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Commit 0daf5f8e authored by Dichen Zhang's avatar Dichen Zhang
Browse files

Update EXIF 

Some tags contain offsets, and need to be modified after an insertion of
a "JR" tag

Test: manual
Bug: b/264715926
Change-Id: I273c43ca86ee2d089abeae84f65aa37dace1e4c4
parent 91dfc57a

libs/jpegrecoverymap/include/jpegrecoverymap/recoverymaputils.h

+45 −4
Original line number Diff line number Diff line
@@ -107,7 +107,6 @@ bool getMetadataFromXMP(uint8_t* xmp_data, size_t xmp_size, jpegr_metadata* meta 
std::string generateXmp(int secondary_image_length, jpegr_metadata& metadata);



/*

 * Helper function

 * Add J R entry to existing exif, or create a new one with J R entry if it's null.

 * EXIF syntax / change:

 * ori:
@@ -120,7 +119,7 @@ std::string generateXmp(int secondary_image_length, jpegr_metadata& metadata); 
 * 06 00 - 6 entries

 * 00 01 - Width Tag

 * 03 00 - 'Short' type

 * 01 00 00 00 - one entry

 * 01 00 00 00 - 1 component

 * 00 05 00 00 - image with 0x500

 *--------------------------------------------------------------------------

 * new:
@@ -133,14 +132,56 @@ std::string generateXmp(int secondary_image_length, jpegr_metadata& metadata); 
 * 07 00 - +1 entry

 * 4A 52   Custom ('J''R') Tag

 * 07 00 - Unknown type

 * 01 00 00 00 - one element

 * 01 00 00 00 - 1 component

 * 00 00 00 00 - empty data

 * 00 01 - Width Tag

 * 03 00 - 'Short' type

 * 01 00 00 00 - one entry

 * 01 00 00 00 - 1 component

 * 00 05 00 00 - image with 0x500

 */

status_t updateExif(jr_exif_ptr exif, jr_exif_ptr dest);



/*

 * Modify offsets in EXIF in place.

 *

 * Each tag has the following structure:

 *

 * 00 01 - Tag

 * 03 00 - data format

 * 01 00 00 00 - number of components

 * 00 05 00 00 - value

 *

 * The value means offset if

 * (1) num_of_components * bytes_per_component > 4 bytes, or

 * (2) tag == 0x8769 (ExifOffset).

 * In both cases, the method will add EXIF_J_R_ENTRY_LENGTH (12) to the offsets.

 */

void updateExifOffsets(jr_exif_ptr exif, int pos, bool use_big_endian);

void updateExifOffsets(jr_exif_ptr exif, int pos, int num_entry, bool use_big_endian);



/*

 * Read data from the target position and target length in bytes;

 */

int readValue(uint8_t* data, int pos, int length, bool use_big_endian);



/*

 * Returns the length of data format in bytes

 *

 *  ----------------------------------------------------------------------------------------------

 *  |       value       |         1       |        2        |        3         |       4         |

 *  |       format      |  unsigned byte  |  ascii strings  |  unsigned short  |  unsigned long  |

 *  |  bytes/component  |         1       |        1        |        2         |       4         |

 *  ----------------------------------------------------------------------------------------------

 *  |       value       |         5       |        6        |        7         |       8         |

 *  |       format      |unsigned rational|   signed byte   |    undefined     |  signed short   |

 *  |  bytes/component  |         8       |        1        |        1         |       2         |

 *  ----------------------------------------------------------------------------------------------

 *  |       value       |         9       |        10       |        11        |       12        |

 *  |       format      |   signed long   | signed rational |   single float   |  double float   |

 *  |  bytes/component  |         4       |        8        |        4         |       8         |

 *  ----------------------------------------------------------------------------------------------

 */

int findFormatLengthInBytes(int data_format);

}



#endif //ANDROID_JPEGRECOVERYMAP_RECOVERYMAPUTILS_H

libs/jpegrecoverymap/recoverymaputils.cpp

+117 −1
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ 
#include <image_io/xml/xml_handler.h>

#include <image_io/xml/xml_rule.h>



#include <utils/Log.h>



using namespace photos_editing_formats::image_io;

using namespace std;
@@ -406,7 +408,121 @@ status_t updateExif(jr_exif_ptr exif, jr_exif_ptr dest) { 


  Write(dest, (uint8_t*)exif->data + 16, exif->length - 16, pos);



  updateExifOffsets(dest,

                    28, // start from the second tag, skip the "JR" tag

                    num_entry - 1,

                    use_big_endian);



  return NO_ERROR;

}



/*

 * Helper function

 * Modify offsets in EXIF in place.

