IOS常用加密GTMBase64

GTMDefines.h

//
// GTMDefines.h
//
//  Copyright 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.
//

// ============================================================================

#include <AvailabilityMacros.h>

// Not all MAC_OS_X_VERSION_10_X macros defined in past SDKs
#ifndef MAC_OS_X_VERSION_10_5
#define MAC_OS_X_VERSION_10_5 1050
#endif
#ifndef MAC_OS_X_VERSION_10_6
#define MAC_OS_X_VERSION_10_6 1060
#endif

// ----------------------------------------------------------------------------
// CPP symbols that can be overridden in a prefix to control how the toolbox
// is compiled.
// ----------------------------------------------------------------------------

// GTMHTTPFetcher will support logging by default but only hook its input
// stream support for logging when requested.  You can control the inclusion of
// the code by providing your own definitions for these w/in a prefix header.
//
#ifndef GTM_HTTPFETCHER_ENABLE_LOGGING
#define GTM_HTTPFETCHER_ENABLE_LOGGING 1
#endif // GTM_HTTPFETCHER_ENABLE_LOGGING
#ifndef GTM_HTTPFETCHER_ENABLE_INPUTSTREAM_LOGGING
#define GTM_HTTPFETCHER_ENABLE_INPUTSTREAM_LOGGING 0
#endif // GTM_HTTPFETCHER_ENABLE_INPUTSTREAM_LOGGING

// By setting the GTM_CONTAINERS_VALIDATION_FAILED_LOG and
// GTM_CONTAINERS_VALIDATION_FAILED_ASSERT macros you can control what happens
// when a validation fails. If you implement your own validators, you may want
// to control their internals using the same macros for consistency.
#ifndef GTM_CONTAINERS_VALIDATION_FAILED_ASSERT
#define GTM_CONTAINERS_VALIDATION_FAILED_ASSERT 0
#endif

// Give ourselves a consistent way to do inlines.  Apple's macros even use
// a few different actual definitions, so we're based off of the foundation
// one.
#if !defined(GTM_INLINE)
#if defined (__GNUC__) && (__GNUC__ == 4)
#define GTM_INLINE static __inline__ __attribute__((always_inline))
#else
#define GTM_INLINE static __inline__
#endif
#endif

// Give ourselves a consistent way of doing externs that links up nicely
// when mixing objc and objc++
#if !defined (GTM_EXTERN)
#if defined __cplusplus
#define GTM_EXTERN extern "C"
#else
#define GTM_EXTERN extern
#endif
#endif

// Give ourselves a consistent way of exporting things if we have visibility
// set to hidden.
#if !defined (GTM_EXPORT)
#define GTM_EXPORT __attribute__((visibility("default")))
#endif

// _GTMDevLog & _GTMDevAssert
//
// _GTMDevLog & _GTMDevAssert are meant to be a very lightweight shell for
// developer level errors.  This implementation simply macros to NSLog/NSAssert.
// It is not intended to be a general logging/reporting system.
//
// Please see http://code.google.com/p/google-toolbox-for-mac/wiki/DevLogNAssert
// for a little more background on the usage of these macros.
//
//    _GTMDevLog           log some error/problem in debug builds
//    _GTMDevAssert        assert if conditon isn't met w/in a method/function
//                           in all builds.
//
// To replace this system, just provide different macro definitions in your
// prefix header.  Remember, any implementation you provide *must* be thread
// safe since this could be called by anything in what ever situtation it has
// been placed in.
//

// We only define the simple macros if nothing else has defined this.
#ifndef _GTMDevLog

#ifdef DEBUG
#define _GTMDevLog(...) NSLog(__VA_ARGS__)
#else
#define _GTMDevLog(...) do { } while (0)
#endif

#endif // _GTMDevLog

// Declared here so that it can easily be used for logging tracking if
// necessary. See GTMUnitTestDevLog.h for details.
@class NSString;
GTM_EXTERN void _GTMUnitTestDevLog(NSString *format, ...);

