sys/src/libbio/brdstr.c

   1 #include        <u.h>
   2 #include        <libc.h>
   3 #include        <bio.h>
   4
   5 static char*
   6 badd(char *p, int *np, char *data, int ndata, int delim, int nulldelim)
   7 {
   8         int n;
   9
  10         n = *np;
  11         p = realloc(p, n+ndata+1);
  12         if(p){
  13                 memmove(p+n, data, ndata);
  14                 n += ndata;
  15                 if(n>0 && nulldelim && p[n-1]==delim)
  16                         p[--n] = '\0';
  17                 else
  18                         p[n] = '\0';
  19                 *np = n;
  20         }
  21         return p;
  22 }
  23
  24 char*
  25 Brdstr(Biobufhdr *bp, int delim, int nulldelim)
  26 {
  27         char *ip, *ep, *p;
  28         int i, j;
  29
  30         i = -bp->icount;
  31         bp->rdline = 0;
  32         if(i == 0) {
  33                 /*
  34                  * eof or other error
  35                  */
  36                 if(bp->state != Bractive) {
  37                         if(bp->state == Bracteof)
  38                                 bp->state = Bractive;
  39                         bp->gbuf = bp->ebuf;
  40                         return nil;
  41                 }
  42         }
  43
  44         /*
  45          * first try in remainder of buffer (gbuf doesn't change)
  46          */
  47         ip = (char*)bp->ebuf - i;
  48         ep = memchr(ip, delim, i);
  49         if(ep) {
  50                 j = (ep - ip) + 1;
  51                 bp->icount += j;
  52                 return badd(nil, &bp->rdline, ip, j, delim, nulldelim);
  53         }
  54
  55         /*
  56          * copy data to beginning of buffer
  57          */
  58         if(i < bp->bsize)
  59                 memmove(bp->bbuf, ip, i);
  60         bp->gbuf = bp->bbuf;
  61
  62         /*
  63          * append to buffer looking for the delim
  64          */
  65         p = nil;
  66         for(;;){
  67                 ip = (char*)bp->bbuf + i;
  68                 while(i < bp->bsize) {
  69                         j = read(bp->fid, ip, bp->bsize-i);
  70                         if(j < 0)
  71                                 Berror(bp, "read error: %r");
  72                         if(j <= 0 && i == 0)
  73                                 return p;
  74                         if(j <= 0 && i > 0){
  75                                 /*
  76                                  * end of file but no delim. pretend we got a delim
  77                                  * by making the delim \0 and smashing it with nulldelim.
  78                                  */
  79                                 j = 1;
  80                                 ep = ip;
  81                                 delim = '\0';
  82                                 nulldelim = 1;
  83                                 *ep = delim;    /* there will be room for this */
  84                         }else{
  85                                 bp->offset += j;
  86                                 ep = memchr(ip, delim, j);
  87                         }
  88                         i += j;
  89                         if(ep) {
  90                                 /*
  91                                  * found in new piece
  92                                  * copy back up and reset everything
  93                                  */
  94                                 ip = (char*)bp->ebuf - i;
  95                                 if(i < bp->bsize){
  96                                         memmove(ip, bp->bbuf, i);
  97                                         bp->gbuf = (uchar*)ip;
  98                                 }
  99                                 j = (ep - (char*)bp->bbuf) + 1;
 100                                 bp->icount = j - i;
 101                                 return badd(p, &bp->rdline, ip, j, delim, nulldelim);
 102                         }
 103                         ip += j;
 104                 }
 105
 106                 /*
 107                  * full buffer without finding; add to user string and continue
 108                  */
 109                 p = badd(p, &bp->rdline, (char*)bp->bbuf, bp->bsize, 0, 0);
 110                 i = 0;
 111                 bp->icount = 0;
 112                 bp->gbuf = bp->ebuf;
 113         }
 114 }