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