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drw: minor improvement to the nomatches cache

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1. use `unsigned int` to store the codepoints, this avoids waste on
   common case where `long` is 64bits. and POSIX guarantees `int` to be
   at least 32bits so there's no risk of truncation.
2. since switching to `unsigned int` cuts down the memory requirement by
   half, double the cache size from 64 to 128.
3. instead of a linear search, use a simple hash-table for O(1) lookups.
This commit is contained in:
NRK 2023-07-07 17:00:42 +06:00 committed by Hiltjo Posthuma
parent 0fe460dbd4
commit 7ab0cb5ef0
3 changed files with 13 additions and 12 deletions
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1
dmenu.c
View file

@ -22,7 +22,6 @@
/* macros */
#define INTERSECT(x,y,w,h,r) (MAX(0, MIN((x)+(w),(r).x_org+(r).width) - MAX((x),(r).x_org)) \
* MAX(0, MIN((y)+(h),(r).y_org+(r).height) - MAX((y),(r).y_org)))
#define LENGTH(X) (sizeof X / sizeof X[0])
#define TEXTW(X) (drw_fontset_getwidth(drw, (X)) + lrpad)
/* enums */

23
drw.c
View file

@ -238,8 +238,8 @@ drw_rect(Drw *drw, int x, int y, unsigned int w, unsigned int h, int filled, int
int
drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lpad, const char *text, int invert)
{
int i, ty, ellipsis_x = 0;
unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len;
int ty, ellipsis_x = 0;
unsigned int tmpw, ew, ellipsis_w = 0, ellipsis_len, hash, h0, h1;
XftDraw *d = NULL;
Fnt *usedfont, *curfont, *nextfont;
int utf8strlen, utf8charlen, render = x || y || w || h;
@ -251,9 +251,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
XftResult result;
int charexists = 0, overflow = 0;
/* keep track of a couple codepoints for which we have no match. */
enum { nomatches_len = 64 };
static struct { long codepoint[nomatches_len]; unsigned int idx; } nomatches;
static unsigned int ellipsis_width = 0;
static unsigned int nomatches[128], ellipsis_width;
if (!drw || (render && (!drw->scheme || !w)) || !text || !drw->fonts)
return 0;
@ -338,11 +336,14 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
* character must be drawn. */
charexists = 1;
for (i = 0; i < nomatches_len; ++i) {
/* avoid calling XftFontMatch if we know we won't find a match */
if (utf8codepoint == nomatches.codepoint[i])
goto no_match;
}
hash = (unsigned int)utf8codepoint;
hash = ((hash >> 16) ^ hash) * 0x21F0AAAD;
hash = ((hash >> 15) ^ hash) * 0xD35A2D97;
h0 = ((hash >> 15) ^ hash) % LENGTH(nomatches);
h1 = (hash >> 17) % LENGTH(nomatches);
/* avoid expensive XftFontMatch call when we know we won't find a match */
if (nomatches[h0] == utf8codepoint || nomatches[h1] == utf8codepoint)
goto no_match;
fccharset = FcCharSetCreate();
FcCharSetAddChar(fccharset, utf8codepoint);
@ -371,7 +372,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
curfont->next = usedfont;
} else {
xfont_free(usedfont);
nomatches.codepoint[++nomatches.idx % nomatches_len] = utf8codepoint;
nomatches[nomatches[h0] ? h1 : h0] = utf8codepoint;
no_match:
usedfont = drw->fonts;
}

1
util.h
View file

@ -3,6 +3,7 @@
#define MAX(A, B) ((A) > (B) ? (A) : (B))
#define MIN(A, B) ((A) < (B) ? (A) : (B))
#define BETWEEN(X, A, B) ((A) <= (X) && (X) <= (B))
#define LENGTH(X) (sizeof (X) / sizeof (X)[0])
void die(const char *fmt, ...);
void *ecalloc(size_t nmemb, size_t size);