teco_string_t is now passed by value like a scalar if the callee isn't expected to modify it

* When passing a struct that should not be modified, I usually use a const pointer.
* Strings however are small 2-word objects and they are often now already passed via separate
  `gchar*` and gsize parameters. So it is consistent to pass teco_string_t by value as well.
  A teco_string_t will usually fit into registers just like a pointer.
* It's now obvious which function just _uses_ and which function _modifies_ a string.
  There is also no chance to pass a NULL pointer to those functions.

1 files changed, 18 insertions, 15 deletions

diff --git a/src/string-utils.h b/src/string-utils.h
index af2c8a1..359329f 100644
--- a/src/string-utils.h
+++ b/src/string-utils.h
@@ -63,6 +63,9 @@ teco_strv_remove(gchar **strv, guint i)
  * to functions expecting traditional null-terminated C strings if you can
  * guarantee that it contains no null-character other than the trailing one.
  *
+ * Since string objects are just two words, they can and should be passed by
+ * value if the callee doesn't have to modify it.
+ *
  * @warning For consistency with C idioms the underlying character type is
  * `char`, which might be signed!
  * Accessing individual characters may yield signed integers and that sign
@@ -164,19 +167,19 @@ gchar *teco_string_echo(const gchar *str, gsize len);
 
 void teco_string_get_coord(const gchar *str, gsize off, guint *pos, guint *line, guint *column);
 
-typedef gsize (*teco_string_diff_t)(const teco_string_t *a, const gchar *b, gsize b_len);
-gsize teco_string_diff(const teco_string_t *a, const gchar *b, gsize b_len);
-gsize teco_string_casediff(const teco_string_t *a, const gchar *b, gsize b_len);
+typedef gsize (*teco_string_diff_t)(teco_string_t a, const gchar *b, gsize b_len);
+gsize teco_string_diff(teco_string_t a, const gchar *b, gsize b_len);
+gsize teco_string_casediff(teco_string_t a, const gchar *b, gsize b_len);
 
-typedef gint (*teco_string_cmp_t)(const teco_string_t *a, const gchar *b, gsize b_len);
-gint teco_string_cmp(const teco_string_t *a, const gchar *b, gsize b_len);
-gint teco_string_casecmp(const teco_string_t *a, const gchar *b, gsize b_len);
+typedef gint (*teco_string_cmp_t)(teco_string_t a, const gchar *b, gsize b_len);
+gint teco_string_cmp(teco_string_t a, const gchar *b, gsize b_len);
+gint teco_string_casecmp(teco_string_t a, const gchar *b, gsize b_len);
 
 /** @memberof teco_string_t */
 static inline gboolean
-teco_string_contains(const teco_string_t *str, gchar chr)
+teco_string_contains(teco_string_t str, gchar chr)
 {
-	return str->data && memchr(str->data, chr, str->len);
+	return str.data && memchr(str.data, chr, str.len);
 }
 
 /**
@@ -188,26 +191,26 @@ teco_string_contains(const teco_string_t *str, gchar chr)
  * @memberof teco_string_t
  */
 static inline gint
-teco_string_rindex(const teco_string_t *str, gchar chr)
+teco_string_rindex(teco_string_t str, gchar chr)
 {
 	gint i;
-	for (i = str->len-1; i >= 0 && str->data[i] != chr; i--);
+	for (i = str.len-1; i >= 0 && str.data[i] != chr; i--);
 	return i;
 }
 
-const gchar *teco_string_last_occurrence(const teco_string_t *str, const gchar *chars);
+const gchar *teco_string_last_occurrence(teco_string_t str, const gchar *chars);
 
 /**
  * Validate whether string consists exclusively of valid UTF-8, but accept null bytes.
  * @note there is g_utf8_validate_len() in Glib 2.60
  */
 static inline gboolean
-teco_string_validate_utf8(const teco_string_t *str)
+teco_string_validate_utf8(teco_string_t str)
 {
-	const gchar *p = str->data;
-	while (!g_utf8_validate(p, str->len - (p - str->data), &p) && !*p)
+	const gchar *p = str.data;
+	while (!g_utf8_validate(p, str.len - (p - str.data), &p) && !*p)
 		p++;
-	return p - str->data == str->len;
+	return p - str.data == str.len;
 }
 
 /** @memberof teco_string_t */