- Pascal Terjan filed bug #2154627

  (http://curl.haxx.se/bug/view.cgi?id=2154627) which pointed out that libcurl
  uses strcasecmp() in multiple places where it causes failures when the
  Turkish locale is used. This is because 'i' and 'I' isn't the same letter so
  strcasecmp() on those letters are different in Turkish than in English (or
  just about all other languages). I thus introduced a totally new internal
  function in libcurl (called Curl_ascii_equal) for doing case insentive
  comparisons for english-(ascii?) style strings that thus will make "file"
  and "FILE" match even if the Turkish locale is selected.

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/strequal.c b/lib/strequal.c
index e8c667497..c1a82f789 100644
--- a/lib/strequal.c
+++ b/lib/strequal.c
@@ -76,6 +76,30 @@ int curl_strnequal(const char *first, const char *second, size_t max)
 #endif
 }
 
+/*
+ * Curl_ascii_equal() is for doing "ascii" case insensitive strings. This is
+ * meant to be locale independent and only compare strings we know are safe
+ * for this.
+ * See http://daniel.haxx.se/blog/2008/10/15/strcasecmp-in-turkish/ for some
+ * further explanation to why this function is necessary.
+ */
+#define TOASCIIUPPER(x) ((((x) >= 'a') && ((x) <= 'z'))?((x) - 0x20):(x))
+
+int Curl_ascii_equal(const char *first, const char *second)
+{
+  while(*first && *second) {
+    if(! (TOASCIIUPPER(*first) == TOASCIIUPPER(*second)))
+      /* get out of the loop as soon as they don't match */
+      break;
+    first++;
+    second++;
+  }
+  /* we do the comparison here (possibly again), just to make sure that if the
+     loop above is skipped because one of the strings reached zero, we must not
+     return this as a successful match */
+  return (TOASCIIUPPER(*first) == TOASCIIUPPER(*second));
+}
+
 #ifndef HAVE_STRLCAT
 /*
  * The strlcat() function appends the NUL-terminated string src to the end