added streaming_memory_usage example

examples/streaming_memory_usage.c

@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2017-present, 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.
+ */
+
+
+/*===   Tuning parameter   ===*/
+#ifndef MAX_TESTED_LEVEL
+#define MAX_TESTED_LEVEL 12
+#endif
+
+
+/*===   Dependencies   ===*/
+#include <stdio.h>   /* printf */
+#define ZSTD_STATIC_LINKING_ONLY
+#include "zstd.h"
+
+
+/*===   functions   ===*/
+
+/*! readU32FromChar() :
+    @return : unsigned integer value read from input in `char` format
+    allows and interprets K, KB, KiB, M, MB and MiB suffix.
+    Will also modify `*stringPtr`, advancing it to position where it stopped reading.
+    Note : function result can overflow if digit string > MAX_UINT */
+static unsigned readU32FromChar(const char** stringPtr)
+{
+    unsigned result = 0;
+    while ((**stringPtr >='0') && (**stringPtr <='9'))
+        result *= 10, result += **stringPtr - '0', (*stringPtr)++ ;
+    if ((**stringPtr=='K') || (**stringPtr=='M')) {
+        result <<= 10;
+        if (**stringPtr=='M') result <<= 10;
+        (*stringPtr)++ ;
+        if (**stringPtr=='i') (*stringPtr)++;
+        if (**stringPtr=='B') (*stringPtr)++;
+    }
+    return result;
+}
+
+
+int main(int argc, char const *argv[]) {
+
+    printf("\n Zstandard (v%u) memory usage for streaming contexts : \n\n", ZSTD_versionNumber());
+
+    unsigned wLog = 0;
+    if (argc > 1) {
+        const char* valStr = argv[1];
+        wLog = readU32FromChar(&valStr);
+    }
+
+    int compressionLevel;
+    for (compressionLevel = 1; compressionLevel <= MAX_TESTED_LEVEL; compressionLevel++) {
+#define INPUT_SIZE 5
+#define COMPRESSED_SIZE 128
+        char const dataToCompress[INPUT_SIZE] = "abcde";
+        char compressedData[COMPRESSED_SIZE];
+        char decompressedData[INPUT_SIZE];
+        ZSTD_CStream* const cstream = ZSTD_createCStream();
+        if (cstream==NULL) {
+            printf("Level %i : ZSTD_CStream Memory allocation failure \n", compressionLevel);
+            return 1;
+        }
+
+        /* forces compressor to use maximum memory size for given compression level,
+         * by not providing any information on input size */
+        ZSTD_parameters params = ZSTD_getParams(compressionLevel, 0, 0);
+        if (wLog) { /* special mode : specific wLog */
+            printf("Using custom compression parameter : level 1 + wLog=%u \n", wLog);
+            params = ZSTD_getParams(1, 1 << wLog, 0);
+            size_t const error = ZSTD_initCStream_advanced(cstream, NULL, 0, params, 0);
+            if (ZSTD_isError(error)) {
+                printf("ZSTD_initCStream_advanced error : %s \n", ZSTD_getErrorName(error));
+                return 1;
+            }
+        } else {
+            size_t const error = ZSTD_initCStream(cstream, compressionLevel);
+            if (ZSTD_isError(error)) {
+                printf("ZSTD_initCStream error : %s \n", ZSTD_getErrorName(error));
+                return 1;
+            }
+        }
+        
+        size_t compressedSize;
+        {   ZSTD_inBuffer inBuff = { dataToCompress, sizeof(dataToCompress), 0 };
+            ZSTD_outBuffer outBuff = { compressedData, sizeof(compressedData), 0 };
+            size_t const cError = ZSTD_compressStream(cstream, &outBuff, &inBuff);
+            if (ZSTD_isError(cError)) {
+                printf("ZSTD_compressStream error : %s \n", ZSTD_getErrorName(cError));
+                return 1;
+            }
+            size_t const fError = ZSTD_endStream(cstream, &outBuff);
+            if (ZSTD_isError(fError)) {
+                printf("ZSTD_endStream error : %s \n", ZSTD_getErrorName(fError));
+                return 1;
+            }
+            compressedSize = outBuff.pos;
+        }
+
+        ZSTD_DStream* dstream = ZSTD_createDStream();
+        if (dstream==NULL) {
+            printf("Level %i : ZSTD_DStream Memory allocation failure \n", compressionLevel);
+            return 1;
+        }
+        {   size_t const error = ZSTD_initDStream(dstream);
+            if (ZSTD_isError(error)) {
+                printf("ZSTD_initDStream error : %s \n", ZSTD_getErrorName(error));
+                return 1;
+            }
+        }
+        /* forces decompressor to use maximum memory size, as decompressed size is not known */
+        {   ZSTD_inBuffer inBuff = { compressedData, compressedSize, 0 };
+            ZSTD_outBuffer outBuff = { decompressedData, sizeof(decompressedData), 0 };
+            size_t const dResult = ZSTD_decompressStream(dstream, &outBuff, &inBuff);
+            if (ZSTD_isError(dResult)) {
+                printf("ZSTD_decompressStream error : %s \n", ZSTD_getErrorName(dResult));
+                return 1;
+            }
+            if (dResult != 0) {
+                printf("ZSTD_decompressStream error : unfinished decompression \n");
+                return 1;
+            }
+            if (outBuff.pos != sizeof(dataToCompress)) {
+                printf("ZSTD_decompressStream error : incorrect decompression \n");
+                return 1;
+            }
+        }
+
+        size_t const cstreamSize = ZSTD_sizeof_CStream(cstream);
+        size_t const cstreamEstimatedSize = wLog ?
+                ZSTD_estimateCStreamSize_advanced_usingCParams(params.cParams) :
+                ZSTD_estimateCStreamSize(compressionLevel);
+        size_t const dstreamSize = ZSTD_sizeof_DStream(dstream);
+
+        printf("Level %2i : Compression Mem = %5u KB (estimated : %5u KB) ; Decompression Mem = %4u KB \n",
+                compressionLevel,
+                (unsigned)(cstreamSize>>10), (unsigned)(cstreamEstimatedSize>>10), (unsigned)(dstreamSize>>10));
+
+        ZSTD_freeDStream(dstream);
+        ZSTD_freeCStream(cstream);
+        if (wLog) break;  /* single test */
+    }
+    return 0;
+}