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authorTim van der Molen <tim@kariliq.nl>2020-06-15 19:51:36 +0200
committerTim van der Molen <tim@kariliq.nl>2020-06-15 19:51:36 +0200
commit5e4c6de73a023e480a909aac1eb23d93ceb4d0fa (patch)
tree0a3f9e59cad621a17c8ed3db447285ae1d983cca /src/strverscmp.c
parenta624883d92ea54886b739f1000e39ccf1afc5577 (diff)
Enable --version-sort on systems without strverscmp()
The --version-sort option requires strverscmp(), but this is a glibc extension that does not exist on OpenBSD and other systems. To enable --version-sort on those systems, provide an internal implementation of strverscmp(). The implementation is from the musl C library and is MIT-licensed. The build process remains the same: the verscmp flag should be set to 1 only if strverscmp() is available in libc. If verscmp is 0, then the internal implementation is used.
Diffstat (limited to 'src/strverscmp.c')
-rw-r--r--src/strverscmp.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/src/strverscmp.c b/src/strverscmp.c
new file mode 100644
index 0000000..92cd877
--- /dev/null
+++ b/src/strverscmp.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2005-2020 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];
+}