[fuzzer] Add dictionary fuzzers

tests/fuzz/zstd_helpers.c

@@ -8,10 +8,14 @@
  */
 
 #define ZSTD_STATIC_LINKING_ONLY
+#define ZDICT_STATIC_LINKING_ONLY
+
+#include <string.h>
 
 #include "zstd_helpers.h"
 #include "fuzz_helpers.h"
 #include "zstd.h"
+#include "zdict.h"
 
 static void set(ZSTD_CCtx *cctx, ZSTD_cParameter param, int value)
 {
@@ -71,7 +75,6 @@ void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, uint32_t *state)
     setRand(cctx, ZSTD_c_contentSizeFlag, 0, 1, state);
     setRand(cctx, ZSTD_c_checksumFlag, 0, 1, state);
     setRand(cctx, ZSTD_c_dictIDFlag, 0, 1, state);
-    setRand(cctx, ZSTD_c_forceAttachDict, 0, 2, state);
     /* Select long distance matchig parameters */
     setRand(cctx, ZSTD_c_enableLongDistanceMatching, 0, 1, state);
     setRand(cctx, ZSTD_c_ldmHashLog, ZSTD_HASHLOG_MIN, 16, state);
@@ -81,4 +84,54 @@ void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, uint32_t *state)
             state);
     setRand(cctx, ZSTD_c_ldmHashRateLog, ZSTD_LDM_HASHRATELOG_MIN,
             ZSTD_LDM_HASHRATELOG_MAX, state);
+    /* Set misc parameters */
+    setRand(cctx, ZSTD_c_nbWorkers, 0, 2, state);
+    setRand(cctx, ZSTD_c_rsyncable, 0, 1, state);
+    setRand(cctx, ZSTD_c_forceMaxWindow, 0, 1, state);
+    setRand(cctx, ZSTD_c_literalCompressionMode, 0, 2, state);
+    setRand(cctx, ZSTD_c_forceAttachDict, 0, 2, state);
+}
+
+FUZZ_dict_t FUZZ_train(void const* src, size_t srcSize, uint32_t *state)
+{
+    size_t const dictSize = MAX(srcSize / 8, 1024);
+    size_t const totalSampleSize = dictSize * 11;
+    FUZZ_dict_t dict = { malloc(dictSize), dictSize };
+    char* const samples = (char*)malloc(totalSampleSize);
+    unsigned nbSamples = 100;
+    size_t* const samplesSizes = (size_t*)malloc(sizeof(size_t) * nbSamples);
+    size_t pos = 0;
+    size_t sample = 0;
+    ZDICT_fastCover_params_t params;
+    FUZZ_ASSERT(dict.buff && samples && samplesSizes);
+
+    for (sample = 0; sample < nbSamples; ++sample) {
+      size_t const remaining = totalSampleSize - pos;
+      size_t const offset = FUZZ_rand32(state, 0, MAX(srcSize, 1) - 1);
+      size_t const limit = MIN(srcSize - offset, remaining);
+      size_t const toCopy = MIN(limit, remaining / (nbSamples - sample));
+      memcpy(samples + pos, src + offset, toCopy);
+      pos += toCopy;
+      samplesSizes[sample] = toCopy;
+
+    }
+    memset(samples + pos, 0, totalSampleSize - pos);
+
+    memset(&params, 0, sizeof(params));
+    params.accel = 5;
+    params.k = 40;
+    params.d = 8;
+    params.f = 14;
+    params.zParams.compressionLevel = 1;
+    dict.size = ZDICT_trainFromBuffer_fastCover(dict.buff, dictSize,
+        samples, samplesSizes, nbSamples, params);
+    if (ZSTD_isError(dict.size)) {
+        free(dict.buff);
+        memset(&dict, 0, sizeof(dict));
+    }
+
+    free(samplesSizes);
+    free(samples);
+
+    return dict;
 }