sys/src/libbio/brdstr.c

   1 #include        <u.h>
   2 #include        <libc.h>
   3 #include        <bio.h>
   4
   5 static char*
   6 badd(char *oldp, int *np, char *data, int ndata, int delim, int nulldelim)
   7 {
   8         int n;
   9         char *p;
  10
  11         n = *np;
  12         p = realloc(oldp, n+ndata+1);
  13         if(p){
  14                 memmove(p+n, data, ndata);
  15                 n += ndata;
  16                 if(n>0 && nulldelim && p[n-1]==delim)
  17                         p[--n] = '\0';
  18                 else
  19                         p[n] = '\0';
  20                 *np = n;
  21         }else
  22                 free(oldp);
  23         return p;
  24 }
  25
  26 char*
  27 Brdstr(Biobufhdr *bp, int delim, int nulldelim)
  28 {
  29         char *ip, *ep, *p;
  30         int i, j;
  31
  32         i = -bp->icount;
  33         bp->rdline = 0;
  34         if(i == 0) {
  35                 /*
  36                  * eof or other error
  37                  */
  38                 if(bp->state != Bractive) {
  39                         if(bp->state == Bracteof)
  40                                 bp->state = Bractive;
  41                         bp->gbuf = bp->ebuf;
  42                         return nil;
  43                 }
  44         }
  45
  46         /*
  47          * first try in remainder of buffer (gbuf doesn't change)
  48          */
  49         ip = (char*)bp->ebuf - i;
  50         ep = memchr(ip, delim, i);
  51         if(ep) {
  52                 j = (ep - ip) + 1;
  53                 bp->icount += j;
  54                 p = badd(nil, &bp->rdline, ip, j, delim, nulldelim);
  55                 goto out;
  56         }
  57
  58         /*
  59          * copy data to beginning of buffer
  60          */
  61         if(i < bp->bsize)
  62                 memmove(bp->bbuf, ip, i);
  63         bp->gbuf = bp->bbuf;
  64
  65         /*
  66          * append to buffer looking for the delim
  67          */
  68         p = nil;
  69         for(;;){
  70                 ip = (char*)bp->bbuf + i;
  71                 while(i < bp->bsize) {
  72                         j = bp->iof(bp, ip, bp->bsize-i);
  73                         if(j < 0)
  74                                 Berror(bp, "read error: %r");
  75                         if(j <= 0 && i == 0)
  76                                 goto out;
  77                         if(j <= 0 && i > 0){
  78                                 /*
  79                                  * end of file but no delim. pretend we got a delim
  80                                  * by making the delim \0 and smashing it with nulldelim.
  81                                  */
  82                                 j = 1;
  83                                 ep = ip;
  84                                 delim = '\0';
  85                                 nulldelim = 1;
  86                                 *ep = delim;    /* there will be room for this */
  87                         }else{
  88                                 bp->offset += j;
  89                                 ep = memchr(ip, delim, j);
  90                         }
  91                         i += j;
  92                         if(ep) {
  93                                 /*
  94                                  * found in new piece
  95                                  * copy back up and reset everything
  96                                  */
  97                                 ip = (char*)bp->ebuf - i;
  98                                 if(i < bp->bsize){
  99                                         memmove(ip, bp->bbuf, i);
 100                                         bp->gbuf = (uchar*)ip;
 101                                 }
 102                                 j = (ep - (char*)bp->bbuf) + 1;
 103                                 bp->icount = j - i;
 104                                 p = badd(p, &bp->rdline, ip, j, delim, nulldelim);
 105                                 goto out;
 106                         }
 107                         ip += j;
 108                 }
 109
 110                 /*
 111                  * full buffer without finding; add to user string and continue
 112                  */
 113                 p = badd(p, &bp->rdline, (char*)bp->bbuf, bp->bsize, 0, 0);
 114                 i = 0;
 115                 bp->icount = 0;
 116                 bp->gbuf = bp->ebuf;
 117         }
 118 out:
 119         setmalloctag(p, getcallerpc(&bp));
 120         return p;
 121 }