1 056fe1ba 2003-11-23 devnull #include <u.h>
  2 056fe1ba 2003-11-23 devnull #include <libc.h>
  3 056fe1ba 2003-11-23 devnull #include <venti.h>
  4 056fe1ba 2003-11-23 devnull #include "cvt.h"
  5 056fe1ba 2003-11-23 devnull 
  6 056fe1ba 2003-11-23 devnull static int
  7 056fe1ba 2003-11-23 devnull checksize(int n)
  8 056fe1ba 2003-11-23 devnull {
  9 75d04888 2009-05-25 rsc 	if(n < 256) {
 10 23fb2edb 2005-07-24 devnull 		werrstr("bad block size %#ux", n);
 11 056fe1ba 2003-11-23 devnull 		return -1;
 12 056fe1ba 2003-11-23 devnull 	}
 13 056fe1ba 2003-11-23 devnull 	return 0;
 14 056fe1ba 2003-11-23 devnull }
 15 056fe1ba 2003-11-23 devnull 
 16 75d04888 2009-05-25 rsc // _VtEntryBig integer format is floating-point:
 17 75d04888 2009-05-25 rsc // (n>>5) << (n&31).
 18 75d04888 2009-05-25 rsc // Convert this number; must be exact or return -1.
 19 75d04888 2009-05-25 rsc int
 20 75d04888 2009-05-25 rsc vttobig(ulong n)
 21 75d04888 2009-05-25 rsc {
 22 75d04888 2009-05-25 rsc 	int shift;
 23 75d04888 2009-05-25 rsc 	ulong n0;
 24 fa325e9b 2020-01-10 cross 
 25 75d04888 2009-05-25 rsc 	n0 = n;
 26 75d04888 2009-05-25 rsc 	shift = 0;
 27 75d04888 2009-05-25 rsc 	while(n >= (1<<(16 - 5))) {
 28 75d04888 2009-05-25 rsc 		if(n & 1)
 29 75d04888 2009-05-25 rsc 			return -1;
 30 75d04888 2009-05-25 rsc 		shift++;
 31 75d04888 2009-05-25 rsc 		n >>= 1;
 32 75d04888 2009-05-25 rsc 	}
 33 fa325e9b 2020-01-10 cross 
 34 75d04888 2009-05-25 rsc 	n = (n<<5) | shift;
 35 75d04888 2009-05-25 rsc 	if(((n>>5)<<(n&31)) != n0)
 36 75d04888 2009-05-25 rsc 		sysfatal("vttobig %#lux => %#lux failed", n0, n);
 37 75d04888 2009-05-25 rsc 	return n;
 38 75d04888 2009-05-25 rsc }
 39 75d04888 2009-05-25 rsc 
 40 056fe1ba 2003-11-23 devnull void
 41 056fe1ba 2003-11-23 devnull vtentrypack(VtEntry *e, uchar *p, int index)
 42 056fe1ba 2003-11-23 devnull {
 43 056fe1ba 2003-11-23 devnull 	ulong t32;
 44 056fe1ba 2003-11-23 devnull 	int flags;
 45 056fe1ba 2003-11-23 devnull 	uchar *op;
 46 056fe1ba 2003-11-23 devnull 	int depth;
 47 75d04888 2009-05-25 rsc 	int psize, dsize;
 48 056fe1ba 2003-11-23 devnull 
 49 056fe1ba 2003-11-23 devnull 	p += index * VtEntrySize;
 50 056fe1ba 2003-11-23 devnull 	op = p;
 51 056fe1ba 2003-11-23 devnull 
 52 056fe1ba 2003-11-23 devnull 	depth = e->type&VtTypeDepthMask;
 53 d23a617a 2004-03-15 devnull 	flags = (e->flags&~(_VtEntryDir|_VtEntryDepthMask));
 54 d23a617a 2004-03-15 devnull 	flags |= depth << _VtEntryDepthShift;
 55 d23a617a 2004-03-15 devnull 	if(e->type - depth == VtDirType)
 56 d23a617a 2004-03-15 devnull 		flags |= _VtEntryDir;
 57 75d04888 2009-05-25 rsc 	U32PUT(p, e->gen);
 58 75d04888 2009-05-25 rsc 	p += 4;
 59 75d04888 2009-05-25 rsc 	psize = e->psize;
 60 75d04888 2009-05-25 rsc 	dsize = e->dsize;
 61 75d04888 2009-05-25 rsc 	if(psize >= (1<<16) || dsize >= (1<<16)) {
 62 75d04888 2009-05-25 rsc 		flags |= _VtEntryBig;
 63 75d04888 2009-05-25 rsc 		psize = vttobig(psize);
 64 75d04888 2009-05-25 rsc 		dsize = vttobig(dsize);
 65 75d04888 2009-05-25 rsc 		if(psize < 0 || dsize < 0)
 66 36c242dd 2011-11-08 rsc 			sysfatal("invalid entry psize/dsize: %ld/%ld", e->psize, e->dsize);
 67 75d04888 2009-05-25 rsc 	}
 68 75d04888 2009-05-25 rsc 	U16PUT(p, psize);
 69 75d04888 2009-05-25 rsc 	p += 2;
