updated decompression streaming example

examples/Makefile

@@ -55,8 +55,8 @@ streaming_decompression : streaming_decompression.c
 clean:
 	@rm -f core *.o tmp* result* *.zst \
         simple_compression simple_decompression \
-		dictionary_compression dictionary_decompression \
+        dictionary_compression dictionary_decompression \
-		streaming_compression streaming_decompression
+        streaming_compression streaming_decompression
 	@echo Cleaning completed
 
 test: all
@@ -64,7 +64,7 @@ test: all
 	@echo starting simple compression
 	./simple_compression tmp
 	./simple_decompression tmp.zst
-	./streaming_decompression tmp.zst
+	./streaming_decompression tmp.zst > /dev/null
 	@echo starting streaming compression
 	./streaming_compression tmp
 	./streaming_decompression tmp.zst

examples/streaming_decompression.c

@@ -42,6 +42,16 @@ static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file)
     exit(4);
 }
 
+static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file)
+{
+    size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file);
+    if (writtenSize == sizeToWrite) return sizeToWrite;   /* good */
+    /* error */
+    perror("fwrite");
+    exit(5);
+}
+
+
 static size_t fclose_orDie(FILE* file)
 {
     if (!fclose(file)) return 0;
@@ -54,28 +64,30 @@ static size_t fclose_orDie(FILE* file)
 static void decompressFile_orDie(const char* fname)
 {
     FILE* const fin  = fopen_orDie(fname, "rb");
-    size_t const buffInSize = ZSTD_DStreamInSize();;
+    size_t const buffInSize = ZSTD_DStreamInSize();
     void*  const buffIn  = malloc_orDie(buffInSize);
-    size_t const buffOutSize = ZSTD_DStreamOutSize();;
+    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);
-    size_t read, toRead = buffInSize;
+    FILE* const fout = stdout;
 
     ZSTD_DStream* const dstream = ZSTD_createDStream();
     if (dstream==NULL) { fprintf(stderr, "ZSTD_createDStream() error \n"); exit(10); }
     size_t const initResult = ZSTD_initDStream(dstream);
     if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_initDStream() error \n"); exit(11); }
+    size_t toRead = initResult;
 
-    while( (read = fread_orDie(buffIn, toRead, fin)) ) {
+    size_t read;
+    while ( (read = fread_orDie(buffIn, toRead, fin)) ) {
         ZSTD_inBuffer input = { buffIn, read, 0 };
         while (input.pos < input.size) {
             ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
-            toRead = ZSTD_decompressStream(dstream, &output , &input);
+            toRead = ZSTD_decompressStream(dstream, &output , &input);  /* toRead : size of next compressed block */
-            /* note : data is just "sinked" into buffOut
+            fwrite_orDie(buffOut, output.pos, fout);
-               a more complete example would write it to disk or stdout */
         }
     }
 
     fclose_orDie(fin);
+    fclose_orDie(fout);
     free(buffIn);
     free(buffOut);
 }

lib/zstd.h

@@ -229,7 +229,7 @@ ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void);
 ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
 
 ZSTDLIB_API size_t ZSTD_CStreamInSize(void);    /**< recommended size for input buffer */
-ZSTDLIB_API size_t ZSTD_CStreamOutSize(void);   /**< recommended size for output buffer */
+ZSTDLIB_API size_t ZSTD_CStreamOutSize(void);   /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */
 
 ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel);
 ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
@@ -268,7 +268,7 @@ ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void);
 ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds);
 
 ZSTDLIB_API size_t ZSTD_DStreamInSize(void);    /*!< recommended size for input buffer */
-ZSTDLIB_API size_t ZSTD_DStreamOutSize(void);   /*!< recommended size for output buffer */
+ZSTDLIB_API size_t ZSTD_DStreamOutSize(void);   /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */
 
 ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds);
 ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input);