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bitMuncher: add EnusreBits method

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This commit is contained in:
gucio321 2021-05-16 12:27:05 +02:00
parent 3260022ffb
commit e685b927a1
5 changed files with 39 additions and 18 deletions
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8
d2common/d2data/d2compression/huffman.go
View File

@ -210,12 +210,10 @@ func decode(input *d2datautils.BitMuncher, head *linkedNode) *linkedNode {
node := head
for node.child0 != nil {
// checks if GetBit causes panic (End of file)
defer func() {
if r := recover(); r != nil {
log.Fatal("HuffmanDecompress: Unexpected end of file")
if !input.EnsureBits(1) {
log.Fatal("Unexpected end of file")
}
}()
bit := input.GetBit()
if bit == 0 {
node = node.child0

11
d2common/d2datautils/bitmuncher.go
View File

@ -136,3 +136,14 @@ func (v *BitMuncher) MakeSigned(value uint32, bits int) int32 {
// Force casting to a signed value
return int32(result)
}
// EnsureBits checks, if `count` bits is available
func (v *BitMuncher) EnsureBits(count int) bool {
bytesRead := v.offset / byteLen
bitOffset := v.offset % byteLen
numBytes := len(v.data)
remainingBytes := numBytes - bytesRead
remainingBits := remainingBytes*byteLen - bitOffset
return count <= remainingBits
}

22
d2common/d2datautils/bitmuncher_test.go
View File

@ -36,7 +36,7 @@ func TestBitmuncherReadBit(t *testing.T) {
var result byte
for i := 0; i < bitsPerByte; i++ {
for i := 0; i < byteLen; i++ {
v := bm.GetBit()
result |= byte(v) << byte(i)
}
@ -47,7 +47,7 @@ func TestBitmuncherReadBit(t *testing.T) {
func TestBitmuncherGetBits(t *testing.T) {
bm := CreateBitMuncher(testData, 0)
assert.Equal(t, byte(bm.GetBits(bitsPerByte)), testData[0], "get bits didn't return expected value")
assert.Equal(t, byte(bm.GetBits(byteLen)), testData[0], "get bits didn't return expected value")
}
func TestBitmuncherGetNoBits(t *testing.T) {
@ -77,7 +77,7 @@ func TestBitmuncherGetOneSignedBit(t *testing.T) {
func TestBitmuncherSkipBits(t *testing.T) {
bm := CreateBitMuncher(testData, 0)
bm.SkipBits(bitsPerByte)
bm.SkipBits(byteLen)
assert.Equal(t, bm.GetByte(), testData[1], "skipping 8 bits didn't moved bit muncher's position into next byte")
}
@ -88,7 +88,7 @@ func TestBitmuncherGetInt32(t *testing.T) {
var testInt int32
for i := 0; i < bytesPerint32; i++ {
testInt |= int32(testData[i]) << int32(bitsPerByte*i)
testInt |= int32(testData[i]) << int32(byteLen*i)
}
assert.Equal(t, bm.GetInt32(), testInt, "int32 value wasn't returned properly")
@ -100,8 +100,20 @@ func TestBitmuncherGetUint32(t *testing.T) {
var testUint uint32
for i := 0; i < bytesPerint32; i++ {
testUint |= uint32(testData[i]) << uint32(bitsPerByte*i)
testUint |= uint32(testData[i]) << uint32(byteLen*i)
}
assert.Equal(t, bm.GetUInt32(), testUint, "uint32 value wasn't returned properly")
}
func TestBitMuncherEnsureBits(t *testing.T) {
bm := CreateBitMuncher(testData, 0)
assert.Equal(t, true, bm.EnsureBits(byteLen*len(testData)), "unexpected value returned by EnsureBits")
assert.Equal(t, false, bm.EnsureBits(byteLen*len(testData)+1), "unexpected value returned by EnsureBits")
bm.SkipBits(5)
assert.Equal(t, true, bm.EnsureBits(byteLen*len(testData)-5), "unexpected value returned by EnsureBits")
assert.Equal(t, false, bm.EnsureBits(byteLen*len(testData)-4), "unexpected value returned by EnsureBits")
}

8
d2common/d2datautils/stream_writer.go
View File

@ -42,7 +42,7 @@ func (v *StreamWriter) PushBit(b bool) {
}
v.bitOffset++
if v.bitOffset != bitsPerByte {
if v.bitOffset != byteLen {
return
}
@ -53,7 +53,7 @@ func (v *StreamWriter) PushBit(b bool) {
// PushBits pushes bits (with max range 8)
func (v *StreamWriter) PushBits(b byte, bits int) {
if bits > bitsPerByte {
if bits > byteLen {
log.Print("input bits number must be less (or equal) than 8")
}
@ -67,7 +67,7 @@ func (v *StreamWriter) PushBits(b byte, bits int) {
// PushBits16 pushes bits (with max range 16)
func (v *StreamWriter) PushBits16(b uint16, bits int) {
if bits > bitsPerByte*bytesPerint16 {
if bits > byteLen*bytesPerint16 {
log.Print("input bits number must be less (or equal) than 16")
}
@ -81,7 +81,7 @@ func (v *StreamWriter) PushBits16(b uint16, bits int) {
// PushBits32 pushes bits (with max range 32)
func (v *StreamWriter) PushBits32(b uint32, bits int) {
if bits > bitsPerByte*bytesPerint32 {
if bits > byteLen*bytesPerint32 {
log.Print("input bits number must be less (or equal) than 32")
}

6
d2common/d2datautils/stream_writer_test.go
View File

@ -9,7 +9,7 @@ func TestStreamWriterBits(t *testing.T) {
data := []byte{221, 19}
for _, i := range data {
sr.PushBits(i, bitsPerByte)
sr.PushBits(i, byteLen)
}
output := sr.GetBytes()
@ -25,7 +25,7 @@ func TestStreamWriterBits16(t *testing.T) {
data := []uint16{1024, 19}
for _, i := range data {
sr.PushBits16(i, bitsPerByte*bytesPerint16)
sr.PushBits16(i, byteLen*bytesPerint16)
}
output := sr.GetBytes()
@ -45,7 +45,7 @@ func TestStreamWriterBits32(t *testing.T) {
data := []uint32{19324, 87}
for _, i := range data {
sr.PushBits32(i, bitsPerByte*bytesPerint32)
sr.PushBits32(i, byteLen*bytesPerint32)
}
output := sr.GetBytes()