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Make BrotliEncoderState into a Writer.

This commit is contained in:
Andy Balholm 2019-03-06 16:16:48 -08:00
parent 69a32ecc1a
commit f036cd04c1
2 changed files with 123 additions and 30 deletions
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64
encode.go
View File

@ -1,5 +1,7 @@
package brotli
import "io"
/* Copyright 2016 Google Inc. All Rights Reserved.
Distributed under MIT license.
@ -92,7 +94,9 @@ const (
BROTLI_STREAM_METADATA_BODY = 4
)
type BrotliEncoderState struct {
type Writer struct {
dst io.Writer
params BrotliEncoderParams
hasher_ HasherHandle
input_pos_ uint64
@ -134,15 +138,15 @@ type BrotliEncoderState struct {
is_initialized_ bool
}
func InputBlockSize(s *BrotliEncoderState) uint {
func InputBlockSize(s *Writer) uint {
return uint(1) << uint(s.params.lgblock)
}
func UnprocessedInputSize(s *BrotliEncoderState) uint64 {
func UnprocessedInputSize(s *Writer) uint64 {
return s.input_pos_ - s.last_processed_pos_
}
func RemainingInputBlockSize(s *BrotliEncoderState) uint {
func RemainingInputBlockSize(s *Writer) uint {
var delta uint64 = UnprocessedInputSize(s)
var block_size uint = InputBlockSize(s)
if delta >= uint64(block_size) {
@ -151,7 +155,7 @@ func RemainingInputBlockSize(s *BrotliEncoderState) uint {
return block_size - uint(delta)
}
func BrotliEncoderSetParameter(state *BrotliEncoderState, p int, value uint32) bool {
func BrotliEncoderSetParameter(state *Writer, p int, value uint32) bool {
/* Changing parameters on the fly is not implemented yet. */
if state.is_initialized_ {
return false
@ -216,7 +220,7 @@ func WrapPosition(position uint64) uint32 {
return result
}
func GetBrotliStorage(s *BrotliEncoderState, size uint) []byte {
func GetBrotliStorage(s *Writer, size uint) []byte {
if s.storage_size_ < size {
s.storage_ = nil
s.storage_ = make([]byte, size)
@ -235,7 +239,7 @@ func HashTableSize(max_table_size uint, input_size uint) uint {
return htsize
}
func GetHashTable(s *BrotliEncoderState, quality int, input_size uint, table_size *uint) []int {
func GetHashTable(s *Writer, quality int, input_size uint, table_size *uint) []int {
var max_table_size uint = MaxHashTableSize(quality)
var htsize uint = HashTableSize(max_table_size, input_size)
/* Use smaller hash table when input.size() is smaller, since we
@ -1100,7 +1104,7 @@ func ChooseDistanceParams(params *BrotliEncoderParams) {
BrotliInitDistanceParams(params, distance_postfix_bits, num_direct_distance_codes)
}
func EnsureInitialized(s *BrotliEncoderState) bool {
func EnsureInitialized(s *Writer) bool {
if s.is_initialized_ {
return true
}
@ -1148,7 +1152,7 @@ func BrotliEncoderInitParams(params *BrotliEncoderParams) {
params.dist.max_distance = BROTLI_MAX_DISTANCE
}
func BrotliEncoderInitState(s *BrotliEncoderState) {
func BrotliEncoderInitState(s *Writer) {
BrotliEncoderInitParams(&s.params)
s.input_pos_ = 0
s.num_commands_ = 0
@ -1190,9 +1194,9 @@ func BrotliEncoderInitState(s *BrotliEncoderState) {
copy(s.saved_dist_cache_[:], s.dist_cache_[:])
}
func BrotliEncoderCreateInstance() *BrotliEncoderState {
var state *BrotliEncoderState = nil
state = new(BrotliEncoderState)
func BrotliEncoderCreateInstance() *Writer {
var state *Writer = nil
state = new(Writer)
if state == nil {
/* BROTLI_DUMP(); */
return nil
@ -1202,7 +1206,7 @@ func BrotliEncoderCreateInstance() *BrotliEncoderState {
return state
}
func BrotliEncoderCleanupState(s *BrotliEncoderState) {
func BrotliEncoderCleanupState(s *Writer) {
s.storage_ = nil
s.commands_ = nil
RingBufferFree(&s.ringbuffer_)
@ -1213,7 +1217,7 @@ func BrotliEncoderCleanupState(s *BrotliEncoderState) {
}
/* Deinitializes and frees BrotliEncoderState instance. */
func BrotliEncoderDestroyInstance(state *BrotliEncoderState) {
func BrotliEncoderDestroyInstance(state *Writer) {
if state == nil {
return
} else {
@ -1228,7 +1232,7 @@ func BrotliEncoderDestroyInstance(state *BrotliEncoderState) {
accumulated input. At most input_block_size() bytes of input data can be
copied to the ring buffer, otherwise the next WriteBrotliData() will fail.
