1 files changed, 133 insertions, 0 deletions
diff --git a/src/zstd/examples/multiple_streaming_compression.c b/src/zstd/examples/multiple_streaming_compression.c
new file mode 100644
index 000000000..8a4dc96c1
--- /dev/null
+++ b/src/zstd/examples/multiple_streaming_compression.c
@@ -0,0 +1,133 @@
+/*
+ * 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.
+ */
+
+
+/* The objective of this example is to show of to compress multiple successive files
+*  while preserving memory management.
+*  All structures and buffers will be created only once,
+*  and shared across all compression operations */
+
+#include <stdio.h>     // printf
+#include <stdlib.h>    // free
+#include <string.h>    // memset, strcat
+#include <zstd.h>      // presumes zstd library is installed
+#include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()
+
+typedef struct {
+    void* buffIn;
+    void* buffOut;
+    size_t buffInSize;
+    size_t buffOutSize;
+    ZSTD_CCtx* cctx;
+} resources;
+
+static resources createResources_orDie(int cLevel)
+{
+    resources ress;
+    ress.buffInSize = ZSTD_CStreamInSize();   /* can always read one full block */
+    ress.buffOutSize= ZSTD_CStreamOutSize();  /* can always flush a full block */
+    ress.buffIn = malloc_orDie(ress.buffInSize);
+    ress.buffOut= malloc_orDie(ress.buffOutSize);
+    ress.cctx = ZSTD_createCCtx();
+    CHECK(ress.cctx != NULL, "ZSTD_createCCtx() failed!");
+
+    /* Set any compression parameters you want here.
+     * They will persist for every compression operation.
+     * Here we set the compression level, and enable the checksum.
+     */
+    CHECK_ZSTD( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_compressionLevel, cLevel) );
+    CHECK_ZSTD( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_checksumFlag, 1) );
+    return ress;
+}
+
+static void freeResources(resources ress)
+{
+    ZSTD_freeCCtx(ress.cctx);
+    free(ress.buffIn);
+    free(ress.buffOut);
+}
+
+static void compressFile_orDie(resources ress, const char* fname, const char* outName)
+{
+    // Open the input and output files.
+    FILE* const fin  = fopen_orDie(fname, "rb");
+    FILE* const fout = fopen_orDie(outName, "wb");
+
+    /* Reset the context to a clean state to start a new compression operation.
+     * The parameters are sticky, so we keep the compression level and extra
+     * parameters that we set in createResources_orDie().
+     */
+    CHECK_ZSTD( ZSTD_CCtx_reset(ress.cctx, ZSTD_reset_session_only) );
+
+    size_t const toRead = ress.buffInSize;
+    size_t read;
+    while ( (read = fread_orDie(ress.buffIn, toRead, fin)) ) {
+        /* This loop is the same as streaming_compression.c.
+         * See that file for detailed comments.
+         */
+        int const lastChunk = (read < toRead);
+        ZSTD_EndDirective const mode = lastChunk ? ZSTD_e_end : ZSTD_e_continue;
+
+        ZSTD_inBuffer input = { ress.buffIn, read, 0 };
+        int finished;
+        do {
+            ZSTD_outBuffer output = { ress.buffOut, ress.buffOutSize, 0 };
+            size_t const remaining = ZSTD_compressStream2(ress.cctx, &output, &input, mode);
+            CHECK_ZSTD(remaining);
+            fwrite_orDie(ress.buffOut, output.pos, fout);
+            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!");
+    }
+
+    fclose_orDie(fout);
+    fclose_orDie(fin);
+}
+
+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(s)\n", exeName);
+        return 1;
+    }
+
+    int const cLevel = 7;
+    resources const ress = createResources_orDie(cLevel);
+    void* ofnBuffer = NULL;
+    size_t ofnbSize = 0;
+
+    int argNb;
+    for (argNb = 1; argNb < argc; argNb++) {
+        const char* const ifn = argv[argNb];
+        size_t const ifnSize = strlen(ifn);
+        size_t const ofnSize = ifnSize + 5;
+        if (ofnbSize <= ofnSize) {
+            ofnbSize = ofnSize + 16;
+            free(ofnBuffer);
+            ofnBuffer = malloc_orDie(ofnbSize);
+        }
+        memset(ofnBuffer, 0, ofnSize);
+        strcat(ofnBuffer, ifn);
+        strcat(ofnBuffer, ".zst");
+        compressFile_orDie(ress, ifn, ofnBuffer);
+    }
+
+    freeResources(ress);
+    free(ofnBuffer);
+
+    printf("compressed %i files \n", argc-1);
+
+    return 0;
+}