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// Copyright 2017 Elias Kosunen
//
// 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.
//
// This file is a part of scnlib:
// https://github.com/eliaskosunen/scnlib
#ifndef SCN_DETAIL_ERROR_H
#define SCN_DETAIL_ERROR_H
#include "fwd.h"
namespace scn {
SCN_BEGIN_NAMESPACE
/**
* Error class.
* Used as a return value for functions without a success value.
*/
class SCN_TRIVIAL_ABI error {
public:
/// Error code
enum code : char {
/// No error
good = 0,
/// EOF
end_of_range,
/// Format string was invalid
invalid_format_string,
/// Scanned value was invalid for given type.
/// e.g. a period '.' when scanning for an int
invalid_scanned_value,
/// Stream does not support the performed operation
invalid_operation,
/// Scanned value was out of range for the desired type.
/// (e.g. `>2^32` for an `uint32_t`)
value_out_of_range,
/// Invalid argument given to operation
invalid_argument,
/// Source range has invalid (utf-8 or utf-16) encoding
invalid_encoding,
/// This operation is only possible with exceptions enabled
exceptions_required,
/// The source range emitted an error.
source_error,
/// The source range emitted an error that cannot be recovered
/// from. The stream is now unusable.
unrecoverable_source_error,
unrecoverable_internal_error,
max_error
};
struct success_tag_t {
};
static constexpr success_tag_t success_tag() noexcept
{
return {};
}
constexpr error() noexcept = default;
constexpr error(success_tag_t) noexcept : error() {}
constexpr error(enum code c, const char* m) noexcept
: m_msg(m), m_code(c)
{
}
/// Evaluated to true if there was no error
constexpr explicit operator bool() const noexcept
{
return m_code == good;
}
constexpr bool operator!() const noexcept
{
return !(operator bool());
}
constexpr operator enum code() const noexcept { return m_code; }
/// Get error code
SCN_NODISCARD constexpr enum code code() const noexcept
{
return m_code;
}
SCN_NODISCARD constexpr const char* msg() const noexcept
{
return m_msg;
}
/// Returns `true` if, after this error, the state of the given input
/// range is consistent, and thus, the range can be used for new
/// scanning operations.
SCN_NODISCARD constexpr bool is_recoverable() const noexcept
{
return !(m_code == unrecoverable_source_error ||
m_code == unrecoverable_internal_error);
}
private:
const char* m_msg{nullptr};
enum code m_code { good };
};
constexpr inline bool operator==(error a, error b) noexcept
{
return a.code() == b.code();
}
constexpr inline bool operator!=(error a, error b) noexcept
{
return !(a == b);
}
namespace detail {
struct error_handler {
constexpr error_handler() = default;
void on_error(error e);
void on_error(const char* msg);
};
} // namespace detail
SCN_END_NAMESPACE
} // namespace scn
#endif
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