How do I do base64 encoding on iOS

Question

I d like to do base64 encoding and decoding  but I could not find any support from the iPhone SDK  How can I do base64 encoding and decoding with or without a library

User · Answer

in iOS 7           NSData  data   NSData alloc init            data base64Encoding

User · Answer

Since this seems to be the number one google hit on base64 encoding and iphone  I felt like sharing my experience with the code snippet above   It works  but it is extremely slow  A benchmark on a random image  0 4 mb  took 37 seconds on native iphone  The main reason is probably all the OOP magic - single char NSStrings etc  which are only autoreleased after the encoding is done   Another suggestion posted here  ab uses the openssl library  which feels like overkill as well   The code below takes 70 ms - that s a 500 times speedup  This only does base64 encoding  decoding will follow as soon as I encounter it      NSString    base64StringFromData   NSData   data length   int length   int lentext    data length    if  lentext  lt  1  return       char  outbuf   malloc lentext 4 3 4      add 4 to be sure  if    outbuf   return nil   const unsigned char  raw    data bytes    int inp   0  int outp   0  int do now   lentext -  lentext 3    for   outp   0  inp   0  inp  lt  do now  inp    3         outbuf outp      base64EncodingTable  raw inp   amp  0xFC   gt  gt  2       outbuf outp      base64EncodingTable   raw inp   amp  0x03   lt  lt  4      raw inp 1   amp  0xF0   gt  gt  4        outbuf outp      base64EncodingTable   raw inp 1   amp  0x0F   lt  lt  2      raw inp 2   amp  0xC0   gt  gt  6        outbuf outp      base64EncodingTable raw inp 2   amp  0x3F      if   do now  lt  lentext         char tmpbuf 2     0 0       int left   lentext 3      for   int i 0  i  lt  left  i                   tmpbuf i    raw do now i             raw   tmpbuf      outbuf outp      base64EncodingTable  raw inp   amp  0xFC   gt  gt  2       outbuf outp      base64EncodingTable   raw inp   amp  0x03   lt  lt  4      raw inp 1   amp  0xF0   gt  gt  4        if   left    2   outbuf outp      base64EncodingTable   raw inp 1   amp  0x0F   lt  lt  2      raw inp 2   amp  0xC0   gt  gt  6       NSString  ret      NSString alloc  initWithBytes outbuf length outp encoding NSASCIIStringEncoding  autorelease   free outbuf    return ret      I left out the line-cutting since I didn t need it  but it s trivial to add   For those who are interested in optimizing  the goal is to minimize what happens in the main loop  Therefore all logic to deal with the last 3 bytes is treated outside the loop   Also  try to work on data in-place  without additional copying to from buffers  And reduce any arithmetic to the bare minimum   Observe that the bits that are put together to look up an entry in the table  would not overlap when they were to be orred together without shifting  A major improvement could therefore be to use 4 separate 256 byte lookup tables and eliminate the shifts  like this   outbuf outp      base64EncodingTable1  raw inp   amp  0xFC    outbuf outp      base64EncodingTable2  raw inp   amp  0x03     raw inp 1   amp  0xF0    outbuf outp      base64EncodingTable3  raw inp 1   amp  0x0F     raw inp 2   amp  0xC0    outbuf outp      base64EncodingTable4 raw inp 2   amp  0x3F     Of course you could take it a whole lot further  but that s beyond the scope here

