aosp12/external/zstd/tests/fuzz/fse_read_ncount.c

101 lines
3.4 KiB
C

/*
* Copyright (c) 2016-2020, 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.
*/
/**
* This fuzz target round trips the FSE normalized count with FSE_writeNCount()
* and FSE_readNcount() to ensure that it can always round trip correctly.
*/
#define FSE_STATIC_LINKING_ONLY
#define ZSTD_STATIC_LINKING_ONLY
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "fuzz_helpers.h"
#include "zstd_helpers.h"
#include "fuzz_data_producer.h"
#include "fse.h"
int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
{
FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size);
/* Pick a random tableLog and maxSymbolValue */
unsigned const tableLog = FUZZ_dataProducer_uint32Range(producer, FSE_MIN_TABLELOG, FSE_MAX_TABLELOG);
unsigned const maxSymbolValue = FUZZ_dataProducer_uint32Range(producer, 0, 255);
unsigned remainingWeight = (1u << tableLog) - 1;
size_t dataSize;
BYTE data[512];
short ncount[256];
/* Randomly fill the normalized count */
memset(ncount, 0, sizeof(ncount));
{
unsigned s;
for (s = 0; s < maxSymbolValue && remainingWeight > 0; ++s) {
short n = (short)FUZZ_dataProducer_int32Range(producer, -1, remainingWeight);
ncount[s] = n;
if (n < 0) {
remainingWeight -= 1;
} else {
assert((unsigned)n <= remainingWeight);
remainingWeight -= n;
}
}
/* Ensure ncount[maxSymbolValue] != 0 and the sum is (1<<tableLog) */
ncount[maxSymbolValue] = remainingWeight + 1;
if (ncount[maxSymbolValue] == 1 && FUZZ_dataProducer_uint32Range(producer, 0, 1) == 1) {
ncount[maxSymbolValue] = -1;
}
}
/* Write the normalized count */
{
FUZZ_ASSERT(sizeof(data) >= FSE_NCountWriteBound(maxSymbolValue, tableLog));
dataSize = FSE_writeNCount(data, sizeof(data), ncount, maxSymbolValue, tableLog);
FUZZ_ZASSERT(dataSize);
}
/* Read & validate the normalized count */
{
short rtNcount[256];
unsigned rtMaxSymbolValue = 255;
unsigned rtTableLog;
/* Copy into a buffer with a random amount of random data at the end */
size_t const buffSize = (size_t)FUZZ_dataProducer_uint32Range(producer, dataSize, sizeof(data));
BYTE* const buff = FUZZ_malloc(buffSize);
size_t rtDataSize;
memcpy(buff, data, dataSize);
{
size_t b;
for (b = dataSize; b < buffSize; ++b) {
buff[b] = (BYTE)FUZZ_dataProducer_uint32Range(producer, 0, 255);
}
}
rtDataSize = FSE_readNCount(rtNcount, &rtMaxSymbolValue, &rtTableLog, buff, buffSize);
FUZZ_ZASSERT(rtDataSize);
FUZZ_ASSERT(rtDataSize == dataSize);
FUZZ_ASSERT(rtMaxSymbolValue == maxSymbolValue);
FUZZ_ASSERT(rtTableLog == tableLog);
{
unsigned s;
for (s = 0; s <= maxSymbolValue; ++s) {
FUZZ_ASSERT(ncount[s] == rtNcount[s]);
}
}
free(buff);
}
FUZZ_dataProducer_free(producer);
return 0;
}