694 lines
25 KiB
Objective-C
Executable File
694 lines
25 KiB
Objective-C
Executable File
//
|
|
// GTMBase64.m
|
|
//
|
|
// Copyright 2006-2008 Google Inc.
|
|
//
|
|
// 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 "QN_GTM_Base64.h"
|
|
|
|
static const char *kBase64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
static const char *kWebSafeBase64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
|
|
static const char kBase64PaddingChar = '=';
|
|
static const char kBase64InvalidChar = 99;
|
|
|
|
static const char kBase64DecodeChars[] = {
|
|
// This array was generated by the following code:
|
|
// #include <sys/time.h>
|
|
// #include <stdlib.h>
|
|
// #include <string.h>
|
|
// main()
|
|
// {
|
|
// static const char Base64[] =
|
|
// "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
// char *pos;
|
|
// int idx, i, j;
|
|
// printf(" ");
|
|
// for (i = 0; i < 255; i += 8) {
|
|
// for (j = i; j < i + 8; j++) {
|
|
// pos = strchr(Base64, j);
|
|
// if ((pos == NULL) || (j == 0))
|
|
// idx = 99;
|
|
// else
|
|
// idx = pos - Base64;
|
|
// if (idx == 99)
|
|
// printf(" %2d, ", idx);
|
|
// else
|
|
// printf(" %2d/*%c*/,", idx, j);
|
|
// }
|
|
// printf("\n ");
|
|
// }
|
|
// }
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 62 /*+*/, 99, 99, 99, 63 /*/ */,
|
|
52 /*0*/, 53 /*1*/, 54 /*2*/, 55 /*3*/, 56 /*4*/, 57 /*5*/, 58 /*6*/, 59 /*7*/,
|
|
60 /*8*/, 61 /*9*/, 99, 99, 99, 99, 99, 99,
|
|
99, 0 /*A*/, 1 /*B*/, 2 /*C*/, 3 /*D*/, 4 /*E*/, 5 /*F*/, 6 /*G*/,
|
|
7 /*H*/, 8 /*I*/, 9 /*J*/, 10 /*K*/, 11 /*L*/, 12 /*M*/, 13 /*N*/, 14 /*O*/,
|
|
15 /*P*/, 16 /*Q*/, 17 /*R*/, 18 /*S*/, 19 /*T*/, 20 /*U*/, 21 /*V*/, 22 /*W*/,
|
|
23 /*X*/, 24 /*Y*/, 25 /*Z*/, 99, 99, 99, 99, 99,
|
|
99, 26 /*a*/, 27 /*b*/, 28 /*c*/, 29 /*d*/, 30 /*e*/, 31 /*f*/, 32 /*g*/,
|
|
33 /*h*/, 34 /*i*/, 35 /*j*/, 36 /*k*/, 37 /*l*/, 38 /*m*/, 39 /*n*/, 40 /*o*/,
|
|
41 /*p*/, 42 /*q*/, 43 /*r*/, 44 /*s*/, 45 /*t*/, 46 /*u*/, 47 /*v*/, 48 /*w*/,
|
|
49 /*x*/, 50 /*y*/, 51 /*z*/, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99};
|
|
|
|
static const char kWebSafeBase64DecodeChars[] = {
|
|
// This array was generated by the following code:
|
|
// #include <sys/time.h>
|
|
// #include <stdlib.h>
|
|
// #include <string.h>
|
|
// main()
|
|
// {
|
|
// static const char Base64[] =
|
|
// "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
|
|
// char *pos;
|
|
// int idx, i, j;
|
|
// printf(" ");
|
|
// for (i = 0; i < 255; i += 8) {
|
|
// for (j = i; j < i + 8; j++) {
|
|
// pos = strchr(Base64, j);
|
|
// if ((pos == NULL) || (j == 0))
|
|
// idx = 99;
|
|
// else
|
|
// idx = pos - Base64;
|
|
// if (idx == 99)
|
|
// printf(" %2d, ", idx);
|
|
// else
|
|
// printf(" %2d/*%c*/,", idx, j);
|
|
// }
|
|
// printf("\n ");
|
|
// }
|
|
// }
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 62 /*-*/, 99, 99,
|
|
52 /*0*/, 53 /*1*/, 54 /*2*/, 55 /*3*/, 56 /*4*/, 57 /*5*/, 58 /*6*/, 59 /*7*/,
|
|
60 /*8*/, 61 /*9*/, 99, 99, 99, 99, 99, 99,
|
|
99, 0 /*A*/, 1 /*B*/, 2 /*C*/, 3 /*D*/, 4 /*E*/, 5 /*F*/, 6 /*G*/,
|
|
7 /*H*/, 8 /*I*/, 9 /*J*/, 10 /*K*/, 11 /*L*/, 12 /*M*/, 13 /*N*/, 14 /*O*/,