User · Answer

import  NSDataAdditions h   implementation NSData  NSDataAdditions      NSData    base64DataFromString   NSString   string     unsigned long ixtext  lentext    unsigned char ch  input 4   output 3     short i  ixinput    Boolean flignore  flendtext   false    const char  temporary    NSMutableData  result     if   string      return  NSData data      ixtext   0    temporary    string UTF8String     lentext    string length     result    NSMutableData dataWithCapacity  lentext     ixinput   0     while  true        if  ixtext  gt   lentext        break      ch   temporary ixtext         flignore   false       if   ch  gt    A    amp  amp   ch  lt    Z          ch   ch -  A       else if   ch  gt    a    amp  amp   ch  lt    z          ch   ch -  a    26      else if   ch  gt    0    amp  amp   ch  lt    9          ch   ch -  0    52      else if  ch               ch   62      else if  ch               flendtext   true      else if  ch               ch   63      else       flignore   true       if   flignore          short ctcharsinput   3        Boolean flbreak   false         if  flendtext             if  ixinput    0             break                         if   ixinput    1      ixinput    2              ctcharsinput   1           else            ctcharsinput   2           ixinput   3           flbreak   true                 input ixinput      ch         if  ixinput    4           ixinput   0          output 0     input 0   lt  lt  2      input 1   amp  0x30   gt  gt  4           output 1      input 1   amp  0x0F   lt  lt  4      input 2   amp  0x3C   gt  gt  2           output 2      input 2   amp  0x03   lt  lt  6     input 3   amp  0x3F           for  i   0  i  lt  ctcharsinput  i             result appendBytes   amp output i  length  1               if  flbreak        break              return result     end

User · Answer

Better solution    There is a built in function in NSData   data base64Encoding     iOS  lt  7 0  data base64EncodedStringWithOptions NSDataBase64Encoding76CharacterLineLength     iOS  gt   7 0

User · Answer

At the time this question was originally posted  people were understandably directing you to third-party base 64 libraries because of the lack of any native routines  But iOS 7 introduced base 64 encoding routines  which actually simply just exposes private methods iOS had going back to iOS 4   So  you can use the NSData method base64EncodedStringWithOptions  to create a base-64 string from a NSData  NSString  string    data base64EncodedStringWithOptions kNilOptions    And you can use initWithBase64EncodedString options  to convert a base-64 string back to a NSData  NSData  data     NSData alloc  initWithBase64EncodedString string options kNilOptions     Or  in Swift  let string   data base64EncodedString    And let data   Data base64Encoded  string

User · Answer

in iOS 7           NSData  data   NSData alloc init            data base64Encoding

User · Answer

Here is an example to convert an NSData object to Base 64  It also shows how to go the other way  decode a base 64 encoded NSData object    NSData  dataTake2         iOS Developer Tips  dataUsingEncoding NSUTF8StringEncoding       Convert to Base64 data NSData  base64Data    dataTake2 base64EncodedDataWithOptions 0       Do something with the data        Now convert back from Base64 NSData  nsdataDecoded    base64Data initWithBase64EncodedData base64Data options 0

User · Answer

Under iOS8 and later use -  NSString   base64EncodedStringWithOptions  NSDataBase64EncodingOptions options of NSData

User · Answer

Download Base64  Do following code to convert an image to base64  NSString  base64String  UIImagePNGRepresentation image  base64Encoding

User · Answer

Under iOS8 and later use -  NSString   base64EncodedStringWithOptions  NSDataBase64EncodingOptions options of NSData

User · Answer

Glad people liked it  The end-game was a little flawed I must admit  Besides rightly setting inp 0 you should either also increase tmpbuf s size to 3  like  unsigned char tmpbuf 3     0 0 0     or leave out the orring of raw inp 2   if we would have a raw inp 2     0 for this chunk we would still be in the loop of course     Either way works  you might consider keeping the final table lookup block identical to the one in the loop for clarity  In the final version I used I did  while   outp 4   outbuf outp             To add the     Sorry I didn t check RFC s and stuff  should have done a better job

