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- /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
- */
- #include <u.h>
- #include <libc.h>
- #include <oventi.h>
- /* score of a zero length block */
- uint8_t vtZeroScore[VtScoreSize] = {
- 0xda, 0x39, 0xa3, 0xee, 0x5e, 0x6b, 0x4b, 0x0d, 0x32, 0x55,
- 0xbf, 0xef, 0x95, 0x60, 0x18, 0x90, 0xaf, 0xd8, 0x07, 0x09
- };
- int
- vtZeroExtend(int type, uint8_t *buf, int n, int nn)
- {
- uint8_t *p, *ep;
- switch(type) {
- default:
- memset(buf+n, 0, nn-n);
- break;
- case VtPointerType0:
- case VtPointerType1:
- case VtPointerType2:
- case VtPointerType3:
- case VtPointerType4:
- case VtPointerType5:
- case VtPointerType6:
- case VtPointerType7:
- case VtPointerType8:
- case VtPointerType9:
- p = buf + (n/VtScoreSize)*VtScoreSize;
- ep = buf + (nn/VtScoreSize)*VtScoreSize;
- while(p < ep) {
- memmove(p, vtZeroScore, VtScoreSize);
- p += VtScoreSize;
- }
- memset(p, 0, buf+nn-p);
- break;
- }
- return 1;
- }
- int
- vtZeroTruncate(int type, uint8_t *buf, int n)
- {
- uint8_t *p;
- switch(type) {
- default:
- for(p = buf + n; p > buf; p--) {
- if(p[-1] != 0)
- break;
- }
- return p - buf;
- case VtRootType:
- if(n < VtRootSize)
- return n;
- return VtRootSize;
- case VtPointerType0:
- case VtPointerType1:
- case VtPointerType2:
- case VtPointerType3:
- case VtPointerType4:
- case VtPointerType5:
- case VtPointerType6:
- case VtPointerType7:
- case VtPointerType8:
- case VtPointerType9:
- /* ignore slop at end of block */
- p = buf + (n/VtScoreSize)*VtScoreSize;
- while(p > buf) {
- if(memcmp(p - VtScoreSize, vtZeroScore, VtScoreSize) != 0)
- break;
- p -= VtScoreSize;
- }
- return p - buf;
- }
- }
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