#ifndef _GTMDevAssert
// we directly invoke the NSAssert handler so we can pass on the varargs
// (NSAssert doesn't have a macro we can use that takes varargs)
#if !defined(NS_BLOCK_ASSERTIONS)
#define _GTMDevAssert(condition, ...)                                       \
do {                                                                      \
if (!(condition)) {                                                     \
[[NSAssertionHandler currentHandler]                                  \
handleFailureInFunction:[NSString stringWithUTF8String:__PRETTY_FUNCTION__] \
file:[NSString stringWithUTF8String:__FILE__]  \
lineNumber:__LINE__                                  \
description:__VA_ARGS__];                             \
}                                                                       \
} )
#else // !defined(NS_BLOCK_ASSERTIONS)
#define _GTMDevAssert(condition, ...) do { } while (0)
#endif // !defined(NS_BLOCK_ASSERTIONS)

#endif // _GTMDevAssert

// _GTMCompileAssert
// _GTMCompileAssert is an assert that is meant to fire at compile time if you
// want to check things at compile instead of runtime. For example if you
// want to check that a wchar is 4 bytes instead of 2 you would use
// _GTMCompileAssert(sizeof(wchar_t) == 4, wchar_t_is_4_bytes_on_OS_X)
// Note that the second "arg" is not in quotes, and must be a valid processor
// symbol in it's own right (no spaces, punctuation etc).

// Wrapping this in an #ifndef allows external groups to define their own
// compile time assert scheme.
#ifndef _GTMCompileAssert
// We got this technique from here:
// http://unixjunkie.blogspot.com/2007/10/better-compile-time-asserts_29.html

#define _GTMCompileAssertSymbolInner(line, msg) _GTMCOMPILEASSERT ## line ## __ ## msg
#define _GTMCompileAssertSymbol(line, msg) _GTMCompileAssertSymbolInner(line, msg)
#define _GTMCompileAssert(test, msg) \
typedef  : -) ]
#endif // _GTMCompileAssert

// Macro to allow fast enumeration when building for 10.5 or later, and
// reliance on NSEnumerator for 10.4.  Remember, NSDictionary w/ FastEnumeration
// does keys, so pick the right thing, nothing is done on the FastEnumeration
// side to be sure you're getting what you wanted.
#ifndef GTM_FOREACH_OBJECT
#if defined(TARGET_OS_IPHONE) || (MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_5)
#define GTM_FOREACH_OBJECT(element, collection) \
for (element in collection)
#define GTM_FOREACH_KEY(element, collection) \
for (element in collection)
#else
#define GTM_FOREACH_OBJECT(element, collection) \
for (NSEnumerator * _ ## element ## _enum = [collection objectEnumerator]; \
(element = [_ ## element ## _enum nextObject]) != nil; )
#define GTM_FOREACH_KEY(element, collection) \
for (NSEnumerator * _ ## element ## _enum = [collection keyEnumerator]; \
(element = [_ ## element ## _enum nextObject]) != nil; )
#endif
#endif

// ============================================================================

// ----------------------------------------------------------------------------
// CPP symbols defined based on the project settings so the GTM code has
// simple things to test against w/o scattering the knowledge of project
// setting through all the code.
// ----------------------------------------------------------------------------

// Provide a single constant CPP symbol that all of GTM uses for ifdefing
// iPhone code.
#include <TargetConditionals.h>
#if TARGET_OS_IPHONE // iPhone SDK
// For iPhone specific stuff
#define GTM_IPHONE_SDK 1
#if TARGET_IPHONE_SIMULATOR
#define GTM_IPHONE_SIMULATOR 1
#else
#define GTM_IPHONE_DEVICE 1
#endif  // TARGET_IPHONE_SIMULATOR
#else
// For MacOS specific stuff
#define GTM_MACOS_SDK 1
#endif

