* include/vlc_common.h, src/extras/libc.c: added GCD() and vlc_reduce().

[vlc] / src / extras / libc.c

diff --git a/src/extras/libc.c b/src/extras/libc.c
index cad26a92a567849a464f6507ab6bbd65e6dbedb9..42911036679b48ca2c92489b90ac1fe18b5ac202 100644 (file)
--- a/src/extras/libc.c
+++ b/src/extras/libc.c
@@ -2,7 +2,7 @@
  * libc.c: Extra libc function for some systems.
  *****************************************************************************
  * Copyright (C) 2002 VideoLAN
- * $Id: libc.c,v 1.16 2004/02/09 16:12:25 sigmunau Exp $
+ * $Id$
  *
  * Authors: Jon Lech Johansen <jon-vl@nanocrew.net>
  *          Samuel Hocevar <sam@zoy.org>
@@ -26,6 +26,15 @@
 
 #include <vlc/vlc.h>
 
+#undef iconv_t
+#undef iconv_open
+#undef iconv
+#undef iconv_close
+
+#if defined(HAVE_ICONV)
+#   include <iconv.h>
+#endif
+
 /*****************************************************************************
  * getenv: just in case, but it should never be called
  *****************************************************************************/
@@ -127,6 +136,37 @@ int vlc_strncasecmp( const char *s1, const char *s2, size_t n )
 }
 #endif
 
+/******************************************************************************
+ * strcasestr: find a substring (little) in another substring (big)
+ * Case sensitive. Return NULL if not found, return big if little == null
+ *****************************************************************************/
+#if !defined( HAVE_STRCASESTR ) && !defined( HAVE_STRISTR )
+char * vlc_strcasestr( const char *psz_big, const char *psz_little )
+{
+    char *p_pos = psz_big;
+
+    if( !psz_big || !psz_little || !*psz_little ) return psz_big;
+ 
+    while( *p_pos ) 
+    {
+        if( toupper( *p_pos ) == toupper( *psz_little ) )
+        {
+            char * psz_cur1 = p_pos + 1;
+            char * psz_cur2 = psz_little + 1;
+            while( *psz_cur1 && *psz_cur2 &&
+                   toupper( *psz_cur1 ) == toupper( *psz_cur2 ) )
+            {
+                psz_cur1++;
+                psz_cur2++;
+            }
+            if( !*psz_cur2 ) return p_pos;
+        }
+        p_pos++;
+    }
+    return NULL;
+}
+#endif
+
 /*****************************************************************************
  * vasprintf:
  *****************************************************************************/
@@ -343,3 +383,106 @@ char *vlc_wraptext( const char *psz_text, int i_line, vlc_bool_t b_utf8 )
 
     return psz_new_text;
 }
+
+/*****************************************************************************
+ * iconv wrapper
+ *****************************************************************************/
+vlc_iconv_t vlc_iconv_open( const char *tocode, const char *fromcode )
+{
+#if defined(HAVE_ICONV)
+    return iconv_open( tocode, fromcode );
+#else
+    return NULL;
+#endif
+}
+
+size_t vlc_iconv( vlc_iconv_t cd, char **inbuf, size_t *inbytesleft,
+                  char **outbuf, size_t *outbytesleft )
+{
+#if defined(HAVE_ICONV)
+    return iconv( cd, inbuf, inbytesleft, outbuf, outbytesleft );
+#else
+    int i_bytes = __MIN(inbytesleft, outbytesleft);
+    if( !inbuf || !outbuf || !i_bytes ) return (size_t)(-1);
+    memcpy( *outbuf, *inbuf, i_bytes );
+    inbuf += i_bytes;
+    outbuf += i_bytes;
+    inbytesleft -= i_bytes;
+    outbytesleft -= i_bytes;
+    return i_bytes;
+#endif
+}
+
+int vlc_iconv_close( vlc_iconv_t cd )
+{
+#if defined(HAVE_ICONV)
+    return iconv_close( cd );
+#else
+    return 0;
+#endif
+}
+
+/*****************************************************************************
+ * reduce a fraction
+ *   (adapted from libavcodec, author Michael Niedermayer <michaelni@gmx.at>)
+ *****************************************************************************/
+vlc_bool_t vlc_reduce( int *pi_dst_nom, int *pi_dst_den,
+                       int64_t i_nom, int64_t i_den, int64_t i_max )
+{
+    vlc_bool_t b_exact = 1, b_sign = 0;
+    int64_t i_gcd;
+
+    if( i_den == 0 )
+    {
+        i_nom = 0;
+        i_den = 1;
+        return 1;
+    }
+
+    if( i_den < 0 )
+    {
+        i_den = - i_den;
+        i_nom = - i_nom;
+    }
+
+    if( i_nom < 0 )
+    {
+        i_nom = - i_nom;
+        b_sign = 1;
+    }
+
+    i_gcd = GCD( i_nom, i_den );
+    i_nom /= i_gcd;
+    i_den /= i_gcd;
+
+    if( i_nom > i_max || i_den > i_max )
+    {
+        int i_a0_num = 0, i_a0_den = 1, i_a1_num = 1, i_a1_den = 0;
+        b_exact = 0;
+
+        for( ; ; )
+        {
+            int64_t i_x = i_nom / i_den;
+            int64_t i_a2n = i_x * i_a1_num + i_a0_num;
+            int64_t i_a2d = i_x * i_a1_den + i_a0_den;
+
+            if( i_a2n > i_max || i_a2d > i_max ) break;
+
+            i_nom %= i_den;
+
+            i_a0_num = i_a1_num; i_a0_den = i_a1_den;
+            i_a1_num = i_a2n; i_a1_den = i_a2d;
+            if( i_nom == 0 ) break;
+            i_x = i_nom; i_nom = i_den; i_den = i_x;
+        }
+        i_nom = i_a1_num;
+        i_den = i_a1_den;
+    }
+
+    if( b_sign ) i_nom = - i_nom;
+
+    *pi_dst_nom = i_nom;
+    *pi_dst_den = i_den;
+
+    return b_exact;
+}