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Copy pathbitwriter_test.go
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bitwriter_test.go
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package nativewebp
import (
//------------------------------
//general
//------------------------------
"bytes"
//------------------------------
//testing
//------------------------------
"testing"
)
func TestWriteBits(t *testing.T) {
for id, tt := range []struct {
initialBuffer []byte
initialBitBuf uint64
initialBufSize int
value uint64
bitCount int
expectedBuffer []byte
expectedBitBuf uint64
expectedBufSize int
expectPanic bool
}{
// Valid cases
{nil, 0, 0, 0b1, 1, nil, 0b1, 1, false}, // Write 1 bit
{nil, 0, 0, 0b11010101, 8, []byte{0b11010101}, 0, 0, false}, // Write 8 bits, flush to buffer
{nil, 0, 0, 0xFFFF, 16, []byte{0xFF, 0xFF}, 0, 0, false}, // Write 16 bits, flush to buffer
{nil, 0, 0, 0b101, 3, nil, 0b101, 3, false}, // Write 3 bits
{nil, 0b1, 1, 0b10, 2, nil, 0b101, 3, false}, // Append 2 bits
{nil, 0b101, 3, 0b1111, 4, nil, 0b1111101, 7, false}, // Append 4 bits
{[]byte{0xFF}, 0, 0, 0b101, 3, []byte{0xFF}, 0b101, 3, false}, // Preserve buffer
// Multiple writes, testing flush
{nil, 0, 0, 0b1101, 4, nil, 0b1101, 4, false}, // First write
{[]byte{}, 0b1101, 4, 0b1111, 4, []byte{0xFD}, 0, 0, false}, // Flush to buffer (8 bits)
{[]byte{0xAB}, 0, 0, 0b1010101010101010, 16, []byte{0xAB, 0xAA, 0xAA}, 0, 0, false}, // Write 16 bits after flush
// Invalid cases (expect panic)
{nil, 0, 0, 0b101, 0, nil, 0, 0, true}, // Bit count is 0
{nil, 0, 0, 0b101, 65, nil, 0, 0, true}, // Bit count exceeds 64
{nil, 0, 0, 0b101, -1, nil, 0, 0, true}, // Bit count exceeds 64
{nil, 0, 0, 0b101, 2, nil, 0, 0, true}, // Value too large for bit count
} {
// Use defer to catch panics
func() {
defer func() {
if r := recover(); r != nil {
if !tt.expectPanic {
t.Errorf("test %v: unexpected panic: %v", id, r)
}
} else if tt.expectPanic {
t.Errorf("test %v: expected panic but did not occur", id)
}
}()
buffer := &bytes.Buffer{}
buffer.Write(tt.initialBuffer)
writer := bitWriter{
Buffer: buffer,
BitBuffer: tt.initialBitBuf,
BitBufferSize: tt.initialBufSize,
}
writer.writeBits(tt.value, tt.bitCount)
// Validate state
if !tt.expectPanic {
if !bytes.Equal(writer.Buffer.Bytes(), tt.expectedBuffer) {
t.Errorf("test %v: buffer mismatch: expected %v, got %v", id, tt.expectedBuffer, writer.Buffer.Bytes())
}
if writer.BitBuffer != tt.expectedBitBuf {
t.Errorf("test %v: bit buffer mismatch: expected %v, got %v", id, tt.expectedBitBuf, writer.BitBuffer)
}
if writer.BitBufferSize != tt.expectedBufSize {
t.Errorf("test %v: bit buffer size mismatch: expected %v, got %v", id, tt.expectedBufSize, writer.BitBufferSize)
}
}
}()
}
}
func TestwriteCode(t *testing.T) {
for id, tt := range []struct {
initialBuffer []byte
initialBitBuf uint64
initialBufSize int
code huffmanCode
expectedBuffer []byte
expectedBitBuf uint64
expectedBufSize int
}{
{nil, 0, 0, huffmanCode{Bits: 0b101, Depth: 3}, nil, 0b101, 3}, // Basic 3-bit code
{nil, 0, 0, huffmanCode{Bits: 0b10, Depth: 2}, nil, 0b01, 2}, // 2-bit code, reversed
{nil, 0, 0, huffmanCode{Bits: 0b1011, Depth: 4}, nil, 0b1101, 4}, // 4-bit code, reversed
{nil, 0b1, 1, huffmanCode{Bits: 0b10, Depth: 2}, nil, 0b011, 3}, // Append 2 bits to existing buffer
{nil, 0, 0, huffmanCode{Bits: 0, Depth: 0}, nil, 0, 0}, // Zero-Depth: code, no operation
{nil, 0b10101010, 8, huffmanCode{Bits: 0b1111, Depth: 4}, []byte{0b10101010}, 0b1111, 4}, // Flush full byte, 4 bits remaining
{nil, 0, 0, huffmanCode{Bits: 0b10011, Depth: 5}, nil, 0b11001, 5}, // 5-bit code, reversed