 */

void updateExifOffsets(jr_exif_ptr exif, int pos, bool use_big_endian) {

  int num_entry = readValue(reinterpret_cast<uint8_t*>(exif->data), pos, 2, use_big_endian);

  updateExifOffsets(exif, pos + 2, num_entry, use_big_endian);

}



void updateExifOffsets(jr_exif_ptr exif, int pos, int num_entry, bool use_big_endian) {

  for (int i = 0; i < num_entry; pos += EXIF_J_R_ENTRY_LENGTH, i++) {

    int tag = readValue(reinterpret_cast<uint8_t*>(exif->data), pos, 2, use_big_endian);

    bool need_to_update_offset = false;

    if (tag == 0x8769) {

      need_to_update_offset = true;

      int sub_ifd_offset =

              readValue(reinterpret_cast<uint8_t*>(exif->data), pos + 8, 4, use_big_endian)

              + 6  // "Exif\0\0";

              + EXIF_J_R_ENTRY_LENGTH;

      updateExifOffsets(exif, sub_ifd_offset, use_big_endian);

    } else {

      int data_format =

              readValue(reinterpret_cast<uint8_t*>(exif->data), pos + 2, 2, use_big_endian);

      int num_of_components =

              readValue(reinterpret_cast<uint8_t*>(exif->data), pos + 4, 4, use_big_endian);

      int data_length = findFormatLengthInBytes(data_format) * num_of_components;

      if (data_length > 4) {

        need_to_update_offset = true;

      }

    }



    if (!need_to_update_offset) {

      continue;

    }



    int offset = readValue(reinterpret_cast<uint8_t*>(exif->data), pos + 8, 4, use_big_endian);



    offset += EXIF_J_R_ENTRY_LENGTH;



    if (use_big_endian) {

      reinterpret_cast<uint8_t*>(exif->data)[pos + 11] = offset & 0xff;

      reinterpret_cast<uint8_t*>(exif->data)[pos + 10] = (offset >> 8) & 0xff;

      reinterpret_cast<uint8_t*>(exif->data)[pos + 9] = (offset >> 16) & 0xff;

      reinterpret_cast<uint8_t*>(exif->data)[pos + 8] = (offset >> 24) & 0xff;

    } else {

      reinterpret_cast<uint8_t*>(exif->data)[pos + 8] = offset & 0xff;

      reinterpret_cast<uint8_t*>(exif->data)[pos + 9] = (offset >> 8) & 0xff;

      reinterpret_cast<uint8_t*>(exif->data)[pos + 10] = (offset >> 16) & 0xff;

      reinterpret_cast<uint8_t*>(exif->data)[pos + 11] = (offset >> 24) & 0xff;

    }

  }

}



/*

 * Read data from the target position and target length in bytes;

 */

int readValue(uint8_t* data, int pos, int length, bool use_big_endian) {

  if (length == 2) {

    if (use_big_endian) {

      return (data[pos] << 8) | data[pos + 1];

    } else {

      return (data[pos + 1] << 8) | data[pos];

    }

  } else if (length == 4) {

    if (use_big_endian) {

      return (data[pos] << 24) | (data[pos + 1] << 16) | (data[pos + 2] << 8) | data[pos + 3];

    } else {

      return (data[pos + 3] << 24) | (data[pos + 2] << 16) | (data[pos + 1] << 8) | data[pos];

    }

  } else {

    // Not support for now.

    ALOGE("Error in readValue(): pos=%d, length=%d", pos, length);

    return -1;

  }

}



/*

 * Helper function

 * Returns the length of data format in bytes

 */

int findFormatLengthInBytes(int data_format) {

  switch (data_format) {

    case 1:  // unsigned byte

    case 2:  // ascii strings

    case 6:  // signed byte

    case 7:  // undefined

      return 1;



    case 3:  // unsigned short

    case 8:  // signed short

      return 2;



    case 4:  // unsigned long

    case 9:  // signed long

    case 11:  // single float

      return 4;



    case 5:  // unsigned rational

    case 10:  // signed rational

    case 12:  // double float

      return 8;



    default:

      // should not hit here

      ALOGE("Error in findFormatLengthInBytes(): data_format=%d", data_format);

      return -1;

  }

}



} // namespace android::recoverymap
 
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