GRASS GIS 8 Programmer's Manual
8.5.0dev(2024)-adcdf28bb2
btree/update.c
Go to the documentation of this file.
1
#include <stdio.h>
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#include <stdlib.h>
3
#include <string.h>
4
#include <
grass/btree.h
>
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static
void
*store(
const
void
*,
int
);
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8
int
btree_update
(
BTREE
*B,
const
void
*key,
int
keylen,
const
void
*data,
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int
datalen)
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{
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int
p = 0;
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int
q;
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int
N
;
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int (*cmp)(
const
void
*,
const
void
*);
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int
dir;
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/* first node is special case */
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N
= B->
N
;
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if
(
N
== 0) {
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N
= B->
N
= 1;
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B->
node
[
N
].
key
= store(key, keylen);
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B->
node
[
N
].
data
= store(data, datalen);
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B->
node
[
N
].
left
= 0;
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B->
node
[
N
].
right
= 0;
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if
(B->
node
[
N
].
key
&& B->
node
[
N
].
data
)
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return
1;
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else
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return
0;
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}
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cmp = B->
cmp
;
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q = 1;
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while
(q > 0) {
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p = q;
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dir = (*cmp)(B->
node
[q].
key
, key);
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if
(dir == 0) {
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free
(B->
node
[q].
data
);
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return
((B->
node
[q].
data
= store(data, datalen))) ? 1 : 0;
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}
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if
(dir > 0)
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q = B->
node
[q].
left
;
/* go left */
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else
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q = B->
node
[q].
right
;
/* go right */
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}
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/* new node */
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B->
N
++;
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N
= B->
N
;
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/* grow the tree? */
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if
(
N
>= B->
tlen
) {
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B->
node
= (
BTREE_NODE
*)realloc(B->
node
,
sizeof
(
BTREE_NODE
) *
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(B->
tlen
+= B->
incr
));
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if
(B->
node
==
NULL
)
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return
0;
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}
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/* add node to tree */
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B->
node
[
N
].
key
= store(key, keylen);
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B->
node
[
N
].
data
= store(data, datalen);
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B->
node
[
N
].
left
= 0;
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if
(dir > 0) {
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B->
node
[
N
].
right
= -p;
/* create thread */
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B->
node
[p].
left
=
N
;
/* insert left */
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}
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else
{
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B->
node
[
N
].
right
= B->
node
[p].
right
;
/* copy right link/thread */
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B->
node
[p].
right
=
N
;
/* add right */
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}
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return
1;
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}
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static
void
*store(
const
void
*s,
int
n)
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{
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void
*
b
;
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if
(n <= 0)
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return
NULL
;
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b
=
malloc
(n);
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if
(
b
==
NULL
)
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return
b
;
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memcpy(
b
, s, n);
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return
b
;
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}
btree_update
int btree_update(BTREE *B, const void *key, int keylen, const void *data, int datalen)
Definition:
btree/update.c:8
btree.h
NULL
#define NULL
Definition:
ccmath.h:32
N
#define N
Definition:
e_intersect.c:926
b
double b
Definition:
r_raster.c:39
malloc
void * malloc(YYSIZE_T)
free
void free(void *)
BTREE_NODE
Definition:
btree.h:4
BTREE_NODE::left
int left
Definition:
btree.h:7
BTREE_NODE::right
int right
Definition:
btree.h:8
BTREE_NODE::key
void * key
Definition:
btree.h:5
BTREE_NODE::data
void * data
Definition:
btree.h:6
BTREE
Definition:
btree.h:11
BTREE::N
int N
Definition:
btree.h:14
BTREE::cmp
int(* cmp)(const void *, const void *)
Definition:
btree.h:17
BTREE::incr
int incr
Definition:
btree.h:15
BTREE::node
BTREE_NODE * node
Definition:
btree.h:12
BTREE::tlen
int tlen
Definition:
btree.h:13
lib
btree
update.c
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