GTMBase64
Base64.h
- //
- // GTMBase64.h
- //
- // 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 <Foundation/Foundation.h>
- #import "GTMDefines.h"
- // GTMBase64
- //
- /// Helper for handling Base64 and WebSafeBase64 encodings
- //
- /// The webSafe methods use different character set and also the results aren't
- /// always padded to a multiple of 4 characters. This is done so the resulting
- /// data can be used in urls and url query arguments without needing any
- /// encoding. You must use the webSafe* methods together, the data does not
- /// interop with the RFC methods.
- //
- @interface GTMBase64 : NSObject
- //
- // Standard Base64 (RFC) handling
- //
- // encodeData:
- //
- /// Base64 encodes contents of the NSData object.
- //
- /// Returns:
- /// A new autoreleased NSData with the encoded payload. nil for any error.
- //
- +(NSData *)encodeData:(NSData *)data;
- // decodeData:
- //
- /// Base64 decodes contents of the NSData object.
- //
- /// Returns:
- /// A new autoreleased NSData with the decoded payload. nil for any error.
- //
- +(NSData *)decodeData:(NSData *)data;
- // encodeBytes:length:
- //
- /// Base64 encodes the data pointed at by |bytes|.
- //
- /// Returns:
- /// A new autoreleased NSData with the encoded payload. nil for any error.
- //
- +(NSData *)encodeBytes:(const void *)bytes length:(NSUInteger)length;
- // decodeBytes:length:
- //
- /// Base64 decodes the data pointed at by |bytes|.
- //
- /// Returns:
- /// A new autoreleased NSData with the encoded payload. nil for any error.
- //
- +(NSData *)decodeBytes:(const void *)bytes length:(NSUInteger)length;
- // stringByEncodingData:
- //
- /// Base64 encodes contents of the NSData object.
- //
- /// Returns:
- /// A new autoreleased NSString with the encoded payload. nil for any error.
- //
- +(NSString *)stringByEncodingData:(NSData *)data;
- // stringByEncodingBytes:length:
- //
- /// Base64 encodes the data pointed at by |bytes|.
- //
- /// Returns:
- /// A new autoreleased NSString with the encoded payload. nil for any error.
- //
- +(NSString *)stringByEncodingBytes:(const void *)bytes length:(NSUInteger)length;
- // decodeString:
- //
- /// Base64 decodes contents of the NSString.
- //
- /// Returns:
- /// A new autoreleased NSData with the decoded payload. nil for any error.
- //
- +(NSData *)decodeString:(NSString *)string;
- //
- // Modified Base64 encoding so the results can go onto urls.
- //
- // The changes are in the characters generated and also allows the result to
- // not be padded to a multiple of 4.
- // Must use the matching call to encode/decode, won't interop with the
- // RFC versions.
- //
- // webSafeEncodeData:padded:
- //
- /// WebSafe Base64 encodes contents of the NSData object. If |padded| is YES
- /// then padding characters are added so the result length is a multiple of 4.
- //
- /// Returns:
- /// A new autoreleased NSData with the encoded payload. nil for any error.
- //
- +(NSData *)webSafeEncodeData:(NSData *)data
- padded:(BOOL)padded;
- // webSafeDecodeData:
- //
- /// WebSafe Base64 decodes contents of the NSData object.
- //
- /// Returns:
- /// A new autoreleased NSData with the decoded payload. nil for any error.
- //
- +(NSData *)webSafeDecodeData:(NSData *)data;
- // webSafeEncodeBytes:length:padded:
- //
- /// WebSafe Base64 encodes the data pointed at by |bytes|. If |padded| is YES
- /// then padding characters are added so the result length is a multiple of 4.
- //
- /// Returns:
- /// A new autoreleased NSData with the encoded payload. nil for any error.
- //
- +(NSData *)webSafeEncodeBytes:(const void *)bytes
- length:(NSUInteger)length
- padded:(BOOL)padded;
- // webSafeDecodeBytes:length:
- //
- /// WebSafe Base64 decodes the data pointed at by |bytes|.
- //
- /// Returns:
- /// A new autoreleased NSData with the encoded payload. nil for any error.
- //
- +(NSData *)webSafeDecodeBytes:(const void *)bytes length:(NSUInteger)length;
- // stringByWebSafeEncodingData:padded:
- //
- /// WebSafe Base64 encodes contents of the NSData object. If |padded| is YES
- /// then padding characters are added so the result length is a multiple of 4.
- //
- /// Returns:
- /// A new autoreleased NSString with the encoded payload. nil for any error.
- //
- +(NSString *)stringByWebSafeEncodingData:(NSData *)data
- padded:(BOOL)padded;
- // stringByWebSafeEncodingBytes:length:padded:
- //
- /// WebSafe Base64 encodes the data pointed at by |bytes|. If |padded| is YES
- /// then padding characters are added so the result length is a multiple of 4.
- //
- /// Returns:
- /// A new autoreleased NSString with the encoded payload. nil for any error.
- //
- +(NSString *)stringByWebSafeEncodingBytes:(const void *)bytes
- length:(NSUInteger)length
- padded:(BOOL)padded;
- // webSafeDecodeString:
- //
- /// WebSafe Base64 decodes contents of the NSString.
- //
- /// Returns:
- /// A new autoreleased NSData with the decoded payload. nil for any error.
- //
- +(NSData *)webSafeDecodeString:(NSString *)string;
- @end
Base64.m
- //
- // 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 "GTMBase64.h"
- #import "GTMDefines.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 charact 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.
- //
- FOUNDATION_STATIC_INLINE BOOL 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
- //
- FOUNDATION_STATIC_INLINE NSUInteger 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.
- // Unlinke 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
- //
- FOUNDATION_STATIC_INLINE NSUInteger GuessDecodedLength(NSUInteger srcLen) {
- return (srcLen + 3) / 4 * 3;
- }
- @interface GTMBase64 (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 GTMBase64
- //
- // 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] autorelease];
- }
- 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] autorelease];
- }
- 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] autorelease];
- }
- 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] autorelease];
- }
- 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 GTMBase64 (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 = 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 = 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;
- destLen -= 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;
- destLen -= 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 (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 (!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 (!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