useful function to join strings using separator.

SVN revision: 40010

legacy/ecore/src/lib/ecore/Ecore_Str.h

@@ -29,6 +29,7 @@
 
 /* we need this for size_t */
 #include <stddef.h>
+#include <string.h>
 
 /**
  * @file Ecore_Str.h
@@ -59,6 +60,57 @@ EAPI int ecore_str_has_extension(const char *str, const char *ext);
 EAPI char **ecore_str_split(const char *string, const char *delimiter, 
                             int max_tokens);
 
+EAPI size_t ecore_str_join_len(char *dst, size_t size, char sep, const char *a, size_t a_len, const char *b, size_t b_len);
+
+
+/**
+ * Join two strings and store the result in @a dst buffer.
+ *
+ * Similar to ecore_str_join_len(), but will compute the length of @a
+ * and @a b using strlen().
+ *
+ * @param dst where to store the result.
+ * @param size byte size of dst, will write at most (size - 1)
+ *     characters and then the '\0' (null terminator).
+ * @param sep separator character to use.
+ * @param a first string to use, before @a sep.
+ * @param b second string to use, after @a sep.
+ *
+ * @return the number of characters printed (not including the
+ *     trailing '\0' used to end output to strings). Just like
+ *     snprintf(), it will not write more than @a size bytes, thus a
+ *     return value of @a size or more means that the output was
+ *     truncated.
+ *
+ * @see ecore_str_join_len() and ecore_str_join_static()
+ */
+static inline size_t ecore_str_join(char *dst, size_t size, char sep, const char *a, const char *b)
+{
+   return ecore_str_join_len(dst, size, sep, a, strlen(a), b, strlen(b));
+}
+
+/**
+ * Join two static strings and store the result in static @a dst buffer.
+ *
+ * Similar to ecore_str_join_len(), but will assume string sizes are
+ * know using sizeof(X).
+ *
+ * @param dst where to store the result.
+ * @param sep separator character to use.
+ * @param a first string to use, before @a sep.
+ * @param b second string to use, after @a sep.
+ *
+ * @return the number of characters printed (not including the
+ *     trailing '\0' used to end output to strings). Just like
+ *     snprintf(), it will not write more than @a size bytes, thus a
+ *     return value of @a size or more means that the output was
+ *     truncated.
+ *
+ * @see ecore_str_join() and ecore_str_join_static()
+ */
+#define ecore_str_join_static(dst, sep, a, b) ecore_str_join_len(dst, sizeof(dst), sep, a, (sizeof(a) > 0) ? sizeof(a) - 1 : 0, b, (sizeof(b) > 0) ? sizeof(b) - 1 : 0)
+
+
 #ifdef __cplusplus
 }
 #endif

legacy/ecore/src/lib/ecore/ecore_str.c

@@ -241,3 +241,62 @@ ecore_str_split(const char *str, const char *delim, int max_tokens)
 
    return str_array;
 }
+
+/**
+ * Join two strings of known length and store the result in @a dst buffer.
+ *
+ * @param dst where to store the result.
+ * @param size byte size of dst, will write at most (size - 1)
+ *     characters and then the '\0' (null terminator).
+ * @param sep separator character to use.
+ * @param a first string to use, before @a sep.
+ * @param a_len length of @a a, not including '\0' (strlen()-like)
+ * @param b second string to use, after @a sep.
+ * @param b_len length of @a b, not including '\0' (strlen()-like)
+ *
+ * @return the number of characters printed (not including the
+ *     trailing '\0' used to end output to strings). Just like
+ *     snprintf(), it will not write more than @a size bytes, thus a
+ *     return value of @a size or more means that the output was
+ *     truncated.
+ *
+ * @see ecore_str_join() and ecore_str_join_static()
+ */
+size_t
+ecore_str_join_len(char *dst, size_t size, char sep, const char *a, size_t a_len, const char *b, size_t b_len)
+{
+   size_t ret = a_len + b_len + 1;
+   size_t off;
+
+   if (size < 1) return ret;
+
+   if (size <= a_len)
+     {
+	memcpy(dst, a, size - 1);
+	dst[size - 1] = '\0';
+	return ret;
+     }
+
+   memcpy(dst, a, a_len);
+   off = a_len;
+
+   if (size <= off + 1)
+     {
+	dst[size - 1] = '\0';
+	return ret;
+     }
+
+   dst[off] = sep;
+   off++;
+
+   if (size <= off + b_len + 1)
+     {
+	memcpy(dst + off, b, size - off - 1);
+	dst[size - 1] = '\0';
+	return ret;
+     }
+
+   memcpy(dst + off, b, b_len);
+   dst[off + b_len] = '\0';
+   return ret;
+}