1*4887Schin /*********************************************************************** 2*4887Schin * * 3*4887Schin * This software is part of the ast package * 4*4887Schin * Copyright (c) 1985-2007 AT&T Knowledge Ventures * 5*4887Schin * and is licensed under the * 6*4887Schin * Common Public License, Version 1.0 * 7*4887Schin * by AT&T Knowledge Ventures * 8*4887Schin * * 9*4887Schin * A copy of the License is available at * 10*4887Schin * http://www.opensource.org/licenses/cpl1.0.txt * 11*4887Schin * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * 12*4887Schin * * 13*4887Schin * Information and Software Systems Research * 14*4887Schin * AT&T Research * 15*4887Schin * Florham Park NJ * 16*4887Schin * * 17*4887Schin * Glenn Fowler <gsf@research.att.com> * 18*4887Schin * David Korn <dgk@research.att.com> * 19*4887Schin * Phong Vo <kpv@research.att.com> * 20*4887Schin * * 21*4887Schin ***********************************************************************/ 22*4887Schin #pragma prototyped 23*4887Schin /* 24*4887Schin * Glenn Fowler 25*4887Schin * AT&T Research 26*4887Schin * 27*4887Schin * internal representation conversion support 28*4887Schin */ 29*4887Schin 30*4887Schin #include <ast.h> 31*4887Schin #include <swap.h> 32*4887Schin 33*4887Schin /* 34*4887Schin * swap n bytes according to op 35*4887Schin * from==to is ok 36*4887Schin */ 37*4887Schin 38*4887Schin void* 39*4887Schin swapmem(int op, const void* from, void* to, register size_t n) 40*4887Schin { 41*4887Schin register char* f = (char*)from; 42*4887Schin register char* t = (char*)to; 43*4887Schin register int c; 44*4887Schin 45*4887Schin switch (op & (n - 1)) 46*4887Schin { 47*4887Schin case 0: 48*4887Schin if (t != f) 49*4887Schin memcpy(t, f, n); 50*4887Schin break; 51*4887Schin case 1: 52*4887Schin for (n >>= 1; n--; f += 2, t += 2) 53*4887Schin { 54*4887Schin c = f[0]; t[0] = f[1]; t[1] = c; 55*4887Schin } 56*4887Schin break; 57*4887Schin case 2: 58*4887Schin for (n >>= 2; n--; f += 4, t += 4) 59*4887Schin { 60*4887Schin c = f[0]; t[0] = f[2]; t[2] = c; 61*4887Schin c = f[1]; t[1] = f[3]; t[3] = c; 62*4887Schin } 63*4887Schin break; 64*4887Schin case 3: 65*4887Schin for (n >>= 2; n--; f += 4, t += 4) 66*4887Schin { 67*4887Schin c = f[0]; t[0] = f[3]; t[3] = c; 68*4887Schin c = f[1]; t[1] = f[2]; t[2] = c; 69*4887Schin } 70*4887Schin break; 71*4887Schin case 4: 72*4887Schin for (n >>= 3; n--; f += 8, t += 8) 73*4887Schin { 74*4887Schin c = f[0]; t[0] = f[4]; t[4] = c; 75*4887Schin c = f[1]; t[1] = f[5]; t[5] = c; 76*4887Schin c = f[2]; t[2] = f[6]; t[6] = c; 77*4887Schin c = f[3]; t[3] = f[7]; t[7] = c; 78*4887Schin } 79*4887Schin break; 80*4887Schin case 5: 81*4887Schin for (n >>= 3; n--; f += 8, t += 8) 82*4887Schin { 83*4887Schin c = f[0]; t[0] = f[5]; t[5] = c; 84*4887Schin c = f[1]; t[1] = f[4]; t[4] = c; 85*4887Schin c = f[2]; t[2] = f[7]; t[7] = c; 86*4887Schin c = f[3]; t[3] = f[6]; t[6] = c; 87*4887Schin } 88*4887Schin break; 89*4887Schin case 6: 90*4887Schin for (n >>= 3; n--; f += 8, t += 8) 91*4887Schin { 92*4887Schin c = f[0]; t[0] = f[6]; t[6] = c; 93*4887Schin c = f[1]; t[1] = f[7]; t[7] = c; 94*4887Schin c = f[2]; t[2] = f[4]; t[4] = c; 95*4887Schin c = f[3]; t[3] = f[5]; t[5] = c; 96*4887Schin } 97*4887Schin break; 98*4887Schin case 7: 99*4887Schin for (n >>= 3; n--; f += 8, t += 8) 100*4887Schin { 101*4887Schin c = f[0]; t[0] = f[7]; t[7] = c; 102*4887Schin c = f[1]; t[1] = f[6]; t[6] = c; 103*4887Schin c = f[2]; t[2] = f[5]; t[5] = c; 104*4887Schin c = f[3]; t[3] = f[4]; t[4] = c; 105*4887Schin } 106*4887Schin break; 107*4887Schin } 108*4887Schin return to; 109*4887Schin } 110