103 lines
2.3 KiB
Go
103 lines
2.3 KiB
Go
package brotli
|
|
|
|
import (
|
|
"errors"
|
|
"io"
|
|
)
|
|
|
|
type decodeError int
|
|
|
|
func (err decodeError) Error() string {
|
|
return "brotli: " + string(decoderErrorString(int(err)))
|
|
}
|
|
|
|
var errExcessiveInput = errors.New("brotli: excessive input")
|
|
var errInvalidState = errors.New("brotli: invalid state")
|
|
|
|
// readBufSize is a "good" buffer size that avoids excessive round-trips
|
|
// between C and Go but doesn't waste too much memory on buffering.
|
|
// It is arbitrarily chosen to be equal to the constant used in io.Copy.
|
|
const readBufSize = 32 * 1024
|
|
|
|
// NewReader creates a new Reader reading the given reader.
|
|
func NewReader(src io.Reader) *Reader {
|
|
r := new(Reader)
|
|
r.Reset(src)
|
|
return r
|
|
}
|
|
|
|
// Reset discards the Reader's state and makes it equivalent to the result of
|
|
// its original state from NewReader, but writing to src instead.
|
|
// This permits reusing a Reader rather than allocating a new one.
|
|
// Error is always nil
|
|
func (r *Reader) Reset(src io.Reader) error {
|
|
decoderStateInit(r)
|
|
r.src = src
|
|
if r.buf == nil {
|
|
r.buf = make([]byte, readBufSize)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (r *Reader) Read(p []byte) (n int, err error) {
|
|
if !decoderHasMoreOutput(r) && len(r.in) == 0 {
|
|
m, readErr := r.src.Read(r.buf)
|
|
if m == 0 {
|
|
// If readErr is `nil`, we just proxy underlying stream behavior.
|
|
return 0, readErr
|
|
}
|
|
r.in = r.buf[:m]
|
|
}
|
|
|
|
if len(p) == 0 {
|
|
return 0, nil
|
|
}
|
|
|
|
for {
|
|
var written uint
|
|
in_len := uint(len(r.in))
|
|
out_len := uint(len(p))
|
|
in_remaining := in_len
|
|
out_remaining := out_len
|
|
result := decoderDecompressStream(r, &in_remaining, &r.in, &out_remaining, &p)
|
|
written = out_len - out_remaining
|
|
n = int(written)
|
|
|
|
switch result {
|
|
case decoderResultSuccess:
|
|
if len(r.in) > 0 {
|
|
return n, errExcessiveInput
|
|
}
|
|
return n, nil
|
|
case decoderResultError:
|
|
return n, decodeError(decoderGetErrorCode(r))
|
|
case decoderResultNeedsMoreOutput:
|
|
if n == 0 {
|
|
return 0, io.ErrShortBuffer
|
|
}
|
|
return n, nil
|
|
case decoderNeedsMoreInput:
|
|
}
|
|
|
|
if len(r.in) != 0 {
|
|
return 0, errInvalidState
|
|
}
|
|
|
|
// Calling r.src.Read may block. Don't block if we have data to return.
|
|
if n > 0 {
|
|
return n, nil
|
|
}
|
|
|
|
// Top off the buffer.
|
|
encN, err := r.src.Read(r.buf)
|
|
if encN == 0 {
|
|
// Not enough data to complete decoding.
|
|
if err == io.EOF {
|
|
return 0, io.ErrUnexpectedEOF
|
|
}
|
|
return 0, err
|
|
}
|
|
r.in = r.buf[:encN]
|
|
}
|
|
}
|