User · Answer

As per your requirement i have created a sample demo using Swift 4 in which you can encode decode string and image as per your requirement    I have also added sample methods of relevant operations          Base64VC swift     SOF SortArrayOfCustomObject        Created by Test User on 09 01 18      Copyright    2018 Test User  All rights reserved      import UIKit import Foundation  class Base64VC  NSObject          ----------------------------------------------------------------        MARK -        MARK - String to Base64 Encode Methods       ----------------------------------------------------------------      func sampleStringEncodingAndDecoding             if let base64String   self base64Encode string   TestString                 print  Base64 Encoded String   n  base64String                if let originalString   self base64Decode base64String  base64String                    print  Base64 Decoded String   n  originalString                                          ----------------------------------------------------------------      func base64Encode string  String  - gt  String            if let stringData   string data using   utf8                return stringData base64EncodedString                     return nil              ----------------------------------------------------------------      func base64Decode base64String  String  - gt  String            if let base64Data   Data base64Encoded  base64String                return String data  base64Data  encoding   utf8                    return nil               ----------------------------------------------------------------        MARK -        MARK - Image to Base64 Encode  Methods       ----------------------------------------------------------------      func sampleImageEncodingAndDecoding             if let base64ImageString   self base64Encode image  UIImage init named   yourImageName                   print  Base64 Encoded Image   n  base64ImageString                if let originaImage   self base64Decode base64ImageString  base64ImageString                    print  originalImageData  n  originaImage                                         ----------------------------------------------------------------      func base64Encode image  UIImage  - gt  String            if let imageData   UIImagePNGRepresentation image                return imageData base64EncodedString                     return nil              ----------------------------------------------------------------      func base64Decode base64ImageString  String  - gt  UIImage            if let base64Data   Data base64Encoded  base64ImageString                return UIImage data  base64Data                     return nil

User · Answer

iOS includes built in support for base64 encoding and decoding  If you look at resolv h you should see the two functions b64 ntop and b64 pton   The Square SocketRocket library provides a reasonable example of how to use these functions from objective-c   These functions are pretty well tested and reliable - unlike many of the implementations you may find in random internet postings  Don t forget to link against libresolv dylib

User · Answer

A really  really fast implementation which was ported  and modified improved  from the PHP Core library into native Objective-C code is available in the QSStrings Class from the QSUtilities Library   I did a quick benchmark  a 5 3MB image  JPEG  file took  lt  50ms to encode  and about 140ms to decode   The code for the entire library  including the Base64 Methods  are available on GitHub   Or alternatively  if you want the code to just the Base64 methods themselves  I ve posted it here   First  you need the mapping tables   static const char  base64EncodingTable 64     ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789     static const short  base64DecodingTable 256          -2  -2  -2  -2  -2  -2  -2  -2  -2  -1  -1  -2  -1  -1  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -1  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  62  -2  -2  -2  63      52  53  54  55  56  57  58  59  60  61  -2  -2  -2  -2  -2  -2      -2   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14      15  16  17  18  19  20  21  22  23  24  25  -2  -2  -2  -2  -2      -2  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40      41  42  43  44  45  46  47  48  49  50  51  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      To Encode      NSString   encodeBase64WithString  NSString   strData       return  QSStrings encodeBase64WithData  strData dataUsingEncoding NSUTF8StringEncoding          NSString   encodeBase64WithData  NSData   objData       const unsigned char   objRawData    objData bytes       char   objPointer      char   strResult          Get the Raw Data length and ensure we actually have data     int intLength    objData length       if  intLength    0  return nil          Setup the String-based Result placeholder and pointer within that placeholder     strResult    char   calloc    intLength   2    3    4    1  sizeof char        objPointer   strResult          Iterate through everything     while  intLength  gt  2       keep going until we have less than 24 bits          objPointer      base64EncodingTable objRawData 0   gt  gt  2            objPointer      base64EncodingTable   objRawData 0   amp  0x03   lt  lt  4     objRawData 1   gt  gt  4             objPointer      base64EncodingTable   objRawData 1   amp  0x0f   lt  lt  2     objRawData 2   gt  gt  6             objPointer      base64EncodingTable objRawData 2   amp  0x3f               we just handled 3 octets  24 bits  of data         objRawData    3          intLength -  3                 now deal with the tail end of things     if  intLength    0             objPointer      base64EncodingTable objRawData 0   gt  gt  2           if  intLength  gt  1                 objPointer      base64EncodingTable   objRawData 0   amp  0x03   lt  lt  4     objRawData 1   gt  gt  4                 objPointer      base64EncodingTable  objRawData 1   amp  0x0f   lt  lt  2                objPointer                    else                objPointer      base64EncodingTable  objRawData 0   amp  0x03   lt  lt  4                objPointer                       objPointer                                  Terminate the string-based result      objPointer     0           Create result NSString object     NSString  base64String    NSString stringWithCString strResult encoding NSASCIIStringEncoding           Free memory     free strResult        return base64String      To Decode      NSData   decodeBase64WithString  NSString   strBase64       const char  objPointer    strBase64 cStringUsingEncoding NSASCIIStringEncoding       size t intLength   strlen objPointer       int intCurrent      int i   0  j   0  k       unsigned char  objResult   calloc intLength  sizeof unsigned char            Run through the whole string  converting as we go     while     intCurrent    objPointer         0    amp  amp   intLength--  gt  0              if  intCurrent                       if   objPointer         amp  amp    i   4     1           intLength  gt  0                        the padding character is invalid at this point -- so this entire string is invalid                 free objResult                   return nil                            continue                     intCurrent    base64DecodingTable intCurrent           if  intCurrent    -1                   we re at a whitespace -- simply skip over             continue            else if  intCurrent    -2                   we re at an invalid character             free objResult               return nil                     switch  i   4                case 0                  objResult j    intCurrent  lt  lt  2                  break               case 1                  objResult j       intCurrent  gt  gt  4                  objResult j     intCurrent  amp  0x0f   lt  lt  4                  break               case 2                  objResult j       intCurrent  gt  gt 2                  objResult j     intCurrent  amp  0x03   lt  lt  6                  break               case 3                  objResult j       intCurrent                  break                    i                  mop things up if we ended on a boundary     k   j      if  intCurrent                   switch  i   4                case 1                     Invalid state                 free objResult                   return nil               case 2                  k                       flow through             case 3                  objResult k    0                          Cleanup and setup the return NSData     NSData   objData      NSData alloc  initWithBytes objResult length j  autorelease       free objResult       return objData

