106 lines
2.6 KiB
Go
106 lines
2.6 KiB
Go
// Copyright 2009 The Go Authors. 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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// Represents bencode data structure using native Go types: booleans, floats,
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// strings, slices, and maps.
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package bencode
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import (
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"io"
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)
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// Decode a bencode stream
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// Decode parses the stream r and returns the
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// generic bencode object representation. The object representation is a tree
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// of Go data types. The data return value may be one of string,
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// int64, uint64, []interface{} or map[string]interface{}. The slice and map
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// elements may in turn contain any of the types listed above and so on.
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//
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// If Decode encounters a syntax error, it returns with err set to an
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// instance of Error.
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func Decode(r io.Reader) (data interface{}, err error) {
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jb := newDecoder(nil, nil)
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err = parse(r, jb)
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if err == nil {
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data = jb.Copy()
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}
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return
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}
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type decoder struct {
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// A value being constructed.
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value interface{}
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// Container entity to flush into. Can be either []interface{} or
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// map[string]interface{}.
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container interface{}
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// The index into the container interface. Either int or string.
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index interface{}
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}
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func newDecoder(container interface{}, key interface{}) *decoder {
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return &decoder{container: container, index: key}
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}
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func (j *decoder) Int64(i int64) { j.value = int64(i) }
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func (j *decoder) Uint64(i uint64) { j.value = uint64(i) }
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func (j *decoder) Float64(f float64) { j.value = float64(f) }
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func (j *decoder) String(s string) { j.value = s }
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func (j *decoder) Bool(b bool) { j.value = b }
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func (j *decoder) Null() { j.value = nil }
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func (j *decoder) Array() { j.value = make([]interface{}, 0, 8) }
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func (j *decoder) Map() { j.value = make(map[string]interface{}) }
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func (j *decoder) Elem(i int) builder {
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v, ok := j.value.([]interface{})
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if !ok {
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v = make([]interface{}, 0, 8)
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j.value = v
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}
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/* XXX There is a bug in here somewhere, but append() works fine.
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lens := len(v)
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if cap(v) <= lens {
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news := make([]interface{}, 0, lens*2)
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copy(news, j.value.([]interface{}))
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v = news
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}
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v = v[0 : lens+1]
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*/
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v = append(v, nil)
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j.value = v
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return newDecoder(v, i)
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}
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func (j *decoder) Key(s string) builder {
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m, ok := j.value.(map[string]interface{})
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if !ok {
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m = make(map[string]interface{})
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j.value = m
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}
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return newDecoder(m, s)
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}
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func (j *decoder) Flush() {
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switch c := j.container.(type) {
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case []interface{}:
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index := j.index.(int)
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c[index] = j.Copy()
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case map[string]interface{}:
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index := j.index.(string)
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c[index] = j.Copy()
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}
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}
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// Get the value built by this builder.
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func (j *decoder) Copy() interface{} {
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return j.value
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}
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