fielding 99/02/06 03:00:18
Modified: src CHANGES
src/modules/standard mod_negotiation.c
Log:
Explain why we do not round the TCN quality calculation to 5 decimal places,
unlike RFC 2296, because the calculation might need 12 decimal places
to get the right result.
Revision Changes Path
1.1235 +4 -0 apache-1.3/src/CHANGES
Index: CHANGES
===================================================================
RCS file: /home/cvs/apache-1.3/src/CHANGES,v
retrieving revision 1.1234
retrieving revision 1.1235
diff -u -r1.1234 -r1.1235
--- CHANGES 1999/02/06 09:58:02 1.1234
+++ CHANGES 1999/02/06 11:00:09 1.1235
@@ -1,5 +1,9 @@
Changes with Apache 1.3.5
+ *) Do not round the TCN quality calculation to 5 decimal places,
+ unlike RFC 2296, because the calculation might need 12 decimal places
+ to get the right result. [Roy Fielding]
+
*) Remove unused code to disable transparent negotiation when
negotiating on encoding only, as we now handle encoding too
(though this is nonstandard for TCN), and fix bugs in debugging
1.94 +8 -7 apache-1.3/src/modules/standard/mod_negotiation.c
Index: mod_negotiation.c
===================================================================
RCS file: /home/cvs/apache-1.3/src/modules/standard/mod_negotiation.c,v
retrieving revision 1.93
retrieving revision 1.94
diff -u -r1.93 -r1.94
--- mod_negotiation.c 1999/02/06 09:58:04 1.93
+++ mod_negotiation.c 1999/02/06 11:00:15 1.94
@@ -1763,13 +1763,14 @@
variant->charset_quality *
variant->lang_quality;
- /* Make sure that variants with a very low nonzero q value
- * do not get rounded down to 0
+ /* RFC 2296 calls for the result to be rounded to 5 decimal places,
+ * but we don't do that because it serves no useful purpose other
+ * than to ensure that a remote algorithm operates on the same
+ * precision as ours. That is silly, since what we obviously want
+ * is for the algorithm to operate on the best available precision
+ * regardless of who runs it. Since the above calculation may
+ * result in significant variance at 1e-12, rounding would be bogus.
*/
- if (q <= 0.0f)
- q = 0.0f;
- else if (q < 0.00001f)
- q = 0.00001f;
#ifdef NEG_DEBUG
fprintf(stderr, "Variant: file=%s type=%s lang=%s sourceq=%1.3f "
@@ -1789,7 +1790,7 @@
variant->definite);
#endif
- if (q == 0.0f) {
+ if (q <= 0.0f) {
return 0;
}
if (q > bestq) {
