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

// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================

#include "FreeImage.h"
#include "Utilities.h"

// ----------------------------------------------------------
//   Constants + headers
// ----------------------------------------------------------

#ifdef _WIN32
#pragma pack(push, 1)
#else
#pragma pack(1)
#endif

typedef struct tagSUNHEADER {
	DWORD magic;		// Magic number
	DWORD width;		// Image width in pixels
	DWORD height;		// Image height in pixels
	DWORD depth;		// Depth (1, 8, 24 or 32 bits) of each pixel
	DWORD length;		// Image length (in bytes)
	DWORD type;			// Format of file (see RT_* below)
	DWORD maptype;		// Type of colormap (see RMT_* below)
	DWORD maplength;	// Length of colormap (in bytes)
} SUNHEADER;

#ifdef _WIN32
#pragma pack(pop)
#else
#pragma pack()
#endif

// ----------------------------------------------------------

// Following the header is the colormap, for maplength bytes (unless maplength is zero),
// then the image. Each row of the image is rounded to 2 bytes.

#define RAS_MAGIC 0x59A66A95 // Magic number for Sun rasterfiles

// Sun supported type's

#define RT_OLD			0	// Old format (raw image in 68000 byte order)
#define RT_STANDARD		1	// Raw image in 68000 byte order
#define RT_BYTE_ENCODED	2	// Run-length encoding of bytes 
#define RT_FORMAT_RGB	3	// XRGB or RGB instead of XBGR or BGR
#define RT_FORMAT_TIFF	4	// TIFF <-> standard rasterfile
#define RT_FORMAT_IFF	5	// IFF (TAAC format) <-> standard rasterfile

#define RT_EXPERIMENTAL 0xffff	// Reserved for testing

// These are the possible colormap types.
// if it's in RGB format, the map is made up of three byte arrays
// (red, green, then blue) that are each 1/3 of the colormap length.

#define RMT_NONE		0	// maplength is expected to be 0
#define RMT_EQUAL_RGB	1	// red[maplength/3], green[maplength/3], blue[maplength/3]
#define RMT_RAW			2	// Raw colormap
#define RESC			128 // Run-length encoding escape character

// ----- NOTES -----
// Each line of the image is rounded out to a multiple of 16 bits.
// This corresponds to the rounding convention used by the memory pixrect
// package (/usr/include/pixrect/memvar.h) of the SunWindows system.
// The ras_encoding field (always set to 0 by Sun's supported software)
// was renamed to ras_length in release 2.0.  As a result, rasterfiles
// of type 0 generated by the old software claim to have 0 length; for
// compatibility, code reading rasterfiles must be prepared to compute the
// TRUE length from the width, height, and depth fields.

// ==========================================================
// Internal functions
// ==========================================================

static void
ReadData(FreeImageIO *io, fi_handle handle, BYTE *buf, DWORD length, BOOL rle) {
	// Read either Run-Length Encoded or normal image data

	static BYTE repchar, remaining= 0;

	if (rle) {
		// Run-length encoded read

		while(length--) {
			if (remaining) {
				remaining--;
				*(buf++)= repchar;
			} else {
				io->read_proc(&repchar, 1, 1, handle);

				if (repchar == RESC) {
					io->read_proc(&remaining, 1, 1, handle);

					if (remaining == 0) {
						*(buf++)= RESC;
					} else {
						io->read_proc(&repchar, 1, 1, handle);

						*(buf++)= repchar;
					}
				} else {
					*(buf++)= repchar;
				}
			}
		}
	} else {
		// Normal read
	
		io->read_proc(buf, length, 1, handle);
	}
}

// ==========================================================
// Plugin Interface
// ==========================================================

static int s_format_id;

// ==========================================================