ref: e7846afe1d81e280898bb40b0966ec0a24b321b7
parent: 443ab2b67e807ff1c4f864feb80229ecd7813fe5
author: qwx <qwx@sciops.net>
date: Wed Nov 30 02:19:06 EST 2022
drawsamp: don't memcpy everything, just fetch chunk slices as intended
--- a/cmd.c
+++ b/cmd.c
@@ -256,6 +256,32 @@
}
uchar *
+getslice(Dot *d, usize n, usize *sz)
+{+ usize Δbuf, Δloop, off;
+ Chunk *c;
+
+ if(d->pos >= totalsz){+ *sz = 0;
+ return nil;
+ }
+ c = p2c(d->pos, &off);
+ Δloop = d->to.pos - d->pos;
+ Δbuf = c->bufsz - off;
+ if(n < Δloop && n < Δbuf){+ *sz = n;
+ d->pos += n;
+ }else if(Δloop <= Δbuf){+ *sz = Δloop;
+ d->pos = d->from.pos;
+ }else{+ *sz = Δbuf;
+ d->pos += Δbuf;
+ }
+ return c->buf + off;
+}
+
+uchar *
getbuf(Dot d, usize n, uchar *scratch, usize *boff)
{uchar *bp, *p;
--- a/draw.c
+++ b/draw.c
@@ -23,8 +23,6 @@
static int bgscalyl, bgscalyr, bgscalf;
static Channel *drawc;
static usize T;
-static uchar *sbuf;
-static usize sbufsz;
static int sampwidth = 1;
static double zoom = 1.0;
@@ -67,7 +65,7 @@
drawsamps(void*)
{int x, lmin, lmax, rmin, rmax;
- usize n, m;
+ usize n, m, k;
s16int s;
uchar *p, *e;
Rectangle l, r;
@@ -77,50 +75,49 @@
end:
recvul(drawc);
again:
- if(sbufsz < T * sampwidth){- sbuf = erealloc(sbuf, T * sampwidth, sbufsz);
- sbufsz = T * sampwidth;
- }
lockdisplay(display);
draw(viewbg, viewbg->r, col[Cbg], nil, ZP);
unlockdisplay(display);
+ d.from.pos = 0;
d.pos = views;
+ d.to.pos = totalsz;
m = viewe - views;
x = 0;
+ qlock(&lsync);
while(m > 0){- qlock(&lsync);
if(nbrecvul(drawc) == 1){qunlock(&lsync);
goto again;
}
n = m < T * sampwidth ? m : T * sampwidth;
- p = getbuf(d, n, sbuf, &n);
- qunlock(&lsync);
- if(p == nil){- if(n > 0)
- fprint(2, "getbuf: %r\n");
- goto end;
- }
- d.pos += n;
- e = p + n;
lmin = lmax = 0;
rmin = rmax = 0;
- while(p < e){- s = (s16int)(p[1] << 8 | p[0]);
- if(s < lmin)
- lmin = s;
- else if(s > lmax)
- lmax = s;
- if(stereo){- s = (s16int)(p[3] << 8 | p[2]);
- if(s < rmin)
- rmin = s;
- else if(s > rmax)
- rmax = s;
+ while(n > 0){+ p = getslice(&d, n, &k);
+ if(p == nil){+ if(k > 0)
+ fprint(2, "getslice: %r\n");
+ goto end;
}
- p += 4 * sampwidth;
+ e = p + k;
+ while(p < e){+ s = (s16int)(p[1] << 8 | p[0]);
+ if(s < lmin)
+ lmin = s;
+ else if(s > lmax)
+ lmax = s;
+ if(stereo){+ s = (s16int)(p[3] << 8 | p[2]);
+ if(s < rmin)
+ rmin = s;
+ else if(s > rmax)
+ rmax = s;
+ }
+ p += 4 * sampwidth;
+ }
+ n -= k;
+ m -= k;
}
- m -= n;
l = Rect(x, bgscalyl - lmax / bgscalf,
x+sampwidth, bgscalyl - lmin / bgscalf);
r = Rect(x, bgscalyr - rmax / bgscalf,
@@ -132,6 +129,7 @@
unlockdisplay(display);
x = (d.pos - views) / T;
}
+ qunlock(&lsync);
}
}
--- a/fns.h
+++ b/fns.h
@@ -14,6 +14,7 @@
Chunk* p2c(usize, usize*);
void setrange(usize, usize);
int setpos(usize);
+uchar* getslice(Dot*, usize, usize*);
uchar* getbuf(Dot, usize, uchar*, usize*);
int loadin(int);
void* emalloc(usize);