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Annotation of 43BSDTahoe/new/X/libis/misc.c, revision 1.1

1.1     ! root        1: /*
        !             2:  *     $Source: /u1/X/libis/RCS/misc.c,v $
        !             3:  *     $Header: misc.c,v 1.1 86/11/17 14:34:18 swick Rel $
        !             4:  */
        !             5: 
        !             6: #ifndef lint
        !             7: static char *rcsid_misc_c = "$Header: misc.c,v 1.1 86/11/17 14:34:18 swick Rel $";
        !             8: #endif lint
        !             9: 
        !            10: #include "is-copyright.h"
        !            11: 
        !            12: /*
        !            13:  *     misc.c          miscellaneous utility functions
        !            14:  *
        !            15:  *     SwapShorts      swap order of bytes in shorts
        !            16:  *     SwapBits        swap order of bits in bytes
        !            17:  *     Overlap         determine if two rectangles overlap
        !            18:  *     Intersection    return the intersection of two rectangles
        !            19:  *
        !            20:  *     Copyright (c) 1986, Integrated Solutions, Inc.
        !            21:  */
        !            22: 
        !            23: #include "Xis.h"
        !            24: 
        !            25: #define MIN(a,b)       (((a)<(b))?(a):(b))
        !            26: #define MAX(a,b)       (((a)>(b))?(a):(b))
        !            27: 
        !            28: /*
        !            29:  *     bit reverse array used by bit swapping routines
        !            30:  */
        !            31: static unsigned char bitrev[] = {
        !            32:     0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
        !            33:     0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
        !            34:     0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
        !            35:     0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
        !            36:     0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
        !            37:     0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
        !            38:     0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
        !            39:     0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
        !            40:     0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
        !            41:     0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
        !            42:     0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
        !            43:     0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
        !            44:     0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
        !            45:     0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
        !            46:     0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
        !            47:     0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
        !            48:     0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
        !            49:     0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
        !            50:     0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
        !            51:     0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
        !            52:     0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
        !            53:     0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
        !            54:     0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
        !            55:     0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
        !            56:     0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
        !            57:     0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
        !            58:     0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
        !            59:     0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
        !            60:     0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
        !            61:     0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
        !            62:     0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
        !            63:     0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
        !            64: };
        !            65: 
        !            66: SwapShorts(wordp, bytecnt)
        !            67: short  *wordp;
        !            68: int    bytecnt;
        !            69: {
        !            70:     register unsigned char *p = (unsigned char *)wordp;
        !            71:     register int cnt = bytecnt >> 1;
        !            72:     while (cnt--) {
        !            73:        register unsigned char tmp = *p;
        !            74:        *p = *(p+1);
        !            75:        *(p+1) = tmp;
        !            76:        p += sizeof(short);
        !            77:     }
        !            78: }
        !            79: 
        !            80: /*
        !            81:  *     SwapBits - slow 'C' version
        !            82:  *
        !            83:  *     swap bit 0 and bit 15, swap bit 1 and bit 14, etc.
        !            84:  */
        !            85: SwapBits(wordp, bytecnt)
        !            86: register short *wordp;
        !            87: int            bytecnt;
        !            88: {
        !            89:     register int cnt = bytecnt >> 1;
        !            90:     while (cnt--) {
        !            91:        *wordp = (bitrev[(unsigned char)((*wordp)>>8)]<<8) |
        !            92:                (bitrev[(unsigned char)*wordp]);
        !            93:        wordp++;
        !            94:     }
        !            95: }
        !            96: 
        !            97: /*
        !            98:  *     Overlap
        !            99:  */
        !           100: int
        !           101: Overlap(r1, r2)
        !           102: CLIP   r1, r2;
        !           103: {
        !           104:     /* normalize rectangles */
        !           105:     if (r1.width < 0) {
        !           106:        r1.width = -r1.width;
        !           107:        r1.left -= r1.width-1;
        !           108:     }
        !           109:     if (r1.height < 0) {
        !           110:        r1.height = -r1.height;
        !           111:        r1.top -= r1.height-1;
        !           112:     }
        !           113:     if (r2.width < 0) {
        !           114:        r2.width = -r2.width;
        !           115:        r2.left -= r2.width-1;
        !           116:     }
        !           117:     if (r2.height < 0) {
        !           118:        r2.height = -r2.height;
        !           119:        r2.top -= r2.height-1;
        !           120:     }
        !           121:     if (r1.left < r2.left) {
        !           122:        if (r2.left >= r1.left + r1.width)
        !           123:            return (FALSE);
        !           124:     } else if (r1.left >= r2.left + r2.width) {
        !           125:        return (FALSE);
        !           126:     }
        !           127: 
        !           128:     if (r1.top < r2.top) {
        !           129:        if (r2.top >= r1.top + r1.height)
        !           130:            return (FALSE);
        !           131:     } else if (r1.top >= r2.top + r2.height) {
        !           132:        return (FALSE);
        !           133:     }
        !           134: 
        !           135:     return (TRUE);
        !           136: }
        !           137: 
        !           138: /*
        !           139:  *     Intersection
        !           140:  */
        !           141: CLIP
        !           142: Intersection(r1, r2)
        !           143: CLIP   r1, r2;
        !           144: {
        !           145:     CLIP i;
        !           146: 
        !           147:     /* normalize rectangles */
        !           148:     if (r1.width < 0) {
        !           149:        r1.width = -r1.width;
        !           150:        r1.left -= r1.width-1;
        !           151:     }
        !           152:     if (r1.height < 0) {
        !           153:        r1.height = -r1.height;
        !           154:        r1.top -= r1.height-1;
        !           155:     }
        !           156:     if (r2.width < 0) {
        !           157:        r2.width = -r2.width;
        !           158:        r2.left -= r2.width-1;
        !           159:     }
        !           160:     if (r2.height < 0) {
        !           161:        r2.height = -r2.height;
        !           162:        r2.top -= r2.height-1;
        !           163:     }
        !           164:     i.left     = MAX(r1.left, r2.left);
        !           165:     i.top      = MAX(r1.top, r2.top);
        !           166:     i.width    = MIN(r1.left+r1.width, r2.left+r2.width) - i.left;
        !           167:     i.height   = MIN(r1.top+r1.height, r2.top+r2.height) - i.top;
        !           168: 
        !           169:     return (i);
        !           170: }

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