libcruft-util/json2/personality/jsonish.cpp

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/*
* 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
*
* http://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.
*
* Copyright 2017 Danny Robson <danny@nerdcruft.net>
*/
#include "./jsonish.hpp"
#include "./base.hpp"
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#include "../event.hpp"
#include "../except.hpp"
#include "../../debug.hpp"
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using util::json2::personality::jsonish;
///////////////////////////////////////////////////////////////////////////////
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const char*
jsonish::consume_whitespace (const char *first, const char *last) noexcept
{
auto cursor = base<jsonish>::consume_whitespace (first, last);
// consume a comment
if (cursor != last && *cursor == '#') {
while (cursor != last && *cursor != '\n')
++cursor;
return consume_whitespace (cursor, last);
}
return cursor;
}
///////////////////////////////////////////////////////////////////////////////
// format is:
// int: '0x' hex+ | '0' oct+ | '0b' bit+
//
// float: significand exp?
// significand: digit+ ('.' digit*)?
// exp: [eE] sign? digit+
//
// number: [+-] (int | float)
const char*
jsonish::parse_number (const std::function<callback_t> &cb,
const char *first,
const char *last)
{
auto cursor = first;
if (cursor != last && (*cursor == '+' || *cursor == '-'))
++cursor;
if (cursor != last && *cursor == '0') {
++cursor;
if (cursor == last)
throw parse_error {cursor};
char max = '9';
switch (*cursor) {
case 'x': {
// parse the hex integer here because we can simplify the
// remaining cases somewhat if we don't need to care about the
// multiple ranges of valid digits.
++cursor;
auto digit_start = cursor;
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while (cursor != last && ((('0' <= *cursor) && (*cursor <= '9')) ||
(('a' <= *cursor) && (*cursor <= 'f')) ||
(('A' <= *cursor) && (*cursor <= 'F'))))
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++cursor;
if (digit_start == cursor)
throw parse_error {cursor};
cb ({first, cursor});
return cursor;
};
case 'b': max = '1'; break;
case '0'...'7': max = '7'; break;
case '.':
goto frac;
}
auto digit_start = ++cursor;
while (cursor != last && '0' <= *cursor && *cursor <= max)
++cursor;
if (digit_start == cursor)
throw parse_error {cursor};
cb ({first, cursor});
return cursor;
}
while (cursor != last && '0' <= *cursor && *cursor <= '9')
++cursor;
if (cursor == last)
goto done;
if (*cursor != '.')
goto exp;
frac:
++cursor;
while (cursor != last && *cursor >= '0' && *cursor <= '9')
++cursor;
if (cursor == last)
goto done;
exp:
if (cursor != last && (*cursor == 'e' || *cursor == 'E')) {
++cursor;
if (cursor != last && (*cursor == '+' || *cursor == '-'))
++cursor;
auto digit_start = cursor;
while (cursor != last && '0' <= *cursor && *cursor <= '9')
++cursor;
if (digit_start == cursor)
throw parse_error {cursor};
}
if (first == cursor)
throw parse_error {cursor};
done:
cb ({first, cursor});
return cursor;
}
///////////////////////////////////////////////////////////////////////////////
const char*
jsonish::parse_key (const std::function<callback_t> &cb,
const char *first,
const char *last)
{
auto cursor = first;
if (cursor == last)
throw parse_error {cursor};
// must start with alpha or underscore
switch (*cursor) {
case 'a'...'z':
case 'A'...'Z':
case '_':
++cursor;
break;
default:
throw parse_error {cursor};
}
while (cursor != last) {
switch (*cursor) {
case 'a'...'z':
case 'A'...'Z':
case '_':
case '0'...'9':
++cursor;
break;
default:
cb ({first, cursor});
return cursor;
}
}
cb ({first, cursor});
return cursor;
}
///////////////////////////////////////////////////////////////////////////////
const char*
jsonish::parse_string (const std::function<callback_t> &cb,
const char *first,
const char *last)
{
if (first == last)
throw parse_error {first};
if (*first == '"')
return base<jsonish>::parse_string (cb, first, last);
else
return parse_key (cb, first, last);
}