57 lines
985 B
C
57 lines
985 B
C
#include <u.h>
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#include <libc.h>
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#include <bio.h>
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int
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Bgetc(Biobufhdr *bp)
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{
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int i;
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loop:
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i = bp->icount;
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if(i != 0) {
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bp->icount = i+1;
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return bp->ebuf[i];
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}
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if(bp->state != Bractive) {
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if(bp->state == Bracteof)
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bp->state = Bractive;
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return Beof;
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}
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/*
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* get next buffer, try to keep Bungetsize
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* characters pre-catenated from the previous
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* buffer to allow that many ungets.
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*/
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memmove(bp->bbuf-Bungetsize, bp->ebuf-Bungetsize, Bungetsize);
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i = bp->iof(bp, bp->bbuf, bp->bsize);
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bp->gbuf = bp->bbuf;
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if(i <= 0) {
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bp->state = Bracteof;
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if(i < 0) {
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bp->state = Binactive;
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Berror(bp, "read error: %r");
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}
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return Beof;
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}
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if(i < bp->bsize) {
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memmove(bp->ebuf-i-Bungetsize, bp->bbuf-Bungetsize, i+Bungetsize);
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bp->gbuf = bp->ebuf-i;
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}
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bp->icount = -i;
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bp->offset += i;
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goto loop;
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}
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int
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Bungetc(Biobufhdr *bp)
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{
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if(bp->state == Bracteof)
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bp->state = Bractive;
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if(bp->state != Bractive)
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return Beof;
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bp->icount--;
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return 1;
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}
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