mirror of
https://github.com/9fans/plan9port.git
synced 2025-01-15 11:20:03 +00:00
112 lines
2.2 KiB
C
112 lines
2.2 KiB
C
#include "stdinc.h"
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#include "dat.h"
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#include "fns.h"
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struct IEStream
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{
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Part *part;
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u64int off; /* read position within part */
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u64int n; /* number of valid ientries left to read */
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u32int size; /* allocated space in buffer */
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u8int *buf;
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u8int *pos; /* current place in buffer */
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u8int *epos; /* end of valid buffer contents */
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};
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IEStream*
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initiestream(Part *part, u64int off, u64int clumps, u32int size)
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{
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IEStream *ies;
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//ZZZ out of memory?
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ies = MKZ(IEStream);
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ies->buf = MKN(u8int, size);
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ies->epos = ies->buf;
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ies->pos = ies->epos;
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ies->off = off;
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ies->n = clumps;
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ies->size = size;
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ies->part = part;
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return ies;
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}
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void
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freeiestream(IEStream *ies)
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{
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if(ies == nil)
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return;
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free(ies->buf);
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free(ies);
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}
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static u8int*
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peekientry(IEStream *ies)
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{
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u32int n, nn;
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n = ies->epos - ies->pos;
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if(n < IEntrySize){
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memmove(ies->buf, ies->pos, n);
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ies->epos = &ies->buf[n];
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ies->pos = ies->buf;
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nn = ies->size;
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if(nn > ies->n * IEntrySize)
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nn = ies->n * IEntrySize;
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nn -= n;
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if(nn == 0)
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return nil;
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if(readpart(ies->part, ies->off, ies->epos, nn) < 0){
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seterr(EOk, "can't read sorted index entries: %r");
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return nil;
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}
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ies->epos += nn;
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ies->off += nn;
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}
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return ies->pos;
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}
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static u32int
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iebuck(Index *ix, u8int *b)
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{
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return hashbits(b, 32) / ix->div;
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}
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u32int
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buildbucket(Index *ix, IEStream *ies, IBucket *ib)
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{
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IEntry ie1, ie2;
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u8int *b;
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u32int buck;
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buck = TWID32;
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ib->n = 0;
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ib->depth = 0;
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while(ies->n){
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b = peekientry(ies);
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if(b == nil)
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return TWID32;
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//fprint(2, "b=%p ies->n=%lld ib.n=%d buck=%d score=%V\n", b, ies->n, ib->n, iebuck(ix, b), b);
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if(ib->n == 0)
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buck = iebuck(ix, b);
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else{
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if(buck != iebuck(ix, b))
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break;
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if(ientrycmp(&ib->data[(ib->n - 1)* IEntrySize], b) == 0){
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/*
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* guess that the larger address is the correct one to use
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*/
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unpackientry(&ie1, &ib->data[(ib->n - 1)* IEntrySize]);
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unpackientry(&ie2, b);
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seterr(EOk, "duplicate index entry for score=%V type=%d\n", ie1.score, ie1.ia.type);
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ib->n--;
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if(ie1.ia.addr > ie2.ia.addr)
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memmove(b, &ib->data[ib->n * IEntrySize], IEntrySize);
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}
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}
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memmove(&ib->data[ib->n * IEntrySize], b, IEntrySize);
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ib->n++;
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ies->n--;
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ies->pos += IEntrySize;
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}
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return buck;
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}
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