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package xdelta
import (
"io"
"fmt"
"math/rand"
)
const (
blocksize = 1<<17
)
func (t *TestGroup) WriteRstreams(desc string, seed, offset, len int64,
src, tgt io.WriteCloser) {
t.Go("src-write:"+desc, func (g *Goroutine) {
writeOne(g, seed, 0, len, src, false)
})
t.Go("tgt-write:"+desc, func (g *Goroutine) {
writeOne(g, seed, offset, len, tgt, true)
})
}
func writeOne(g *Goroutine, seed, offset, len int64, stream io.WriteCloser, readall bool) {
if !readall {
// Allow the source-read to fail or block until the process terminates.
// This behavior is reserved for the decoder, which is not required to
// read the entire source.
g.OK()
}
if offset != 0 {
// Fill with other random data until the offset
fmt.Println(g, "pre-offset case", offset)
if err := writeRand(g, rand.New(rand.NewSource(^seed)), offset, stream); err != nil {
g.Panic(err)
}
}
fmt.Println(g, "offset case", len - offset)
if err := writeRand(g, rand.New(rand.NewSource(seed)),
len - offset, stream); err != nil {
g.Panic(err)
}
if err := stream.Close(); err != nil {
g.Panic(err)
}
g.OK()
}
func writeRand(g *Goroutine, r *rand.Rand, len int64, s io.Writer) error {
blk := make([]byte, blocksize)
for len > 0 {
fillRand(r, blk)
c := blocksize
if len < blocksize {
c = int(len)
}
if _, err := s.Write(blk[0:c]); err != nil {
return err
}
len -= int64(c)
}
return nil
}
func fillRand(r *rand.Rand, blk []byte) {
for p := 0; p < len(blk); {
v := r.Int63()
for i := 7; i != 0 && p < len(blk); i-- {
blk[p] = byte(v)
p++
v >>= 8
}
}
}
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