|
|
15 /*P*/, 16 /*Q*/, 17 /*R*/, 18 /*S*/, 19 /*T*/, 20 /*U*/, 21 /*V*/, 22 /*W*/,
|
|
23 /*X*/, 24 /*Y*/, 25 /*Z*/, 99, 99, 99, 99, 63 /*_*/,
|
|
99, 26 /*a*/, 27 /*b*/, 28 /*c*/, 29 /*d*/, 30 /*e*/, 31 /*f*/, 32 /*g*/,
|
|
33 /*h*/, 34 /*i*/, 35 /*j*/, 36 /*k*/, 37 /*l*/, 38 /*m*/, 39 /*n*/, 40 /*o*/,
|
|
41 /*p*/, 42 /*q*/, 43 /*r*/, 44 /*s*/, 45 /*t*/, 46 /*u*/, 47 /*v*/, 48 /*w*/,
|
|
49 /*x*/, 50 /*y*/, 51 /*z*/, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99,
|
|
99, 99, 99, 99, 99, 99, 99, 99};
|
|
|
|
// Tests a character to see if it's a whitespace character.
|
|
//
|
|
// Returns:
|
|
// YES if the character is a whitespace character.
|
|
// NO if the character is not a whitespace character.
|
|
//
|
|
BOOL QN_IsSpace(unsigned char c) {
|
|
// we use our own mapping here because we don't want anything w/ locale
|
|
// support.
|
|
static BOOL kSpaces[256] = {
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 1, // 0-9
|
|
1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 10-19
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20-29
|
|
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, // 30-39
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40-49
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 50-59
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60-69
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 70-79
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 80-89
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 90-99
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 100-109
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 110-119
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 120-129
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 130-139
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 140-149
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 150-159
|
|
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 160-169
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 170-179
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 180-189
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 190-199
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 200-209
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 210-219
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 220-229
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 230-239
|
|
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 240-249
|
|
0, 0, 0, 0, 0, 1, // 250-255
|
|
};
|
|
return kSpaces[c];
|
|
}
|
|
|
|
// Calculate how long the data will be once it's base64 encoded.
|
|
//
|
|
// Returns:
|
|
// The guessed encoded length for a source length
|
|
//
|
|
NSUInteger QN_CalcEncodedLength(NSUInteger srcLen, BOOL padded) {
|
|
NSUInteger intermediate_result = 8 * srcLen + 5;
|
|
NSUInteger len = intermediate_result / 6;
|
|
if (padded) {
|
|
len = ((len + 3) / 4) * 4;
|
|
}
|
|
return len;
|
|
}
|
|
|
|
// Tries to calculate how long the data will be once it's base64 decoded.
|
|
// Unlike the above, this is always an upperbound, since the source data
|
|
// could have spaces and might end with the padding characters on them.
