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package bencode
import (
"errors"
"fmt"
"sort"
)
// Encode encodes a string, int, dict or list value to a bencoded string.
func Encode(data interface{}) ([]byte, error) {
return encodeItem(data)
}
// EncodeString encodes a string value.
func EncodeString(data string) ([]byte, error) {
length := fmt.Sprintf("%d:", len(data))
out := make([]byte, 0, len(length)+len(data)+1)
out = append(out, []byte(length)...)
return append(out, []byte(data)...), nil
}
// EncodeInt encodes a int value.
func EncodeInt(data int64) ([]byte, error) {
ib := fmt.Sprintf("i%de", data)
return []byte(ib), nil
}
// EncodeDict encodes a dict value.
func EncodeDict(data map[string]interface{}) ([]byte, error) {
out := make([]byte, 0, 2)
out = append(out, 'd')
// Sort keys
list := make(sort.StringSlice, len(data))
i := 0
for key := range data {
list[i] = key
i++
}
list.Sort()
for _, key := range list {
keyb, err := EncodeString(key)
if err != nil {
return nil, err
}
value, err := encodeItem(data[key])
if err != nil {
return nil, err
}
out = append(out, keyb...)
out = append(out, value...)
}
return append(out, 'e'), nil
}
// EncodeList encodes a list value.
func EncodeList(data []interface{}) ([]byte, error) {
out := make([]byte, 0, 2)
out = append(out, 'l')
for _, item := range data {
b, err := encodeItem(item)
if err != nil {
return nil, err
}
out = append(out, b...)
}
return append(out, 'e'), nil
}
// EncodeItem encodes an item of dict or list.
func encodeItem(data interface{}) ([]byte, error) {
switch v := data.(type) {
case []byte:
return EncodeString(string(v))
case string:
return EncodeString(v)
case int:
return EncodeInt(int64(v))
case int16:
return EncodeInt(int64(v))
case int32:
return EncodeInt(int64(v))
case int64:
return EncodeInt(int64(v))
case []interface{}:
return EncodeList(v)
case map[string]interface{}:
return EncodeDict(v)
default:
return nil, errors.New("bencode: invalid type to encode")
}
}
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