33 lines
905 B
Go
33 lines
905 B
Go
|
// Copyright 2012 The Go Authors. All rights reserved.
|
||
|
// Use of this source code is governed by a BSD-style
|
||
|
// license that can be found in the LICENSE file.
|
||
|
|
||
|
package flate
|
||
|
|
||
|
// forwardCopy is like the built-in copy function except that it always goes
|
||
|
// forward from the start, even if the dst and src overlap.
|
||
|
// It is equivalent to:
|
||
|
// for i := 0; i < n; i++ {
|
||
|
// mem[dst+i] = mem[src+i]
|
||
|
// }
|
||
|
func forwardCopy(mem []byte, dst, src, n int) {
|
||
|
if dst <= src {
|
||
|
copy(mem[dst:dst+n], mem[src:src+n])
|
||
|
return
|
||
|
}
|
||
|
for {
|
||
|
if dst >= src+n {
|
||
|
copy(mem[dst:dst+n], mem[src:src+n])
|
||
|
return
|
||
|
}
|
||
|
// There is some forward overlap. The destination
|
||
|
// will be filled with a repeated pattern of mem[src:src+k].
|
||
|
// We copy one instance of the pattern here, then repeat.
|
||
|
// Each time around this loop k will double.
|
||
|
k := dst - src
|
||
|
copy(mem[dst:dst+k], mem[src:src+k])
|
||
|
n -= k
|
||
|
dst += k
|
||
|
}
|
||
|
}
|