|
|
//
|
|
// Returns:
|
|
// The guessed decoded length for a source length
|
|
//
|
|
NSUInteger QN_GuessDecodedLength(NSUInteger srcLen) {
|
|
return (srcLen + 3) / 4 * 3;
|
|
}
|
|
|
|
@interface QN_GTM_Base64 (PrivateMethods)
|
|
|
|
+ (NSData *)baseEncode:(const void *)bytes
|
|
length:(NSUInteger)length
|
|
charset:(const char *)charset
|
|
padded:(BOOL)padded;
|
|
|
|
+ (NSData *)baseDecode:(const void *)bytes
|
|
length:(NSUInteger)length
|
|
charset:(const char *)charset
|
|
requirePadding:(BOOL)requirePadding;
|
|
|
|
+ (NSUInteger)baseEncode:(const char *)srcBytes
|
|
srcLen:(NSUInteger)srcLen
|
|
destBytes:(char *)destBytes
|
|
destLen:(NSUInteger)destLen
|
|
charset:(const char *)charset
|
|
padded:(BOOL)padded;
|
|
|
|
+ (NSUInteger)baseDecode:(const char *)srcBytes
|
|
srcLen:(NSUInteger)srcLen
|
|
destBytes:(char *)destBytes
|
|
destLen:(NSUInteger)destLen
|
|
charset:(const char *)charset
|
|
requirePadding:(BOOL)requirePadding;
|
|
|
|
@end
|
|
|
|
@implementation QN_GTM_Base64
|
|
|
|
//
|
|
// Standard Base64 (RFC) handling
|
|
//
|
|
|
|
+ (NSData *)encodeData:(NSData *)data {
|
|
return [self baseEncode:[data bytes]
|
|
length:[data length]
|
|
charset:kBase64EncodeChars
|
|
padded:YES];
|
|
}
|
|
|
|
+ (NSData *)decodeData:(NSData *)data {
|
|
return [self baseDecode:[data bytes]
|
|
length:[data length]
|
|
charset:kBase64DecodeChars
|
|
requirePadding:YES];
|
|
}
|
|
|
|
+ (NSData *)encodeBytes:(const void *)bytes length:(NSUInteger)length {
|
|
return [self baseEncode:bytes
|
|
length:length
|
|
charset:kBase64EncodeChars
|
|
padded:YES];
|
|
}
|
|
|
|
+ (NSData *)decodeBytes:(const void *)bytes length:(NSUInteger)length {
|
|
return [self baseDecode:bytes
|
|
length:length
|
|
charset:kBase64DecodeChars
|
|
requirePadding:YES];
|
|
}
|
|
|
|
+ (NSString *)stringByEncodingData:(NSData *)data {
|
|
NSString *result = nil;
|
|
NSData *converted = [self baseEncode:[data bytes]
|
|
length:[data length]
|
|
charset:kBase64EncodeChars
|
|
padded:YES];
|
|
if (converted) {
|
|
result = [[NSString alloc] initWithData:converted
|
|
encoding:NSASCIIStringEncoding];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
+ (NSString *)stringByEncodingBytes:(const void *)bytes length:(NSUInteger)length {
|
|
NSString *result = nil;
|
|
NSData *converted = [self baseEncode:bytes
|
|
length:length
|
|
charset:kBase64EncodeChars
|
|
padded:YES];
|
|
if (converted) {
|
|
result = [[NSString alloc] initWithData:converted
|
|
encoding:NSASCIIStringEncoding];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
+ (NSData *)decodeString:(NSString *)string {
|
|
NSData *result = nil;
|
|
NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
|
|
if (data) {
|
|
result = [self baseDecode:[data bytes]
|
|
length:[data length]
|
|
charset:kBase64DecodeChars
|
|
requirePadding:YES];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
//
|
|
// Modified Base64 encoding so the results can go onto urls.
|
|
//
|
|
// The changes are in the characters generated and also the result isn't
|
|
// padded to a multiple of 4.
|
|
// Must use the matching call to encode/decode, won't interop with the
|
|
// RFC versions.
|
|
//
|
|
|
|
+ (NSData *)webSafeEncodeData:(NSData *)data
|
|
padded:(BOOL)padded {
|
|
return [self baseEncode:[data bytes]
|
|
length:[data length]
|
|
charset:kWebSafeBase64EncodeChars
|
|
padded:padded];
|
|
}
|
|
|
|
+ (NSData *)webSafeDecodeData:(NSData *)data {
|
|
return [self baseDecode:[data bytes]
|
|
length:[data length]
|
|
charset:kWebSafeBase64DecodeChars
|
|
requirePadding:NO];
|
|
}
|
|
|
|
+ (NSData *)webSafeEncodeBytes:(const void *)bytes
|
|
length:(NSUInteger)length
|
|
padded:(BOOL)padded {
|
|
return [self baseEncode:bytes
|
|
length:length
|
|
charset:kWebSafeBase64EncodeChars
|
|
padded:padded];
|
|
}
|
|
|
|
+ (NSData *)webSafeDecodeBytes:(const void *)bytes length:(NSUInteger)length {
|
|
return [self baseDecode:bytes
|
|
length:length
|
|
charset:kWebSafeBase64DecodeChars
|
