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-rw-r--r--vendor/github.com/klauspost/pgzip/gunzip.go573
1 files changed, 573 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/pgzip/gunzip.go b/vendor/github.com/klauspost/pgzip/gunzip.go
new file mode 100644
index 000000000..93efec714
--- /dev/null
+++ b/vendor/github.com/klauspost/pgzip/gunzip.go
@@ -0,0 +1,573 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package pgzip implements reading and writing of gzip format compressed files,
+// as specified in RFC 1952.
+//
+// This is a drop in replacement for "compress/gzip".
+// This will split compression into blocks that are compressed in parallel.
+// This can be useful for compressing big amounts of data.
+// The gzip decompression has not been modified, but remains in the package,
+// so you can use it as a complete replacement for "compress/gzip".
+//
+// See more at https://github.com/klauspost/pgzip
+package pgzip
+
+import (
+ "bufio"
+ "errors"
+ "hash"
+ "hash/crc32"
+ "io"
+ "sync"
+ "time"
+
+ "github.com/klauspost/compress/flate"
+)
+
+const (
+ gzipID1 = 0x1f
+ gzipID2 = 0x8b
+ gzipDeflate = 8
+ flagText = 1 << 0
+ flagHdrCrc = 1 << 1
+ flagExtra = 1 << 2
+ flagName = 1 << 3
+ flagComment = 1 << 4
+)
+
+func makeReader(r io.Reader) flate.Reader {
+ if rr, ok := r.(flate.Reader); ok {
+ return rr
+ }
+ return bufio.NewReader(r)
+}
+
+var (
+ // ErrChecksum is returned when reading GZIP data that has an invalid checksum.
+ ErrChecksum = errors.New("gzip: invalid checksum")
+ // ErrHeader is returned when reading GZIP data that has an invalid header.
+ ErrHeader = errors.New("gzip: invalid header")
+)
+
+// The gzip file stores a header giving metadata about the compressed file.
+// That header is exposed as the fields of the Writer and Reader structs.
+type Header struct {
+ Comment string // comment
+ Extra []byte // "extra data"
+ ModTime time.Time // modification time
+ Name string // file name
+ OS byte // operating system type
+}
+
+// A Reader is an io.Reader that can be read to retrieve
+// uncompressed data from a gzip-format compressed file.
+//
+// In general, a gzip file can be a concatenation of gzip files,
+// each with its own header. Reads from the Reader
+// return the concatenation of the uncompressed data of each.
+// Only the first header is recorded in the Reader fields.
+//
+// Gzip files store a length and checksum of the uncompressed data.
+// The Reader will return a ErrChecksum when Read
+// reaches the end of the uncompressed data if it does not
+// have the expected length or checksum. Clients should treat data
+// returned by Read as tentative until they receive the io.EOF
+// marking the end of the data.
+type Reader struct {
+ Header
+ r flate.Reader
+ decompressor io.ReadCloser
+ digest hash.Hash32
+ size uint32
+ flg byte
+ buf [512]byte
+ err error
+ closeErr chan error
+ multistream bool
+
+ readAhead chan read
+ roff int // read offset
+ current []byte
+ closeReader chan struct{}
+ lastBlock bool
+ blockSize int
+ blocks int
+
+ activeRA bool // Indication if readahead is active
+ mu sync.Mutex // Lock for above
+
+ blockPool chan []byte
+}
+
+type read struct {
+ b []byte
+ err error
+}
+
+// NewReader creates a new Reader reading the given reader.
+// The implementation buffers input and may read more data than necessary from r.
+// It is the caller's responsibility to call Close on the Reader when done.
+func NewReader(r io.Reader) (*Reader, error) {
+ z := new(Reader)
+ z.blocks = defaultBlocks
+ z.blockSize = defaultBlockSize
+ z.r = makeReader(r)
+ z.digest = crc32.NewIEEE()
+ z.multistream = true
+ z.blockPool = make(chan []byte, z.blocks)
+ for i := 0; i < z.blocks; i++ {
+ z.blockPool <- make([]byte, z.blockSize)
+ }
+ if err := z.readHeader(true); err != nil {
+ return nil, err
+ }
+ return z, nil
+}
+
+// NewReaderN creates a new Reader reading the given reader.
