NAME
XAO::IndexerSupport - utility functions for XAO::Indexer
SYNOPSIS
use XAO::IndexerSupport;DESCRIPTION
This is a very specific module used by XAO::Indexer internally.
METHODS
- sorted_intersection
-
C-optimized variant of finding the intersection of multiple arrays sorted in the same way (all being sub-sets of some master sorted set). Used when finding multiple words search results.
- sorted_intersection_perl
-
Pure-perl variant of finding the intersection of multiple arrays sorted in the same way (all being sub-sets of some master sorted set). Used when finding multiple words search results.
Not used except for benchmarking.
- template_sort_clear
-
Clears data from the internal index, but keeps the memory still allocated. Useful if a different ordering of the same data is about to be used.
This is called automatically in template_sort_prepare(), no need to call it manually.
- template_sort_compare
-
Compares positions of two U32 arguments in the array template_sort_prepare() was called on.
- template_sort_free
-
Frees memory occupied by the internal index.
- template_sort_position
-
For a given unsigned integer returns its position in the array template_sort_prepare() was called on.
- template_sort_prepare
-
Gets a reference to an array of unsigned integers (U32) and prepares internal index for later sorting of its subsets using this array as a template.
The C routine underneath is optimised for the case of relatively sequential distribution of integers in the array -- meaning that the order can be anything, but they are not randomly distributed over the entire U32 range, they form a couple of clusters instead. This is usually the case with auto-increment database IDs.
Performance wise there is no difference, but it will take much more memory if the distribution is random.
- template_sort_print_tree
-
For debugging only -- prints the internal index representation to the standard error.
- template_sort
-
Takes a reference to an array of integers -- a subset of array earlier given to template_sort_prepare(). Returns a reference to an sorted array.
Values that are not in the template array will be grouped in the end in random order.
AUTHOR
Andrew Maltsev <am@xao.com>