Add a string comparison function and a string equality predicate.

Write test cases for the former.

include/cryb/string.h

@@ -41,6 +41,8 @@
 #define string_append_string	cryb_string_append_string
 #define string_printf		cryb_string_printf
 #define string_vprintf		cryb_string_vprintf
+#define string_compare		cryb_string_compare
+#define string_equal		cryb_string_equal
 
 typedef struct cryb_string string;
 
@@ -57,5 +59,7 @@ ssize_t	 string_printf(string *, const char *, ...);
 #ifdef va_start
 ssize_t	 string_vprintf(string *, const char *, va_list);
 #endif
+int	 string_compare(const string *, const string *);
+int	 string_equal(const string *, const string *);
 
 #endif

include/cryb/wstring.h

@@ -41,6 +41,8 @@
 #define wstring_append_wstring	cryb_wstring_append_wstring
 #define wstring_printf		cryb_wstring_printf
 #define wstring_vprintf		cryb_wstring_vprintf
+#define wstring_compare		cryb_wstring_compare
+#define wstring_equal		cryb_wstring_equal
 
 typedef struct cryb_wstring wstring;
 
@@ -50,12 +52,14 @@ void	 wstring_delete(wstring *);
 int	 wstring_expand(wstring *, size_t);
 void	 wstring_shrink(wstring *);
 ssize_t	 wstring_trunc(wstring *, size_t);
-ssize_t	 wstring_append_c(wstring *, wchar_t);
-ssize_t	 wstring_append_cs(wstring *, const wchar_t *, size_t);
+ssize_t	 wstring_append_wc(wstring *, wchar_t);
+ssize_t	 wstring_append_wcs(wstring *, const wchar_t *, size_t);
 ssize_t	 wstring_append_wstring(wstring *, const wstring *, size_t);
 ssize_t	 wstring_printf(wstring *, const wchar_t *, ...);
 #ifdef va_start
 ssize_t	 wstring_vprintf(wstring *, const wchar_t *, va_list);
 #endif
+int	 wstring_compare(const wstring *, const wstring *);
+int	 wstring_equal(const wstring *, const wstring *);
 
 #endif

lib/core/_string.c

@@ -280,3 +280,34 @@ string_vprintf(string *str, const char_t *fmt, va_list ap)
 	str->buf[str->len] = 0;
 	return (str->len);
 }
+
+/*
+ * Compare two strings, returning a negative value if the first is
+ * lexically less than the second, a positive value if the opposite is
+ * true, and zero if they are equal.
+ */
+int
+string_compare(const string *s1, const string *s2)
+{
+	const char_t *p1, *p2;
+
+	for (p1 = s1->buf, p2 = s2->buf; *p1 && *p2; ++p1, ++p2)
+		if (*p1 != *p2)
+			return (*p1 < *p2 ? -1 : 1);
+	return (*p1 ? 1 : *p2 ? -1 : 0);
+}
+
+/*
+ * Compare two strings, returning true (non-zero) if they are equal and
+ * false (zero) if they are not.
+ */
+int
+string_equal(const string *s1, const string *s2)
+{
+	const char_t *p1, *p2;
+
+	for (p1 = s1->buf, p2 = s2->buf; *p1 && *p2; ++p1, ++p2)
+		if (*p1 != *p2)
+			return (0);
+	return (1);
+}

lib/core/wstring.c

@@ -54,5 +54,7 @@
 #define string_append_string	wstring_append_wstring
 #define string_printf		wstring_printf
 #define string_vprintf		wstring_vprintf
+#define string_compare		wstring_compare
+#define string_equal		wstring_equal
 
 #include "_string.c"

t/t__string.c

@@ -28,7 +28,7 @@
  */
 
 static int
-t_foo(char **desc CRYB_UNUSED, void *arg)
+t_noop(char **desc CRYB_UNUSED, void *arg)
 {
 	string *str;
 
