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-rw-r--r--src/base/strnatcmp.c302
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diff --git a/src/base/strnatcmp.c b/src/base/strnatcmp.c
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+/* -*- mode: c; c-file-style: "k&r" -*-
+
+ strnatcmp.c -- Perform 'natural order' comparisons of strings in C.
+ Copyright (C) 2000, 2004 by Martin Pool <mbp sourcefrog net>
+
+ This software is provided 'as-is', without any express or implied
+ warranty. In no event will the authors be held liable for any damages
+ arising from the use of this software.
+
+ Permission is granted to anyone to use this software for any purpose,
+ including commercial applications, and to alter it and redistribute it
+ freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+ 2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+ 3. This notice may not be removed or altered from any source distribution.
+*/
+
+
+/* partial change history:
+ *
+ * 2004-10-10 mbp: Lift out character type dependencies into macros.
+ *
+ * Eric Sosman pointed out that ctype functions take a parameter whose
+ * value must be that of an unsigned int, even on platforms that have
+ * negative chars in their default char type.
+ */
+
+#include <assert.h>
+#include <ctype.h>
+
+#include "strnatcmp.h"
+
+
+/* These are defined as macros to make it easier to adapt this code to
+ * different characters types or comparison functions. */
+static inline int
+nat_isdigit(nat_char a)
+{
+ return isdigit((unsigned char) a);
+}
+
+
+static inline int
+nat_isspace(nat_char a)
+{
+ return isspace((unsigned char) a);
+}
+
+
+static inline nat_char
+nat_toupper(nat_char a)
+{
+ return toupper((unsigned char) a);
+}
+
+
+
+static int
+compare_right(int a_len, nat_char const *a, int b_len, nat_char const *b, int *len_out)
+{
+ int bias = 0;
+
+ /* The longest run of digits wins. That aside, the greatest
+ value wins, but we can't know that it will until we've scanned
+ both numbers to know that they have the same magnitude, so we
+ remember it in BIAS. */
+ for (;; a++, b++, a_len--, b_len--, (*len_out)++) {
+ if (a_len == 0 && b_len == 0)
+ return bias;
+ if (a_len == 0)
+ return -1;
+ if (b_len == 0)
+ return 1;
+ if (!nat_isdigit(*a) && !nat_isdigit(*b))
+ return bias;
+ else if (!nat_isdigit(*a))
+ return -1;
+ else if (!nat_isdigit(*b))
+ return +1;
+ else if (*a < *b) {
+ if (!bias)
+ bias = -1;
+ } else if (*a > *b) {
+ if (!bias)
+ bias = +1;
+ } else if (!*a && !*b)
+ return bias;
+ }
+
+ return 0;
+}
+
+static int
+compare_left(int a_len, nat_char const *a, int b_len, nat_char const *b, int *len_out)
+{
+ /* Compare two left-aligned numbers: the first to have a
+ different value wins. */
+ for (;; a++, b++, a_len--, b_len--, (*len_out)++) {
+ if (a_len == 0 && b_len == 0)
+ return 0;
+ if (a_len == 0)
+ return -1;
+ if (b_len == 0)
+ return 1;
+ if (!nat_isdigit(*a) && !nat_isdigit(*b))
+ return 0;
+ else if (!nat_isdigit(*a))
+ return -1;
+ else if (!nat_isdigit(*b))
+ return +1;
+ else if (*a < *b)
+ return -1;
+ else if (*a > *b)
