// Convert a stream into a destination manager.
public static void StreamToDestinationManager
(ref jpeg_compress_struct cinfo, Stream stream)
{
// Allocate a state structure and store it in "cinfo".
IntPtr buf = Marshal.AllocHGlobal(4096);
StreamState state = new StreamState();
state.buf = buf;
state.buffer = new byte [4096];
state.stream = stream;
cinfo.client_data = (IntPtr)(GCHandle.Alloc(state));
// Create the managed version of "jpeg_destination_mgr".
jpeg_destination_mgr mgr = new jpeg_destination_mgr();
mgr.next_output_byte = buf;
mgr.free_in_buffer = (size_t)4096;
mgr.init_destination =
new init_destination_type(init_destination);
mgr.empty_output_buffer =
new empty_output_buffer_type(empty_output_buffer);
mgr.term_destination =
new term_destination_type(term_destination);
// Convert it into the unmanaged version and store it.
#if __CSCC__
IntPtr umgr = Marshal.AllocHGlobal
(sizeof(jpeg_destination_mgr));
Marshal.StructureToPtr(mgr, umgr, false);
cinfo.dest = (jpeg_destination_mgr *)umgr;
#endif
}
// Basic output routines.
//
// Note that we do not support suspension while writing a marker.
// Therefore, an application using suspension must ensure that there is
// enough buffer space for the initial markers (typ. 600-700 bytes) before
// calling jpeg_start_compress, and enough space to write the trailing EOI
// (a few bytes) before calling jpeg_finish_compress. Multipass compression
// modes are not supported at all with suspension, so those two are the only
// points where markers will be written.
// Emit a byte
static void emit_byte(jpeg_compress cinfo, int val)
{
jpeg_destination_mgr dest=cinfo.dest;
dest.output_bytes[dest.next_output_byte++]=(byte)val;
if(--dest.free_in_buffer==0)
{
if(!dest.empty_output_buffer(cinfo)) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CANT_SUSPEND);
}
}
// Outputting bytes to the file.
// NB: these must be called only when actually outputting,
// that is, entropy.gather_statistics == false.
// Empty the output buffer; we do not support suspension in this module.
static void dump_buffer(phuff_entropy_encoder entropy)
{
jpeg_destination_mgr dest = entropy.cinfo.dest;
if (!dest.empty_output_buffer(entropy.cinfo))
{
ERREXIT(entropy.cinfo, J_MESSAGE_CODE.JERR_CANT_SUSPEND);
}
// After a successful buffer dump, must reset buffer pointers
entropy.output_bytes = dest.output_bytes;
entropy.next_output_byte = dest.next_output_byte;
entropy.free_in_buffer = dest.free_in_buffer;
}
// Outputting bytes to the file
// Empty the output buffer; return true if successful, false if must suspend
static bool dump_buffer(ref working_state_ls state)
{
jpeg_destination_mgr dest = state.cinfo.dest;
if (!dest.empty_output_buffer(state.cinfo))
{
return(false);
}
// After a successful buffer dump, must reset buffer pointers
state.output_bytes = dest.output_bytes;
state.next_output_byte = dest.next_output_byte;
state.free_in_buffer = dest.free_in_buffer;
return(true);
}
// Convert a stream into a destination manager.
public static void StreamToDestinationManager
(ref jpeg_compress_struct cinfo, Stream stream)
{
// Allocate a state structure and store it in "cinfo".
IntPtr buf = Marshal.AllocHGlobal(4096);
StreamState state = new StreamState();
state.buf = buf;
state.buffer = new byte [4096];
state.stream = stream;
cinfo.client_data = (IntPtr)(GCHandle.Alloc(state));
// Create the managed version of "jpeg_destination_mgr".
jpeg_destination_mgr mgr = new jpeg_destination_mgr();
mgr.next_output_byte = buf;
mgr.free_in_buffer = (size_t)4096;
mgr.init_destination =
new init_destination_type(init_destination);
mgr.empty_output_buffer =
new empty_output_buffer_type(empty_output_buffer);
mgr.term_destination =
new term_destination_type(term_destination);
// Convert it into the unmanaged version and store it.
#if __CSCC__
IntPtr umgr = Marshal.AllocHGlobal
(sizeof(jpeg_destination_mgr));
Marshal.StructureToPtr(mgr, umgr, false);
cinfo.dest = (jpeg_destination_mgr *)umgr;
#endif
}
