1 #include "lib9.h" 2 #include <bio.h> 3 4 int Bgetc(Biobuf * bp)5Bgetc(Biobuf *bp) 6 { 7 int i; 8 9 loop: 10 i = bp->icount; 11 if(i != 0) { 12 bp->icount = i+1; 13 return bp->ebuf[i]; 14 } 15 if(bp->state != Bractive) { 16 if(bp->state == Bracteof) 17 bp->state = Bractive; 18 return Beof; 19 } 20 /* 21 * get next buffer, try to keep Bungetsize 22 * characters pre-catenated from the previous 23 * buffer to allow that many ungets. 24 */ 25 memmove(bp->bbuf-Bungetsize, bp->ebuf-Bungetsize, Bungetsize); 26 i = read(bp->fid, bp->bbuf, bp->bsize); 27 bp->gbuf = bp->bbuf; 28 if(i <= 0) { 29 bp->state = Bracteof; 30 if(i < 0) 31 bp->state = Binactive; 32 return Beof; 33 } 34 if(i < bp->bsize) { 35 memmove(bp->ebuf-i-Bungetsize, bp->bbuf-Bungetsize, i+Bungetsize); 36 bp->gbuf = bp->ebuf-i; 37 } 38 bp->icount = -i; 39 bp->offset += i; 40 goto loop; 41 } 42 43 int Bungetc(Biobuf * bp)44Bungetc(Biobuf *bp) 45 { 46 47 if(bp->state == Bracteof) 48 bp->state = Bractive; 49 if(bp->state != Bractive) 50 return Beof; 51 bp->icount--; 52 return 1; 53 } 54