misc: add find_char.h

misc/find_char.h

@@ -0,0 +1,58 @@
+/**
+ * @file find_char.h
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the
+ *    names of its contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef BADVPN_FIND_CHAR_H
+#define BADVPN_FIND_CHAR_H
+
+#include <stddef.h>
+
+#include <misc/debug.h>
+
+/**
+ * Finds the first character 'c' in the string represented by 'str' and 'len'.
+ * If found, returns 1 and writes the position to *out_pos (if out_pos!=NULL).
+ * If not found, returns 0 and does not modify *out_pos.
+ */
+static int b_find_char_bin (const char *str, size_t len, char c, size_t *out_pos)
+{
+    ASSERT(str)
+    
+    for (size_t i = 0; i < len; i++) {
+        if (str[i] == c) {
+            if (out_pos) {
+                *out_pos = i;
+            }
+            return 1;
+        }
+    }
+    
+    return 0;
+}
+
+#endif