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// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
package images
import (
"fmt"
"runtime"
"sync"
"sync/atomic"
)
var _ = fmt.Print
type Context struct {
num_of_threads atomic.Int32
}
func (self *Context) SetNumberOfThreads(n int) {
self.num_of_threads.Store(int32(n))
}
func (self *Context) NumberOfThreads() int {
return int(self.num_of_threads.Load())
}
// parallel processes the data in separate goroutines.
func (self *Context) Parallel(start, stop int, fn func(<-chan int)) {
count := stop - start
if count < 1 {
return
}
procs := self.NumberOfThreads()
if procs <= 0 {
procs = runtime.NumCPU()
}
if procs > count {
procs = count
}
c := make(chan int, count)
for i := start; i < stop; i++ {
c <- i
}
close(c)
var wg sync.WaitGroup
for i := 0; i < procs; i++ {
wg.Add(1)
go func() {
defer wg.Done()
fn(c)
}()
}
wg.Wait()
}
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