From 1f2d5f95684e93f8523e369ef1fed7a75c444082 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Tue, 8 Aug 2023 09:39:15 +0000
Subject:  Fix back slurpn

Signed-off-by: Laurent Bercot <ska@appnovation.com>
---
 doc/libstddjb/djbunix.html |  8 ++++++++
 src/libstddjb/slurpn.c     | 13 +++----------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/doc/libstddjb/djbunix.html b/doc/libstddjb/djbunix.html
index a48a57f..a892bde 100644
--- a/doc/libstddjb/djbunix.html
+++ b/doc/libstddjb/djbunix.html
@@ -512,6 +512,14 @@ to the amount of heap memory it can get.
 The function returns 1 if it succeeds, or 0 (and sets errno) if it fails.
 </p>
 
+<p>
+<code> int slurpn (stralloc *sa, int fd, size_t max) </code> <br />
+Same as <tt>slurp</tt>, but only grows the stralloc to a maximum
+of <em>max</em> bytes of total length. If there is still more to
+read on <em>fd</em> after <em>sa&rarr;len</em> has reached <em>max</em>,
+the function returns 0 with errno set to ENOBUFS.
+</p>
+
 <p>
 <code> int openslurpclose (stralloc *sa, char const *file) </code> <br />
 Slurps the contents of file <em>file</em> into *<em>sa</em>.
diff --git a/src/libstddjb/slurpn.c b/src/libstddjb/slurpn.c
index ee5157f..317e300 100644
--- a/src/libstddjb/slurpn.c
+++ b/src/libstddjb/slurpn.c
@@ -11,25 +11,18 @@
 
 int slurpn (int fd, stralloc *sa, size_t max)
 {
-  size_t sabase = sa->len ;
-  int wasnull = !sa->s ;
   for (;;)
   {
     ssize_t r ;
-    size_t n = max && sa->len - sabase + N > max ? max - (sa->len - sabase) : N ;
-    if (!n) { errno = ENOBUFS ; goto err ; }
+    size_t n = max && sa->len + N > max ? max - sa->len : N ;
+    if (!n) return (errno = ENOBUFS, 0) ;
     if (!stralloc_readyplus(sa, n)) break ;
     r = fd_read(fd, sa->s + sa->len, n) ;
     switch (r)
     {
-      case -1 : goto err ;
+      case -1 : return 0 ;
       case 0 : return 1 ;
       default : sa->len += r ;
     }
   }
-
-err:
-  if (wasnull) stralloc_free(sa) ;
-  else sa->len = sabase ;
-  return 0 ;
 }
-- 
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