/*

 * Copyright (C)2021-2024, 2026 D. R. Commander.  All Rights Reserved.

 * Copyright (C)2025 Leslie P. Polzer.  All Rights Reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * - Redistributions of source code must retain the above copyright notice,

 *   this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright notice,

 *   this list of conditions and the following disclaimer in the documentation

 *   and/or other materials provided with the distribution.

 * - Neither the name of the libjpeg-turbo Project nor the names of its

 *   contributors may be used to endorse or promote products derived from this

 *   software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS",

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

/* This fuzzer uses the libjpeg API to exercise code paths that are not covered

 * by the other fuzzers (or by the TurboJPEG API in general):

 *

 * - JCS_UNKNOWN (NULL color conversion with a component count other than 3 or

 *   4)

 * - Floating point IDCT

 * - Buffered-image mode

 * - Interstitial line skipping

 * - jpeg_save_markers() with a length limit

 * - Custom marker processor

 * - JCS_RGB565

 * - Color quantization

 */

#include <stdint.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <setjmp.h>

extern "C" {

#include "../src/jpeglib.h"

#include "../src/jerror.h"

}

struct fuzzer_error_mgr {

  struct jpeg_error_mgr pub;

  jmp_buf setjmp_buffer;

};

static void fuzzer_error_exit(j_common_ptr cinfo)

{

  struct fuzzer_error_mgr *fuzz_err = (struct fuzzer_error_mgr *)cinfo->err;

  longjmp(fuzz_err->setjmp_buffer, 1);

}

static void fuzzer_emit_message(j_common_ptr cinfo, int msg_level)

{

}

static int64_t marker_sum = 0;

static boolean custom_marker_processor(j_decompress_ptr cinfo)

{

  struct jpeg_source_mgr *src = cinfo->src;

  INT32 length;

  /* Read and consume the 2-byte length field. */

  if (src->bytes_in_buffer < 2)

    return FALSE;

  length = ((INT32)src->next_input_byte[0] << 8) +

            (INT32)src->next_input_byte[1];

  src->next_input_byte += 2;

  src->bytes_in_buffer -= 2;

  length -= 2;

  if (length < 0)

    return FALSE;

  /* Consume and touch all marker data in order to catch uninitialized reads

     when using MemorySanitizer. */

  while (length > 0) {

    if (src->bytes_in_buffer == 0) {

      if (!(*src->fill_input_buffer) (cinfo))

        return FALSE;

    }

    size_t available = (size_t)length < src->bytes_in_buffer ?

                       (size_t)length : src->bytes_in_buffer;

    for (size_t i = 0; i < available; i++)

      marker_sum += src->next_input_byte[i];

    src->next_input_byte += available;

    src->bytes_in_buffer -= available;

    length -= (INT32)available;

  }

  return TRUE;

}

#define NUMTESTS  7

struct test {

  J_COLOR_SPACE out_color_space;

  boolean quantize_colors;

  boolean two_pass_quantize;

  J_DITHER_MODE dither_mode;

};

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

{

  struct jpeg_decompress_struct cinfo;

  struct fuzzer_error_mgr jerr;

  JSAMPARRAY buffer = NULL;

  int row_stride;

  int numTests = 1;

  struct test tests[NUMTESTS] = {

    /*

      Output       Quantize 2-Pass Dither

      Colorspace   Colors   Quant  Mode

    */

    { JCS_RGB565,  FALSE,   FALSE, JDITHER_NONE    },

    { JCS_RGB565,  FALSE,   FALSE, JDITHER_ORDERED },

    { JCS_UNKNOWN, TRUE,    FALSE, JDITHER_NONE    },

    { JCS_UNKNOWN, TRUE,    FALSE, JDITHER_ORDERED },

    { JCS_UNKNOWN, TRUE,    FALSE, JDITHER_FS      },

    { JCS_UNKNOWN, TRUE,    TRUE,  JDITHER_NONE    },

    { JCS_UNKNOWN, TRUE,    TRUE,  JDITHER_FS      }

  };

  /* Reject too-small input. */

  if (size < 2)

    return 0;

  cinfo.err = jpeg_std_error(&jerr.pub);

  jerr.pub.error_exit = fuzzer_error_exit;

  jerr.pub.emit_message = fuzzer_emit_message;

  jpeg_create_decompress(&cinfo);

  for (int ti = 0; ti < numTests; ti++) {

    int64_t sum = 0;

    marker_sum = 0;

    if (setjmp(jerr.setjmp_buffer)) {

      jpeg_abort_decompress(&cinfo);

      continue;