User · Answer

Here is an example to convert an NSData object to Base 64  It also shows how to go the other way  decode a base 64 encoded NSData object    NSData  dataTake2         iOS Developer Tips  dataUsingEncoding NSUTF8StringEncoding       Convert to Base64 data NSData  base64Data    dataTake2 base64EncodedDataWithOptions 0       Do something with the data        Now convert back from Base64 NSData  nsdataDecoded    base64Data initWithBase64EncodedData base64Data options 0

User · Answer

Better solution    There is a built in function in NSData   data base64Encoding     iOS  lt  7 0  data base64EncodedStringWithOptions NSDataBase64Encoding76CharacterLineLength     iOS  gt   7 0

User · Answer

Glad people liked it  The end-game was a little flawed I must admit  Besides rightly setting inp 0 you should either also increase tmpbuf s size to 3  like  unsigned char tmpbuf 3     0 0 0     or leave out the orring of raw inp 2   if we would have a raw inp 2     0 for this chunk we would still be in the loop of course     Either way works  you might consider keeping the final table lookup block identical to the one in the loop for clarity  In the final version I used I did  while   outp 4   outbuf outp             To add the     Sorry I didn t check RFC s and stuff  should have done a better job

User · Answer

I Think This will be helpful      NSString   toBase64String  NSString   string       NSData  data    string dataUsingEncoding  NSUnicodeStringEncoding        NSString  ret    data base64EncodedStringWithOptions NSDataBase64Encoding64CharacterLineLength        return ret                NSString   fromBase64String  NSString   string   NSData  aData    string dataUsingEncoding NSUTF8StringEncoding   NSData  aDataDecoded     NSData alloc initWithBase64EncodedString string options 0   NSString  decryptedStr     NSString alloc initWithData aDataDecoded encoding NSUTF8StringEncoding    return  decryptedStr autorelease

