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src/Source/FreeImage/MemoryIO.cpp  view on Meta::CPAN

	SetMemoryIO(&io);

	if (stream != NULL) {
		return FreeImage_GetFileTypeFromHandle(&io, (fi_handle)stream, size);
	}

	return FIF_UNKNOWN;
}

// =====================================================================
// Seeking in Memory stream
// =====================================================================

/**
Moves the memory pointer to a specified location
@param stream Pointer to FIMEMORY structure
@param offset Number of bytes from origin
@param origin Initial position
@return Returns TRUE if successful, returns FALSE otherwise
*/
BOOL DLL_CALLCONV
FreeImage_SeekMemory(FIMEMORY *stream, long offset, int origin) {
	FreeImageIO io;
	SetMemoryIO(&io);

	if (stream != NULL) {
		int success = io.seek_proc((fi_handle)stream, offset, origin);
		return (success == 0) ? TRUE : FALSE;
	}

	return FALSE;
}

/**
Gets the current position of a memory pointer
@param stream Target FIMEMORY structure
@return Returns the current file position if successful, -1 otherwise
*/
long DLL_CALLCONV
FreeImage_TellMemory(FIMEMORY *stream) {
	FreeImageIO io;
	SetMemoryIO(&io);

	if (stream != NULL) {
		return io.tell_proc((fi_handle)stream);
	}

	return -1L;
}

// =====================================================================
// Reading or Writing in Memory stream
// =====================================================================

/**
Reads data from a memory stream
@param buffer Storage location for data
@param size Item size in bytes
@param count Maximum number of items to be read
@param stream Pointer to FIMEMORY structure
@return Returns the number of full items actually read, which may be less than count if an error occurs
*/
unsigned DLL_CALLCONV 
FreeImage_ReadMemory(void *buffer, unsigned size, unsigned count, FIMEMORY *stream) {
	FreeImageIO io;
	SetMemoryIO(&io);

	if (stream != NULL) {
		return io.read_proc(buffer, size, count, stream);
	}

	return 0;
}

/**
Writes data to a memory stream.
@param buffer Pointer to data to be written
@param size Item size in bytes
@param count Maximum number of items to be written
@param stream Pointer to FIMEMORY structure
@return Returns the number of full items actually written, which may be less than count if an error occurs
*/
unsigned DLL_CALLCONV 
FreeImage_WriteMemory(const void *buffer, unsigned size, unsigned count, FIMEMORY *stream) {
	if (stream != NULL) {
		FreeImageIO io;
		SetMemoryIO(&io);

		FIMEMORYHEADER *mem_header = (FIMEMORYHEADER*)(((FIMEMORY*)stream)->data);

		if(mem_header->delete_me == TRUE) {
			return io.write_proc((void *)buffer, size, count, stream);
		} else {
			// do not write in a user buffer
			FreeImage_OutputMessageProc(FIF_UNKNOWN, "Memory buffer is read only");
		}
	}

	return 0;
}