drygdryg/calc
1
0
Fork 0
mirror of https://github.com/lcn2/calc.git synced 2025-08-16 01:03:29 +03:00
Code Issues Packages Projects Releases Wiki Activity

Improve pi cache

Browse Source 
Explicitly initialize static pi cache.
Use enums to identify pi cache elements.
Verify pi cache elements used have useful values.
This commit is contained in:
Landon Curt Noll
2021-09-07 06:30:21 -07:00
parent 45665f94a7
commit 7c0ebc5887
1 changed files with 30 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

49
qtrans.c
View File

@@ -53,16 +53,23 @@ STATIC NUMBER *ln_10_epsilon = NULL;
* pivalue[LAST_PI_EPSILON] - last epsilon used to calculate pi
* pivalue[LAST_PI_VALUE] - last calculated pi
* given pivalue[LAST_PI_EPSILON] epsilon
* pivalue[LAST_PI_DIV_180_EPSILON] last epsilon used to calculate pi/180
* pivalue[LAST_PI_DIV_180] - last calculated pi/180 given
* pivalue[LAST_PI_DIV_180_EPSILON] epsilon
* pivalue[LAST_PI_DIV_180_EPSILON] - last epsilon used to calculate pi/180
* pivalue[LAST_PI_DIV_180_VALUE] - last calculated pi/180 given
* pivalue[LAST_PI_DIV_180_EPSILON] epsilon
*/
#define PI_CACHE_LEN (4)
#define LAST_PI_EPSILON (0)
#define LAST_PI_VALUE (1)
#define LAST_PI_DIV_180_EPSILON (2)
#define LAST_PI_DIV_180 (3)
STATIC NUMBER *pivalue[PI_CACHE_LEN];
enum pi_cache {
LAST_PI_EPSILON = 0,
LAST_PI_VALUE,
LAST_PI_DIV_180_EPSILON,
LAST_PI_DIV_180_VALUE,
PI_CACHE_LEN /* must be last */
};
STATIC NUMBER *pivalue[PI_CACHE_LEN] = {
NULL, /* LAST_PI_EPSILON */
NULL, /* LAST_PI_VALUE */
NULL, /* LAST_PI_DIV_180_EPSILON */
NULL, /* LAST_PI_DIV_180_VALUE */
};
/*
* other static function decls
@@ -751,13 +758,15 @@ qpi(NUMBER *epsilon)
}
/* use pi cache if epsilon marches, else flush if needed */
if (epsilon == pivalue[LAST_PI_EPSILON]) {
if (pivalue[LAST_PI_EPSILON] != NULL &&
pivalue[LAST_PI_VALUE] != NULL &&
epsilon == pivalue[LAST_PI_EPSILON]) {
return qlink(pivalue[LAST_PI_VALUE]);
}
if (pivalue[LAST_PI_EPSILON]) {
if (pivalue[LAST_PI_EPSILON] != NULL) {
qfree(pivalue[LAST_PI_EPSILON]);
}
if (pivalue[LAST_PI_VALUE]) {
if (pivalue[LAST_PI_VALUE] != NULL) {
qfree(pivalue[LAST_PI_VALUE]);
}
@@ -817,25 +826,27 @@ qpidiv180(NUMBER *epsilon)
}
/* use pi/180 cache if epsilon marches, else flush if needed */
if (epsilon == pivalue[LAST_PI_DIV_180_EPSILON]) {
return qlink(pivalue[LAST_PI_DIV_180]);
if (pivalue[LAST_PI_DIV_180_EPSILON] != NULL &&
pivalue[LAST_PI_DIV_180_VALUE] != NULL &&
epsilon == pivalue[LAST_PI_DIV_180_EPSILON]) {
return qlink(pivalue[LAST_PI_DIV_180_VALUE]);
}
if (pivalue[LAST_PI_DIV_180_EPSILON]) {
if (pivalue[LAST_PI_DIV_180_EPSILON] != NULL) {
qfree(pivalue[LAST_PI_DIV_180_EPSILON]);
}
if (pivalue[LAST_PI_DIV_180]) {
qfree(pivalue[LAST_PI_DIV_180]);
if (pivalue[LAST_PI_DIV_180_VALUE] != NULL) {
qfree(pivalue[LAST_PI_DIV_180_VALUE]);
}
/* let qpi() returned cached pi or calculate new as needed */
pi = qpi(epsilon);
/* now calculate pi/180 */
/* calculate pi/180 */
pidiv180 = qdivi(pi, 180);
/* cache epsilon and pi/180 */
pivalue[LAST_PI_DIV_180_EPSILON] = qlink(epsilon);
pivalue[LAST_PI_DIV_180] = qlink(pidiv180);
pivalue[LAST_PI_DIV_180_VALUE] = qlink(pidiv180);
/* return pi/180 */
return pidiv180;