string: add strverscmp

The actual implementation is from musl (MIT license).

Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/newlib/libc/string/strverscmp.c b/newlib/libc/string/strverscmp.c
new file mode 100644
index 000000000..83f053222
--- /dev/null
+++ b/newlib/libc/string/strverscmp.c
@@ -0,0 +1,99 @@
+/*
+FUNCTION
+	<<strverscmp>>---version string compare
+
+INDEX
+	strverscmp
+
+ANSI_SYNOPSIS
+	#define _GNU_SOURCE
+	#include <string.h>
+	int strverscmp(const char *<[a]>, const char *<[b]>);
+
+TRAD_SYNOPSIS
+	#define _GNU_SOURCE
+	#include <string.h>
+	int strverscmp(<[a]>, <[b]>)
+	char *<[a]>;
+	char *<[b]>;
+
+DESCRIPTION
+	<<strverscmp>> compares the string at <[a]> to
+	the string at <[b]> in a version-logical order.
+
+RETURNS
+
+	If <<*<[a]>>> version-sorts after <<*<[b]>>>, <<strverscmp>> returns
+	a number greater than zero.  If the two strings match, <<strverscmp>>
+	returns zero.  If <<*<[a]>>> version-sorts before <<*<[b]>>>,
+	<<strverscmp>> returns a number less than zero.
+
+PORTABILITY
+<<strverscmp>> is a GNU extension.
+
+<<strverscmp>> requires no supporting OS subroutines. It uses
+isdigit() from elsewhere in this library.
+
+QUICKREF
+	strverscmp
+*/
+
+/*
+From musl src/string/strverscmp.c
+
+Copyright © 2005-2014 Rich Felker, et al.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#define _GNU_SOURCE
+#include <ctype.h>
+#include <string.h>
+
+int strverscmp(const char *l0, const char *r0)
+{
+	const unsigned char *l = (const void *)l0;
+	const unsigned char *r = (const void *)r0;
+	size_t i, dp, j;
+	int z = 1;
+
+	/* Find maximal matching prefix and track its maximal digit
+	 * suffix and whether those digits are all zeros. */
+	for (dp=i=0; l[i]==r[i]; i++) {
+		int c = l[i];
+		if (!c) return 0;
+		if (!isdigit(c)) dp=i+1, z=1;
+		else if (c!='0') z=0;
+	}
+
+	if (l[dp]!='0' && r[dp]!='0') {
+		/* If we're not looking at a digit sequence that began
+		 * with a zero, longest digit string is greater. */
+		for (j=i; isdigit(l[j]); j++)
+			if (!isdigit(r[j])) return 1;
+		if (isdigit(r[j])) return -1;
+	} else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
+		/* Otherwise, if common prefix of digit sequence is
+		 * all zeros, digits order less than non-digits. */
+		return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
+	}
+
+	return l[i] - r[i];
+}