84 lines
1.6 KiB
Go
84 lines
1.6 KiB
Go
package crc32
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import (
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"context"
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"flag"
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"fmt"
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"hash/crc32"
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"hash_utils/tools"
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"os"
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"github.com/google/subcommands"
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)
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type (
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CRC32Cmd struct {
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file string
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table string
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}
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)
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func (*CRC32Cmd) Name() string { return "crc32" }
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func (*CRC32Cmd) Synopsis() string { return "" }
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func (*CRC32Cmd) Usage() string {
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return `Usage: hash_utils crc32
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Algorithm available:
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- Castagnoli
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- Koopman
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- IEEE
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Options:
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`
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}
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func (p *CRC32Cmd) SetFlags(f *flag.FlagSet) {
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f.StringVar(&p.file, "file", "", "get the checksum of a file")
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f.StringVar(&p.table, "table", "IEEE", "Predefined CRC-32 algorithms")
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}
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func (p *CRC32Cmd) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
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var err error
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var param uint32 = crc32.IEEE
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if len(p.table) > 0 {
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param, err = parse(p.table)
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if err != nil {
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fmt.Println("Available tables: IEEE Castagnoli Koopman")
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return subcommands.ExitFailure
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}
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}
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if len(p.file) > 0 {
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b, err := os.ReadFile(p.file)
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if err != nil {
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fmt.Fprintln(os.Stderr, "error: failed to read file:", err)
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return subcommands.ExitFailure
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}
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h := tools.CRC32(b, param)
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fmt.Printf("%s: %s\n", f.Name(), h)
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return subcommands.ExitSuccess
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}
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for _, arg := range f.Args() {
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h := tools.CRC32([]byte(arg), param)
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fmt.Printf("%s: %s\n", arg, h)
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}
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return subcommands.ExitSuccess
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}
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func parse(tableName string) (uint32, error) {
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switch tableName {
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case "Castagnoli":
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return crc32.Castagnoli, nil
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case "Koopman":
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return crc32.Koopman, nil
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case "IEEE":
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return crc32.IEEE, nil
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}
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return 0, fmt.Errorf("invalid table name: %s", tableName)
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}
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