From 1f43445813fbcdb7405102ceda0529857ed20993 Mon Sep 17 00:00:00 2001
From: Laurence Withers <lwithers@amethyst.(none)>
Date: Fri, 4 Jan 2008 22:47:10 +0000
Subject: [PATCH] Fix bug where iso8601_print() could overrun... If a date with
 a timezone offset of 0 had a length exactly matching the buffer size, we
 would write past the end of the buffer.

---
 README                     | 6 ++++++
 src/libiso8601/200_print.c | 8 ++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/README b/README
index 947ffbe..1e4734f 100644
--- a/README
+++ b/README
@@ -14,4 +14,10 @@ You might want to edit 'config' first. You might also want to set
 'INSTALL_PREFIX', which is prepended onto the destination of any
 installed file.
 
+Thanks
+------
+
+Robert Dunlop, <rjd@xyzzy.org.uk>
+ * found null terminating bug with iso8601_print()
+
 @TODO@
diff --git a/src/libiso8601/200_print.c b/src/libiso8601/200_print.c
index 69786a1..9998e2e 100644
--- a/src/libiso8601/200_print.c
+++ b/src/libiso8601/200_print.c
@@ -130,15 +130,11 @@ char* iso8601_print(char* str, int amt, const struct iso8601_date* date,
         break;
     }
 
-    if(ret < 1 || ret >= amt) return str_orig;
+    if(ret < 1 || (ret + 1) >= amt) return str_orig;
     str += ret;
     amt -= ret;
 
     if(details->tz_sec) {
-        if(!--amt) {
-            *str = 0;
-            return str_orig;
-        }
         if(details->tz_sec < 0) {
             *str++ = '-';
             ret = -details->tz_sec;
@@ -146,6 +142,7 @@ char* iso8601_print(char* str, int amt, const struct iso8601_date* date,
             *str++ = '+';
             ret = details->tz_sec;
         }
+        --amt;
 
         y = ret / 3600;
         ret -= y * 3600;
@@ -158,7 +155,6 @@ char* iso8601_print(char* str, int amt, const struct iso8601_date* date,
         else snprintf(str, amt, "%02d", y);
     } else {
         *str++ = 'Z';
-        if(amt > 1) *str = 0;
     }
     
     return str_orig;