Better progdocs for filters

This commit is contained in:
Pavel Machek 2000-06-07 13:54:06 +00:00
parent fa6c2405e2
commit 771ae456a5
3 changed files with 33 additions and 4 deletions

View file

@ -1,2 +1,3 @@
H Filters H Filters
S filter.c S filter.c
S tree.c

View file

@ -260,6 +260,16 @@ rta_cow(void)
* *
* Interpret given tree of filter instructions. This is core function * Interpret given tree of filter instructions. This is core function
* of filter system and does all the hard work. * of filter system and does all the hard work.
*
* Each instruction has 4 fields: code (which is instruction code),
* aux (which is extension to instruction code, typically type),
* arg1 and arg2 - arguments. Depending on instruction, arguments
* are either integers, or pointers to instruction trees. Common
* instructions like +, that have two expressions as arguments use
* TWOARGS macro to get both of them evaluated.
*
* &f_val structures are copied around, so there are no problems with
* memory managment.
*/ */
static struct f_val static struct f_val
interpret(struct f_inst *what) interpret(struct f_inst *what)

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@ -10,7 +10,9 @@
#include "conf/conf.h" #include "conf/conf.h"
#include "filter/filter.h" #include "filter/filter.h"
/* Finds n-th item in list linked by right. Trashes pointers in right. */ /*
* find_nth - finds n-th element in linked list. Don't be confused by tree structures.
*/
static struct f_tree * static struct f_tree *
find_nth(struct f_tree *from, int nth) find_nth(struct f_tree *from, int nth)
{ {
@ -41,7 +43,9 @@ find_nth(struct f_tree *from, int nth)
return find_nth(left, nth); return find_nth(left, nth);
} }
/* Gets list linked by left, finds its median, trashes pointers in right */ /*
* Gets list linked by left, finds its median, trashes pointers in right */
*/
static struct f_tree * static struct f_tree *
find_median(struct f_tree *from) find_median(struct f_tree *from)
{ {
@ -57,6 +61,15 @@ find_median(struct f_tree *from)
return find_nth(from, cnt/2); return find_nth(from, cnt/2);
} }
/**
* find_tree
* @t: tree to search in
* @val: value to find
*
* Search for given value in the tree. I relies on fact that sorted tree is populated
* by &f_val structures (that can be compared by val_compare()). In each node of tree,
* either single value (then t->from==t->to) or range is present.
*/
struct f_tree * struct f_tree *
find_tree(struct f_tree *t, struct f_val val) find_tree(struct f_tree *t, struct f_val val)
{ {
@ -71,7 +84,12 @@ find_tree(struct f_tree *t, struct f_val val)
return find_tree(t->left, val); return find_tree(t->left, val);
} }
/* Gets list linked by left */ /**
* build_tree
* @from: degenerated tree (linked by tree->left) to be transformed into form suitable for find_tree()
*
* Transforms denerated tree into balanced tree.
*/
struct f_tree * struct f_tree *
build_tree(struct f_tree *from) build_tree(struct f_tree *from)
{ {