Added ID3 searching

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@5683 a1c6a512-1295-4272-9138-f99709370657

firmware/common/strcasestr.c

@@ -0,0 +1,122 @@
+/* Return the offset of one string within another.
+   Copyright (C) 1994,1996,1997,1998,1999,2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/*
+ * My personal strstr() implementation that beats most other algorithms.
+ * Until someone tells me otherwise, I assume that this is the
+ * fastest implementation of strstr() in C.
+ * I deliberately chose not to comment it.  You should have at least
+ * as much fun trying to understand it, as I had to write it :-).
+ *
+ * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de*/
+
+/* Faster looping by precalculating bl, bu, cl, cu before looping.
+ * 2004 Apr 08 Jose Da Silva, digital@joescat@com */
+
+#include <string.h>
+#include <ctype.h>
+
+typedef unsigned chartype;
+
+char* strcasestr (const char* phaystack, const char* pneedle)
+{
+    const unsigned char *haystack, *needle;
+    chartype bl, bu, cl, cu;
+
+    haystack = (const unsigned char *) phaystack;
+    needle = (const unsigned char *) pneedle;
+
+    bl = tolower (*needle);
+    if (bl != '\0')
+    {
+        bu = toupper (bl);
+        haystack--;/* possible ANSI violation */
+        do
+        {
+            cl = *++haystack;
+            if (cl == '\0')
+                goto ret0;
+        }
+        while ((cl != bl) && (cl != bu));
+
+        cl = tolower (*++needle);
+        if (cl == '\0')
+            goto foundneedle;
+        cu = toupper (cl);
+        ++needle;
+        goto jin;
+
+        for (;;)
+        {
+            chartype a;
+            const unsigned char *rhaystack, *rneedle;
+
+            do
+            {
+                a = *++haystack;
+                if (a == '\0')
+                    goto ret0;
+                if ((a == bl) || (a == bu))
+                    break;
+                a = *++haystack;
+                if (a == '\0')
+                    goto ret0;
+              shloop:
+                ;
+            }
+            while ((a != bl) && (a != bu));
+
+          jin:  a = *++haystack;
+            if (a == '\0')
+                goto ret0;
+
+            if ((a != cl) && (a != cu))
+                goto shloop;
+
+            rhaystack = haystack-- + 1;
+            rneedle = needle;
+            a = tolower (*rneedle);
+
+            if (tolower (*rhaystack) == (int) a)
+                do
+                {
+                    if (a == '\0')
+                        goto foundneedle;
+                    ++rhaystack;
+                    a = tolower (*++needle);
+                    if (tolower (*rhaystack) != (int) a)
+                        break;
+                    if (a == '\0')
+                        goto foundneedle;
+                    ++rhaystack;
+                    a = tolower (*++needle);
+                }
+                while (tolower (*rhaystack) == (int) a);
+
+            needle = rneedle;/* took the register-poor approach */
+
+            if (a == '\0')
+                break;
+        }
+    }
+  foundneedle:
+    return (char*) haystack;
+  ret0:
+    return 0;
+}