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-rw-r--r--compiler/byte.go281
1 files changed, 281 insertions, 0 deletions
diff --git a/compiler/byte.go b/compiler/byte.go
new file mode 100644
index 0000000..464887e
--- /dev/null
+++ b/compiler/byte.go
@@ -0,0 +1,281 @@
+package compiler
+
+import "fmt"
+
+type byteRange struct {
+ from byte
+ to byte
+}
+
+func newByteRange(from, to byte) byteRange {
+ return byteRange{
+ from: from,
+ to: to,
+ }
+}
+
+func (r byteRange) String() string {
+ return fmt.Sprintf("%X-%X (%v-%v)", r.from, r.to, r.from, r.to)
+}
+
+func newByteRangeSequence(from, to []byte) ([]byteRange, error) {
+ if len(from) != len(to) {
+ return nil, fmt.Errorf("length of `from` and `to` are mismatched; from: %+v, to: %+v", from, to)
+ }
+ seq := []byteRange{}
+ for i := 0; i < len(from); i++ {
+ seq = append(seq, newByteRange(from[i], to[i]))
+ }
+ return seq, nil
+}
+
+func excludeByteRangeSequence(b1, b2 []byteRange) [][]byteRange {
+ if len(b1) != len(b2) {
+ // no overlapping
+ return [][]byteRange{b2}
+ }
+ switch len(b1) {
+ case 1:
+ return exclude1Byte(b1, b2)
+ case 2:
+ return exclude2Byte(b1, b2)
+ case 3:
+ return exclude3Byte(b1, b2)
+ case 4:
+ return exclude4Byte(b1, b2)
+ }
+ panic(fmt.Errorf("excludeByteRangeSequence can only handle sequences up to 4 bytes in size; b1: %+v, b2: %+v", b1, b2))
+}
+
+func exclude1Byte(b1, b2 []byteRange) [][]byteRange {
+ r01, r02, overlapping0 := excludeByteRange(&b1[0], &b2[0])
+ if !overlapping0 {
+ // no overlapping
+ return [][]byteRange{b2}
+ }
+ result := [][]byteRange{}
+ {
+ if r01 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r01.from, r01.to),
+ })
+ }
+ if r02 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r02.from, r02.to),
+ })
+ }
+ }
+ return result
+}
+
+func exclude2Byte(b1, b2 []byteRange) [][]byteRange {
+ r01, r02, overlapping0 := excludeByteRange(&b1[0], &b2[0])
+ r11, r12, overlapping1 := excludeByteRange(&b1[1], &b2[1])
+ if !overlapping0 || !overlapping1 {
+ // no overlapping
+ return [][]byteRange{b2}
+ }
+ result := [][]byteRange{}
+ {
+ if r11 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(r11.from, r11.to),
+ })
+ }
+ if r12 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(r12.from, r12.to),
+ })
+ }
+ if r01 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r01.from, r01.to),
+ newByteRange(b2[1].from, b2[1].to),
+ })
+ }
+ if r02 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r02.from, r02.to),
+ newByteRange(b2[1].from, b2[1].to),
+ })
+ }
+ }
+ return result
+}
+
+func exclude3Byte(b1, b2 []byteRange) [][]byteRange {
+ r01, r02, overlapping0 := excludeByteRange(&b1[0], &b2[0])
+ r11, r12, overlapping1 := excludeByteRange(&b1[1], &b2[1])
+ r21, r22, overlapping2 := excludeByteRange(&b1[2], &b2[2])
+ if !overlapping0 || !overlapping1 || !overlapping2 {
+ // no overlapping
+ return [][]byteRange{b2}
+ }
+ result := [][]byteRange{}
+ {
+ if r21 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(b1[1].from, b1[1].to),
+ newByteRange(r21.from, r21.to),
+ })
+ }
+ if r22 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(b1[1].from, b1[1].to),
+ newByteRange(r22.from, r22.to),
+ })
+ }
+ if r11 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(r11.from, r11.to),
+ newByteRange(b2[2].from, b2[2].to),
+ })
