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Refactor DiffCleanupMerge to use runes instead of strings #41

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Merged
merged 1 commit into from
Oct 29, 2016
Merged

Refactor DiffCleanupMerge to use runes instead of strings #41

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30 changes: 15 additions & 15 deletions diffmatchpatch/dmp.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1230,44 +1230,44 @@ func (dmp *DiffMatchPatch) DiffCleanupMerge(diffs []Diff) []Diff {
countDelete := 0
countInsert := 0
commonlength := 0
textDelete := ""
textInsert := ""
textDelete := []rune(nil)
textInsert := []rune(nil)

for pointer < len(diffs) {
switch diffs[pointer].Type {
case DiffInsert:
countInsert++
textInsert += diffs[pointer].Text
textInsert = append(textInsert, []rune(diffs[pointer].Text)...)
pointer++
break
case DiffDelete:
countDelete++
textDelete += diffs[pointer].Text
textDelete = append(textDelete, []rune(diffs[pointer].Text)...)
pointer++
break
case DiffEqual:
// Upon reaching an equality, check for prior redundancies.
if countDelete+countInsert > 1 {
if countDelete != 0 && countInsert != 0 {
// Factor out any common prefixies.
commonlength = dmp.DiffCommonPrefix(textInsert, textDelete)
commonlength = commonPrefixLength(textInsert, textDelete)
if commonlength != 0 {
x := pointer - countDelete - countInsert
if x > 0 && diffs[x-1].Type == DiffEqual {
diffs[x-1].Text += textInsert[:commonlength]
diffs[x-1].Text += string(textInsert[:commonlength])
} else {
diffs = append([]Diff{Diff{DiffEqual, textInsert[:commonlength]}}, diffs...)
diffs = append([]Diff{Diff{DiffEqual, string(textInsert[:commonlength])}}, diffs...)
pointer++
}
textInsert = textInsert[commonlength:]
textDelete = textDelete[commonlength:]
}
// Factor out any common suffixies.
commonlength = dmp.DiffCommonSuffix(textInsert, textDelete)
commonlength = commonSuffixLength(textInsert, textDelete)
if commonlength != 0 {
insertIndex := len(textInsert) - commonlength
deleteIndex := len(textDelete) - commonlength
diffs[pointer].Text = textInsert[insertIndex:] + diffs[pointer].Text
diffs[pointer].Text = string(textInsert[insertIndex:]) + diffs[pointer].Text
textInsert = textInsert[:insertIndex]
textDelete = textDelete[:deleteIndex]
}
Expand All @@ -1276,16 +1276,16 @@ func (dmp *DiffMatchPatch) DiffCleanupMerge(diffs []Diff) []Diff {
if countDelete == 0 {
diffs = splice(diffs, pointer-countInsert,
countDelete+countInsert,
Diff{DiffInsert, textInsert})
Diff{DiffInsert, string(textInsert)})
} else if countInsert == 0 {
diffs = splice(diffs, pointer-countDelete,
countDelete+countInsert,
Diff{DiffDelete, textDelete})
Diff{DiffDelete, string(textDelete)})
} else {
diffs = splice(diffs, pointer-countDelete-countInsert,
countDelete+countInsert,
Diff{DiffDelete, textDelete},
Diff{DiffInsert, textInsert})
Diff{DiffDelete, string(textDelete)},
Diff{DiffInsert, string(textInsert)})
}

pointer = pointer - countDelete - countInsert + 1
Expand All @@ -1304,8 +1304,8 @@ func (dmp *DiffMatchPatch) DiffCleanupMerge(diffs []Diff) []Diff {
}
countInsert = 0
countDelete = 0
textDelete = ""
textInsert = ""
textDelete = nil
textInsert = nil
break
}
}
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5 changes: 5 additions & 0 deletions diffmatchpatch/dmp_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -351,6 +351,11 @@ func Test_diffCleanupMerge(t *testing.T) {
diffs = dmp.DiffCleanupMerge(diffs)
assertDiffEqual(t, []Diff{Diff{DiffEqual, "xa"}, Diff{DiffDelete, "d"}, Diff{DiffInsert, "b"}, Diff{DiffEqual, "cy"}}, diffs)

// Same test as above but with unicode (\u0101 will appear in diffs with at least 257 unique lines)
diffs = []Diff{Diff{DiffEqual, "x"}, Diff{DiffDelete, "\u0101"}, Diff{DiffInsert, "\u0101bc"}, Diff{DiffDelete, "dc"}, Diff{DiffEqual, "y"}}
diffs = dmp.DiffCleanupMerge(diffs)
assertDiffEqual(t, []Diff{Diff{DiffEqual, "x\u0101"}, Diff{DiffDelete, "d"}, Diff{DiffInsert, "b"}, Diff{DiffEqual, "cy"}}, diffs)

// Slide edit left.
diffs = []Diff{Diff{DiffEqual, "a"}, Diff{DiffInsert, "ba"}, Diff{DiffEqual, "c"}}
diffs = dmp.DiffCleanupMerge(diffs)
Expand Down