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package main
import "reflect"
type Recipe []Chunk
type RecipeDel int
type RecipeIns struct {
Idx int
Value []Chunk
}
type RecipePatch struct {
Del []RecipeDel
Ins []RecipeIns
}
func patchRecipe(source Recipe, patch RecipePatch) (target Recipe) {
// apply Del part from patch to source into temp
size := len(source) - len(patch.Del)
temp := make(Recipe, size)
fill := 0
prev := 0
for _, del := range patch.Del {
di := int(del)
copy(temp[fill:], source[prev:di])
fill += di - prev
prev = di + 1
}
copy(temp[fill:], source[prev:])
// apply Ins part from patch to temp into target
for _, ins := range patch.Ins {
size += len(ins.Value)
}
target = make(Recipe, size)
fill = 0
prev = 0
tpos := 0
for _, ins := range patch.Ins {
offset := ins.Idx - prev
copy(target[fill:], temp[tpos:tpos+offset])
fill += offset
tpos += offset
copy(target[fill:], ins.Value)
fill += len(ins.Value)
prev = ins.Idx + len(ins.Value)
}
return
}
func diffRecipe(source Recipe, target Recipe) (patch RecipePatch) {
var si, ti int
var found bool
for ; si < len(source); si++ {
for i := ti; i < len(target); i++ {
found = reflect.DeepEqual(target[i], source[si])
if found {
if i != ti {
patch.Ins = append(patch.Ins, RecipeIns{ti, target[ti:i]})
}
ti = i + 1
break
}
}
if !found {
patch.Del = append(patch.Del, RecipeDel(si))
}
}
if ti < len(target) {
patch.Ins = append(patch.Ins, RecipeIns{ti, target[ti:]})
}
return
}
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