locale-independent ASCII character case handling

Basically, I and i are different letters in Turkic languages, and this
causes problems for str(n)casecmp and toupper/tolower in these locales
when dillo is dealing with ASCII.

2 files changed, 35 insertions, 7 deletions

diff --git a/dlib/dlib.c b/dlib/dlib.c
index a3c59060..002adcdf 100644
--- a/dlib/dlib.c
+++ b/dlib/dlib.c
@@ -173,16 +173,21 @@ char *dStrsep(char **orig, const char *delim)
 }
 
 /*
+ * ASCII functions to avoid the case difficulties introduced by I/i in
+ * Turkic locales.
+ */
+
+/*
  * Case insensitive strstr
  */
-char *dStristr(const char *haystack, const char *needle)
+char *dStriAsciiStr(const char *haystack, const char *needle)
 {
    int i, j;
    char *ret = NULL;
 
    if (haystack && needle) {
       for (i = 0, j = 0; haystack[i] && needle[j]; ++i)
-         if (tolower(haystack[i]) == tolower(needle[j])) {
+         if (D_ASCII_TOLOWER(haystack[i]) == D_ASCII_TOLOWER(needle[j])) {
             ++j;
          } else if (j) {
             i -= j;
@@ -194,6 +199,29 @@ char *dStristr(const char *haystack, const char *needle)
    return ret;
 }
 
+int dStrAsciiCasecmp(const char *s1, const char *s2)
+{
+   int ret = 0;
+
+   while ((*s1 || *s2) &&
+          !(ret = D_ASCII_TOLOWER(*s1) - D_ASCII_TOLOWER(*s2))) {
+      s1++;
+      s2++;
+   }
+   return ret;
+}
+
+int dStrnAsciiCasecmp(const char *s1, const char *s2, size_t n)
+{
+   int ret = 0;
+
+   while (n-- && (*s1 || *s2) &&
+          !(ret = D_ASCII_TOLOWER(*s1) - D_ASCII_TOLOWER(*s2))) {
+      s1++;
+      s2++;
+   }
+   return ret;
+}
 
 /*
  *- dStr ----------------------------------------------------------------------
diff --git a/dlib/dlib.h b/dlib/dlib.h
index cd612d28..8dc324a7 100644
--- a/dlib/dlib.h
+++ b/dlib/dlib.h
@@ -5,7 +5,6 @@
 #include <stddef.h>    /* for size_t */
 #include <stdarg.h>    /* for va_list */
 #include <string.h>    /* for strerror */
-#include <strings.h>   /* for strcasecmp, strncasecmp (POSIX 2001) */
 
 #include "d_size.h"
 
@@ -34,6 +33,8 @@ extern "C" {
 #define dIsspace(c) isspace((uchar_t)(c))
 #define dIsalnum(c) isalnum((uchar_t)(c))
 
+#define D_ASCII_TOUPPER(c) (((c) >= 'a' && (c) <= 'z') ? (c) - 0x20 : (c))
+#define D_ASCII_TOLOWER(c) (((c) >= 'A' && (c) <= 'Z') ? (c) + 0x20 : (c))
 /*
  *-- Casts -------------------------------------------------------------------
  */
@@ -86,12 +87,11 @@ char *dStrconcat(const char *s1, ...);
 char *dStrstrip(char *s);
 char *dStrnfill(size_t len, char c);
 char *dStrsep(char **orig, const char *delim);
-char *dStristr(const char *haystack, const char *needle);
 void dStrshred(char *s);
+char *dStriAsciiStr(const char *haystack, const char *needle);
+int dStrAsciiCasecmp(const char *s1, const char *s2);
+int dStrnAsciiCasecmp(const char *s1, const char *s2, size_t n);
 
-/* these are in POSIX 2001. Could be implemented if a port requires it */
-#define dStrcasecmp strcasecmp
-#define dStrncasecmp strncasecmp
 #define dStrerror strerror
 
 /*