+// The implementation buffers input and may read more data than necessary from r.
+// It is the caller's responsibility to call Close on the Reader when done.
+//
+// With this you can control the approximate size of your blocks,
+// as well as how many blocks you want to have prefetched.
+//
+// Default values for this is blockSize = 250000, blocks = 16,
+// meaning up to 16 blocks of maximum 250000 bytes will be
+// prefetched.
+func NewReaderN(r io.Reader, blockSize, blocks int) (*Reader, error) {
+ z := new(Reader)
+ z.blocks = blocks
+ z.blockSize = blockSize
+ z.r = makeReader(r)
+ z.digest = crc32.NewIEEE()
+ z.multistream = true
+
+ // Account for too small values
+ if z.blocks <= 0 {
+ z.blocks = defaultBlocks
+ }
+ if z.blockSize <= 512 {
+ z.blockSize = defaultBlockSize
+ }
+ z.blockPool = make(chan []byte, z.blocks)
+ for i := 0; i < z.blocks; i++ {
+ z.blockPool <- make([]byte, z.blockSize)
+ }
+ if err := z.readHeader(true); err != nil {
+ return nil, err
+ }
+ return z, nil
+}
+
+// Reset discards the Reader z's state and makes it equivalent to the
+// result of its original state from NewReader, but reading from r instead.
+// This permits reusing a Reader rather than allocating a new one.
+func (z *Reader) Reset(r io.Reader) error {
+ z.killReadAhead()
+ z.r = makeReader(r)
+ z.digest = crc32.NewIEEE()
+ z.size = 0
+ z.err = nil
+ z.multistream = true
+
+ // Account for uninitialized values
+ if z.blocks <= 0 {
+ z.blocks = defaultBlocks
+ }
+ if z.blockSize <= 512 {
+ z.blockSize = defaultBlockSize
+ }
+
+ if z.blockPool == nil {
+ z.blockPool = make(chan []byte, z.blocks)
+ for i := 0; i < z.blocks; i++ {
+ z.blockPool <- make([]byte, z.blockSize)
+ }
+ }
+
+ return z.readHeader(true)
+}
+
+// Multistream controls whether the reader supports multistream files.
+//
+// If enabled (the default), the Reader expects the input to be a sequence
+// of individually gzipped data streams, each with its own header and
+// trailer, ending at EOF. The effect is that the concatenation of a sequence
+// of gzipped files is treated as equivalent to the gzip of the concatenation
+// of the sequence. This is standard behavior for gzip readers.
+//
+// Calling Multistream(false) disables this behavior; disabling the behavior
+// can be useful when reading file formats that distinguish individual gzip
+// data streams or mix gzip data streams with other data streams.
+// In this mode, when the Reader reaches the end of the data stream,
+// Read returns io.EOF. If the underlying reader implements io.ByteReader,
+// it will be left positioned just after the gzip stream.
+// To start the next stream, call z.Reset(r) followed by z.Multistream(false).
+// If there is no next stream, z.Reset(r) will return io.EOF.
+func (z *Reader) Multistream(ok bool) {
+ z.multistream = ok
+}
+
+// GZIP (RFC 1952) is little-endian, unlike ZLIB (RFC 1950).
+func get4(p []byte) uint32 {
+ return uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 | uint32(p[3])<<24
+}
+
+func (z *Reader) readString() (string, error) {
+ var err error
+ needconv := false
+ for i := 0; ; i++ {
+ if i >= len(z.buf) {
+ return "", ErrHeader
+ }
+ z.buf[i], err = z.r.ReadByte()
+ if err != nil {
+ return "", err
+ }
+ if z.buf[i] > 0x7f {
+ needconv = true
+ }
+ if z.buf[i] == 0 {
+ // GZIP (RFC 1952) specifies that strings are NUL-terminated ISO 8859-1 (Latin-1).
