ref: 8a1c1c951066705b98b417f26eebcb293e3b549d
dir: /sys/src/libbio/bgetc.c/
#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 = bp->iof(bp, bp->bbuf, bp->bsize); bp->gbuf = bp->bbuf; if(i <= 0) { bp->state = Bracteof; if(i < 0) { bp->state = Binactive; Berror(bp, "read error: %r"); } 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; }