#include "zbuild.h"

#include <assert.h>

#ifdef ZLIB_COMPAT

#  include "zlib.h"

#else

#  include "zlib-ng.h"

#endif

#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;

/* ===========================================================================

 * Test deflate() with small buffers

 */

void test_deflate(unsigned char *compr, size_t comprLen) {

    PREFIX3(stream) c_stream; /* compression stream */

    int err;

    unsigned long len = (unsigned long)dataLen;

    c_stream.zalloc = zalloc;

    c_stream.zfree = zfree;

    c_stream.opaque = (void *)0;

    err = PREFIX(deflateInit)(&c_stream, Z_DEFAULT_COMPRESSION);

    CHECK_ERR(err, "deflateInit");

    c_stream.next_in = (z_const unsigned char *)data;

    c_stream.next_out = compr;

    while (c_stream.total_in != len && c_stream.total_out < comprLen) {

        c_stream.avail_in = c_stream.avail_out = 1; /* force small buffers */

        err = PREFIX(deflate)(&c_stream, Z_NO_FLUSH);

        CHECK_ERR(err, "deflate small 1");

    }

    /* Finish the stream, still forcing small buffers: */

    for (;;) {

        c_stream.avail_out = 1;

        err = PREFIX(deflate)(&c_stream, Z_FINISH);

        if (err == Z_STREAM_END)

            break;

        CHECK_ERR(err, "deflate small 2");

    }

    err = PREFIX(deflateEnd)(&c_stream);

    CHECK_ERR(err, "deflateEnd");

}

/* ===========================================================================

 * Test inflate() with small buffers

 */

void test_inflate(unsigned char *compr, size_t comprLen, unsigned char *uncompr, size_t uncomprLen) {

    int err;

    PREFIX3(stream) d_stream; /* decompression stream */

    d_stream.zalloc = zalloc;

    d_stream.zfree = zfree;

    d_stream.opaque = (void *)0;

    d_stream.next_in = compr;

    d_stream.avail_in = 0;

    d_stream.next_out = uncompr;

    err = PREFIX(inflateInit)(&d_stream);

    CHECK_ERR(err, "inflateInit");

    while (d_stream.total_out < uncomprLen && d_stream.total_in < comprLen) {

        d_stream.avail_in = d_stream.avail_out = 1; /* force small buffers */

        err = PREFIX(inflate)(&d_stream, Z_NO_FLUSH);

        if (err == Z_STREAM_END)

            break;

        CHECK_ERR(err, "inflate");

    }

    err = PREFIX(inflateEnd)(&d_stream);

    CHECK_ERR(err, "inflateEnd");

    if (memcmp(uncompr, data, dataLen)) {

        fprintf(stderr, "bad inflate\n");

        exit(1);

    }

}

int LLVMFuzzerTestOneInput(const uint8_t *d, size_t size) {

    size_t comprLen = PREFIX(compressBound)((z_uintmax_t)size);

    size_t uncomprLen = size;

    uint8_t *compr, *uncompr;

    /* Discard inputs larger than 1Mb. */

    static size_t kMaxSize = 1024 * 1024;

    if (size < 1 || size > kMaxSize)

        return 0;

    data = d;

    dataLen = size;

    compr = (uint8_t *)calloc(1, comprLen);

    uncompr = (uint8_t *)calloc(1, uncomprLen);

    test_deflate(compr, comprLen);

    test_inflate(compr, comprLen, uncompr, uncomprLen);

    free(compr);

    free(uncompr);

    /* This function must return 0. */

    return 0;

}