90 lines
2.2 KiB
C++
90 lines
2.2 KiB
C++
// Copyright 2022 The Pigweed Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not
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// use this file except in compliance with the License. You may obtain a copy of
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// the License at
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//
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// https://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, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations under
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// the License.
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#include "pw_sys_io/sys_io.h"
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#include <cinttypes>
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#include "pico/stdlib.h"
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#include "pw_status/status.h"
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namespace {
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void LazyInitSysIo() {
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static bool initialized = false;
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if (!initialized) {
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stdio_init_all();
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initialized = true;
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}
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}
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// Spin until host connects.
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void WaitForConnect() {
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while (!stdio_usb_connected()) {
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sleep_ms(50);
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}
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}
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} // namespace
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// This whole implementation is very inefficient because it only reads / writes
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// 1 byte at a time. It also does lazy initialization checks with every byte.
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namespace pw::sys_io {
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Status ReadByte(std::byte* dest) {
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LazyInitSysIo();
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WaitForConnect();
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int c = PICO_ERROR_TIMEOUT;
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while (c == PICO_ERROR_TIMEOUT) {
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c = getchar_timeout_us(0);
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}
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*dest = static_cast<std::byte>(c);
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return OkStatus();
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}
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Status TryReadByte(std::byte* dest) {
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LazyInitSysIo();
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int c = getchar_timeout_us(0);
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if (c == PICO_ERROR_TIMEOUT) {
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return Status::DeadlineExceeded();
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}
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*dest = static_cast<std::byte>(c);
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return OkStatus();
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}
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Status WriteByte(std::byte b) {
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// The return value of this is just the character sent.
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LazyInitSysIo();
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putchar_raw(static_cast<int>(b));
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return OkStatus();
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}
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// Writes a string using pw::sys_io, and add newline characters at the end.
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StatusWithSize WriteLine(const std::string_view& s) {
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size_t chars_written = 0;
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StatusWithSize result = WriteBytes(as_bytes(span(s)));
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if (!result.ok()) {
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return result;
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}
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chars_written += result.size();
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// Write trailing newline.
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result = WriteBytes(as_bytes(span("\r\n", 2)));
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chars_written += result.size();
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return StatusWithSize(OkStatus(), chars_written);
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}
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} // namespace pw::sys_io
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