+ }
+ if r12 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(r12.from, r12.to),
+ newByteRange(b2[2].from, b2[2].to),
+ })
+ }
+ if r01 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r01.from, r01.to),
+ newByteRange(b2[1].from, b2[1].to),
+ newByteRange(b2[2].from, b2[2].to),
+ })
+ }
+ if r02 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r02.from, r02.to),
+ newByteRange(b2[1].from, b2[1].to),
+ newByteRange(b2[2].from, b2[2].to),
+ })
+ }
+ }
+ return result
+}
+
+func exclude4Byte(b1, b2 []byteRange) [][]byteRange {
+ r01, r02, overlapping0 := excludeByteRange(&b1[0], &b2[0])
+ r11, r12, overlapping1 := excludeByteRange(&b1[1], &b2[1])
+ r21, r22, overlapping2 := excludeByteRange(&b1[2], &b2[2])
+ r31, r32, overlapping3 := excludeByteRange(&b1[3], &b2[3])
+ if !overlapping0 || !overlapping1 || !overlapping2 || !overlapping3 {
+ // no overlapping
+ return [][]byteRange{b2}
+ }
+ result := [][]byteRange{}
+ {
+ if r31 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(b1[1].from, b1[1].to),
+ newByteRange(b1[2].from, b1[2].to),
+ newByteRange(r31.from, r31.to),
+ })
+ }
+ if r32 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(b1[1].from, b1[1].to),
+ newByteRange(b1[2].from, b1[2].to),
+ newByteRange(r32.from, r32.to),
+ })
+ }
+ if r21 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(b1[1].from, b1[1].to),
+ newByteRange(r21.from, r21.to),
+ newByteRange(b2[3].from, b2[3].to),
+ })
+ }
+ if r22 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(b1[1].from, b1[1].to),
+ newByteRange(r22.from, r22.to),
+ newByteRange(b2[3].from, b2[3].to),
+ })
+ }
+ if r11 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(r11.from, r11.to),
+ newByteRange(b2[2].from, b2[2].to),
+ newByteRange(b2[3].from, b2[3].to),
+ })
+ }
+ if r12 != nil {
+ result = append(result, []byteRange{
+ newByteRange(b1[0].from, b1[0].to),
+ newByteRange(r12.from, r12.to),
+ newByteRange(b2[2].from, b2[2].to),
+ newByteRange(b2[3].from, b2[3].to),
+ })
+ }
+ if r01 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r01.from, r01.to),
+ newByteRange(b2[1].from, b2[1].to),
+ newByteRange(b2[2].from, b2[2].to),
+ newByteRange(b2[3].from, b2[3].to),
+ })
+ }
+ if r02 != nil {
+ result = append(result, []byteRange{
+ newByteRange(r02.from, r02.to),
+ newByteRange(b2[1].from, b2[1].to),
+ newByteRange(b2[2].from, b2[2].to),
+ newByteRange(b2[3].from, b2[3].to),
+ })
+ }
+ }
+ return result
+}
+
+// excludeByteRange excludes `r1` from `r2`.
+func excludeByteRange(r1, r2 *byteRange) (*byteRange, *byteRange, bool) {
+ if r1.from <= r2.from {
+ if r1.to < r2.from {
+ // no overlapping
+ return nil, nil, false
+ }
+ if r1.to < r2.to {
+ // The beginning of `r2` overlaps with `r1`.
+ return &byteRange{
+ from: r1.to + 1,
+ to: r2.to,
+ }, nil, true
+ }
+ // `symbol` overlaps with `base` entirely.
+ return nil, nil, true
+ }
+ if r1.from > r2.to {
+ // no overlapping
+ return nil, nil, false
+ }
+ if r1.to >= r2.to {
+ // The end of `r2` overlaps with `r1`.
+ return &byteRange{
+ from: r2.from,
+ to: r1.from - 1,
+ }, nil, true
+ }
+ // `r2` overlaps with `r1` entirely.
+ return &byteRange{
+ from: r2.from,
+ to: r1.from - 1,
+ },
+ &byteRange{
+ from: r1.to + 1,
+ to: r2.to,
+ }, true
+}
generated by cgit v1.2.3 (git 2.49.0) at 2025-07-13 00:38:50 +0000