1 files changed, 71 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/chgext.c b/reference/C/CONTRIB/SNIP/chgext.c
new file mode 100755
index 0000000..b394572
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/chgext.c
@@ -0,0 +1,71 @@
+/*
+**  chgext.c - Change a file's extension
+**
+**  public domain by Bob Stout
+**
+**  Arguments: 1 - Pathname
+**             2 - Old extension (NULL if don't care)
+**             3 - New extension
+**
+**  Returns: Pathname or NULL if failed
+**
+**  Note: Pathname buffer must be long enough to append new extension
+**
+**  Side effect: Converts Unix style pathnames to DOS style
+*/
+
+#include <stdio.h>
+#include <string.h>
+
+char *chgext(char *path, char *oldext, char *newext)
+{
+      char *p;
+
+      /* Convert to DOS-style path name */
+
+      for (p = path; *p; ++p)
+            if ('/' == *p)
+                  *p = '\\';
+
+      /* Find extension or point to end for appending */
+
+      if (NULL == (p = strrchr(path, '.')) || NULL != strchr(p, '\\'))
+            p = strcpy(&path[strlen(path)], ".");
+      ++p;
+
+      /* Check for old extension */
+
+      if (oldext && strcmp(p, oldext))
+            return NULL;
+
+      /* Add new extension */
+
+      while ('.' == *newext)
+            ++newext;
+      strncpy(p, newext, 3);
+      return path;
+}
+
+#ifdef TEST
+
+void main(int argc, char *argv[])
+{
+      char *retval, *old_ext = NULL, path[128];
+
+      if (2 > argc)
+      {
+            puts("Usage: CHGEXT path [old_ext]");
+            puts("\nChanges extension to \".TST\"");
+            puts("Old extension optional");
+            return;
+      }
+      strcpy(path, strupr(argv[1]));
+      if (2 < argc)
+            old_ext = strupr(argv[2]);
+      if (NULL == (retval = chgext(path, old_ext, ".TSTstuff")))
+            puts("chgext() failed");
+      else  printf("chgext(%s, %s, TST)\n...returned...\n%s\n", argv[1],
+            old_ext ? old_ext : "NULL", path);
+}
+
+#endif /* TEST */