+ if needconv {
+ s := make([]rune, 0, i)
+ for _, v := range z.buf[0:i] {
+ s = append(s, rune(v))
+ }
+ return string(s), nil
+ }
+ return string(z.buf[0:i]), nil
+ }
+ }
+}
+
+func (z *Reader) read2() (uint32, error) {
+ _, err := io.ReadFull(z.r, z.buf[0:2])
+ if err != nil {
+ return 0, err
+ }
+ return uint32(z.buf[0]) | uint32(z.buf[1])<<8, nil
+}
+
+func (z *Reader) readHeader(save bool) error {
+ z.killReadAhead()
+
+ _, err := io.ReadFull(z.r, z.buf[0:10])
+ if err != nil {
+ return err
+ }
+ if z.buf[0] != gzipID1 || z.buf[1] != gzipID2 || z.buf[2] != gzipDeflate {
+ return ErrHeader
+ }
+ z.flg = z.buf[3]
+ if save {
+ z.ModTime = time.Unix(int64(get4(z.buf[4:8])), 0)
+ // z.buf[8] is xfl, ignored
+ z.OS = z.buf[9]
+ }
+ z.digest.Reset()
+ z.digest.Write(z.buf[0:10])
+
+ if z.flg&flagExtra != 0 {
+ n, err := z.read2()
+ if err != nil {
+ return err
+ }
+ data := make([]byte, n)
+ if _, err = io.ReadFull(z.r, data); err != nil {
+ return err
+ }
+ if save {
+ z.Extra = data
+ }
+ }
+
+ var s string
+ if z.flg&flagName != 0 {
+ if s, err = z.readString(); err != nil {
+ return err
+ }
+ if save {
+ z.Name = s
+ }
+ }
+
+ if z.flg&flagComment != 0 {
+ if s, err = z.readString(); err != nil {
+ return err
+ }
+ if save {
+ z.Comment = s
+ }
+ }
+
+ if z.flg&flagHdrCrc != 0 {
+ n, err := z.read2()
+ if err != nil {
+ return err
+ }
+ sum := z.digest.Sum32() & 0xFFFF
+ if n != sum {
+ return ErrHeader
+ }
+ }
+
+ z.digest.Reset()
+ z.decompressor = flate.NewReader(z.r)
+ z.doReadAhead()
+ return nil
+}
+
+func (z *Reader) killReadAhead() error {
+ z.mu.Lock()
+ defer z.mu.Unlock()
+ if z.activeRA {
+ if z.closeReader != nil {
+ close(z.closeReader)
+ }
+
+ // Wait for decompressor to be closed and return error, if any.
+ e, ok := <-z.closeErr
+ z.activeRA = false
+ if !ok {
+ // Channel is closed, so if there was any error it has already been returned.
+ return nil
+ }
+ return e
+ }
+ return nil
+}
+
+// Starts readahead.
+// Will return on error (including io.EOF)
+// or when z.closeReader is closed.
+func (z *Reader) doReadAhead() {
+ z.mu.Lock()
+ defer z.mu.Unlock()
+ z.activeRA = true
+
+ if z.blocks <= 0 {
+ z.blocks = defaultBlocks
+ }
+ if z.blockSize <= 512 {
+ z.blockSize = defaultBlockSize
+ }
+ ra := make(chan read, z.blocks)
+ z.readAhead = ra
+ closeReader := make(chan struct{}, 0)
+ z.closeReader = closeReader
+ z.lastBlock = false
+ closeErr := make(chan error, 1)
+ z.closeErr = closeErr
+ z.size = 0
+ z.roff = 0
+ z.current = nil
+ decomp := z.decompressor
+
+ go func() {
+ defer func() {
+ closeErr <- decomp.Close()
+ close(closeErr)
+ close(ra)
+ }()
+
+ // We hold a local reference to digest, since
+ // it way be changed by reset.
+ digest := z.digest
+ var wg sync.WaitGroup
+ for {
+ var buf []byte
+ select {
+ case buf = <-z.blockPool:
+ case <-closeReader:
+ return
+ }
+ buf = buf[0:z.blockSize]
+ // Try to fill the buffer
+ n, err := io.ReadFull(decomp, buf)
+ if err == io.ErrUnexpectedEOF {
+ if n > 0 {
+ err = nil
+ } else {
+ // If we got zero bytes, we need to establish if
+ // we reached end of stream or truncated stream.
