Re: speed up getndelim2

[Bruno Haible]

Eric Blake wrote:
> And all I did was make getndelim2 smarter to process data in blocks
> instead of bytes

I'm adding these comments. Otherwise, it is impossible to understand why
there is no buffer overrun at the end (when the terminating '\0' is stored).


*** lib/getndelim2.c.orig       2008-05-01 16:41:09.000000000 +0200
--- lib/getndelim2.c    2008-05-01 16:40:13.000000000 +0200
***************
*** 105,111 ****
  
    while (!done)
      {
!       /* Here always ptr + size == read_pos + nbytes_avail.  */
  
        int c IF_LINT (= 0);
        const char *buffer;
--- 105,112 ----
  
    while (!done)
      {
!       /* Here always ptr + size == read_pos + nbytes_avail.
!        Also nbytes_avail > 0 || size < nmax.  */
  
        int c IF_LINT (= 0);
        const char *buffer;
***************
*** 171,176 ****
--- 172,180 ----
          read_pos = size - nbytes_avail + ptr;
        }
  
+       /* Here, if size < nmax, nbytes_avail >= buffer_len + 1.
+        If size == nmax, nbytes_avail > 0.  */
+ 
        if (1 < nbytes_avail)
        {
          size_t copy_len = nbytes_avail - 1;
***************
*** 183,188 ****
--- 187,195 ----
          read_pos += copy_len;
          nbytes_avail -= copy_len;
        }
+ 
+       /* Here still nbytes_avail > 0.  */
+ 
        if (buffer && freadseek (stream, buffer_len))
        goto unlock_done;
      }