986f076276
Add a new generic container registry client via a new `container` package. Use this to create a command line utility as well as a new upload target for container registries. The code uses the github.com/containers/* project and packages to interact with container registires that is also used by skopeo, podman et al. One if the dependencies is `proglottis/gpgme` that is using cgo to bind libgpgme, so we have to add the corresponding devel package to the BuildRequires as well as installing it on CI. Checks will follow later via an integration test.
122 lines
3 KiB
Go
122 lines
3 KiB
Go
// Copyright 2018 Klaus Post. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Based on work Copyright (c) 2013, Yann Collet, released under BSD License.
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package fse
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import (
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"encoding/binary"
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"errors"
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"io"
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)
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// bitReader reads a bitstream in reverse.
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// The last set bit indicates the start of the stream and is used
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// for aligning the input.
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type bitReader struct {
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in []byte
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off uint // next byte to read is at in[off - 1]
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value uint64
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bitsRead uint8
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}
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// init initializes and resets the bit reader.
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func (b *bitReader) init(in []byte) error {
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if len(in) < 1 {
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return errors.New("corrupt stream: too short")
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}
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b.in = in
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b.off = uint(len(in))
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// The highest bit of the last byte indicates where to start
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v := in[len(in)-1]
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if v == 0 {
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return errors.New("corrupt stream, did not find end of stream")
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}
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b.bitsRead = 64
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b.value = 0
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if len(in) >= 8 {
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b.fillFastStart()
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} else {
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b.fill()
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b.fill()
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}
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b.bitsRead += 8 - uint8(highBits(uint32(v)))
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return nil
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}
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// getBits will return n bits. n can be 0.
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func (b *bitReader) getBits(n uint8) uint16 {
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if n == 0 || b.bitsRead >= 64 {
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return 0
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}
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return b.getBitsFast(n)
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}
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// getBitsFast requires that at least one bit is requested every time.
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// There are no checks if the buffer is filled.
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func (b *bitReader) getBitsFast(n uint8) uint16 {
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const regMask = 64 - 1
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v := uint16((b.value << (b.bitsRead & regMask)) >> ((regMask + 1 - n) & regMask))
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b.bitsRead += n
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return v
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}
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// fillFast() will make sure at least 32 bits are available.
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// There must be at least 4 bytes available.
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func (b *bitReader) fillFast() {
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if b.bitsRead < 32 {
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return
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}
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// 2 bounds checks.
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v := b.in[b.off-4:]
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v = v[:4]
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low := (uint32(v[0])) | (uint32(v[1]) << 8) | (uint32(v[2]) << 16) | (uint32(v[3]) << 24)
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b.value = (b.value << 32) | uint64(low)
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b.bitsRead -= 32
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b.off -= 4
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}
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// fill() will make sure at least 32 bits are available.
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func (b *bitReader) fill() {
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if b.bitsRead < 32 {
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return
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}
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if b.off > 4 {
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v := b.in[b.off-4:]
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v = v[:4]
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low := (uint32(v[0])) | (uint32(v[1]) << 8) | (uint32(v[2]) << 16) | (uint32(v[3]) << 24)
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b.value = (b.value << 32) | uint64(low)
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b.bitsRead -= 32
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b.off -= 4
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return
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}
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for b.off > 0 {
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b.value = (b.value << 8) | uint64(b.in[b.off-1])
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b.bitsRead -= 8
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b.off--
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}
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}
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// fillFastStart() assumes the bitreader is empty and there is at least 8 bytes to read.
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func (b *bitReader) fillFastStart() {
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// Do single re-slice to avoid bounds checks.
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b.value = binary.LittleEndian.Uint64(b.in[b.off-8:])
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b.bitsRead = 0
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b.off -= 8
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}
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// finished returns true if all bits have been read from the bit stream.
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func (b *bitReader) finished() bool {
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return b.bitsRead >= 64 && b.off == 0
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}
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// close the bitstream and returns an error if out-of-buffer reads occurred.
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func (b *bitReader) close() error {
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// Release reference.
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b.in = nil
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if b.bitsRead > 64 {
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return io.ErrUnexpectedEOF
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}
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return nil
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}
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