xref: /xsrc/external/mit/xorg-server/dist/mi/midash.c

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

Copyright 1987, 1998  The Open Group

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in this Software without prior written authorization from The Open Group.

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
software without specific, written prior permission.

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
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DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
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******************************************************************/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include "regionstr.h"
#include "mistruct.h"

void
miStepDash(int dist,            /* distance to step */
           int *pDashIndex,     /* current dash */
           unsigned char *pDash,        /* dash list */
           int numInDashList,   /* total length of dash list */
           int *pDashOffset     /* offset into current dash */
    )
{
    int dashIndex, dashOffset;
    int totallen;
    int i;

    dashIndex = *pDashIndex;
    dashOffset = *pDashOffset;
    if (dist < pDash[dashIndex] - dashOffset) {
        *pDashOffset = dashOffset + dist;
        return;
    }
    dist -= pDash[dashIndex] - dashOffset;
    if (++dashIndex == numInDashList)
        dashIndex = 0;
    totallen = 0;
    for (i = 0; i < numInDashList; i++)
        totallen += pDash[i];
    if (totallen <= dist)
        dist = dist % totallen;
    while (dist >= pDash[dashIndex]) {
        dist -= pDash[dashIndex];
        if (++dashIndex == numInDashList)
            dashIndex = 0;
    }
    *pDashIndex = dashIndex;
    *pDashOffset = dist;
}