Edit
IABSD.fr/xenocara/lib/liblbxutil/src/delta
matthieu
- lbxdelta.c
-
/* * $NCDXorg: @(#)lbxdelta.c,v 1.2 1994/01/22 02:23:40 dct Exp $ * $Xorg: lbxdelta.c,v 1.5 2000/08/17 19:46:40 cpqbld Exp $ * $XdotOrg: lib/lbxutil/src/delta/lbxdelta.c,v 1.7 2005/07/30 21:07:25 alanc Exp $ * * Copyright 1993 Network Computing Devices * * Permission to use, copy, modify, distribute, and sell this software and its * documentation for any purpose is hereby granted without fee, 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 NCD. not be used in advertising or * publicity pertaining to distribution of the software without specific, * written prior permission. NCD. makes no representations about the * suitability of this software for any purpose. It is provided "as is" * without express or implied warranty. * * NCD. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL NCD. * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Author: Dale Tonogai, Network Computing Devices */ /* $XFree86: xc/lib/lbxutil/delta/lbxdelta.c,v 1.7 2001/07/25 15:04:57 dawes Exp $ */ #include <X11/X.h> #include <X11/Xproto.h> #define _XLBX_SERVER_ #include <X11/extensions/lbxstr.h> #include <X11/extensions/lbxdeltastr.h> #include <stddef.h> #include <string.h> #ifdef LBXREQSTATS #include "../lbx_zlib/reqstats.h" extern int LbxWhoAmI; extern struct ReqStats CoreRequestStats[128]; extern struct ReqStats LbxRequestStats[LbxNumberReqs]; #define LBX_CODE 136 /* XXX - this should not be hardcoded - on todo list */ #endif /* Copied from xc/programs/Xserver/include/xorg/os.h */ #ifndef _HAVE_XALLOC_DECLS #define _HAVE_XALLOC_DECLS #include <X11/Xdefs.h> extern pointer Xalloc(unsigned long /*amount*/); extern pointer Xcalloc(unsigned long /*amount*/); extern pointer Xrealloc(pointer /*ptr*/, unsigned long /*amount*/); extern void Xfree(pointer /*ptr*/); #endif /* * Allocate data structures needed for doing Delta compaction */ int LBXInitDeltaCache(LBXDeltasPtr pcache, int nDeltas, int maxDeltasize) { int i; unsigned char *mem; if ((pcache->nDeltas = nDeltas)) { pcache->maxDeltasize = maxDeltasize; if ((pcache->deltas = (LBXDeltaElemPtr) Xalloc(pcache->nDeltas * sizeof(LBXDeltaElemRec) + pcache->nDeltas * pcache->maxDeltasize)) == NULL) { return -1; } mem = (unsigned char *) (pcache->deltas + pcache->nDeltas); for (i = 0; i < pcache->nDeltas; i++) { pcache->deltas[i].buf = mem; mem += pcache->maxDeltasize; } } else pcache->maxDeltasize = 0; pcache->nextDelta = 0; pcache->activeDeltas = 0; return 0; } /* * Free data structures used for doing Delta compaction */ void LBXFreeDeltaCache(LBXDeltasPtr pcache) { if (pcache->nDeltas && pcache->deltas) Xfree(pcache->deltas); } static int BytesDiff(unsigned char *ptr1, unsigned char *ptr2, int n, int maxn) { int result = 0; while (n--) if (*(ptr1++) != *(ptr2++)) if (++result >= maxn) break; return (result); } /* * Find the message in the outgoing delta cache with the least number of * differing bytes and return the number of differences. If all * messages have greater than maxdiff differences, return -1. */ int LBXDeltaMinDiffs(LBXDeltasPtr pcache, unsigned char *inmsg, int inmsglen, int maxdiff, int *pindex) { int i, j, k = 0, l = maxdiff + 1; int m; LBXDeltaElemPtr dm; for (m = pcache->nextDelta-1, dm = &pcache->deltas[m], i = 0; i < pcache->activeDeltas; i++, m--, dm-- ) { if (m < 0) { m = pcache->nDeltas - 1; dm = &pcache->deltas[m]; } if (dm->length == inmsglen) { j = BytesDiff(inmsg, dm->buf, inmsglen, l); if (j < l) { k = m; l = j; } } } if (l > maxdiff) return -1; else { *pindex = k; return l; } } /* * Delta compact a given message */ void LBXEncodeDelta(LBXDeltasPtr pcache, unsigned char *inmsg, int ndiff, int index, unsigned char *buf) { int i, off, diff; xLbxDiffItem *deltas = (xLbxDiffItem *)buf; for (off = i = 0; i < ndiff; off++) { if ((diff = inmsg[off] - pcache->deltas[index].buf[off])) { deltas[i].offset = off; deltas[i++].diff = diff; } } } /* * Uncompact a message */ int LBXDecodeDelta(LBXDeltasPtr pcache, xLbxDiffItem *deltas, int ndiff, int index, unsigned char **buf) { int i; int newindex = pcache->nextDelta; int len = pcache->deltas[index].length; unsigned char *p = pcache->deltas[newindex].buf; #ifdef LBXREQSTATS xReq *req; #endif pcache->nextDelta = (pcache->nextDelta + 1) % pcache->nDeltas; if (index != newindex) { memcpy(p, pcache->deltas[index].buf, len); pcache->deltas[newindex].length = len; } for (i = 0; i < ndiff; i++) p[deltas[i].offset] += deltas[i].diff; *buf = p; #ifdef LBXREQSTATS req = (xReq *) p; if (LbxWhoAmI == 1) /* server */ { struct ReqStats *reqStat = NULL; if (req->reqType == LBX_CODE) reqStat = &LbxRequestStats[req->data]; else if (req->reqType < 128) reqStat = &CoreRequestStats[req->reqType]; if (reqStat) { reqStat->delta_count++; reqStat->pre_delta_bytes += (req->length << 2); reqStat->post_delta_bytes += (((sz_xLbxDeltaReq + sz_xLbxDiffItem * ndiff + 3) >> 2) << 2); } } #endif return len; } /* * Add a message to the outgoing delta cache */ void LBXAddDeltaOut(LBXDeltasPtr pcache, unsigned char *inmsg, int inmsglen) { memcpy(pcache->deltas[pcache->nextDelta].buf, inmsg, inmsglen); pcache->deltas[pcache->nextDelta].length = inmsglen; pcache->nextDelta = (pcache->nextDelta + 1) % pcache->nDeltas; if (pcache->activeDeltas < pcache->nDeltas) pcache->activeDeltas++; } /* * Add a message to the incoming delta cache */ void LBXAddDeltaIn(LBXDeltasPtr pcache, unsigned char *inmsg, int inmsglen) { memcpy(pcache->deltas[pcache->nextDelta].buf, inmsg, inmsglen); pcache->deltas[pcache->nextDelta].length = inmsglen; pcache->nextDelta = (pcache->nextDelta + 1) % pcache->nDeltas; }