@@ -38,3 +38,106 @@ t_foo(char **desc CRYB_UNUSED, void *arg)
 	string_delete(str);
 	return (1);
 }
+
+
+/***************************************************************************
+ * Comparisons
+ */
+
+static struct t_compare_case {
+	const char *desc;
+	const char_t *s1, *s2;
+	int cmp;
+} t_compare_cases[] = {
+	{
+		"both empty",
+		CS(""),
+		CS(""),
+		0,
+	},
+	{
+		"empty with non-empty (left)",
+		CS(""),
+		CS("xyzzy"),
+		-1,
+	},
+	{
+		"empty with non-empty (right)",
+		CS("xyzzy"),
+		CS(""),
+		1,
+	},
+	{
+		"equal non-empty",
+		CS("xyzzy"),
+		CS("xyzzy"),
+		0,
+	},
+	{
+		"unequal of equal length (left)",
+		CS("abba"),
+		CS("baba"),
+		-1,
+	},
+	{
+		"unequal of equal length (right)",
+		CS("baba"),
+		CS("abba"),
+		1,
+	},
+	{
+		"prefix (left)",
+		CS("baba"),
+		CS("babaorum"),
+		-1,
+	},
+	{
+		"prefix (right)",
+		CS("babaorum"),
+		CS("baba"),
+		1,
+	},
+};
+
+static int
+t_compare_test(char **desc CRYB_UNUSED, void *arg)
+{
+	struct t_compare_case *t = arg;
+	string *s1, *s2;
+	int ret;
+
+	if ((s1 = string_new()) == NULL ||
+	    string_append_cs(s1, t->s1, SIZE_MAX) < 0 ||
+	    (s2 = string_new()) == NULL ||
+	    string_append_cs(s2, t->s2, SIZE_MAX) < 0)
+		return (0);
+	ret = string_compare(s1, s2) == t->cmp;
+	string_delete(s2);
+	string_delete(s1);
+	return (ret);
+}
+
+
+/***************************************************************************
+ * Boilerplate
+ */
+
+int
+t_prepare(int argc, char *argv[])
+{
+	unsigned int i;
+
+	(void)argc;
+	(void)argv;
+
+	t_add_test(t_noop, NULL, "no-op");
+	for (i = 0; i < sizeof t_compare_cases / sizeof *t_compare_cases; ++i)
+		t_add_test(t_compare_test, &t_compare_cases[i],
+		    t_compare_cases[i].desc);
+	return (0);
+}
+
+void
+t_cleanup(void)
+{
+}

t/t_string.c

@@ -38,24 +38,8 @@
 
 #include "t.h"
 
+#define char_t			char
+
+#define CS(lit)			lit
+
 #include "t__string.c"
-
-
-/***************************************************************************
- * Boilerplate
- */
-
-int
-t_prepare(int argc, char *argv[])
-{
-
-	(void)argc;
-	(void)argv;
-	t_add_test(t_foo, NULL, "foo");
-	return (0);
-}
-
-void
-t_cleanup(void)
-{
-}

t/t_wstring.c

@@ -40,6 +40,7 @@
 #include "t.h"
 
 #define char_t			wchar_t
+#define vsnprintf		vswprintf
 
 #define cryb_string		cryb_wstring
 #define string			wstring
@@ -55,25 +56,9 @@
 #define string_append_string	wstring_append_wstring
 #define string_printf		wstring_printf
 #define string_vprintf		wstring_vprintf
+#define string_compare		wstring_compare
+#define string_equal		wstring_equal
+
+#define CS(lit)			L ## lit
 
 #include "t__string.c"
-
-
-/***************************************************************************
- * Boilerplate
- */
-
-int
-t_prepare(int argc, char *argv[])
-{
-
-	(void)argc;
-	(void)argv;
-	t_add_test(t_foo, NULL, "foo");
-	return (0);
-}
-
-void
-t_cleanup(void)
-{
-}