60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
// Copyright (C) 2014 Jakob Borg. All rights reserved. Use of this source code
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// is governed by an MIT-style license that can be found in the LICENSE file.
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package xdr
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import (
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"fmt"
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"reflect"
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)
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var padBytes = []byte{0, 0, 0}
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// Pad returns the number of bytes that should be added to an item of length l
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// bytes to conform to the XDR padding standard. This function is used by the
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// generated marshalling code.
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func Padding(l int) int {
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d := l % 4
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if d == 0 {
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return 0
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}
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return 4 - d
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}
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// ElementSizeExceeded returns an error describing the violated size
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// constraint. This function is used by the generated marshalling code.
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func ElementSizeExceeded(field string, size, limit int) error {
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return fmt.Errorf("%s exceeds size limit; %d > %d", field, size, limit)
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}
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type XDRSizer interface {
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XDRSize() int
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}
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// SizeOfSlice returns the XDR encoded size of the given []T. Supported types
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// for T are string, []byte and types implementing XDRSizer. SizeOfSlice
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// panics if the parameter is not a slice or if T is not one of the supported
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// types. This function is used by the generated marshalling code.
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func SizeOfSlice(ss interface{}) int {
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l := 0
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switch ss := ss.(type) {
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case []string:
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for _, s := range ss {
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l += 4 + len(s) + Padding(len(s))
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}
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case [][]byte:
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for _, s := range ss {
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l += 4 + len(s) + Padding(len(s))
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}
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default:
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v := reflect.ValueOf(ss)
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for i := 0; i < v.Len(); i++ {
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l += v.Index(i).Interface().(XDRSizer).XDRSize()
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}
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}
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return l
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}
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