tesseract/unittest/fuzzers/fuzzer-api.cpp

#include "baseapi.h"
#include "leptonica/allheaders.h"

#include <libgen.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <string>

class BitReader {
 private:
  uint8_t const* data;
  size_t size;
  size_t shift;

 public:
  BitReader(const uint8_t* data, size_t size)
      : data(data), size(size), shift(0) {}

  int Read(void) {
    if (size == 0) {
      return 0;
    }

    const int ret = ((*data) >> shift) & 1;

    shift++;
    if (shift >= 8) {
      shift = 0;
      data++;
      size--;
    }

    return ret;
  }
};

tesseract::TessBaseAPI* api = nullptr;

extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) {
  (void)argc;
  (void)argv;

  {
    char* binary_path = strdup(*argv[0]);
    const std::string filepath = dirname(binary_path);
    free(binary_path);

    const std::string tessdata_path = filepath + "/" + "tessdata";
    if (setenv("TESSDATA_PREFIX", tessdata_path.c_str(), 1) != 0) {
      printf("Setenv failed\n");
      abort();
    }
  }

  api = new tesseract::TessBaseAPI();
  if (api->Init(nullptr, "eng") != 0) {
    printf("Cannot initialize API\n");
    abort();
  }

  /* Silence output */
  api->SetVariable("debug_file", "/dev/null");

  return 0;
}

static PIX* createPix(BitReader& BR, const size_t width, const size_t height) {
  Pix* pix = pixCreate(width, height, 1);

  if (pix == nullptr) {
    printf("pix creation failed\n");
    abort();
  }

  for (size_t i = 0; i < width; i++) {
    for (size_t j = 0; j < height; j++) {
      pixSetPixel(pix, i, j, BR.Read());
    }
  }

  return pix;
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
  BitReader BR(data, size);

  auto pix = createPix(BR, 100, 100);

  api->SetImage(pix);

  char* outText = api->GetUTF8Text();

  pixDestroy(&pix);
  delete[] outText;

  return 0;
}