148 lines
3.9 KiB
Objective-C
148 lines
3.9 KiB
Objective-C
//
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// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
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//
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#import "NSData+OWS.h"
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#import <SessionProtocolKit/OWSAsserts.h>
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NS_ASSUME_NONNULL_BEGIN
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@implementation NSData (OWS)
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+ (NSData *)join:(NSArray<NSData *> *)datas
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{
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OWSAssert(datas);
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NSMutableData *result = [NSMutableData new];
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for (NSData *data in datas) {
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[result appendData:data];
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}
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return [result copy];
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}
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- (NSData *)dataByAppendingData:(NSData *)data
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{
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NSMutableData *result = [self mutableCopy];
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[result appendData:data];
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return [result copy];
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}
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#pragma mark - Hex
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- (NSString *)hexadecimalString
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{
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/* Returns hexadecimal string of NSData. Empty string if data is empty. */
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const unsigned char *dataBuffer = (const unsigned char *)[self bytes];
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if (!dataBuffer) {
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return @"";
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}
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NSUInteger dataLength = [self length];
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NSMutableString *hexString = [NSMutableString stringWithCapacity:(dataLength * 2)];
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for (NSUInteger i = 0; i < dataLength; ++i) {
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[hexString appendFormat:@"%02x", dataBuffer[i]];
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}
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return [hexString copy];
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}
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+ (nullable NSData *)dataFromHexString:(NSString *)hexString {
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NSMutableData *data = [NSMutableData new];
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if (hexString.length % 2 != 0) {
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OWSFailDebug(@"Hexadecimal string has unexpected length: %@ (%lu)", hexString, (unsigned long)hexString.length);
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return nil;
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}
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for (NSUInteger i = 0; i + 2 <= hexString.length; i += 2) {
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NSString *_Nullable byteString = [hexString substringWithRange:NSMakeRange(i, 2)];
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if (!byteString) {
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OWSFailDebug(@"Couldn't slice hexadecimal string.");
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return nil;
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}
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unsigned byteValue;
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if (![[NSScanner scannerWithString:byteString] scanHexInt:&byteValue]) {
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OWSFailDebug(@"Couldn't parse hex byte: %@.", byteString);
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return nil;
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}
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if (byteValue > 0xff) {
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OWSFailDebug(@"Invalid hex byte: %@ (%d).", byteString, byteValue);
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return nil;
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}
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uint8_t byte = (uint8_t)(0xff & byteValue);
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[data appendBytes:&byte length:1];
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}
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return [data copy];
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}
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#pragma mark - Base64
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+ (nullable NSData *)dataFromBase64StringNoPadding:(NSString *)aString
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{
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int padding = aString.length % 4;
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NSMutableString *strResult = [aString mutableCopy];
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if (padding != 0) {
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int charsToAdd = 4 - padding;
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for (int i = 0; i < charsToAdd; i++) {
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[strResult appendString:@"="];
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}
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}
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return [self dataFromBase64String:strResult];
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}
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//
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// dataFromBase64String:
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//
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// Creates an NSData object containing the base64 decoded representation of
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// the base64 string 'aString'
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//
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// Parameters:
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// aString - the base64 string to decode
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//
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// returns the NSData representation of the base64 string
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//
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+ (nullable NSData *)dataFromBase64String:(NSString *)aString
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{
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return [[NSData alloc] initWithBase64EncodedString:aString options:NSDataBase64DecodingIgnoreUnknownCharacters];
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}
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//
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// base64EncodedString
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//
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// Creates an NSString object that contains the base 64 encoding of the
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// receiver's data. Lines are broken at 64 characters long.
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//
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// returns an NSString being the base 64 representation of the
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// receiver.
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//
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- (NSString *)base64EncodedString
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{
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return [self base64EncodedStringWithOptions:0];
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}
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#pragma mark -
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- (BOOL)ows_constantTimeIsEqualToData:(NSData *)other
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{
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volatile UInt8 isEqual = 0;
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if (self.length != other.length) {
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return NO;
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}
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UInt8 *leftBytes = (UInt8 *)self.bytes;
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UInt8 *rightBytes = (UInt8 *)other.bytes;
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for (int i = 0; i < self.length; i++) {
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// rather than returning as soon as we find a discrepency, we compare the rest of
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// the byte stream to maintain a constant time comparison
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isEqual |= leftBytes[i] ^ rightBytes[i];
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}
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return isEqual == 0;
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}
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@end
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NS_ASSUME_NONNULL_END
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