null+****@clear*****
null+****@clear*****
2011年 11月 19日 (土) 20:42:22 JST
Kouhei Sutou 2011-11-19 11:42:22 +0000 (Sat, 19 Nov 2011)
New Revision: 26140ca342f75597552770c7cf9e918ffc38bf62
Log:
[geo] add a comment about data.
Modified files:
lib/geo.c
Modified: lib/geo.c (+47 -0)
===================================================================
--- lib/geo.c 2011-11-19 11:13:42 +0000 (819dca7)
+++ lib/geo.c 2011-11-19 11:42:22 +0000 (42239b0)
@@ -1157,6 +1157,53 @@ grn_geo_cursor_entry_next(grn_ctx *ctx,
grn_geo_cursor_entry next_entry0, next_entry1;
grn_bool pushed = GRN_FALSE;
+ /*
+ top_left_key: tl
+ bottom_right_key: br
+
+ e.g.: top_left_key is at the top left sub mesh and
+ bottom_right_key is at the bottom right sub mesh.
+ top_left_key is also at the top left - bottom right
+ sub-sub mesh and
+ bottom_right_key is at the bottom right - bottom left
+ sub-sub mesh.
+
+ ^latitude +----+----+----+----+
+ | 1 |1010|1011|1110|1111|
+ | | | | | |
+ | 1 +----+----+----+----+
+ \/ 0 |1000|1001|1100|1101|
+ | | tl | | |
+ +----+----+----+----+
+ 1 |0010|0011|0110|0111|
+ | | | | |
+ 0 +----+----+----+----+
+ 0 |0000|0001|0100|0101|
+ | | | br | |
+ +----+----+----+----+
+ 0 1 0 1
+ |-------| |-------|
+ 0 1
+ <------>
+ longitude
+
+ entry.target_bit + 1 -> next_entry0
+ entry.target_bit + 1 and entry.base_key ^ (entry.target_bit + 1) in bit
+ -> next_entry1
+
+ entry: represents the biggest mesh.
+ (1010, 1011, 1110, 1111,
+ 1000, 1001, 1100, 1101,
+ 0010, 0011, 0110, 0111,
+ 0000, 0001, 0100, 0101)
+ next_entry0: represents bottom sub-mesh.
+ (0010, 0011, 0110, 0111,
+ 0000, 0001, 0100, 0101)
+ next_entry1: represents top sub-mesh.
+ (1010, 1011, 1110, 1111,
+ 1000, 1001, 1100, 1101)
+ */
+
#ifdef GEO_DEBUG
inspect_cursor_entry(ctx, entry);
#endif