sys/src/libbio/brdline.c

   1 #include        <u.h>
   2 #include        <libc.h>
   3 #include        <bio.h>
   4
   5 void*
   6 Brdline(Biobufhdr *bp, int delim)
   7 {
   8         char *ip, *ep;
   9         int i, j;
  10
  11         i = -bp->icount;
  12         if(i == 0) {
  13                 /*
  14                  * eof or other error
  15                  */
  16                 if(bp->state != Bractive) {
  17                         if(bp->state == Bracteof)
  18                                 bp->state = Bractive;
  19                         bp->rdline = 0;
  20                         bp->gbuf = bp->ebuf;
  21                         return 0;
  22                 }
  23         }
  24
  25         /*
  26          * first try in remainder of buffer (gbuf doesn't change)
  27          */
  28         ip = (char*)bp->ebuf - i;
  29         ep = memchr(ip, delim, i);
  30         if(ep) {
  31                 j = (ep - ip) + 1;
  32                 bp->rdline = j;
  33                 bp->icount += j;
  34                 return ip;
  35         }
  36
  37         /*
  38          * copy data to beginning of buffer
  39          */
  40         if(i < bp->bsize)
  41                 memmove(bp->bbuf, ip, i);
  42         bp->gbuf = bp->bbuf;
  43
  44         /*
  45          * append to buffer looking for the delim
  46          */
  47         ip = (char*)bp->bbuf + i;
  48         while(i < bp->bsize) {
  49                 j = read(bp->fid, ip, bp->bsize-i);
  50                 if(j <= 0) {
  51                         /*
  52                          * end of file with no delim
  53                          */
  54                         memmove(bp->ebuf-i, bp->bbuf, i);
  55                         bp->rdline = i;
  56                         bp->icount = -i;
  57                         bp->gbuf = bp->ebuf-i;
  58                         return 0;
  59                 }
  60                 bp->offset += j;
  61                 i += j;
  62                 ep = memchr(ip, delim, j);
  63                 if(ep) {
  64                         /*
  65                          * found in new piece
  66                          * copy back up and reset everything
  67                          */
  68                         ip = (char*)bp->ebuf - i;
  69                         if(i < bp->bsize){
  70                                 memmove(ip, bp->bbuf, i);
  71                                 bp->gbuf = (uchar*)ip;
  72                         }
  73                         j = (ep - (char*)bp->bbuf) + 1;
  74                         bp->rdline = j;
  75                         bp->icount = j - i;
  76                         return ip;
  77                 }
  78                 ip += j;
  79         }
  80
  81         /*
  82          * full buffer without finding
  83          */
  84         bp->rdline = bp->bsize;
  85         bp->icount = -bp->bsize;
  86         bp->gbuf = bp->bbuf;
  87         return 0;
  88 }
  89
  90 int
  91 Blinelen(Biobufhdr *bp)
  92 {
  93
  94         return bp->rdline;
  95 }