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// ==========================================================
// Load From Memory Example
//
// Design and implementation by Floris van den Berg
//
// This file is part of FreeImage 3
//
// Use at own risk!
// ==========================================================
//
// This example shows how to load a bitmap from memory
// rather than from a file. To do this we make use of the
// FreeImage_LoadFromHandle functions where we override
// the i/o functions to simulate FILE* access in memory.
//
// For seeking purposes the fi_handle passed to the i/o
// functions contain the start of the data block where the
// bitmap is stored.
//
// ==========================================================
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "FreeImage.h"
// ----------------------------------------------------------
fi_handle g_load_address;
// ----------------------------------------------------------
inline unsigned _stdcall
_ReadProc(void *buffer, unsigned size, unsigned count, fi_handle handle) {
BYTE *tmp = (BYTE *)buffer;
for (unsigned c = 0; c < count; c++) {
memcpy(tmp, g_load_address, size);
g_load_address = (BYTE *)g_load_address + size;
tmp += size;
}
return count;
}
inline unsigned _stdcall
_WriteProc(void *buffer, unsigned size, unsigned count, fi_handle handle) {
// there's not much use for saving the bitmap into memory now, is there?
return size;
}
inline int _stdcall
_SeekProc(fi_handle handle, long offset, int origin) {
assert(origin != SEEK_END);
if (origin == SEEK_SET) {
g_load_address = (BYTE *)handle + offset;
} else {
g_load_address = (BYTE *)g_load_address + offset;
}
return 0;
}
inline long _stdcall
_TellProc(fi_handle handle) {
assert((int)handle > (int)g_load_address);
return ((int)g_load_address - (int)handle);
}
// ----------------------------------------------------------
int
main(int argc, char *argv[]) {
FreeImageIO io;
io.read_proc = _ReadProc;
io.write_proc = _WriteProc;
io.tell_proc = _TellProc;
io.seek_proc = _SeekProc;
// allocate some memory for the bitmap
BYTE *test = new BYTE[159744];
if (test != NULL) {
// load the bitmap into memory. ofcourse you can do this any way you want
FILE *file = fopen("e:\\projects\\images\\money-256.tif", "rb");
fread(test, 159744, 1, file);
fclose(file);
// we store the load address of the bitmap for internal reasons
g_load_address = test;
// convert the bitmap
FIBITMAP *dib = FreeImage_LoadFromHandle(FIF_TIFF, &io, (fi_handle)test);
// don't forget to free the dib !
FreeImage_Unload(dib);
delete [] test;
}
return 0;
}
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