|
requirePadding:NO];
|
|
}
|
|
|
|
+ (NSString *)stringByWebSafeEncodingData:(NSData *)data
|
|
padded:(BOOL)padded {
|
|
NSString *result = nil;
|
|
NSData *converted = [self baseEncode:[data bytes]
|
|
length:[data length]
|
|
charset:kWebSafeBase64EncodeChars
|
|
padded:padded];
|
|
if (converted) {
|
|
result = [[NSString alloc] initWithData:converted
|
|
encoding:NSASCIIStringEncoding];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
+ (NSString *)stringByWebSafeEncodingBytes:(const void *)bytes
|
|
length:(NSUInteger)length
|
|
padded:(BOOL)padded {
|
|
NSString *result = nil;
|
|
NSData *converted = [self baseEncode:bytes
|
|
length:length
|
|
charset:kWebSafeBase64EncodeChars
|
|
padded:padded];
|
|
if (converted) {
|
|
result = [[NSString alloc] initWithData:converted
|
|
encoding:NSASCIIStringEncoding];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
+ (NSData *)webSafeDecodeString:(NSString *)string {
|
|
NSData *result = nil;
|
|
NSData *data = [string dataUsingEncoding:NSASCIIStringEncoding];
|
|
if (data) {
|
|
result = [self baseDecode:[data bytes]
|
|
length:[data length]
|
|
charset:kWebSafeBase64DecodeChars
|
|
requirePadding:NO];
|
|
}
|
|
return result;
|
|
}
|
|
|
|
@end
|
|
|
|
@implementation QN_GTM_Base64 (PrivateMethods)
|
|
|
|
//
|
|
// baseEncode:length:charset:padded:
|
|
//
|
|
// Does the common lifting of creating the dest NSData. it creates & sizes the
|
|
// data for the results. |charset| is the characters to use for the encoding
|
|
// of the data. |padding| controls if the encoded data should be padded to a
|
|
// multiple of 4.
|
|
//
|
|
// Returns:
|
|
// an autorelease NSData with the encoded data, nil if any error.
|
|
//
|
|
+ (NSData *)baseEncode:(const void *)bytes
|
|
length:(NSUInteger)length
|
|
charset:(const char *)charset
|
|
padded:(BOOL)padded {
|
|
// how big could it be?
|
|
NSUInteger maxLength = QN_CalcEncodedLength(length, padded);
|
|
// make space
|
|
NSMutableData *result = [NSMutableData data];
|
|
[result setLength:maxLength];
|
|
// do it
|
|
NSUInteger finalLength = [self baseEncode:bytes
|
|
srcLen:length
|
|
destBytes:[result mutableBytes]
|
|
destLen:[result length]
|
|
charset:charset
|
|
padded:padded];
|
|
if (finalLength) {
|
|
// _GTMDevAssert(finalLength == maxLength, @"how did we calc the length wrong?");
|
|
} else {
|
|
// shouldn't happen, this means we ran out of space
|
|
result = nil;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
//
|
|
// baseDecode:length:charset:requirePadding:
|
|
//
|
|
// Does the common lifting of creating the dest NSData. it creates & sizes the
|
|
// data for the results. |charset| is the characters to use for the decoding
|
|
// of the data.
|
|
//
|
|
// Returns:
|
|
// an autorelease NSData with the decoded data, nil if any error.
|
|
//
|
|
//
|
|
+ (NSData *)baseDecode:(const void *)bytes
|
|
length:(NSUInteger)length
|
|
charset:(const char *)charset
|
|
requirePadding:(BOOL)requirePadding {
|
|
// could try to calculate what it will end up as
|
|
NSUInteger maxLength = QN_GuessDecodedLength(length);
|
|
// make space
|
|
NSMutableData *result = [NSMutableData data];
|
|
[result setLength:maxLength];
|
|
// do it
|
|
NSUInteger finalLength = [self baseDecode:bytes
|
|
srcLen:length
|
|
destBytes:[result mutableBytes]
|
|
destLen:[result length]
|
|
charset:charset
|
|
requirePadding:requirePadding];
|
|
if (finalLength) {
|
|
if (finalLength != maxLength) {
|
|
// resize down to how big it was
|
|
[result setLength:finalLength];
|
|
}
|
|
} else {
|
|
// either an error in the args, or we ran out of space
|
|
result = nil;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
//
|
|
// baseEncode:srcLen:destBytes:destLen:charset:padded:
|
|
//
|
|
// Encodes the buffer into the larger. returns the length of the encoded
|
|
// data, or zero for an error.
|
|
// |charset| is the characters to use for the encoding
|
|
// |padded| tells if the result should be padded to a multiple of 4.
