "ZSTD_compressStream() error : %s \n", ZSTD_getErrorName(toRead)); exit(12); }
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if (toRead > ress.buffInSize) toRead = ress.buffInSize; /* Safely handle when `buffInSize` is manually changed to a smaller value */
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size_t const remaining = ZSTD_compressStream2(ress.cctx, &output, &input, mode);
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CHECK_ZSTD(remaining);
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fwrite_orDie(ress.buffOut, output.pos, fout);
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finished = lastChunk ? (remaining == 0) : (input.pos == input.size);
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} while (!finished);
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assert(input.pos == input.size);
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}
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}
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ZSTD_outBuffer output = { ress.buffOut, ress.buffOutSize, 0 };
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size_t const remainingToFlush = ZSTD_endStream(ress.cstream, &output); /* close frame */
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if (remainingToFlush) { fprintf(stderr, "not fully flushed"); exit(13); }
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fwrite_orDie(ress.buffOut, output.pos, fout);
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fclose_orDie(fout);
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fclose_orDie(fin);
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@ -89,7 +104,8 @@ int main(int argc, const char** argv)
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return 1;
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}
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resources const ress = createResources_orDie();
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int const cLevel = 7;
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resources const ress = createResources_orDie(cLevel);
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void* ofnBuffer = NULL;
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size_t ofnbSize = 0;
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@ -106,7 +122,7 @@ int main(int argc, const char** argv)
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memset(ofnBuffer, 0, ofnSize);
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strcat(ofnBuffer, ifn);
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strcat(ofnBuffer, ".zst");
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compressFile_orDie(ress, ifn, ofnBuffer, 7);
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compressFile_orDie(ress, ifn, ofnBuffer);
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}
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freeResources(ress);
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