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// Copyright 2010 Todd Ditchendorf
//
// 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.
#import "PKScientificNumberState.h"
#import <ParseKit/PKReader.h>
#import <ParseKit/PKTypes.h>
@interface PKTokenizerState ()
- (void)append:(PKUniChar)c;
@end
@interface PKNumberState ()
- (CGFloat)absorbDigitsFromReader:(PKReader *)r isFraction:(BOOL)isFraction;
- (void)parseRightSideFromReader:(PKReader *)r;
- (void)reset:(PKUniChar)cin;
- (CGFloat)value;
@end
@implementation PKScientificNumberState
- (id)init {
if (self = [super init]) {
self.allowsScientificNotation = YES;
}
return self;
}
- (void)parseRightSideFromReader:(PKReader *)r {
NSParameterAssert(r);
[super parseRightSideFromReader:r];
if (!allowsScientificNotation) {
return;
}
if ('e' == c || 'E' == c) {
PKUniChar e = c;
c = [r read];
BOOL hasExp = isdigit(c);
negativeExp = ('-' == c);
BOOL positiveExp = ('+' == c);
if (!hasExp && (negativeExp || positiveExp)) {
c = [r read];
hasExp = isdigit(c);
}
if (PKEOF != c) {
[r unread];
}
if (hasExp) {
[self append:e];
if (negativeExp) {
[self append:'-'];
} else if (positiveExp) {
[self append:'+'];
}
c = [r read];
exp = [super absorbDigitsFromReader:r isFraction:NO];
}
}
}
- (void)reset:(PKUniChar)cin {
[super reset:cin];
exp = (CGFloat)0.0;
negativeExp = NO;
}
- (CGFloat)value {
CGFloat result = (CGFloat)floatValue;
NSUInteger i = 0;
for ( ; i < exp; i++) {
if (negativeExp) {
result /= (CGFloat)10.0;
} else {
result *= (CGFloat)10.0;
}
}
return (CGFloat)result;
}
@synthesize allowsScientificNotation;
@end