+ _, err = decomp.Read([]byte{})
+ if err == io.EOF {
+ err = nil
+ }
+ }
+ }
+ if n < len(buf) {
+ buf = buf[0:n]
+ }
+ wg.Wait()
+ wg.Add(1)
+ go func() {
+ digest.Write(buf)
+ wg.Done()
+ }()
+ z.size += uint32(n)
+
+ // If we return any error, out digest must be ready
+ if err != nil {
+ wg.Wait()
+ }
+ select {
+ case z.readAhead <- read{b: buf, err: err}:
+ case <-closeReader:
+ // Sent on close, we don't care about the next results
+ return
+ }
+ if err != nil {
+ return
+ }
+ }
+ }()
+}
+
+func (z *Reader) Read(p []byte) (n int, err error) {
+ if z.err != nil {
+ return 0, z.err
+ }
+ if len(p) == 0 {
+ return 0, nil
+ }
+
+ for {
+ if len(z.current) == 0 && !z.lastBlock {
+ read := <-z.readAhead
+
+ if read.err != nil {
+ // If not nil, the reader will have exited
+ z.closeReader = nil
+
+ if read.err != io.EOF {
+ z.err = read.err
+ return
+ }
+ if read.err == io.EOF {
+ z.lastBlock = true
+ err = nil
+ }
+ }
+ z.current = read.b
+ z.roff = 0
+ }
+ avail := z.current[z.roff:]
+ if len(p) >= len(avail) {
+ // If len(p) >= len(current), return all content of current
+ n = copy(p, avail)
+ z.blockPool <- z.current
+ z.current = nil
+ if z.lastBlock {
+ err = io.EOF
+ break
+ }
+ } else {
+ // We copy as much as there is space for
+ n = copy(p, avail)
+ z.roff += n
+ }
+ return
+ }
+
+ // Finished file; check checksum + size.
+ if _, err := io.ReadFull(z.r, z.buf[0:8]); err != nil {
+ z.err = err
+ return 0, err
+ }
+ crc32, isize := get4(z.buf[0:4]), get4(z.buf[4:8])
+ sum := z.digest.Sum32()
+ if sum != crc32 || isize != z.size {
+ z.err = ErrChecksum
+ return 0, z.err
+ }
+
+ // File is ok; should we attempt reading one more?
+ if !z.multistream {
+ return 0, io.EOF
+ }
+
+ // Is there another?
+ if err = z.readHeader(false); err != nil {
+ z.err = err
+ return
+ }
+
+ // Yes. Reset and read from it.
+ return z.Read(p)
+}
+
+func (z *Reader) WriteTo(w io.Writer) (n int64, err error) {
+ total := int64(0)
+ for {
+ if z.err != nil {
+ return total, z.err
+ }
+ // We write both to output and digest.
+ for {
+ // Read from input
+ read := <-z.readAhead
+ if read.err != nil {
+ // If not nil, the reader will have exited
+ z.closeReader = nil
+
+ if read.err != io.EOF {
+ z.err = read.err
+ return total, z.err
+ }
+ if read.err == io.EOF {
+ z.lastBlock = true
+ err = nil
+ }
+ }
+ // Write what we got
+ n, err := w.Write(read.b)
+ if n != len(read.b) {
+ return total, io.ErrShortWrite
+ }
+ total += int64(n)
+ if err != nil {
+ return total, err
+ }
+ // Put block back
+ z.blockPool <- read.b
+ if z.lastBlock {
+ break
+ }
+ }
+
+ // Finished file; check checksum + size.
+ if _, err := io.ReadFull(z.r, z.buf[0:8]); err != nil {
+ z.err = err
+ return total, err
+ }
+ crc32, isize := get4(z.buf[0:4]), get4(z.buf[4:8])
+ sum := z.digest.Sum32()
+ if sum != crc32 || isize != z.size {
+ z.err = ErrChecksum
+ return total, z.err
+ }
+ // File is ok; should we attempt reading one more?
+ if !z.multistream {
+ return total, nil
+ }
+
+ // Is there another?
+ err = z.readHeader(false)
+ if err == io.EOF {
+ return total, nil
+ }
+ if err != nil {
+ z.err = err
+ return total, err
+ }
+ }
+}
+
+// Close closes the Reader. It does not close the underlying io.Reader.
+func (z *Reader) Close() error {
+ return z.killReadAhead()
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-09-30 03:22:29 +0000