xserver/include/servermd.h

/***********************************************************

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Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
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******************************************************************/

#ifndef SERVERMD_H
#define SERVERMD_H 1

#include <stddef.h>
#include <X11/Xarch.h>		/* for X_LITTLE_ENDIAN/X_BIG_ENDIAN */

#if X_BYTE_ORDER == X_LITTLE_ENDIAN
#define IMAGE_BYTE_ORDER        LSBFirst
#define BITMAP_BIT_ORDER        LSBFirst
#elif X_BYTE_ORDER == X_BIG_ENDIAN
#define IMAGE_BYTE_ORDER        MSBFirst
#define BITMAP_BIT_ORDER        MSBFirst
#else
#error "Too weird to live."
#endif

#define BITMAP_SCANLINE_PAD  32
#define LOG2_BITMAP_PAD		5
#define LOG2_BYTES_PER_SCANLINE_PAD	2

#include <X11/Xfuncproto.h>
/*
 *   This returns the number of padding units, for depth d and width w.
 * For bitmaps this can be calculated with the macros above.
 * Other depths require either grovelling over the formats field of the
 * screenInfo or hardwired constants.
 */

typedef struct _PaddingInfo {
    int padRoundUp;             /* pixels per pad unit - 1 */
    int padPixelsLog2;          /* log 2 (pixels per pad unit) */
    int padBytesLog2;           /* log 2 (bytes per pad unit) */
    int notPower2;              /* bitsPerPixel not a power of 2 */
    int bytesPerPixel;          /* only set when notPower2 is TRUE */
    int bitsPerPixel;           /* bits per pixel */
} PaddingInfo;
extern _X_EXPORT PaddingInfo PixmapWidthPaddingInfo[];

/* The only portable way to get the bpp from the depth is to look it up */
#define BitsPerPixel(d) (PixmapWidthPaddingInfo[d].bitsPerPixel)

#define PixmapWidthInPadUnits(w, d) \
    (PixmapWidthPaddingInfo[d].notPower2 ? \
    (((int)(w) * PixmapWidthPaddingInfo[d].bytesPerPixel +  \
	         PixmapWidthPaddingInfo[d].bytesPerPixel) >> \
	PixmapWidthPaddingInfo[d].padBytesLog2) : \
    ((int)((w) + PixmapWidthPaddingInfo[d].padRoundUp) >> \
	PixmapWidthPaddingInfo[d].padPixelsLog2))

/*
 *	Return the number of bytes to which a scanline of the given
 * depth and width will be padded.
 */
#define PixmapBytePad(w, d) \
    (PixmapWidthInPadUnits(w, d) << PixmapWidthPaddingInfo[d].padBytesLog2)

static inline size_t BitmapBytePad(size_t w) {
    return ((((w) + BITMAP_SCANLINE_PAD - 1) >> LOG2_BITMAP_PAD) << LOG2_BYTES_PER_SCANLINE_PAD);
}

#endif                          /* SERVERMD_H */