55 lines
1.6 KiB
C++
55 lines
1.6 KiB
C++
// Copyright 2019 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_string/format.h"
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#include <cstdio>
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namespace pw::string {
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StatusWithSize Format(std::span<char> buffer, const char* format, ...) {
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va_list args;
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va_start(args, format);
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const StatusWithSize result = FormatVaList(buffer, format, args);
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va_end(args);
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return result;
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}
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StatusWithSize FormatVaList(std::span<char> buffer,
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const char* format,
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va_list args) {
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if (buffer.empty()) {
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return StatusWithSize::ResourceExhausted();
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}
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const int result = std::vsnprintf(buffer.data(), buffer.size(), format, args);
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// If an error occurred, the number of characters written is unknown.
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// Discard any output by terminating the buffer.
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if (result < 0) {
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buffer[0] = '\0';
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return StatusWithSize::InvalidArgument();
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}
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// If result >= buffer.size(), the output was truncated and null-terminated.
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if (static_cast<unsigned>(result) >= buffer.size()) {
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return StatusWithSize::ResourceExhausted(buffer.size() - 1);
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}
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return StatusWithSize(result);
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}
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} // namespace pw::string
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