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authorGravatar Runxi Yu2026-02-20 19:06:13 +0800
committerGravatar Runxi Yu2026-02-20 19:07:14 +0800
commitaa513c069c1418734aea894dc944e27c6a78a3bb (patch)
tree687f0a11bb550fa088fd82a98ceb8979bbc35f69 /internal/zlib
parentComment on prior reverts removing the pack writing API (diff)
signatureNo signature
Delete everything, I'm redesigning this.
I'll stop using a flat package and make things much more modular. And also experiment with streaming APIs so large blobs don't OOM us.
Diffstat (limited to 'internal/zlib')
-rw-r--r--internal/zlib/LICENSE27
-rw-r--r--internal/zlib/reader.go199
-rw-r--r--internal/zlib/writer.go228
3 files changed, 0 insertions, 454 deletions
diff --git a/internal/zlib/LICENSE b/internal/zlib/LICENSE
deleted file mode 100644
index 2a7cf70d..00000000
--- a/internal/zlib/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright 2009 The Go Authors.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
- * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
- * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
- * Neither the name of Google LLC nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/internal/zlib/reader.go b/internal/zlib/reader.go
deleted file mode 100644
index 2234e7e0..00000000
--- a/internal/zlib/reader.go
+++ /dev/null
@@ -1,199 +0,0 @@
-// 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 zlib implements reading and writing of zlib format compressed data,
-as specified in RFC 1950.
-
-This package differs from the standard library's compress/zlib package
-in that it pools readers and writers to reduce allocations.
-
-Note that closing a reader or writer causes it to be returned to a pool
-for reuse. Therefore, the caller must not retain references to a
-reader or writer after closing it; in the standard library's
-compress/zlib package, it is legal to Reset a closed reader or writer
-and continue using it; that is not allowed here, so there is simply no
-Resetter interface.
-
-The implementation provides filters that uncompress during reading
-and compress during writing. For example, to write compressed data
-to a buffer:
-
- var b bytes.Buffer
- w := zlib.NewWriter(&b)
- w.Write([]byte("hello, world\n"))
- w.Close()
-
-and to read that data back:
-
- r, err := zlib.NewReader(&b)
- io.Copy(os.Stdout, r)
- r.Close()
-*/
-package zlib
-
-import (
- "bufio"
- "compress/flate"
- "encoding/binary"
- "errors"
- "hash"
- "io"
- "sync"
-
- "codeberg.org/lindenii/furgit/internal/adler32"
-)
-
-const (
- zlibDeflate = 8
- zlibMaxWindow = 7
-)
-
-var (
- // ErrChecksum is returned when reading ZLIB data that has an invalid checksum.
- ErrChecksum = errors.New("zlib: invalid checksum")
- // ErrDictionary is returned when reading ZLIB data that has an invalid dictionary.
- ErrDictionary = errors.New("zlib: invalid dictionary")
- // ErrHeader is returned when reading ZLIB data that has an invalid header.
- ErrHeader = errors.New("zlib: invalid header")
-)
-
-var readerPool = sync.Pool{
- New: func() any {
- r := new(reader)
- return r
- },
-}
-
-type reader struct {
- r flate.Reader
- decompressor io.ReadCloser
- digest hash.Hash32
- err error
- scratch [4]byte
-}
-
-// NewReader creates a new ReadCloser.
-// Reads from the returned ReadCloser read and decompress data from r.
-// If r does not implement [io.ByteReader], the decompressor may read more
-// data than necessary from r.
-// It is the caller's responsibility to call Close on the ReadCloser when done.
-func NewReader(r io.Reader) (io.ReadCloser, error) {
- return NewReaderDict(r, nil)
-}
-
-// NewReaderDict is like [NewReader] but uses a preset dictionary.
-// NewReaderDict ignores the dictionary if the compressed data does not refer to it.
-// If the compressed data refers to a different dictionary, NewReaderDict returns [ErrDictionary].
-func NewReaderDict(r io.Reader, dict []byte) (io.ReadCloser, error) {
- v := readerPool.Get()
- z, ok := v.(*reader)
- if !ok {
- panic("zlib: pool returned unexpected type")
- }
- err := z.Reset(r, dict)
- if err != nil {
- return nil, err
- }
- return z, nil
-}
-
-func (z *reader) Read(p []byte) (int, error) {
- if z.err != nil {
- return 0, z.err
- }
-
- var n int
- n, z.err = z.decompressor.Read(p)
- z.digest.Write(p[0:n])
- if z.err != io.EOF {
- // In the normal case we return here.
- return n, z.err
- }
-
- // Finished file; check checksum.
- if _, err := io.ReadFull(z.r, z.scratch[0:4]); err != nil {
- if err == io.EOF {
- err = io.ErrUnexpectedEOF
- }
- z.err = err
- return n, z.err
- }
- // ZLIB (RFC 1950) is big-endian, unlike GZIP (RFC 1952).