    }

    jpeg_mem_src(&cinfo, data, (unsigned long)size);

    for (int m = JPEG_APP0; m <= JPEG_APP0 + 15; m++) {

      if (m != JPEG_APP0 + 3)

        jpeg_save_markers(&cinfo, m, 256);

    }

    jpeg_set_marker_processor(&cinfo, JPEG_APP0 + 3, custom_marker_processor);

    jpeg_read_header(&cinfo, TRUE);

    /* Sanity check dimensions to avoid memory exhaustion.  Casting width to

       (uint64_t) prevents integer overflow if width * height > INT_MAX. */

    if (cinfo.image_width < 1 || cinfo.image_height < 1 ||

        (uint64_t)cinfo.image_width * cinfo.image_height > 1048576)

      goto bailout;

    cinfo.dct_method = JDCT_FLOAT;

    cinfo.buffered_image = jpeg_has_multiple_scans(&cinfo);

    if (((cinfo.jpeg_color_space == JCS_YCbCr ||

          cinfo.jpeg_color_space == JCS_RGB) && cinfo.num_components == 3) ||

        (cinfo.jpeg_color_space == JCS_GRAYSCALE &&

         cinfo.num_components == 1)) {

      cinfo.out_color_space = tests[ti].out_color_space;

      if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {

        numTests = 5;

        if (cinfo.out_color_space == JCS_UNKNOWN)

          cinfo.out_color_space = JCS_GRAYSCALE;

      } else {

        numTests = 7;

        if (cinfo.out_color_space == JCS_UNKNOWN)

          cinfo.out_color_space = ti % 2 ? JCS_RGB : JCS_EXT_BGR;

      }

      cinfo.quantize_colors = tests[ti].quantize_colors;

      cinfo.two_pass_quantize = tests[ti].two_pass_quantize;

      cinfo.dither_mode = tests[ti].dither_mode;

    }

    if (!jpeg_start_decompress(&cinfo)) {

      jpeg_abort_decompress(&cinfo);

      continue;

    }

    row_stride = cinfo.output_width * cinfo.output_components;

    buffer = (*cinfo.mem->alloc_sarray)

      ((j_common_ptr)&cinfo, JPOOL_IMAGE, row_stride, 1);

    if (cinfo.buffered_image) {

      /* Process all scans. */

      while (!jpeg_input_complete(&cinfo) &&

             cinfo.input_scan_number != cinfo.output_scan_number) {

        int retval;

        if (cinfo.input_scan_number > 500) {

          jpeg_abort_decompress(&cinfo);

          goto bailout;

        }

        /* Consume input data until we have a complete scan or reach the end

           of input. */

        do {

          retval = jpeg_consume_input(&cinfo);

        } while (retval != JPEG_SUSPENDED && retval != JPEG_REACHED_SOS &&

                 retval != JPEG_REACHED_EOI);

        if (retval == JPEG_REACHED_EOI || retval == JPEG_SUSPENDED)

          break;

        /* Start outputting the current scan. */

        if (!jpeg_start_output(&cinfo, cinfo.input_scan_number))

          break;

        while (cinfo.output_scanline < cinfo.output_height) {

          if (!cinfo.two_pass_quantize &&

              (cinfo.output_scanline == 0 || cinfo.output_scanline == 16))

            jpeg_skip_scanlines(&cinfo, 8);

          else {

            jpeg_read_scanlines(&cinfo, buffer, 1);

            /* Touch all of the output pixels in order to catch uninitialized

               reads when using MemorySanitizer. */

            for (int i = 0; i < row_stride; i++)

              sum += buffer[0][i];

          }

        }

        /* Finish this output pass. */

        if (!jpeg_finish_output(&cinfo))

          break;

      }

    } else {

      while (cinfo.output_scanline < cinfo.output_height) {

        if (!cinfo.two_pass_quantize &&

            (cinfo.output_scanline == 0 || cinfo.output_scanline == 16))

          jpeg_skip_scanlines(&cinfo, 8);

        else {

          jpeg_read_scanlines(&cinfo, buffer, 1);

          for (int i = 0; i < row_stride; i++)

            sum += buffer[0][i];

        }

      }

    }

    jpeg_finish_decompress(&cinfo);

    /* Prevent the sums above from being optimized out.  This test should never

       be true, but the compiler doesn't know that. */

    if (sum > (int64_t)255 * 1048576 * 4 ||

        marker_sum > (int64_t)255 * 1048576)

      goto bailout;

  }

bailout:

  jpeg_destroy_decompress(&cinfo);

  return 0;

}