*/
func CopyInputToRingBuffer(s *BrotliEncoderState, input_size uint, input_buffer []byte) {
func CopyInputToRingBuffer(s *Writer, input_size uint, input_buffer []byte) {
var ringbuffer_ *RingBuffer = &s.ringbuffer_
RingBufferWrite(input_buffer, input_size, ringbuffer_)
s.input_pos_ += uint64(input_size)
@ -1283,14 +1287,14 @@ func CopyInputToRingBuffer(s *BrotliEncoderState, input_size uint, input_buffer
/* Marks all input as processed.
Returns true if position wrapping occurs. */
func UpdateLastProcessedPos(s *BrotliEncoderState) bool {
func UpdateLastProcessedPos(s *Writer) bool {
var wrapped_last_processed_pos uint32 = WrapPosition(s.last_processed_pos_)
var wrapped_input_pos uint32 = WrapPosition(s.input_pos_)
s.last_processed_pos_ = s.input_pos_
return wrapped_input_pos < wrapped_last_processed_pos
}
func ExtendLastCommand(s *BrotliEncoderState, bytes *uint32, wrapped_last_processed_pos *uint32) {
func ExtendLastCommand(s *Writer, bytes *uint32, wrapped_last_processed_pos *uint32) {
var last_command *Command = &s.commands_[s.num_commands_-1]
var data []byte = s.ringbuffer_.buffer_
var mask uint32 = s.ringbuffer_.mask_
@ -1331,7 +1335,7 @@ func ExtendLastCommand(s *BrotliEncoderState, bytes *uint32, wrapped_last_proces
Returns false if the size of the input data is larger than
input_block_size().
*/
func EncodeData(s *BrotliEncoderState, is_last bool, force_flush bool, out_size *uint, output *[]byte) bool {
func EncodeData(s *Writer, is_last bool, force_flush bool, out_size *uint, output *[]byte) bool {
var delta uint64 = UnprocessedInputSize(s)
var bytes uint32 = uint32(delta)
var wrapped_last_processed_pos uint32 = WrapPosition(s.last_processed_pos_)
@ -1509,7 +1513,7 @@ func EncodeData(s *BrotliEncoderState, is_last bool, force_flush bool, out_size
Returns number of produced bytes.
REQUIRED: |header| should be 8-byte aligned and at least 16 bytes long.
REQUIRED: |block_size| <= (1 << 24). */
func WriteMetadataHeader(s *BrotliEncoderState, block_size uint, header []byte) uint {
func WriteMetadataHeader(s *Writer, block_size uint, header []byte) uint {
var storage_ix uint
storage_ix = uint(s.last_bytes_bits_)
header[0] = byte(s.last_bytes_)
@ -1792,7 +1796,7 @@ func MakeUncompressedStream(input []byte, input_size uint, output []byte) uint {
}
func BrotliEncoderCompress(quality int, lgwin int, mode int, input_size uint, input_buffer []byte, encoded_size *uint, encoded_buffer []byte) bool {
var s *BrotliEncoderState
var s *Writer
var out_size uint = *encoded_size
var input_start []byte = input_buffer
var output_start []byte = encoded_buffer
@ -1866,7 +1870,7 @@ fallback:
return false
}
func InjectBytePaddingBlock(s *BrotliEncoderState) {
func InjectBytePaddingBlock(s *Writer) {
var seal uint32 = uint32(s.last_bytes_)
var seal_bits uint = uint(s.last_bytes_bits_)
var destination []byte
@ -1899,7 +1903,7 @@ func InjectBytePaddingBlock(s *BrotliEncoderState) {
/* Injects padding bits or pushes compressed data to output.
Returns false if nothing is done. */
func InjectFlushOrPushOutput(s *BrotliEncoderState, available_out *uint, next_out *[]byte, total_out *uint) bool {
func InjectFlushOrPushOutput(s *Writer, available_out *uint, next_out *[]byte, total_out *uint) bool {
if s.stream_state_ == BROTLI_STREAM_FLUSH_REQUESTED && s.last_bytes_bits_ != 0 {
InjectBytePaddingBlock(s)
return true
@ -1922,14 +1926,14 @@ func InjectFlushOrPushOutput(s *BrotliEncoderState, available_out *uint, next_ou
return false
}
func CheckFlushComplete(s *BrotliEncoderState) {
func CheckFlushComplete(s *Writer) {
if s.stream_state_ == BROTLI_STREAM_FLUSH_REQUESTED && s.available_out_ == 0 {
s.stream_state_ = BROTLI_STREAM_PROCESSING
s.next_out_ = nil
}
}
func BrotliEncoderCompressStreamFast(s *BrotliEncoderState, op int, available_in *uint, next_in *[]byte, available_out *uint, next_out *[]byte, total_out *uint) bool {
func BrotliEncoderCompressStreamFast(s *Writer, op int, available_in *uint, next_in *[]byte, available_out *uint, next_out *[]byte, total_out *uint) bool {
var block_size_limit uint = uint(1) << s.params.lgwin
var buf_size uint = brotli_min_size_t(kCompressFragmentTwoPassBlockSize, brotli_min_size_t(*available_in, block_size_limit))
var tmp_command_buf []uint32 = nil