- checksum := binary.BigEndian.Uint32(z.scratch[:4])
- if checksum != z.digest.Sum32() {
- z.err = ErrChecksum
- return n, z.err
- }
- return n, io.EOF
-}
-
-// Calling Close does not close the wrapped [io.Reader] originally passed to [NewReader].
-// In order for the ZLIB checksum to be verified, the reader must be
-// fully consumed until the [io.EOF].
-func (z *reader) Close() error {
- if z.err != nil && z.err != io.EOF {
- return z.err
- }
- z.err = z.decompressor.Close()
- if z.err != nil {
- return z.err
- }
-
- readerPool.Put(z)
- return nil
-}
-
-func (z *reader) Reset(r io.Reader, dict []byte) error {
- *z = reader{decompressor: z.decompressor}
- if fr, ok := r.(flate.Reader); ok {
- z.r = fr
- } else {
- z.r = bufio.NewReader(r)
- }
-
- // Read the header (RFC 1950 section 2.2.).
- _, z.err = io.ReadFull(z.r, z.scratch[0:2])
- if z.err != nil {
- if z.err == io.EOF {
- z.err = io.ErrUnexpectedEOF
- }
- return z.err
- }
- h := binary.BigEndian.Uint16(z.scratch[:2])
- if (z.scratch[0]&0x0f != zlibDeflate) || (z.scratch[0]>>4 > zlibMaxWindow) || (h%31 != 0) {
- z.err = ErrHeader
- return z.err
- }
- haveDict := z.scratch[1]&0x20 != 0
- if haveDict {
- _, z.err = io.ReadFull(z.r, z.scratch[0:4])
- if z.err != nil {
- if z.err == io.EOF {
- z.err = io.ErrUnexpectedEOF
- }
- return z.err
- }
- checksum := binary.BigEndian.Uint32(z.scratch[:4])
- if checksum != adler32.Checksum(dict) {
- z.err = ErrDictionary
- return z.err
- }
- }
-
- if z.decompressor == nil {
- if haveDict {
- z.decompressor = flate.NewReaderDict(z.r, dict)
- } else {
- z.decompressor = flate.NewReader(z.r)
- }
- } else {
- z.err = z.decompressor.(flate.Resetter).Reset(z.r, dict)
- if z.err != nil {
- return z.err
- }
- }
- z.digest = adler32.New()
- return nil
-}
diff --git a/internal/zlib/writer.go b/internal/zlib/writer.go
deleted file mode 100644
index 81c57f55..00000000
--- a/internal/zlib/writer.go
+++ /dev/null
@@ -1,228 +0,0 @@
-// 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 zlib
-
-import (
- "compress/flate"
- "encoding/binary"
- "fmt"
- "hash"
- "io"
- "sync"
-
- "codeberg.org/lindenii/furgit/internal/adler32"
-)
-
-// These constants are copied from the [flate] package, so that code that imports
-// [compress/zlib] does not also have to import [compress/flate].
-const (
- NoCompression = flate.NoCompression
- BestSpeed = flate.BestSpeed
- BestCompression = flate.BestCompression
- DefaultCompression = flate.DefaultCompression
- HuffmanOnly = flate.HuffmanOnly
-)
-
-// A Writer takes data written to it and writes the compressed
-// form of that data to an underlying writer (see [NewWriter]).
-type Writer struct {
- w io.Writer
- level int
- dict []byte
- compressor *flate.Writer
- digest hash.Hash32
- err error
- scratch [4]byte
- wroteHeader bool
-}
-
-var writerPool = sync.Pool{
- New: func() any {
- return new(Writer)
- },
-}
-
-// NewWriter creates a new [Writer].
-// Writes to the returned Writer are compressed and written to w.
-//
-// It is the caller's responsibility to call Close on the Writer when done.
-// Writes may be buffered and not flushed until Close.
-func NewWriter(w io.Writer) *Writer {
- z, _ := NewWriterLevelDict(w, DefaultCompression, nil)
- return z
-}
-
-// NewWriterLevel is like [NewWriter] but specifies the compression level instead
-// of assuming [DefaultCompression].
-//
-// The compression level can be [DefaultCompression], [NoCompression], [HuffmanOnly]
-// or any integer value between [BestSpeed] and [BestCompression] inclusive.
-// The error returned will be nil if the level is valid.
-func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
- return NewWriterLevelDict(w, level, nil)
-}
-
-// NewWriterLevelDict is like [NewWriterLevel] but specifies a dictionary to
-// compress with.
-//
-// The dictionary may be nil. If not, its contents should not be modified until
-// the Writer is closed.
