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php4-beta | 200004

[PHP4BETA] cvs: /php4/ext/standard strnatcmp.c From: Andrei Zmievski (andrei <email protected>)
Date: 04/29/00

andrei Sat Apr 29 11:57:36 2000 EDT

  Modified files:
    /php4/ext/standard strnatcmp.c
  Log:
  
  @ Updated natural comparison/sorting algorithm by Martin Pool
  @ <mbp <email protected>>. (Andrei)
  
  Martin Pool updated the natural comparison/sort algorithm so that fractions
  compare more "naturally", e.g. 1.002 < 1.1.
  
  
Index: php4/ext/standard/strnatcmp.c
diff -u php4/ext/standard/strnatcmp.c:1.3 php4/ext/standard/strnatcmp.c:1.4
--- php4/ext/standard/strnatcmp.c:1.3 Thu Apr 13 09:08:49 2000
+++ php4/ext/standard/strnatcmp.c Sat Apr 29 11:57:06 2000
@@ -37,70 +37,102 @@
 #endif
 
 static char const *version UNUSED =
- "$Id: strnatcmp.c,v 1.3 2000/04/13 16:08:49 zeev Exp $";
+ "$Id: strnatcmp.c,v 1.4 2000/04/29 18:57:06 andrei Exp $";
 
+static int
+compare_right(char const **a, char const *aend, char const **b, char const *bend)
+{
+ 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)++) {
+ if ((*a == aend || !isdigit((int)**a)) &&
+ (*b == bend || !isdigit((int)**b)))
+ return bias;
+ else if (*a == aend || !isdigit((int)**a))
+ return -1;
+ else if (*b == bend || !isdigit((int)**b))
+ return +1;
+ else if (**a < **b) {
+ if (!bias)
+ bias = -1;
+ } else if (**a > **b) {
+ if (!bias)
+ bias = +1;
+ }
+ }
+
+ return 0;
+}
+
+
+static int
+compare_left(char const **a, char const *aend, char const **b, char const *bend)
+{
+ /* Compare two left-aligned numbers: the first to have a
+ different value wins. */
+ for(;; (*a)++, (*b)++) {
+ if ((*a == aend || !isdigit((int)**a)) &&
+ (*b == bend || !isdigit((int)**b)))
+ return 0;
+ else if (*a == aend || !isdigit((int)**a))
+ return -1;
+ else if (*b == bend || !isdigit((int)**b))
+ return +1;
+ else if (**a < **b)
+ return -1;
+ else if (**a > **b)
+ return +1;
+ }
+
+ return 0;
+}
+
+
 PHPAPI int strnatcmp_ex(char const *a, size_t a_len, char const *b, size_t b_len, int fold_case)
 {
- int ai, bi;
         char ca, cb;
- const char *aend = a + a_len,
+ char const *ap, *bp;
+ char const *aend = a + a_len,
                            *bend = b + b_len;
+ int fractional, result;
 
         if (a_len == 0 || b_len == 0)
                 return a_len - b_len;
-
-/*
- assert(a && b);
-*/
 
- ai = bi = 0;
+ ap = a;
+ bp = b;
         while (1) {
- ca = a[ai]; cb = b[bi];
+ ca = *ap; cb = *bp;
 
                 /* skip over leading spaces or zeros */
- while (isspace(ca) || ca == '0')
- ca = a[++ai];
+ while (isspace((int)ca))
+ ca = *++ap;
 
- while (isspace(cb) || cb == '0')
- cb = b[++bi];
+ while (isspace((int)cb))
+ cb = *++bp;
 
                 /* process run of digits */
- if (isdigit(ca) && isdigit(cb)) {
- int bias = 0;
- /* The longest run of digits (stripping off leading
- zeros) 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. */
- while (1) {
- if (!isdigit(ca) && !isdigit(cb))
- goto done_number;
- else if (!isdigit(ca))
- return -1;
- else if (!isdigit(cb))
- return +1;
- else if (ca < cb) {
- if (!bias)
- bias = -1;
- } else if (ca > cb) {
- if (!bias)
- bias = +1;
- }
-
- ++ai; ++bi;
- if (a + ai == aend && b + bi == bend)
- /* Return the current bias if at the end of both strings. */
- return bias;
- else if (a + ai == aend)
- return -1;
- else if (b + bi == bend)
- return 1;
+ if (isdigit((int)ca) && isdigit((int)cb)) {
+ fractional = (ca == '0' || cb == '0');
 
- ca = a[ai]; cb = b[bi];
+ if (fractional)
+ result = compare_left(&ap, aend, &bp, bend);
+ else
+ result = compare_right(&ap, aend, &bp, bend);
+
+ if (result != 0)
+ return result;
+ else if (ap == aend && bp == bend)
+ /* End of the strings. Let caller sort them out. */
+ return 0;
+ else {
+ /* Keep on comparing from the current point. */
+ ca = *ap; cb = *bp;
                         }
-done_number:
- if (bias)
- return bias;
                 }
 
                 if (fold_case) {
@@ -113,14 +145,14 @@
                 else if (ca > cb)
                         return +1;
 
- ++ai; ++bi;
- if (a + ai == aend && b + bi == bend)
+ ++ap; ++bp;
+ if (ap == aend && bp == bend)
                         /* The strings compare the same. Perhaps the caller
                            will want to call strcmp to break the tie. */
                         return 0;
- else if (a + ai == aend)
+ else if (ap == aend)
                         return -1;
- else if (b + bi == bend)
+ else if (bp == bend)
                         return 1;
         }
 } 

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