ref: 18046fd8153076782863f968db6fe1a1af0ddd2b
dir: /sys/src/libventi/entry.c/
#include <u.h> #include <libc.h> #include <venti.h> #include "cvt.h" static int checksize(int n) { if(n < 256 || n > VtMaxLumpSize) { werrstr("bad block size %#ux", n); return -1; } return 0; } void vtentrypack(VtEntry *e, uchar *p, int index) { ulong t32; int flags; uchar *op; int depth; p += index * VtEntrySize; op = p; U32PUT(p, e->gen); p += 4; U16PUT(p, e->psize); p += 2; U16PUT(p, e->dsize); p += 2; depth = e->type&VtTypeDepthMask; flags = (e->flags&~(_VtEntryDir|_VtEntryDepthMask)); flags |= depth << _VtEntryDepthShift; if(e->type - depth == VtDirType) flags |= _VtEntryDir; U8PUT(p, flags); p++; memset(p, 0, 5); p += 5; U48PUT(p, e->size, t32); p += 6; memmove(p, e->score, VtScoreSize); p += VtScoreSize; assert(p-op == VtEntrySize); } int vtentryunpack(VtEntry *e, uchar *p, int index) { uchar *op; p += index * VtEntrySize; op = p; e->gen = U32GET(p); p += 4; e->psize = U16GET(p); p += 2; e->dsize = U16GET(p); p += 2; e->flags = U8GET(p); e->type = (e->flags&_VtEntryDir) ? VtDirType : VtDataType; e->type += (e->flags & _VtEntryDepthMask) >> _VtEntryDepthShift; e->flags &= ~(_VtEntryDir|_VtEntryDepthMask); p++; p += 5; e->size = U48GET(p); p += 6; memmove(e->score, p, VtScoreSize); p += VtScoreSize; assert(p-op == VtEntrySize); if(!(e->flags & VtEntryActive)) return 0; /* * Some old vac files use psize==0 and dsize==0 when the * file itself has size 0 or is zeros. Just to make programs not * have to figure out what block sizes of 0 means, rewrite them. */ if(e->psize == 0 && e->dsize == 0 && memcmp(e->score, vtzeroscore, VtScoreSize) == 0){ e->psize = 4096; e->dsize = 4096; } if(checksize(e->psize) < 0 || checksize(e->dsize) < 0) return -1; return 0; }