moved simple c utils

Originally committed as revision 804 to svn://svn.ffmpeg.org/ffmpeg/trunk

libav/cutils.c

+/*
+ * Various simple utilities for ffmpeg system
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
+ *
+ * This 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 of the License, or (at your option) any later version.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "avformat.h"
+#include <ctype.h>
+
+#if !defined(CONFIG_NOCUTILS)
+/**
+ * Return TRUE if val is a prefix of str. If it returns TRUE, ptr is
+ * set to the next character in 'str' after the prefix.
+ *
+ * @param str input string
+ * @param val prefix to test
+ * @param ptr updated after the prefix in str in there is a match
+ * @return TRUE if there is a match
+ */
+int strstart(const char *str, const char *val, const char **ptr)
+{
+    const char *p, *q;
+    p = str;
+    q = val;
+    while (*q != '\0') {
+        if (*p != *q)
+            return 0;
+        p++;
+        q++;
+    }
+    if (ptr)
+        *ptr = p;
+    return 1;
+}
+
+/**
+ * Return TRUE if val is a prefix of str (case independent). If it
+ * returns TRUE, ptr is set to the next character in 'str' after the
+ * prefix.
+ *
+ * @param str input string
+ * @param val prefix to test
+ * @param ptr updated after the prefix in str in there is a match
+ * @return TRUE if there is a match */
+int stristart(const char *str, const char *val, const char **ptr)
+{
+    const char *p, *q;
+    p = str;
+    q = val;
+    while (*q != '\0') {
+        if (toupper(*(unsigned char *)p) != toupper(*(unsigned char *)q))
+            return 0;
+        p++;
+        q++;
+    }
+    if (ptr)
+        *ptr = p;
+    return 1;
+}
+
+/**
+ * Copy the string str to buf. If str length is bigger than buf_size -
+ * 1 then it is clamped to buf_size - 1.
+ * NOTE: this function does what strncpy should have done to be
+ * useful. NEVER use strncpy.
+ * 
+ * @param buf destination buffer
+ * @param buf_size size of destination buffer
+ * @param str source string
+ */
+void pstrcpy(char *buf, int buf_size, const char *str)
+{
+    int c;
+    char *q = buf;
+
+    if (buf_size <= 0)
+        return;
+
+    for(;;) {
+        c = *str++;
+        if (c == 0 || q >= buf + buf_size - 1)
+            break;
+        *q++ = c;
+    }
+    *q = '\0';
+}
+
+/* strcat and truncate. */
+char *pstrcat(char *buf, int buf_size, const char *s)
+{
+    int len;
+    len = strlen(buf);
+    if (len < buf_size) 
+        pstrcpy(buf + len, buf_size - len, s);
+    return buf;
+}
+
+#endif