/* Derived from zlib fuzzers at http://github.com/google/oss-fuzz/tree/master/projects/zlib,

 * see ossfuzz.sh for full license text.

 */

#include <stdio.h>

#include <stddef.h>

#include <stdint.h>

#include <string.h>

#include <stdlib.h>

#include <inttypes.h>

#include "miniz.h"

#define CHECK_ERR(err, msg)                              \

    {                                                    \

        if (err != Z_OK)                                 \

        {                                                \

            fprintf(stderr, "%s error: %d\n", msg, err); \

            exit(1);                                     \

        }                                                \

    }

static const uint8_t *data;

static size_t dataLen;

static alloc_func zalloc = NULL;

static free_func zfree = NULL;

static unsigned int diff;

/* Test deflate() with large buffers and dynamic change of compression level */

void test_large_deflate(unsigned char *compr, size_t comprLen,

                        unsigned char *uncompr, size_t uncomprLen)

{

    z_stream c_stream; /* compression stream */

    int err;

    c_stream.zalloc = zalloc;

    c_stream.zfree = zfree;

    c_stream.opaque = NULL;

    err = deflateInit(&c_stream, Z_BEST_COMPRESSION);

    CHECK_ERR(err, "deflateInit");

    c_stream.next_out = compr;

    c_stream.avail_out = (unsigned int)comprLen;

    /* At this point, uncompr is still mostly zeroes, so it should compress

     * very well:

     */

    c_stream.next_in = uncompr;

    c_stream.avail_in = (unsigned int)uncomprLen;

    err = deflate(&c_stream, Z_NO_FLUSH);

    CHECK_ERR(err, "deflate large 1");

    if (c_stream.avail_in != 0)

    {

        fprintf(stderr, "deflate not greedy\n");

        exit(1);

    }

    /* Feed in already compressed data: */

    c_stream.next_in = compr;

    diff = (unsigned int)(c_stream.next_out - compr);

    c_stream.avail_in = diff;

    deflate(&c_stream, Z_NO_FLUSH);

    err = deflate(&c_stream, Z_FINISH);

    if (err != Z_STREAM_END)

    {

        fprintf(stderr, "deflate large should report Z_STREAM_END\n");

        exit(1);

    }

    err = deflateEnd(&c_stream);

    CHECK_ERR(err, "deflateEnd");

}

/* Test inflate() with large buffers */

void test_large_inflate(unsigned char *compr, size_t comprLen,

                        unsigned char *uncompr, size_t uncomprLen)

{

    int err;

    z_stream d_stream; /* decompression stream */

    d_stream.zalloc = zalloc;

    d_stream.zfree = zfree;

    d_stream.opaque = NULL;

    d_stream.next_in = compr;

    d_stream.avail_in = (unsigned int)comprLen;

    err = inflateInit(&d_stream);

    CHECK_ERR(err, "inflateInit");

    for (;;)

    {

        d_stream.next_out = uncompr; /* discard the output */

        d_stream.avail_out = (unsigned int)uncomprLen;

        err = inflate(&d_stream, Z_NO_FLUSH);

        if (err == Z_STREAM_END)

            break;

        CHECK_ERR(err, "large inflate");

    }

    err = inflateEnd(&d_stream);

    CHECK_ERR(err, "inflateEnd");

}

int LLVMFuzzerTestOneInput(const uint8_t *d, size_t size)

{

    size_t comprLen = 100 + 3 * size;

    size_t uncomprLen = comprLen;

    uint8_t *compr, *uncompr;

    /* Discard inputs larger than 512Kb. */

    static size_t kMaxSize = 512 * 1024;

    if (size < 1 || size > kMaxSize)

        return 0;

    data = d;

    dataLen = size;

    compr = calloc(1, comprLen);

    uncompr = calloc(1, uncomprLen);

    test_large_deflate(compr, comprLen, uncompr, uncomprLen);

    test_large_inflate(compr, comprLen, uncompr, uncomprLen);

    free(compr);

    free(uncompr);

    return 0;

}