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-rw-r--r--versioncmp.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/versioncmp.c b/versioncmp.c
new file mode 100644
index 0000000000..7511e08271
--- /dev/null
+++ b/versioncmp.c
@@ -0,0 +1,93 @@
+#include "cache.h"
+
+/*
+ * versioncmp(): copied from string/strverscmp.c in glibc commit
+ * ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
+ * style. The implementation is under LGPL-2.1 and Git relicenses it
+ * to GPLv2.
+ */
+
+/*
+ * states: S_N: normal, S_I: comparing integral part, S_F: comparing
+ * fractionnal parts, S_Z: idem but with leading Zeroes only
+ */
+#define S_N 0x0
+#define S_I 0x3
+#define S_F 0x6
+#define S_Z 0x9
+
+/* result_type: CMP: return diff; LEN: compare using len_diff/diff */
+#define CMP 2
+#define LEN 3
+
+
+/*
+ * Compare S1 and S2 as strings holding indices/version numbers,
+ * returning less than, equal to or greater than zero if S1 is less
+ * than, equal to or greater than S2 (for more info, see the texinfo
+ * doc).
+ */
+
+int versioncmp(const char *s1, const char *s2)
+{
+ const unsigned char *p1 = (const unsigned char *) s1;
+ const unsigned char *p2 = (const unsigned char *) s2;
+ unsigned char c1, c2;
+ int state, diff;
+
+ /*
+ * Symbol(s) 0 [1-9] others
+ * Transition (10) 0 (01) d (00) x
+ */
+ static const uint8_t next_state[] = {
+ /* state x d 0 */
+ /* S_N */ S_N, S_I, S_Z,
+ /* S_I */ S_N, S_I, S_I,
+ /* S_F */ S_N, S_F, S_F,
+ /* S_Z */ S_N, S_F, S_Z
+ };
+
+ static const int8_t result_type[] = {
+ /* state x/x x/d x/0 d/x d/d d/0 0/x 0/d 0/0 */
+
+ /* S_N */ CMP, CMP, CMP, CMP, LEN, CMP, CMP, CMP, CMP,
+ /* S_I */ CMP, -1, -1, +1, LEN, LEN, +1, LEN, LEN,
+ /* S_F */ CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP,
+ /* S_Z */ CMP, +1, +1, -1, CMP, CMP, -1, CMP, CMP
+ };
+
+ if (p1 == p2)
+ return 0;
+
+ c1 = *p1++;
+ c2 = *p2++;
+ /* Hint: '0' is a digit too. */
+ state = S_N + ((c1 == '0') + (isdigit (c1) != 0));
+
+ while ((diff = c1 - c2) == 0) {
+ if (c1 == '\0')
+ return diff;
+
+ state = next_state[state];
+ c1 = *p1++;
+ c2 = *p2++;
+ state += (c1 == '0') + (isdigit (c1) != 0);
+ }
+
+ state = result_type[state * 3 + (((c2 == '0') + (isdigit (c2) != 0)))];
+
+ switch (state) {
+ case CMP:
+ return diff;
+
+ case LEN:
+ while (isdigit (*p1++))
+ if (!isdigit (*p2++))
+ return 1;
+
+ return isdigit (*p2) ? -1 : diff;
+
+ default:
+ return state;
+ }
+}