{nil, 0, 0, huffmanCode{Bits: 0b1, Depth: -1}, nil, 0, 0}, // Negative Depth:, no operation
} {
buffer := &bytes.Buffer{}
buffer.Write(tt.initialBuffer)
writer := bitWriter{
Buffer: buffer,
BitBuffer: tt.initialBitBuf,
BitBufferSize: tt.initialBufSize,
}
func() {
defer func() {
if r := recover(); r != nil {
t.Errorf("test %v: unexpected panic: %v", id, r)
}
}()
writer.writeCode(tt.code)
}()
if !bytes.Equal(writer.Buffer.Bytes(), tt.expectedBuffer) {
t.Errorf("test %v: buffer mismatch: expected %v, got %v", id, tt.expectedBuffer, writer.Buffer.Bytes())
}
if writer.BitBuffer != tt.expectedBitBuf {
t.Errorf("test %v: bit buffer mismatch: expected %064b, got %064b", id, tt.expectedBitBuf, writer.BitBuffer)
}
if writer.BitBufferSize != tt.expectedBufSize {
t.Errorf("test %v: bit buffer size mismatch: expected %v, got %v", id, tt.expectedBufSize, writer.BitBufferSize)
}
}
}
func TestWriteThrough(t *testing.T) {
for id, tt := range []struct {
initialBuffer []byte
initialBitBuf uint64
initialBufSize int
expectedBuffer []byte
expectedBitBuf uint64
expectedBufSize int
}{
{nil, 0b11010101, 8, []byte{0b11010101}, 0, 0}, // Exactly 8 bits
{nil, 0b1111111111111111, 16, []byte{0xFF, 0xFF}, 0, 0}, // Multiple of 8 bits
{nil, 0b1010101010101010, 12, []byte{0b10101010}, 0b10101010, 4}, // More than 8 bits, remainder in buffer
{nil, 0b11110000, 4, nil, 0b11110000, 4}, // Less than 8 bits, nothing flushed
{[]byte{0xAB}, 0b11010101, 8, []byte{0xAB, 0xD5}, 0, 0}, // Preserves existing buffer contents
{[]byte{0xAB}, 0b1010101010101010, 12, []byte{0xAB, 0xAA}, 0b10101010, 4}, // Mixed existing buffer and partial flush
} {
buffer := &bytes.Buffer{}
buffer.Write(tt.initialBuffer)
writer := bitWriter{
Buffer: buffer,
BitBuffer: tt.initialBitBuf,
BitBufferSize: tt.initialBufSize,
}
writer.writeThrough()
if !bytes.Equal(writer.Buffer.Bytes(), tt.expectedBuffer) {
t.Errorf("test %v: buffer mismatch: expected %v, got %v", id, tt.expectedBuffer, writer.Buffer.Bytes())
}
if writer.BitBuffer != tt.expectedBitBuf {
t.Errorf("test %v: bit buffer mismatch: expected %064b, got %064b", id, tt.expectedBitBuf, writer.BitBuffer)
}
if writer.BitBufferSize != tt.expectedBufSize {
t.Errorf("test %v: bit buffer size mismatch: expected %v, got %v", id, tt.expectedBufSize, writer.BitBufferSize)
}
}
}
func TestAlignByte(t *testing.T) {
for id, tt := range []struct {
initialBuffer []byte
initialBitBuf uint64
initialBufSize int
expectedBuffer []byte
expectedBitBuf uint64
expectedBufSize int
}{
{nil, 0b1101, 4, []byte{0x0D}, 0, 0}, // Align 4 bits, no padding
{nil, 0b10101010, 8, []byte{0b10101010}, 0, 0}, // Already aligned
{nil, 0b1010101010101010, 12, []byte{0xAA, 0xAA}, 0, 0}, // Align 12 bits
{[]byte{0xAB}, 0b1111, 4, []byte{0xAB, 0x0F}, 0, 0}, // Existing buffer, no padding
{[]byte{0xAB}, 0b1010101010101010, 10, []byte{0xAB, 0xAA, 0xAA}, 0, 0}, // Align 10 bits
{nil, 0, 0, nil, 0, 0}, // Empty buffer
} {
buffer := &bytes.Buffer{}
buffer.Write(tt.initialBuffer)
writer := bitWriter{
Buffer: buffer,
BitBuffer: tt.initialBitBuf,
BitBufferSize: tt.initialBufSize,
}
writer.AlignByte()
if !bytes.Equal(writer.Buffer.Bytes(), tt.expectedBuffer) {
t.Errorf("test %v: buffer mismatch: expected %v, got %v", id, tt.expectedBuffer, writer.Buffer.Bytes())
}
if writer.BitBuffer != tt.expectedBitBuf {
t.Errorf("test %v: bit buffer mismatch: expected %064b, got %064b", id, tt.expectedBitBuf, writer.BitBuffer)
}
if writer.BitBufferSize != tt.expectedBufSize {
t.Errorf("test %v: bit buffer size mismatch: expected %v, got %v", id, tt.expectedBufSize, writer.BitBufferSize)
}
}
}