 70 75d04888 2009-05-25 rsc 	U16PUT(p, dsize);
 71 75d04888 2009-05-25 rsc 	p += 2;
 72 056fe1ba 2003-11-23 devnull 	U8PUT(p, flags);
 73 056fe1ba 2003-11-23 devnull 	p++;
 74 056fe1ba 2003-11-23 devnull 	memset(p, 0, 5);
 75 056fe1ba 2003-11-23 devnull 	p += 5;
 76 056fe1ba 2003-11-23 devnull 	U48PUT(p, e->size, t32);
 77 056fe1ba 2003-11-23 devnull 	p += 6;
 78 056fe1ba 2003-11-23 devnull 	memmove(p, e->score, VtScoreSize);
 79 056fe1ba 2003-11-23 devnull 	p += VtScoreSize;
 80 056fe1ba 2003-11-23 devnull 
 81 056fe1ba 2003-11-23 devnull 	assert(p-op == VtEntrySize);
 82 056fe1ba 2003-11-23 devnull }
 83 056fe1ba 2003-11-23 devnull 
 84 056fe1ba 2003-11-23 devnull int
 85 056fe1ba 2003-11-23 devnull vtentryunpack(VtEntry *e, uchar *p, int index)
 86 056fe1ba 2003-11-23 devnull {
 87 056fe1ba 2003-11-23 devnull 	uchar *op;
 88 056fe1ba 2003-11-23 devnull 
 89 056fe1ba 2003-11-23 devnull 	p += index * VtEntrySize;
 90 056fe1ba 2003-11-23 devnull 	op = p;
 91 056fe1ba 2003-11-23 devnull 
 92 056fe1ba 2003-11-23 devnull 	e->gen = U32GET(p);
 93 056fe1ba 2003-11-23 devnull 	p += 4;
 94 056fe1ba 2003-11-23 devnull 	e->psize = U16GET(p);
 95 056fe1ba 2003-11-23 devnull 	p += 2;
 96 056fe1ba 2003-11-23 devnull 	e->dsize = U16GET(p);
 97 056fe1ba 2003-11-23 devnull 	p += 2;
 98 056fe1ba 2003-11-23 devnull 	e->flags = U8GET(p);
 99 75d04888 2009-05-25 rsc 	p++;
100 75d04888 2009-05-25 rsc 	if(e->flags & _VtEntryBig) {
101 75d04888 2009-05-25 rsc 		e->psize = (e->psize>>5)<<(e->psize & 31);
102 75d04888 2009-05-25 rsc 		e->dsize = (e->dsize>>5)<<(e->dsize & 31);
103 75d04888 2009-05-25 rsc 	}
104 d23a617a 2004-03-15 devnull 	e->type = (e->flags&_VtEntryDir) ? VtDirType : VtDataType;
105 d23a617a 2004-03-15 devnull 	e->type += (e->flags & _VtEntryDepthMask) >> _VtEntryDepthShift;
106 75d04888 2009-05-25 rsc 	e->flags &= ~(_VtEntryDir|_VtEntryDepthMask|_VtEntryBig);
107 056fe1ba 2003-11-23 devnull 	p += 5;
108 056fe1ba 2003-11-23 devnull 	e->size = U48GET(p);
109 056fe1ba 2003-11-23 devnull 	p += 6;
110 056fe1ba 2003-11-23 devnull 	memmove(e->score, p, VtScoreSize);
111 056fe1ba 2003-11-23 devnull 	p += VtScoreSize;
112 056fe1ba 2003-11-23 devnull 
113 056fe1ba 2003-11-23 devnull 	assert(p-op == VtEntrySize);
114 fa325e9b 2020-01-10 cross 
115 056fe1ba 2003-11-23 devnull 	if(!(e->flags & VtEntryActive))
116 056fe1ba 2003-11-23 devnull 		return 0;
117 056fe1ba 2003-11-23 devnull 
118 fa325e9b 2020-01-10 cross 	/*
119 23fb2edb 2005-07-24 devnull 	 * Some old vac files use psize==0 and dsize==0 when the
120 23fb2edb 2005-07-24 devnull 	 * file itself has size 0 or is zeros.  Just to make programs not
121 23fb2edb 2005-07-24 devnull 	 * have to figure out what block sizes of 0 means, rewrite them.
122 23fb2edb 2005-07-24 devnull 	 */
123 23fb2edb 2005-07-24 devnull 	if(e->psize == 0 && e->dsize == 0
124 23fb2edb 2005-07-24 devnull 	&& memcmp(e->score, vtzeroscore, VtScoreSize) == 0){
125 23fb2edb 2005-07-24 devnull 		e->psize = 4096;
126 23fb2edb 2005-07-24 devnull 		e->dsize = 4096;
127 23fb2edb 2005-07-24 devnull 	}
128 056fe1ba 2003-11-23 devnull 	if(checksize(e->psize) < 0 || checksize(e->dsize) < 0)
129 056fe1ba 2003-11-23 devnull 		return -1;
130 056fe1ba 2003-11-23 devnull 
131 056fe1ba 2003-11-23 devnull 	return 0;
132 056fe1ba 2003-11-23 devnull }