|
|
//
|
|
// Returns:
|
|
// the length of the encoded data. zero if any error.
|
|
//
|
|
+ (NSUInteger)baseEncode:(const char *)srcBytes
|
|
srcLen:(NSUInteger)srcLen
|
|
destBytes:(char *)destBytes
|
|
destLen:(NSUInteger)destLen
|
|
charset:(const char *)charset
|
|
padded:(BOOL)padded {
|
|
if (!srcLen || !destLen || !srcBytes || !destBytes) {
|
|
return 0;
|
|
}
|
|
|
|
char *curDest = destBytes;
|
|
const unsigned char *curSrc = (const unsigned char *)(srcBytes);
|
|
|
|
// Three bytes of data encodes to four characters of cyphertext.
|
|
// So we can pump through three-byte chunks atomically.
|
|
while (srcLen > 2) {
|
|
// space?
|
|
// _GTMDevAssert(destLen >= 4, @"our calc for encoded length was wrong");
|
|
curDest[0] = charset[curSrc[0] >> 2];
|
|
curDest[1] = charset[((curSrc[0] & 0x03) << 4) + (curSrc[1] >> 4)];
|
|
curDest[2] = charset[((curSrc[1] & 0x0f) << 2) + (curSrc[2] >> 6)];
|
|
curDest[3] = charset[curSrc[2] & 0x3f];
|
|
|
|
curDest += 4;
|
|
curSrc += 3;
|
|
srcLen -= 3;
|
|
destLen -= 4;
|
|
}
|
|
|
|
// now deal with the tail (<=2 bytes)
|
|
switch (srcLen) {
|
|
case 0:
|
|
// Nothing left; nothing more to do.
|
|
break;
|
|
|
|
case 1:
|
|
// One byte left: this encodes to two characters, and (optionally)
|
|
// two pad characters to round out the four-character cypherblock.
|
|
// _GTMDevAssert(destLen >= 2, @"our calc for encoded length was wrong");
|
|
curDest[0] = charset[curSrc[0] >> 2];
|
|
curDest[1] = charset[(curSrc[0] & 0x03) << 4];
|
|
curDest += 2;
|
|
destLen -= 2;
|
|
if (padded) {
|
|
// _GTMDevAssert(destLen >= 2, @"our calc for encoded length was wrong");
|
|
curDest[0] = kBase64PaddingChar;
|
|
curDest[1] = kBase64PaddingChar;
|
|
curDest += 2;
|
|
}
|
|
break;
|
|
|
|
case 2:
|
|
// Two bytes left: this encodes to three characters, and (optionally)
|
|
// one pad character to round out the four-character cypherblock.
|
|
// _GTMDevAssert(destLen >= 3, @"our calc for encoded length was wrong");
|
|
curDest[0] = charset[curSrc[0] >> 2];
|
|
curDest[1] = charset[((curSrc[0] & 0x03) << 4) + (curSrc[1] >> 4)];
|
|
curDest[2] = charset[(curSrc[1] & 0x0f) << 2];
|
|
curDest += 3;
|
|
destLen -= 3;
|
|
if (padded) {
|
|
// _GTMDevAssert(destLen >= 1, @"our calc for encoded length was wrong");
|
|
curDest[0] = kBase64PaddingChar;
|
|
curDest += 1;
|
|
}
|
|
break;
|
|
}
|
|
// return the length
|
|
return (curDest - destBytes);
|
|
}
|
|
|
|
//
|
|
// baseDecode:srcLen:destBytes:destLen:charset:requirePadding:
|
|
//
|
|
// Decodes the buffer into the larger. returns the length of the decoded
|
|
// data, or zero for an error.
|
|
// |charset| is the character decoding buffer to use
|
|
//
|
|
// Returns:
|
|
// the length of the encoded data. zero if any error.
|
|
//
|
|
+ (NSUInteger)baseDecode:(const char *)srcBytes
|
|
srcLen:(NSUInteger)srcLen
|
|
destBytes:(char *)destBytes
|
|
destLen:(NSUInteger)destLen
|
|
charset:(const char *)charset
|
|
requirePadding:(BOOL)requirePadding {
|
|
if (!srcLen || !destLen || !srcBytes || !destBytes) {
|
|
return 0;
|
|
}
|
|
|
|
int decode;
|
|
NSUInteger destIndex = 0;
|
|
int state = 0;
|
|
char ch = 0;
|
|
while (srcLen-- && (ch = *srcBytes++) != 0) {
|
|
if (QN_IsSpace(ch)) // Skip whitespace
|
|
continue;
|
|
|
|
if (ch == kBase64PaddingChar)
|
|
break;
|
|
|
|
decode = charset[(unsigned int)ch];
|
|
if (decode == kBase64InvalidChar)
|
|
return 0;
|
|
|
|
// Four cyphertext characters decode to three bytes.
