Index: trunk/psLib/src/sys/psString.c
===================================================================
--- trunk/psLib/src/sys/psString.c	(revision 3264)
+++ trunk/psLib/src/sys/psString.c	(revision 3866)
@@ -9,6 +9,6 @@
  *  @author Eric Van Alst, MHPCC
  *
- *  @version $Revision: 1.15 $ $Name: not supported by cvs2svn $
- *  @date $Date: 2005-02-17 19:26:24 $
+ *  @version $Revision: 1.16 $ $Name: not supported by cvs2svn $
+ *  @date $Date: 2005-05-06 18:15:25 $
  *
  *  Copyright 2004-2005 Maui High Performance Computing Center, University of Hawaii
@@ -55,2 +55,93 @@
     return returnValue;
 }
+
+ssize_t psStringAppend(char **dest, const char *format, ...)
+{
+    va_list         args;
+    size_t          length;             // complete string length (sans \0)
+    size_t          oldLength;          // original string length (sans \0)
+    ssize_t         tailLength;         // length of string to append
+
+    if (!*dest) {
+        *dest = psStringCopy("");
+        oldLength = 0;
+    } else {
+        // size of existing string
+        oldLength = strlen(*dest);
+    }
+
+    // find the size of the string to append
+    va_start(args, format);
+    // C99 guarentees vsnprintf() to work as expected with size = 0
+    tailLength = vsnprintf(*dest, 0, format, args);
+    va_end(args);
+
+    // if the new tail is zero length, return the length of the old string.  if
+    // it's a format error, return the error code.
+    if (tailLength < 1) {
+        return tailLength == 0 ? oldLength : tailLength;
+    }
+
+    // new string length (sans \0)
+    length = oldLength + tailLength;
+
+    // realloc string to string + tail + \0
+    *dest = psRealloc(*dest, length + 1);
+
+    // append tail + \0
+    va_start(args, format);
+    vsnprintf(*dest + oldLength, tailLength + 1, format, args);
+    va_end(args);
+
+    return length;
+}
+
+ssize_t psStringPrepend(char **dest, const char *format, ...)
+{
+    va_list         args;
+    size_t          length;             // complete string length (sans \0)
+    ssize_t         headLength;         // length of string to prepend
+    char            *oldDest;           // copy of original string
+
+    if (!*dest) {
+        // makes the string backup and concatination pointless
+        *dest = psStringCopy("");
+        length = 0;
+    } else {
+        // size of existing string
+        length = strlen(*dest);
+    }
+
+    // find the size of the string to prepend
+    va_start(args, format);
+    // C99 guarentees vsnprintf() to work as expected with size = 0
+    headLength = vsnprintf(*dest, 0, format, args);
+    va_end(args);
+
+    // if the new head is zero length, return the length of the old string.  if
+    // it's a format error, return the error code.
+    if (headLength < 1) {
+        return headLength == 0 ? length : headLength;
+    }
+
+    // backup original string
+    oldDest = psStringCopy(*dest);
+
+    // new string length (sans \0)
+    length += headLength;
+
+    // realloc string to head + string + \0
+    *dest = psRealloc(*dest, length + 1);
+
+    // copy the new head to the beginning of string
+    va_start(args, format);
+    vsnprintf(*dest, length + 1, format, args);
+    va_end(args);
+
+    // append the original string
+    strncat(*dest, oldDest, length + 1);
+
+    psFree(oldDest);
+
+    return length;
+}