94 lines
3.0 KiB
C++
94 lines
3.0 KiB
C++
// error_policy.hh
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// This file is part of libpbe; see http://anyterm.org/
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// (C) 2008 Philip Endecott
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// Distributed under the Boost Software License, Version 1.0:
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//
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// Permission is hereby granted, free of charge, to any person or organization
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// obtaining a copy of the software and accompanying documentation covered by
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// this license (the "Software") to use, reproduce, display, distribute,
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// execute, and transmit the Software, and to prepare derivative works of the
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// Software, and to permit third-parties to whom the Software is furnished to
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// do so, all subject to the following:
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//
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// The copyright notices in the Software and this entire statement, including
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// the above license grant, this restriction and the following disclaimer,
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// must be included in all copies of the Software, in whole or in part, and
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// all derivative works of the Software, unless such copies or derivative
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// works are solely in the form of machine-executable object code generated by
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// a source language processor.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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#ifndef libpbe_charset_error_policy_hh
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#define libpbe_charset_error_policy_hh
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namespace pbe {
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// Error Policies
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// --------------
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//
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// The function template char_conv takes a template parameter that specifies
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// its behaviour on error. This file supplies implementations of the
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// error_policy concept, though the user is free to supply
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// their own.
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//
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// An error_policy class should provide the following static
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// member functions, corresponding to the different errors that char_conv
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// may detect:
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//
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// static int no_equivalent()
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// Called when the output character set does not have an equivalent
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// character.
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//
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// static int invalid_input()
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// Called when the input is not valid for the input character set.
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//
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// TODO - perhaps something for approximate equivalents?
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//
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// If the function returns, the value that it returns is used as the return
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// value of char_conv.
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// In cases where these error policies throw an exception, by default it
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// is the following:
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struct conversion_error {};
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// Throw an exception on error:
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template <typename exception = conversion_error>
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struct error_policy_throw {
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static int no_equivalent() {
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throw exception();
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}
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static int invalid_input() {
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throw exception();
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}
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};
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// Return a sentinel value on error:
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template <int sentinel>
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struct error_policy_return_sentinel {
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static int no_equivalent() {
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return sentinel;
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}
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static int invalid_input() {
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return sentinel;
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}
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};
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// The default error policy is error_policy_throw:
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typedef error_policy_throw<> default_error_policy;
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};
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#endif
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