// Provide a symbol to include/exclude extra code for GC support.  (This mainly
// just controls the inclusion of finalize methods).
#ifndef GTM_SUPPORT_GC
#if GTM_IPHONE_SDK
// iPhone never needs GC
#define GTM_SUPPORT_GC 0
#else
// We can't find a symbol to tell if GC is supported/required, so best we
// do on Mac targets is include it if we're on 10.5 or later.
#if MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4
#define GTM_SUPPORT_GC 0
#else
#define GTM_SUPPORT_GC 1
#endif
#endif
#endif

// To simplify support for 64bit (and Leopard in general), we provide the type
// defines for non Leopard SDKs
#if MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4
// NSInteger/NSUInteger and Max/Mins
#ifndef NSINTEGER_DEFINED
#if __LP64__ || NS_BUILD_32_LIKE_64
typedef long NSInteger;
typedef unsigned long NSUInteger;
#else
typedef int NSInteger;
typedef unsigned int NSUInteger;
#endif
#define NSIntegerMax    LONG_MAX
#define NSIntegerMin    LONG_MIN
#define NSUIntegerMax   ULONG_MAX
#define NSINTEGER_DEFINED 1
#endif  // NSINTEGER_DEFINED
// CGFloat
#ifndef CGFLOAT_DEFINED
#if defined(__LP64__) && __LP64__
// This really is an untested path (64bit on Tiger?)
typedef double CGFloat;
#define CGFLOAT_MIN DBL_MIN
#define CGFLOAT_MAX DBL_MAX
#define CGFLOAT_IS_DOUBLE 1
#else /* !defined(__LP64__) || !__LP64__ */
typedef float CGFloat;
#define CGFLOAT_MIN FLT_MIN
#define CGFLOAT_MAX FLT_MAX
#define CGFLOAT_IS_DOUBLE 0
#endif /* !defined(__LP64__) || !__LP64__ */
#define CGFLOAT_DEFINED 1
#endif // CGFLOAT_DEFINED
#endif  // MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_4

GTMBase64.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

GTMBase64.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 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    ");
    //   }
    // }
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      /*/ */,
    */,
    ,      ,      ,      ,      ,      ,
    ,       /*G*/,
    /*O*/,
    /*W*/,
    ,      ,      ,      ,      ,
    ,      /*g*/,
    /*o*/,
    /*w*/,
    ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,
};

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    ");
    //   }
    // }
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,
    */,
    ,      ,      ,      ,      ,      ,
    ,       /*G*/,
    /*O*/,
    /*W*/,
    ,      ,      ,      ,      /*_*/,
    ,      /*g*/,
    /*o*/,
    /*w*/,
    ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,      ,
    ,      ,      ,      ,      ,      ,      ,
};

// 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.
    ] = {
        , , , , , , , , , ,  // 0-9
        , , , , , , , , , ,  // 10-19
        , , , , , , , , , ,  // 20-29
        , , , , , , , , , ,  // 30-39
        , , , , , , , , , ,  // 40-49
        , , , , , , , , , ,  // 50-59
        , , , , , , , , , ,  // 60-69
        , , , , , , , , , ,  // 70-79
        , , , , , , , , , ,  // 80-89
        , , , , , , , , , ,  // 90-99
        , , , , , , , , , ,  // 100-109
        , , , , , , , , , ,  // 110-119
        , , , , , , , , , ,  // 120-129
        , , , , , , , , , ,  // 130-139
        , , , , , , , , , ,  // 140-149
        , , , , , , , , , ,  // 150-159
        , , , , , , , , , ,  // 160-169
        , , , , , , , , , ,  // 170-179
        , , , , , , , , , ,  // 180-189
        , , , , , , , , , ,  // 190-199
        , , , , , , , , , ,  // 200-209
        , , , , , , , , , ,  // 210-219
        , , , , , , , , , ,  // 220-229
        , , , , , , , , , ,  // 230-239
        , , , , , , , , , ,  // 240-249
        , , , , , ,              // 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 =  * srcLen + ;
    NSUInteger len = intermediate_result / ;
    if (padded) {
        len = ((len + ) / ) * ;
    }
    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) {
    ) /  * ;
}

