Subversion Repositories planix.SVN

#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 = read(bp->fid, bp->bbuf, bp->bsize);
                        if(i <= 0) {
                                bp->state = Bracteof;
                                if(i < 0)
                                        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;
}