5c10dc8f4e
Defines a WriteStream structure for buffering writes, similar to the existing ReadStream. WriteStreams can be created on OutEndpoints by using ep.NewStream().
59 lines
2.0 KiB
Go
59 lines
2.0 KiB
Go
// Copyright 2017 the gousb Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package gousb
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func (e *endpoint) newStream(size, count int) (*stream, error) {
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var ts []transferIntf
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for i := 0; i < count; i++ {
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t, err := newUSBTransfer(e.ctx, e.h, &e.Desc, size, e.Timeout)
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if err != nil {
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for _, t := range ts {
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t.free()
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}
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return nil, err
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}
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ts = append(ts, t)
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}
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return newStream(ts), nil
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}
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// NewStream prepares a new read stream that will keep reading data from the
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// endpoint until closed.
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// Size defines a buffer size for a single read transaction and count
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// defines how many transactions should be active at any time.
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// By keeping multiple transfers active at the same time, a Stream reduces
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// the latency between subsequent transfers and increases reading throughput.
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func (e *InEndpoint) NewStream(size, count int) (*ReadStream, error) {
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s, err := e.newStream(size, count)
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if err != nil {
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return nil, err
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}
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s.submitAll()
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return &ReadStream{s: s}, nil
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}
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// NewStream prepares a new write stream that will write data in the background.
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// Size defines a buffer size for a single write transaction and count
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// defines how many transactions may be active at any time.
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// By buffering the writes, a Stream reduces the latency between subsequent
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// transfers and increases writing throughput.
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func (e *OutEndpoint) NewStream(size, count int) (*WriteStream, error) {
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s, err := e.newStream(size, count)
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if err != nil {
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return nil, err
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}
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return &WriteStream{s: s}, nil
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}
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