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// Copyright 2014-2021 Ulrich Kunitz. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xz
import (
"errors"
"io"
)
// putUint32LE puts the little-endian representation of x into the first
// four bytes of p.
func putUint32LE(p []byte, x uint32) {
p[0] = byte(x)
p[1] = byte(x >> 8)
p[2] = byte(x >> 16)
p[3] = byte(x >> 24)
}
// putUint64LE puts the little-endian representation of x into the first
// eight bytes of p.
func putUint64LE(p []byte, x uint64) {
p[0] = byte(x)
p[1] = byte(x >> 8)
p[2] = byte(x >> 16)
p[3] = byte(x >> 24)
p[4] = byte(x >> 32)
p[5] = byte(x >> 40)
p[6] = byte(x >> 48)
p[7] = byte(x >> 56)
}
// uint32LE converts a little endian representation to an uint32 value.
func uint32LE(p []byte) uint32 {
return uint32(p[0]) | uint32(p[1])<<8 | uint32(p[2])<<16 |
uint32(p[3])<<24
}
// putUvarint puts a uvarint representation of x into the byte slice.
func putUvarint(p []byte, x uint64) int {
i := 0
for x >= 0x80 {
p[i] = byte(x) | 0x80
x >>= 7
i++
}
p[i] = byte(x)
return i + 1
}
// errOverflow indicates an overflow of the 64-bit unsigned integer.
var errOverflowU64 = errors.New("xz: uvarint overflows 64-bit unsigned integer")
// readUvarint reads a uvarint from the given byte reader.
func readUvarint(r io.ByteReader) (x uint64, n int, err error) {
const maxUvarintLen = 10
var s uint
i := 0
for {
b, err := r.ReadByte()
if err != nil {
return x, i, err
}
i++
if i > maxUvarintLen {
return x, i, errOverflowU64
}
if b < 0x80 {
if i == maxUvarintLen && b > 1 {
return x, i, errOverflowU64
}
return x | uint64(b)<<s, i, nil
}
x |= uint64(b&0x7f) << s
s += 7
}
}
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