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- /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
- */
- #include <u.h>
- #include <libc.h>
- #include <bio.h>
- int
- Bgetc(Biobufhdr *bp)
- {
- int i;
- loop:
- i = bp->icount;
- if(i != 0) {
- bp->icount = i+1;
- return bp->ebuf[i];
- }
- if(bp->state != Bractive) {
- if(bp->state == Bracteof)
- bp->state = Bractive;
- return Beof;
- }
- /*
- * get next buffer, try to keep Bungetsize
- * characters pre-catenated from the previous
- * buffer to allow that many ungets.
- */
- memmove(bp->bbuf-Bungetsize, bp->ebuf-Bungetsize, Bungetsize);
- i = read(bp->fid, bp->bbuf, bp->bsize);
- bp->gbuf = bp->bbuf;
- if(i <= 0) {
- bp->state = Bracteof;
- if(i < 0)
- bp->state = Binactive;
- return Beof;
- }
- if(i < bp->bsize) {
- memmove(bp->ebuf-i-Bungetsize, bp->bbuf-Bungetsize, i+Bungetsize);
- bp->gbuf = bp->ebuf-i;
- }
- bp->icount = -i;
- bp->offset += i;
- goto loop;
- }
- int
- Bungetc(Biobufhdr *bp)
- {
- if(bp->state == Bracteof)
- bp->state = Bractive;
- if(bp->state != Bractive)
- return Beof;
- bp->icount--;
- return 1;
- }
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