ref: 1046d3e30be09d7f1f07bf0a49f0e32584e86874
dir: /sys/src/libbio/bread.c/
#include <u.h> #include <libc.h> #include <bio.h> long Bread(Biobufhdr *bp, void *ap, long count) { long c; uchar *p; int i, n, ic; p = ap; c = count; ic = bp->icount; while(c > 0) { n = -ic; if(n > c) n = c; if(n == 0) { if(bp->state != Bractive) break; i = bp->iof(bp, bp->bbuf, bp->bsize); if(i <= 0) { bp->state = Bracteof; if(i < 0) { Berror(bp, "read error: %r"); bp->state = Binactive; } break; } bp->gbuf = bp->bbuf; bp->offset += i; if(i < bp->bsize) { memmove(bp->ebuf-i, bp->bbuf, i); bp->gbuf = bp->ebuf-i; } ic = -i; continue; } memmove(p, bp->ebuf+ic, n); c -= n; ic += n; p += n; } bp->icount = ic; if(count == c && bp->state == Binactive) return -1; return count-c; }