@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] ;
    }
    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 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) {
        ;
    }

    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.
    ) {
        // space?
        _GTMDevAssert(destLen >= , @"our calc for encoded length was wrong");
        curDest[] = charset[curSrc[] >> ];
        curDest[] = charset[((curSrc[] & ) + (curSrc[] >> )];
        curDest[] = charset[((curSrc[] & ) + (curSrc[] >> )];
        curDest[] = charset[curSrc[] & 0x3f];

        curDest += ;
        curSrc += ;
        srcLen -= ;
        destLen -= ;
    }

    // now deal with the tail (<=2 bytes)
    switch (srcLen) {
        :
            // Nothing left; nothing more to do.
            break;
        :
            // One byte left: this encodes to two characters, and (optionally)
            // two pad characters to round out the four-character cypherblock.
            _GTMDevAssert(destLen >= , @"our calc for encoded length was wrong");
            curDest[] = charset[curSrc[] >> ];
            curDest[] = charset[(curSrc[] & ];
            curDest += ;
            destLen -= ;
            if (padded) {
                _GTMDevAssert(destLen >= , @"our calc for encoded length was wrong");
                curDest[] = kBase64PaddingChar;
                curDest[] = kBase64PaddingChar;
                curDest += ;
                destLen -= ;
            }
            break;
        :
            // Two bytes left: this encodes to three characters, and (optionally)
            // one pad character to round out the four-character cypherblock.
            _GTMDevAssert(destLen >= , @"our calc for encoded length was wrong");
            curDest[] = charset[curSrc[] >> ];
            curDest[] = charset[((curSrc[] & ) + (curSrc[] >> )];
            curDest[] = charset[(curSrc[] & ];
            curDest += ;
            destLen -= ;
            if (padded) {
                _GTMDevAssert(destLen >= , @"our calc for encoded length was wrong");
                curDest[] = kBase64PaddingChar;
                curDest += ;
                destLen -= ;
            }
            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) {
        ;
    }

    int decode;
    NSUInteger destIndex = ;
    ;
    ;
    )  {
        if (IsSpace(ch))  // Skip whitespace
            continue;

        if (ch == kBase64PaddingChar)
            break;

        decode = charset[(unsigned int)ch];
        if (decode == kBase64InvalidChar)
            ;

        // Four cyphertext characters decode to three bytes.
        // Therefore we can be in one of four states.
        switch (state) {
            :
                // 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 << ;
                state = ;
                break;
            :
                // 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+) < destLen, @"our calc for decoded length was wrong");
                destBytes[destIndex] |= decode >> ;
                destBytes[destIndex+] = (decode & ;
                destIndex++;
                state = ;
                break;
            :
                // 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+) < destLen, @"our calc for decoded length was wrong");
                destBytes[destIndex] |= decode >> ;
                destBytes[destIndex+] = (decode & ;
                destIndex++;
                state = ;
                break;
            :
                // 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 = ;
                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
        ) || (state == )) {
            ;  // Invalid '=' in first or second position
        }
        ) {
            ) { // We run out of input but we still need another '='
                ;
            }
            // Otherwise, we are in state 3 and only need this '='
        } else {
            ) {  // need another '='
                )) {
                    if (!IsSpace(ch))
                        break;
                }
                if (ch != kBase64PaddingChar) {
                    ;
                }
            }
            // state = 1 or 2, check if all remain padding is space
            )) {
                if (!IsSpace(ch)) {
                    ;
                }
            }
        }
    } else {
        // We ended by seeing the end of the string.

        if (requirePadding) {
            // If we require padding, then anything but state 0 is an error.
            ) {
                ;
            }
        } 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 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] != )) {
        ;
    }

    return destIndex;
}

@end