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#include "../src/meshoptimizer.h"
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
void fuzzDecoder(const uint8_t* data, size_t size, size_t stride, int (*decode)(void*, size_t, size_t, const unsigned char*, size_t))
{
size_t count = 66; // must be divisible by 3 for decodeIndexBuffer; should be >=64 to cover large vertex blocks
void* destination = malloc(count * stride);
assert(destination);
int rc = decode(destination, count, stride, reinterpret_cast<const unsigned char*>(data), size);
(void)rc;
free(destination);
}
void fuzzRoundtrip(const uint8_t* data, size_t size, size_t stride, int level)
{
size_t count = size / stride;
size_t bound = meshopt_encodeVertexBufferBound(count, stride);
void* encoded = malloc(bound);
void* decoded = malloc(count * stride);
assert(encoded && decoded);
size_t res = meshopt_encodeVertexBufferLevel(static_cast<unsigned char*>(encoded), bound, data, count, stride, level, -1);
assert(res > 0 && res <= bound);
// encode again at the boundary to check for memory safety
// this should produce the same output because encoder is deterministic
size_t rese = meshopt_encodeVertexBufferLevel(static_cast<unsigned char*>(encoded) + bound - res, res, data, count, stride, level, -1);
assert(rese == res);
int rc = meshopt_decodeVertexBuffer(decoded, count, stride, static_cast<unsigned char*>(encoded) + bound - res, res);
assert(rc == 0);
assert(memcmp(data, decoded, count * stride) == 0);
free(decoded);
free(encoded);
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
{
// decodeIndexBuffer supports 2 and 4-byte indices
fuzzDecoder(data, size, 2, meshopt_decodeIndexBuffer);
fuzzDecoder(data, size, 4, meshopt_decodeIndexBuffer);
// decodeIndexSequence supports 2 and 4-byte indices
fuzzDecoder(data, size, 2, meshopt_decodeIndexSequence);
fuzzDecoder(data, size, 4, meshopt_decodeIndexSequence);
// decodeVertexBuffer supports any strides divisible by 4 in 4-256 interval
// it's a waste of time to check all of them, so we'll just check a few with different alignment mod 16
fuzzDecoder(data, size, 4, meshopt_decodeVertexBuffer);
fuzzDecoder(data, size, 16, meshopt_decodeVertexBuffer);
fuzzDecoder(data, size, 24, meshopt_decodeVertexBuffer);
fuzzDecoder(data, size, 32, meshopt_decodeVertexBuffer);
// encodeVertexBuffer/decodeVertexBuffer should roundtrip for any stride, check a few with different alignment mod 16
// this also checks memory safety properties of the encoder
// to conserve time, we only check one version/level combination, biased towards version 1
uint8_t data0 = size > 0 ? data[0] : 0;
int level = data0 % 5;
meshopt_encodeVertexVersion(level < 4 ? 1 : 0);
fuzzRoundtrip(data, size, 4, level);
fuzzRoundtrip(data, size, 16, level);
fuzzRoundtrip(data, size, 24, level);
fuzzRoundtrip(data, size, 32, level);
return 0;
}
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