+ return +1;
+ }
+
+ return 0;
+}
+
+static int strnatcmp0(int a_len, nat_char const *a,
+ int b_len, nat_char const *b,
+ int fold_case)
+{
+ int ai, bi;
+ nat_char ca, cb;
+ int fractional, result;
+
+ assert(a && b);
+ ai = bi = 0;
+ while (1) {
+ if (ai >= a_len)
+ ca = 0;
+ else
+ ca = a[ai];
+ if (bi >= b_len)
+ cb = 0;
+ else
+ cb = b[bi];
+
+ /* skip over leading spaces or zeros */
+ while (nat_isspace(ca)) {
+ ai += 1;
+ if (ai >= a_len)
+ ca = 0;
+ else
+ ca = a[ai];
+ }
+
+ while (nat_isspace(cb)) {
+ bi += 1;
+ if (bi >= b_len)
+ cb = 0;
+ else
+ cb = b[bi];
+ }
+
+ /* process run of digits */
+ if (nat_isdigit(ca) && nat_isdigit(cb)) {
+ int num_len = 0;
+
+ fractional = (ca == '0' || cb == '0');
+
+ if (fractional) {
+ if ((result = compare_left(a_len - ai, a + ai, b_len - bi,
+ b + bi, &num_len)) != 0) {
+ return result;
+ }
+ } else {
+ if ((result = compare_right(a_len - ai, a + ai, b_len - bi,
+ b + bi, &num_len)) != 0) {
+ return result;
+ }
+ }
+
+ ai += num_len;
+ bi += num_len;
+ continue;
+ }
+
+ if (!ca && !cb) {
+ /* The strings compare the same. Perhaps the caller
+ will want to call strcmp to break the tie. */
+ return 0;
+ }
+
+ if (fold_case) {
+ ca = nat_toupper(ca);
+ cb = nat_toupper(cb);
+ }
+
+ if (ca < cb)
+ return -1;
+ else if (ca > cb)
+ return +1;
+
+ ++ai;
+ ++bi;
+ }
+}
+
+int ipv4cmp(int a_len, nat_char const *a,
+ int b_len, nat_char const *b,
+ int *res_out)
+{
+ int ai, bi;
+ nat_char ca, cb;
+ int fractional, result = 0;
+
+ assert(a && b);
+ ai = bi = 0;
+ while (result == 0) {
+ if (ai >= a_len)
+ ca = 0;
+ else
+ ca = a[ai];
+ if (bi >= b_len)
+ cb = 0;
+ else
+ cb = b[bi];
+
+ /* skip over leading spaces or zeros */
+ while (nat_isspace(ca)) {
+ ai += 1;
+ if (ai >= a_len)
+ ca = 0;
+ else
+ ca = a[ai];
+ }
+
+ while (nat_isspace(cb)) {
+ bi += 1;
+ if (bi >= b_len)
+ cb = 0;
+ else
+ cb = b[bi];
+ }
+
+ /* process run of digits */
+ if (nat_isdigit(ca) && nat_isdigit(cb)) {
+ int num_len = 0;
+
+ fractional = (ca == '0' || cb == '0');
+
+ if (fractional) {
+ result = compare_left(a_len - ai, a + ai, b_len - bi,
+ b + bi, &num_len);
+ } else {
+ result = compare_right(a_len - ai, a + ai, b_len - bi,
+ b + bi, &num_len);
+ }
+
+ ai += num_len;
+ bi += num_len;
+ continue;
+ }
+
+ if (!ca && !cb) {
+ /* The strings compare the same. Perhaps the caller
+ will want to call strcmp to break the tie. */
+ *res_out = result;
+ return 1;
+ }
+
+ if (ca != '.' || cb != '.') {
+ return 0;
+ }
+
+ ++ai;
+ ++bi;
+ }
+
+ for (; ai < a_len; ai++) {
+ if (!isdigit(a[ai]) || a[ai] != '.') {
+ return 0;
+ }
+ }
+
+ for (; bi < b_len; bi++) {
+ if (!isdigit(b[bi]) || b[bi] != '.') {
+ return 0;
+ }
+ }
+
+ *res_out = result;
+ return 1;
+}
+
+int strnatcmp(int a_len, nat_char const *a, int b_len, nat_char const *b)
+{
+ return strnatcmp0(a_len, a, b_len, b, 0);
+}
+
+/* Compare, recognizing numeric string and ignoring case. */
+int strnatcasecmp(int a_len, nat_char const *a, int b_len, nat_char const *b)
+{
+ return strnatcmp0(a_len, a, b_len, b, 1);
+}
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