|
|
// Therefore we can be in one of four states.
|
|
switch (state) {
|
|
case 0:
|
|
// We're at the beginning of a four-character cyphertext block.
|
|
// This sets the high six bits of the first byte of the
|
|
// plaintext block.
|
|
// _GTMDevAssert(destIndex < destLen, @"our calc for decoded length was wrong");
|
|
destBytes[destIndex] = decode << 2;
|
|
state = 1;
|
|
break;
|
|
|
|
case 1:
|
|
// We're one character into a four-character cyphertext block.
|
|
// This sets the low two bits of the first plaintext byte,
|
|
// and the high four bits of the second plaintext byte.
|
|
// _GTMDevAssert((destIndex+1) < destLen, @"our calc for decoded length was wrong");
|
|
destBytes[destIndex] |= decode >> 4;
|
|
destBytes[destIndex + 1] = (decode & 0x0f) << 4;
|
|
destIndex++;
|
|
state = 2;
|
|
break;
|
|
|
|
case 2:
|
|
// We're two characters into a four-character cyphertext block.
|
|
// This sets the low four bits of the second plaintext
|
|
// byte, and the high two bits of the third plaintext byte.
|
|
// However, if this is the end of data, and those two
|
|
// bits are zero, it could be that those two bits are
|
|
// leftovers from the encoding of data that had a length
|
|
// of two mod three.
|
|
// _GTMDevAssert((destIndex+1) < destLen, @"our calc for decoded length was wrong");
|
|
destBytes[destIndex] |= decode >> 2;
|
|
destBytes[destIndex + 1] = (decode & 0x03) << 6;
|
|
destIndex++;
|
|
state = 3;
|
|
break;
|
|
|
|
case 3:
|
|
// We're at the last character of a four-character cyphertext block.
|
|
// This sets the low six bits of the third plaintext byte.
|
|
// _GTMDevAssert(destIndex < destLen, @"our calc for decoded length was wrong");
|
|
destBytes[destIndex] |= decode;
|
|
destIndex++;
|
|
state = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// We are done decoding Base-64 chars. Let's see if we ended
|
|
// on a byte boundary, and/or with erroneous trailing characters.
|
|
if (ch == kBase64PaddingChar) { // We got a pad char
|
|
if ((state == 0) || (state == 1)) {
|
|
return 0; // Invalid '=' in first or second position
|
|
}
|
|
if (srcLen == 0) {
|
|
if (state == 2) { // We run out of input but we still need another '='
|
|
return 0;
|
|
}
|
|
// Otherwise, we are in state 3 and only need this '='
|
|
} else {
|
|
if (state == 2) { // need another '='
|
|
while ((ch = *srcBytes++) && (srcLen-- > 0)) {
|
|
if (!QN_IsSpace(ch))
|
|
break;
|
|
}
|
|
if (ch != kBase64PaddingChar) {
|
|
return 0;
|
|
}
|
|
}
|
|
// state = 1 or 2, check if all remain padding is space
|
|
while ((ch = *srcBytes++) && (srcLen-- > 0)) {
|
|
if (!QN_IsSpace(ch)) {
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
// We ended by seeing the end of the string.
|
|
|
|
if (requirePadding) {
|
|
// If we require padding, then anything but state 0 is an error.
|
|
if (state != 0) {
|
|
return 0;
|
|
}
|
|
} else {
|
|
// Make sure we have no partial bytes lying around. Note that we do not
|
|
// require trailing '=', so states 2 and 3 are okay too.
|
|
if (state == 1) {
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If then next piece of output was valid and got written to it means we got a
|
|
// very carefully crafted input that appeared valid but contains some trailing
|
|
// bits past the real length, so just toss the thing.
|
|
if ((destIndex < destLen) &&
|
|
(destBytes[destIndex] != 0)) {
|
|
return 0;
|
|
}
|
|
|
|
return destIndex;
|
|
}
|
|
|
|
@end
|