void testSaveMemIO(const char *lpszPathName) {
FIMEMORY *hmem = NULL;
// load a regular file
FREE_IMAGE_FORMAT fif = FreeImage_GetFileType(lpszPathName);
FIBITMAP *dib = FreeImage_Load(fif, lpszPathName, 0);
// open a memory handle
hmem = FreeImage_OpenMemory();
// save the file to memory
FreeImage_SaveToMemory(fif, dib, hmem, 0);
// at this point, hmem contains the entire PNG data in memory.
// the amount of space used by the memory is equal to file_size
long file_size = FreeImage_TellMemory(hmem);
printf("File size : %ld\n", file_size);
// its easy load an image from memory as well
// seek to the start of the memory stream
FreeImage_SeekMemory(hmem, 0L, SEEK_SET);
// get the file type
FREE_IMAGE_FORMAT mem_fif = FreeImage_GetFileTypeFromMemory(hmem, 0);
// load an image from the memory handle
FIBITMAP *check = FreeImage_LoadFromMemory(mem_fif, hmem, 0);
// save as a regular file
FreeImage_Save(FIF_PNG, check, "dump.png", PNG_DEFAULT);
// make sure to free the data since FreeImage_SaveToMemory
// will cause it to be malloc'd
FreeImage_CloseMemory(hmem);
FreeImage_Unload(check);
FreeImage_Unload(dib);
}
long fipMemoryIO::tell() const {
return FreeImage_TellMemory(_hmem);
}
/**
Write a metadata model as a TIF IFD to a FIMEMORY handle.
The entries in the TIF IFD are sorted in ascending order by tag id.
The last entry is written as 0 (4 bytes) which means no more IFD to follow.
Supported metadata models are
<ul>
<li>FIMD_EXIF_MAIN
<li>FIMD_EXIF_EXIF
<li>FIMD_EXIF_GPS
<li>FIMD_EXIF_INTEROP
</ul>
The end of the buffer is filled with 4 bytes equal to 0 (end of IFD offset)
@param dib Input FIBITMAP
@param md_model Metadata model to write
@param hmem Memory handle
@return Returns TRUE if successful, FALSE otherwise
@see tiff_get_ifd_profile
*/
static BOOL
tiff_write_ifd(FIBITMAP *dib, FREE_IMAGE_MDMODEL md_model, FIMEMORY *hmem) {
FITAG *tag = NULL;
FIMETADATA *mdhandle = NULL;
std::vector<FITAG*> vTagList;
TagLib::MDMODEL internal_md_model;
DWORD ifd_offset = 0; // WORD-aligned IFD value offset
const BYTE empty_byte = 0;
// start of the file
const long start_of_file = FreeImage_TellMemory(hmem);
// get the metadata count
unsigned metadata_count = FreeImage_GetMetadataCount(md_model, dib);
if(metadata_count == 0) {
return FALSE;
}
TagLib& s = TagLib::instance();
// check for supported metadata models
switch(md_model) {
case FIMD_EXIF_MAIN:
internal_md_model = TagLib::EXIF_MAIN;
break;
case FIMD_EXIF_EXIF:
internal_md_model = TagLib::EXIF_EXIF;
break;
case FIMD_EXIF_GPS:
internal_md_model = TagLib::EXIF_GPS;
break;
case FIMD_EXIF_INTEROP:
internal_md_model = TagLib::EXIF_INTEROP;
break;
default:
return FALSE;
}
try {
// 1) according to the TIFF specifications,
// the entries in a TIF IFD must be sorted in ascending order by tag id
// store the tags into a vector
vTagList.reserve(metadata_count);
mdhandle = FreeImage_FindFirstMetadata(md_model, dib, &tag);
if(mdhandle) {
// parse the tags and store them inside vTagList
do {
// rewrite the tag id using FreeImage internal database
// (in case the tag id is wrong or missing)
const char *key = FreeImage_GetTagKey(tag);
int tag_id = s.getTagID(internal_md_model, key);
if(tag_id != -1) {
// this is a known tag, set the tag ID
FreeImage_SetTagID(tag, (WORD)tag_id);
// record the tag
vTagList.push_back(tag);
}
// else ignore this tag
} while(FreeImage_FindNextMetadata(mdhandle, &tag));
FreeImage_FindCloseMetadata(mdhandle);
// sort the vector by tag id
std::sort(vTagList.begin(), vTagList.end(), PredicateTagIDCompare());
// update the metadata_count
metadata_count = (unsigned)vTagList.size();
} else {
throw(1);
}
// 2) prepare the place for each IFD entries.
/*
An Image File Directory (IFD) consists of a 2-byte count of the number of directory entries (i.e., the number of fields),
followed by a sequence of 12-byte field entries,
followed by a 4-byte offset of the next IFD (or 0 if none). Do not forget to write the 4 bytes of 0 after the last IFD.
*/
{
// prepare place for 2 bytes for number of entries + 12 bytes for each entry
unsigned ifd_size = 2 + 12 * metadata_count;
FreeImage_WriteMemory(&empty_byte, 1, ifd_size, hmem);
// record the offset used to write values > 4-bytes
ifd_offset = FreeImage_TellMemory(hmem);
// rewind
FreeImage_SeekMemory(hmem, start_of_file, SEEK_SET);
}
// 3) write each IFD entry in tag id ascending order
// number of directory entries
WORD nde = (WORD)metadata_count;
FreeImage_WriteMemory(&nde, 1, 2, hmem);
// for each entry ...
for(unsigned i = 0; i < metadata_count; i++) {
FITAG *tag = vTagList[i];
// tag id
WORD tag_id = FreeImage_GetTagID(tag);
FreeImage_WriteMemory(&tag_id, 1, 2, hmem);
// tag type (compliant with TIFF specification)
WORD tag_type = (WORD)FreeImage_GetTagType(tag);
FreeImage_WriteMemory(&tag_type, 1, 2, hmem);
// tag count
DWORD tag_count = FreeImage_GetTagCount(tag);
FreeImage_WriteMemory(&tag_count, 1, 4, hmem);
// tag value or offset (results are in BYTE's units)
unsigned tag_length = FreeImage_GetTagLength(tag);
if(tag_length <= 4) {
// 4 bytes or less, write the value (left justified)
const BYTE *tag_value = (BYTE*)FreeImage_GetTagValue(tag);
FreeImage_WriteMemory(tag_value, 1, tag_length, hmem);
for(unsigned k = tag_length; k < 4; k++) {
FreeImage_WriteMemory(&empty_byte, 1, 1, hmem);
}
} else {
// write an offset
FreeImage_WriteMemory(&ifd_offset, 1, 4, hmem);
// write the value
long current_position = FreeImage_TellMemory(hmem);
FreeImage_SeekMemory(hmem, ifd_offset, SEEK_SET);
FreeImage_WriteMemory(FreeImage_GetTagValue(tag), 1, tag_length, hmem);
if(tag_length & 1) {
// align to the next WORD boundary
FreeImage_WriteMemory(&empty_byte, 1, 1, hmem);
}
// next offset to use
ifd_offset = FreeImage_TellMemory(hmem);
// rewind
FreeImage_SeekMemory(hmem, current_position, SEEK_SET);
}
}
// end-of-IFD or next IFD (0 == none)
FreeImage_SeekMemory(hmem, ifd_offset, SEEK_SET);
FreeImage_WriteMemory(&empty_byte, 1, 4, hmem);
return TRUE;
}
catch(int) {
return FALSE;
}
}
