ml
63 lines
1.6 KiB
Go
63 lines
1.6 KiB
Go
package resource
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import (
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"bytes"
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"io"
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)
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type listMerger struct {
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list List
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}
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// Compound indicates whether the resource is a compound one, which can contain zero, one, or more blocks.
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// Simple resources always contain exactly one block.
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func (view listMerger) Compound() bool {
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return view.list[0].Compound()
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}
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// ContentType specifies how the data in the resource shall be interpreted.
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func (view listMerger) ContentType() ContentType {
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return view.list[0].ContentType()
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}
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// Compressed indicates whether the data should be compressed when serialized.
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func (view listMerger) Compressed() bool {
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return view.list[0].Compressed()
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}
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// BlockCount returns the maximum count of all resources.
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func (view listMerger) BlockCount() (max int) {
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for _, layer := range view.list {
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count := layer.BlockCount()
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if max < count {
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max = count
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}
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}
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return
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}
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// Block returns a reader for the identified block in the resource.
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// The view returns the block from the first resource that has a non-empty block.
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// The resources are checked from last-to-first.
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func (view listMerger) Block(index int) (reader io.Reader, err error) {
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blockCount := view.BlockCount()
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if (index < 0) || (index >= blockCount) {
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return nil, ErrBlockNotFound(index, blockCount)
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}
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for layer := len(view.list) - 1; (layer >= 0) && (reader == nil); layer-- {
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tempReader, tempErr := view.list[layer].Block(index)
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if tempErr == nil {
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var buf [1]byte
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read, _ := tempReader.Read(buf[:])
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if read == 1 {
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reader, err = view.list[layer].Block(index)
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}
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}
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}
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if (reader == nil) && (err == nil) {
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reader = bytes.NewBuffer(nil)
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}
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return
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}
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