#include <qpdf/Pl_DCT.hh>

#include <qpdf/Pl_Discard.hh>

#include <cstdlib>

#include <iostream>

#include <stdexcept>

class FuzzHelper

{

  public:

    FuzzHelper(unsigned char const* data, size_t size);

    void run();

  private:

    void doChecks();

    unsigned char const* data;

    size_t size;

};

FuzzHelper::FuzzHelper(unsigned char const* data, size_t size) :

    data(data),

    size(size)

{

}

void

FuzzHelper::doChecks()

{

    // Limit the memory used to decompress JPEG files during fuzzing. Excessive memory use during

    // fuzzing is due to corrupt JPEG data which sometimes cannot be detected before

    // jpeg_start_decompress is called. During normal use of qpdf very large JPEGs can occasionally

    // occur legitimately and therefore must be allowed during normal operations.

    Pl_DCT::setMemoryLimit(200'000'000);

    Pl_DCT::setScanLimit(50);

    // Do not decompress corrupt data. This may cause extended runtime within jpeglib without

    // exercising additional code paths in qpdf.

    Pl_DCT::setThrowOnCorruptData(true);

    Pl_Discard discard;

    Pl_DCT p("decode", &discard);

    p.write(const_cast<unsigned char*>(data), size);

    p.finish();

}

void

FuzzHelper::run()

{

    try {

        doChecks();

    } catch (std::runtime_error const& e) {

        std::cerr << "runtime_error: " << e.what() << '\n';

    }

}

extern "C" int

LLVMFuzzerTestOneInput(unsigned char const* data, size_t size)

{

#ifndef _WIN32

    // Used by jpeg library to work around false positives in memory

    // sanitizer.

    setenv("JSIMD_FORCENONE", "1", 1);

#endif

    FuzzHelper f(data, size);

    f.run();

    return 0;

}