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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:45:59 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:45:59 +0000
commit19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch)
tree42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/zstd/examples/streaming_decompression.c
parentInitial commit. (diff)
downloadceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.tar.xz
ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.zip
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/zstd/examples/streaming_decompression.c')
-rw-r--r--src/zstd/examples/streaming_decompression.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/src/zstd/examples/streaming_decompression.c b/src/zstd/examples/streaming_decompression.c
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+++ b/src/zstd/examples/streaming_decompression.c
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+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * 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> // fprintf
+#include <stdlib.h> // free
+#include <zstd.h> // presumes zstd library is installed
+#include "common.h" // Helper functions, CHECK(), and CHECK_ZSTD()
+
+static void decompressFile_orDie(const char* fname)
+{
+ FILE* const fin = fopen_orDie(fname, "rb");
+ size_t const buffInSize = ZSTD_DStreamInSize();
+ void* const buffIn = malloc_orDie(buffInSize);
+ FILE* const fout = stdout;
+ size_t const buffOutSize = ZSTD_DStreamOutSize(); /* Guarantee to successfully flush at least one complete compressed block in all circumstances. */
+ void* const buffOut = malloc_orDie(buffOutSize);
+
+ ZSTD_DCtx* const dctx = ZSTD_createDCtx();
+ CHECK(dctx != NULL, "ZSTD_createDCtx() failed!");
+
+ /* This loop assumes that the input file is one or more concatenated zstd
+ * streams. This example won't work if there is trailing non-zstd data at
+ * the end, but streaming decompression in general handles this case.
+ * ZSTD_decompressStream() returns 0 exactly when the frame is completed,
+ * and doesn't consume input after the frame.
+ */
+ size_t const toRead = buffInSize;
+ size_t read;
+ size_t lastRet = 0;
+ int isEmpty = 1;
+ while ( (read = fread_orDie(buffIn, toRead, fin)) ) {
+ isEmpty = 0;
+ ZSTD_inBuffer input = { buffIn, read, 0 };
+ /* Given a valid frame, zstd won't consume the last byte of the frame
+ * until it has flushed all of the decompressed data of the frame.
+ * Therefore, instead of checking if the return code is 0, we can
+ * decompress just check if input.pos < input.size.
+ */
+ while (input.pos < input.size) {
+ ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
+ /* The return code is zero if the frame is complete, but there may
+ * be multiple frames concatenated together. Zstd will automatically
+ * reset the context when a frame is complete. Still, calling
+ * ZSTD_DCtx_reset() can be useful to reset the context to a clean
+ * state, for instance if the last decompression call returned an
+ * error.
+ */
+ size_t const ret = ZSTD_decompressStream(dctx, &output , &input);
+ CHECK_ZSTD(ret);
+ fwrite_orDie(buffOut, output.pos, fout);
+ lastRet = ret;
+ }
+ }
+
+ if (isEmpty) {
+ fprintf(stderr, "input is empty\n");
+ exit(1);
+ }
+
+ if (lastRet != 0) {
+ /* The last return value from ZSTD_decompressStream did not end on a
+ * frame, but we reached the end of the file! We assume this is an
+ * error, and the input was truncated.
+ */
+ fprintf(stderr, "EOF before end of stream: %zu\n", lastRet);
+ exit(1);
+ }
+
+ ZSTD_freeDCtx(dctx);
+ fclose_orDie(fin);
+ fclose_orDie(fout);
+ free(buffIn);
+ free(buffOut);
+}
+
+
+int main(int argc, const char** argv)
+{
+ const char* const exeName = argv[0];
+
+ if (argc!=2) {
+ fprintf(stderr, "wrong arguments\n");
+ fprintf(stderr, "usage:\n");
+ fprintf(stderr, "%s FILE\n", exeName);
+ return 1;
+ }
+
+ const char* const inFilename = argv[1];
+
+ decompressFile_orDie(inFilename);
+ return 0;
+}