Alexander
136 lines
4.0 KiB
Go
136 lines
4.0 KiB
Go
// Copyright (C) MongoDB, Inc. 2025-present.
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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// Package binaryutil provides utility functions for working with binary data.
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package binaryutil
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import (
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"bytes"
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"encoding/binary"
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)
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// Append32 appends a uint32 or int32 value to dst in little-endian byte order.
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// Byte shifting is done directly to prevent overflow security errors, in
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// compliance with gosec G115.
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//
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// See: https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/encoding/binary/binary.go;l=92
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func Append32[T ~uint32 | ~int32](dst []byte, v T) []byte {
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return append(dst,
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byte(v),
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byte(v>>8),
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byte(v>>16),
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byte(v>>24),
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)
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}
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// Append64 appends a uint64 or int64 value to dst in little-endian byte order.
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// Byte shifting is done directly to prevent overflow security errors, in
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// compliance with gosec G115.
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//
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// See: https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/encoding/binary/binary.go;l=119
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func Append64[T ~uint64 | ~int64](dst []byte, v T) []byte {
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return append(dst,
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byte(v),
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byte(v>>8),
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byte(v>>16),
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byte(v>>24),
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byte(v>>32),
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byte(v>>40),
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byte(v>>48),
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byte(v>>56),
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)
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}
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// ReadU32 reads a uint32 from src in little-endian byte order. ReadU32 and
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// ReadI32 are separate functions to avoid unsafe casting between unsigned and
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// signed integers.
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func ReadU32(src []byte) (uint32, []byte, bool) {
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if len(src) < 4 {
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return 0, src, false
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}
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return binary.LittleEndian.Uint32(src), src[4:], true
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}
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// ReadI32 reads an int32 from src in little-endian byte order.
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// Byte shifting is done directly to prevent overflow security errors, in
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// compliance with gosec G115. ReadU32 and ReadI32 are separate functions to
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// avoid unsafe casting between unsigned and signed integers.
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//
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// See: https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/encoding/binary/binary.go;l=79
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func ReadI32(src []byte) (int32, []byte, bool) {
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if len(src) < 4 {
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return 0, src, false
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}
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_ = src[3] // bounds check hint to compiler
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value := int32(src[0]) |
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int32(src[1])<<8 |
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int32(src[2])<<16 |
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int32(src[3])<<24
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return value, src[4:], true
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}
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// ReadU64 reads a uint64 from src in little-endian byte order. ReadU64 and
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// ReadI64 are separate functions to avoid unsafe casting between unsigned and
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// signed integers.
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func ReadU64(src []byte) (uint64, []byte, bool) {
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if len(src) < 8 {
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return 0, src, false
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}
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return binary.LittleEndian.Uint64(src), src[8:], true
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}
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// ReadI64 reads an int64 from src in little-endian byte order.
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// Byte shifting is done directly to prevent overflow security errors, in
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// compliance with gosec G115. ReadU64 and ReadI64 are separate functions to
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// avoid unsafe casting between unsigned and signed integers.
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//
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// See: https://cs.opensource.google/go/go/+/refs/tags/go1.19:src/encoding/binary/binary.go;l=101
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func ReadI64(src []byte) (int64, []byte, bool) {
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if len(src) < 8 {
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return 0, src, false
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}
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_ = src[7] // bounds check hint to compiler
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value := int64(src[0]) |
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int64(src[1])<<8 |
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int64(src[2])<<16 |
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int64(src[3])<<24 |
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int64(src[4])<<32 |
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int64(src[5])<<40 |
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int64(src[6])<<48 |
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int64(src[7])<<56
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return value, src[8:], true
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}
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// ReadCStringBytes reads a null-terminated C string from src as a byte slice.
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// This is the base implementation used by ReadCString to ensure a single source
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// of truth for C string parsing logic.
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func ReadCStringBytes(src []byte) ([]byte, []byte, bool) {
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idx := bytes.IndexByte(src, 0x00)
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if idx < 0 {
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return nil, src, false
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}
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return src[:idx], src[idx+1:], true
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}
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// ReadCString reads a null-terminated C string from src as a string.
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// It delegates to ReadCStringBytes to maintain a single source of truth for
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// C string parsing logic.
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func ReadCString(src []byte) (string, []byte, bool) {
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cstr, rem, ok := ReadCStringBytes(src)
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if !ok {
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return "", src, false
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}
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return string(cstr), rem, true
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}
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