@ -2037,7 +2041,7 @@ func BrotliEncoderCompressStreamFast(s *BrotliEncoderState, op int, available_in
return true
}
func ProcessMetadata(s *BrotliEncoderState, available_in *uint, next_in *[]byte, available_out *uint, next_out *[]byte, total_out *uint) bool {
func ProcessMetadata(s *Writer, available_in *uint, next_in *[]byte, available_out *uint, next_out *[]byte, total_out *uint) bool {
if *available_in > 1<<24 {
return false
}
@ -2110,7 +2114,7 @@ func ProcessMetadata(s *BrotliEncoderState, available_in *uint, next_in *[]byte,
return true
}
func UpdateSizeHint(s *BrotliEncoderState, available_in uint) {
func UpdateSizeHint(s *Writer, available_in uint) {
if s.params.size_hint == 0 {
var delta uint64 = UnprocessedInputSize(s)
var tail uint64 = uint64(available_in)
@ -2126,7 +2130,7 @@ func UpdateSizeHint(s *BrotliEncoderState, available_in uint) {
}
}
func BrotliEncoderCompressStream(s *BrotliEncoderState, op int, available_in *uint, next_in *[]byte, available_out *uint, next_out *[]byte, total_out *uint) bool {
func BrotliEncoderCompressStream(s *Writer, op int, available_in *uint, next_in *[]byte, available_out *uint, next_out *[]byte, total_out *uint) bool {
if !EnsureInitialized(s) {
return false
}
@ -2202,15 +2206,15 @@ func BrotliEncoderCompressStream(s *BrotliEncoderState, op int, available_in *ui
return true
}
func BrotliEncoderIsFinished(s *BrotliEncoderState) bool {
func BrotliEncoderIsFinished(s *Writer) bool {
return s.stream_state_ == BROTLI_STREAM_FINISHED && !BrotliEncoderHasMoreOutput(s)
}
func BrotliEncoderHasMoreOutput(s *BrotliEncoderState) bool {
func BrotliEncoderHasMoreOutput(s *Writer) bool {
return s.available_out_ != 0
}
func BrotliEncoderTakeOutput(s *BrotliEncoderState, size *uint) []byte {
func BrotliEncoderTakeOutput(s *Writer, size *uint) []byte {
var consumed_size uint = s.available_out_
var result []byte = s.next_out_
if *size != 0 {

89
writer.go Normal file
View File

@ -0,0 +1,89 @@
package brotli
import (
"errors"
"io"
)
// WriterOptions configures Writer.
type WriterOptions struct {
// Quality controls the compression-speed vs compression-density trade-offs.
// The higher the quality, the slower the compression. Range is 0 to 11.
Quality int
// LGWin is the base 2 logarithm of the sliding window size.
// Range is 10 to 24. 0 indicates automatic configuration based on Quality.
LGWin int
}
var (
errEncode = errors.New("brotli: encode error")
errWriterClosed = errors.New("brotli: Writer is closed")
)
// NewWriter initializes new Writer instance.
func NewWriter(dst io.Writer, options WriterOptions) *Writer {
w := new(Writer)
BrotliEncoderInitState(w)
BrotliEncoderSetParameter(w, BROTLI_PARAM_QUALITY, uint32(options.Quality))
if options.LGWin > 0 {
BrotliEncoderSetParameter(w, BROTLI_PARAM_LGWIN, uint32(options.LGWin))
}
w.dst = dst
return w
}
func (w *Writer) writeChunk(p []byte, op int) (n int, err error) {
if w.dst == nil {
return 0, errWriterClosed
}
for {
availableIn := uint(len(p))
nextIn := p
availableOut := uint(0)
success := BrotliEncoderCompressStream(w, op, &availableIn, &nextIn, &availableOut, nil, nil)
bytesConsumed := len(p) - int(availableIn)
p = p[bytesConsumed:]
n += bytesConsumed
if !success {
return n, errEncode
}
var outputDataSize uint
outputData := BrotliEncoderTakeOutput(w, &outputDataSize)
outputData = outputData[:outputDataSize]
if outputDataSize > 0 {
_, err = w.dst.Write(outputData)
if err != nil {
return n, err
}
}
if len(p) == 0 && !BrotliEncoderHasMoreOutput(w) {
return n, nil
}
}
}
// Flush outputs encoded data for all input provided to Write. The resulting
// output can be decoded to match all input before Flush, but the stream is
// not yet complete until after Close.
// Flush has a negative impact on compression.
func (w *Writer) Flush() error {
_, err := w.writeChunk(nil, BROTLI_OPERATION_FLUSH)
return err
}
// Close flushes remaining data to the decorated writer.
func (w *Writer) Close() error {
// If stream is already closed, it is reported by `writeChunk`.
_, err := w.writeChunk(nil, BROTLI_OPERATION_FINISH)
w.dst = nil
return err
}
// Write implements io.Writer. Flush or Close must be called to ensure that the
// encoded bytes are actually flushed to the underlying Writer.
func (w *Writer) Write(p []byte) (n int, err error) {
return w.writeChunk(p, BROTLI_OPERATION_PROCESS)
}