/*

# Copyright 2018 Google Inc.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#      http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

#

################################################################################

*/

#include <cstdint>

#include <stdlib.h>

#include <string.h>

#include <stdio.h>

#include "jbig2.h"

#define ALIGNMENT ((size_t) 16)

#define KBYTE ((size_t) 1024)

#define MBYTE (1024 * KBYTE)

#define GBYTE (1024 * MBYTE)

#define MAX_ALLOCATION (32 * MBYTE)

static size_t used;

static void *jbig2_fuzzer_reached_limit(size_t oldsize, size_t size)

{

  if (oldsize == 0)

    fprintf(stderr, "limit: %zu Mbyte used: %zu Mbyte allocation: %zu: limit reached\n", MAX_ALLOCATION / MBYTE, used / MBYTE, size);

  else

    fprintf(stderr, "limit: %zu Mbyte used: %zu Mbyte reallocation: %zu -> %zu: limit reached\n", MAX_ALLOCATION / MBYTE, used / MBYTE, oldsize, size);

  fflush(0);

  return NULL;

}

static void *jbig2_fuzzer_alloc(Jbig2Allocator *allocator, size_t size)

{

  char *ptr = NULL;

  if (size == 0)

    return NULL;

  if (size > SIZE_MAX - ALIGNMENT)

    return NULL;

  if (size + ALIGNMENT > MAX_ALLOCATION - used)

    return jbig2_fuzzer_reached_limit(0, size + ALIGNMENT);

  ptr = (char *) malloc(size + ALIGNMENT);

  if (ptr == NULL)

    return NULL;

  memcpy(ptr, &size, sizeof(size));

  used += size + ALIGNMENT;

  return ptr + ALIGNMENT;

}

static void jbig2_fuzzer_free(Jbig2Allocator *allocator, void *ptr)

{

  size_t size;

  if (ptr == NULL)

    return;

  if (ptr < (void *) ALIGNMENT)

    return;

  ptr = (char *) ptr - ALIGNMENT;

  memcpy(&size, ptr, sizeof(size));

  used -= size + ALIGNMENT;

  free(ptr);

}

static void *jbig2_fuzzer_realloc(Jbig2Allocator *allocator, void *old, size_t size)

{

  size_t oldsize;

  char *ptr;

  if (old == NULL)

    return jbig2_fuzzer_alloc(allocator, size);

  if (old < (void *) ALIGNMENT)

    return NULL;

  if (size == 0) {

    jbig2_fuzzer_free(allocator, old);

    return NULL;

  }

  if (size > SIZE_MAX - ALIGNMENT)

    return NULL;

  old = (char *) old - ALIGNMENT;

  memcpy(&oldsize, old, sizeof(oldsize));

  if (size + ALIGNMENT > MAX_ALLOCATION - used + oldsize + ALIGNMENT)

    return jbig2_fuzzer_reached_limit(oldsize + ALIGNMENT, size + ALIGNMENT);

  ptr = (char *) realloc(old, size + ALIGNMENT);

  if (ptr == NULL)

    return NULL;

  used -= oldsize + ALIGNMENT;

  memcpy(ptr, &size, sizeof(size));

  used += size + ALIGNMENT;

  return ptr + ALIGNMENT;

}

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

  Jbig2Allocator allocator;

  Jbig2Ctx *ctx = NULL;

  used = 0;

  allocator.alloc = jbig2_fuzzer_alloc;

  allocator.free = jbig2_fuzzer_free;

  allocator.realloc = jbig2_fuzzer_realloc;

  ctx = jbig2_ctx_new(&allocator, (Jbig2Options) 0, NULL, NULL, NULL);

  if (jbig2_data_in(ctx, data, size) == 0)

  {

    if (jbig2_complete_page(ctx) == 0)

    {

      Jbig2Image *image = jbig2_page_out(ctx);

      if (image != NULL)

      {

        int sum = 0;

        for (int i = 0; i < image->height * image->stride; i++)

          sum += image->data[i];

        printf("sum of image data bytes: %d\n", sum);

      }

      jbig2_release_page(ctx, image);

    }

  }

  jbig2_ctx_free(ctx);

  return 0;

}