/* *  Copyright 2012 The LibYuv Project Authors. All rights reserved. * *  Use of this source code is governed by a BSD-style license *  that can be found in the LICENSE file in the root of the source *  tree. An additional intellectual property rights grant can be found *  in the file PATENTS. All contributing project authors may *  be found in the AUTHORS file in the root of the source tree. */ #include "libyuv/mjpeg_decoder.h" #include <string.h>  // For memchr. #ifdef __cplusplusnamespace libyuv {extern "C" {#endif // Helper function to scan for EOI marker (0xff 0xd9).static LIBYUV_BOOL ScanEOI(const uint8_t* sample, size_t sample_size) {  if (sample_size >= 2) {    const uint8_t* end = sample + sample_size - 1;    const uint8_t* it = sample;    while (it < end) {      // TODO(fbarchard): scan for 0xd9 instead.      it = (const uint8_t*)(memchr(it, 0xff, end - it));      if (it == NULL) {        break;      }      if (it[1] == 0xd9) {        return LIBYUV_TRUE;  // Success: Valid jpeg.      }      ++it;  // Skip over current 0xff.    }  }  // ERROR: Invalid jpeg end code not found. Size sample_size  return LIBYUV_FALSE;} // Helper function to validate the jpeg appears intact.LIBYUV_BOOL ValidateJpeg(const uint8_t* sample, size_t sample_size) {  // Maximum size that ValidateJpeg will consider valid.  const size_t kMaxJpegSize = 0x7fffffffull;  const size_t kBackSearchSize = 1024;  if (sample_size < 64 || sample_size > kMaxJpegSize || !sample) {    // ERROR: Invalid jpeg size: sample_size    return LIBYUV_FALSE;  }  if (sample[0] != 0xff || sample[1] != 0xd8) {  // SOI marker    // ERROR: Invalid jpeg initial start code    return LIBYUV_FALSE;  }   // Look for the End Of Image (EOI) marker near the end of the buffer.  if (sample_size > kBackSearchSize) {    if (ScanEOI(sample + sample_size - kBackSearchSize, kBackSearchSize)) {      return LIBYUV_TRUE;  // Success: Valid jpeg.    }    // Reduce search size for forward search.    sample_size = sample_size - kBackSearchSize + 1;  }  // Step over SOI marker and scan for EOI.  return ScanEOI(sample + 2, sample_size - 2);} #ifdef __cplusplus}  // extern "C"}  // namespace libyuv#endif