-func NewWriterLevelDict(w io.Writer, level int, dict []byte) (*Writer, error) {
- if level < HuffmanOnly || level > BestCompression {
- return nil, fmt.Errorf("zlib: invalid compression level: %d", level)
- }
- v := writerPool.Get()
- z, ok := v.(*Writer)
- if !ok {
- panic("zlib: pool returned unexpected type")
- }
-
- // flate.Writer can only be Reset with the same level/dictionary mode.
- // Reuse it only when the configuration is unchanged and dictionary-free.
- reuseCompressor := z.compressor != nil && z.level == level && z.dict == nil && dict == nil
- if !reuseCompressor {
- z.compressor = nil
- }
- if z.digest != nil {
- z.digest.Reset()
- }
-
- *z = Writer{
- w: w,
- level: level,
- dict: dict,
- compressor: z.compressor,
- digest: z.digest,
- }
- if z.compressor != nil {
- z.compressor.Reset(w)
- }
- return z, nil
-}
-
-// Reset clears the state of the [Writer] z such that it is equivalent to its
-// initial state from [NewWriterLevel] or [NewWriterLevelDict], but instead writing
-// to w.
-func (z *Writer) Reset(w io.Writer) {
- z.w = w
- // z.level and z.dict left unchanged.
- if z.compressor != nil {
- z.compressor.Reset(w)
- }
- if z.digest != nil {
- z.digest.Reset()
- }
- z.err = nil
- z.scratch = [4]byte{}
- z.wroteHeader = false
-}
-
-// writeHeader writes the ZLIB header.
-func (z *Writer) writeHeader() (err error) {
- z.wroteHeader = true
- // ZLIB has a two-byte header (as documented in RFC 1950).
- // The first four bits is the CINFO (compression info), which is 7 for the default deflate window size.
- // The next four bits is the CM (compression method), which is 8 for deflate.
- z.scratch[0] = 0x78
- // The next two bits is the FLEVEL (compression level). The four values are:
- // 0=fastest, 1=fast, 2=default, 3=best.
- // The next bit, FDICT, is set if a dictionary is given.
- // The final five FCHECK bits form a mod-31 checksum.
- switch z.level {
- case -2, 0, 1:
- z.scratch[1] = 0 << 6
- case 2, 3, 4, 5:
- z.scratch[1] = 1 << 6
- case 6, -1:
- z.scratch[1] = 2 << 6
- case 7, 8, 9:
- z.scratch[1] = 3 << 6
- default:
- panic("unreachable")
- }
- if z.dict != nil {
- z.scratch[1] |= 1 << 5
- }
- z.scratch[1] += uint8(31 - binary.BigEndian.Uint16(z.scratch[:2])%31)
- if _, err = z.w.Write(z.scratch[0:2]); err != nil {
- return err
- }
- if z.dict != nil {
- // The next four bytes are the Adler-32 checksum of the dictionary.
- binary.BigEndian.PutUint32(z.scratch[:], adler32.Checksum(z.dict))
- if _, err = z.w.Write(z.scratch[0:4]); err != nil {
- return err
- }
- }
- if z.compressor == nil {
- // Initialize deflater unless the Writer is being reused
- // after a Reset call.
- z.compressor, err = flate.NewWriterDict(z.w, z.level, z.dict)
- if err != nil {
- return err
- }
- z.digest = adler32.New()
- }
- return nil
-}
-
-// Write writes a compressed form of p to the underlying [io.Writer]. The
-// compressed bytes are not necessarily flushed until the [Writer] is closed or
-// explicitly flushed.
-func (z *Writer) Write(p []byte) (n int, err error) {
- if !z.wroteHeader {
- z.err = z.writeHeader()
- }
- if z.err != nil {
- return 0, z.err
- }
- if len(p) == 0 {
- return 0, nil
- }
- n, err = z.compressor.Write(p)
- if err != nil {
- z.err = err
- return
- }
- z.digest.Write(p)
- return
-}
-
-// Flush flushes the Writer to its underlying [io.Writer].
-func (z *Writer) Flush() error {
- if !z.wroteHeader {
- z.err = z.writeHeader()
- }
- if z.err != nil {
- return z.err
- }
- z.err = z.compressor.Flush()
- return z.err
-}
-
-// Close closes the Writer, flushing any unwritten data to the underlying
-// [io.Writer], but does not close the underlying io.Writer.
-func (z *Writer) Close() error {
- if !z.wroteHeader {
- z.err = z.writeHeader()
- }
- if z.err != nil {
- return z.err
- }
- z.err = z.compressor.Close()
- if z.err != nil {
- return z.err
- }
- checksum := z.digest.Sum32()
- // ZLIB (RFC 1950) is big-endian, unlike GZIP (RFC 1952).
- binary.BigEndian.PutUint32(z.scratch[:], checksum)
- _, z.err = z.w.Write(z.scratch[0:4])
- if z.err != nil {
- return z.err
- }
-
- writerPool.Put(z)
- return nil
-}