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Since this seems to be the number one google hit on base64 encoding and iphone  I felt like sharing my experience with the code snippet above   It works  but it is extremely slow  A benchmark on a random image  0 4 mb  took 37 seconds on native iphone  The main reason is probably all the OOP magic - single char NSStrings etc  which are only autoreleased after the encoding is done   Another suggestion posted here  ab uses the openssl library  which feels like overkill as well   The code below takes 70 ms - that s a 500 times speedup  This only does base64 encoding  decoding will follow as soon as I encounter it      NSString    base64StringFromData   NSData   data length   int length   int lentext    data length    if  lentext  lt  1  return       char  outbuf   malloc lentext 4 3 4      add 4 to be sure  if    outbuf   return nil   const unsigned char  raw    data bytes    int inp   0  int outp   0  int do now   lentext -  lentext 3    for   outp   0  inp   0  inp  lt  do now  inp    3         outbuf outp      base64EncodingTable  raw inp   amp  0xFC   gt  gt  2       outbuf outp      base64EncodingTable   raw inp   amp  0x03   lt  lt  4      raw inp 1   amp  0xF0   gt  gt  4        outbuf outp      base64EncodingTable   raw inp 1   amp  0x0F   lt  lt  2      raw inp 2   amp  0xC0   gt  gt  6        outbuf outp      base64EncodingTable raw inp 2   amp  0x3F      if   do now  lt  lentext         char tmpbuf 2     0 0       int left   lentext 3      for   int i 0  i  lt  left  i                   tmpbuf i    raw do now i             raw   tmpbuf      outbuf outp      base64EncodingTable  raw inp   amp  0xFC   gt  gt  2       outbuf outp      base64EncodingTable   raw inp   amp  0x03   lt  lt  4      raw inp 1   amp  0xF0   gt  gt  4        if   left    2   outbuf outp      base64EncodingTable   raw inp 1   amp  0x0F   lt  lt  2      raw inp 2   amp  0xC0   gt  gt  6       NSString  ret      NSString alloc  initWithBytes outbuf length outp encoding NSASCIIStringEncoding  autorelease   free outbuf    return ret      I left out the line-cutting since I didn t need it  but it s trivial to add   For those who are interested in optimizing  the goal is to minimize what happens in the main loop  Therefore all logic to deal with the last 3 bytes is treated outside the loop   Also  try to work on data in-place  without additional copying to from buffers  And reduce any arithmetic to the bare minimum   Observe that the bits that are put together to look up an entry in the table  would not overlap when they were to be orred together without shifting  A major improvement could therefore be to use 4 separate 256 byte lookup tables and eliminate the shifts  like this   outbuf outp      base64EncodingTable1  raw inp   amp  0xFC    outbuf outp      base64EncodingTable2  raw inp   amp  0x03     raw inp 1   amp  0xF0    outbuf outp      base64EncodingTable3  raw inp 1   amp  0x0F     raw inp 2   amp  0xC0    outbuf outp      base64EncodingTable4 raw inp 2   amp  0x3F     Of course you could take it a whole lot further  but that s beyond the scope here

User · Answer

I have done it using the following class     implementation Base64Converter static char base64EncodingTable 64       A    B    C    D    E    F    G    H    I    J    K    L     M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z    a    b    c    d    e    f    g    h    i    j    k    l    m    n    o    p    q    r    s    t    u    v    w    x    y    z    0    1    2    3    4    5    6    7       8    9                  NSString    base64StringFromData   NSData   data length   int length    unsigned long ixtext  lentext   long ctremaining   unsigned char input 3   output 4    short i  charsonline   0  ctcopy   const unsigned char  raw   NSMutableString  result   lentext    data length    if  lentext  lt  1      return       result    NSMutableString stringWithCapacity  lentext    raw    data bytes    ixtext   0   while  true         ctremaining   lentext - ixtext       if  ctremaining  lt   0          break       for  i   0  i  lt  3  i              unsigned long ix   ixtext   i          if  ix  lt  lentext              input i    raw ix           else             input i    0             output 0     input 0   amp  0xFC   gt  gt  2       output 1      input 0   amp  0x03   lt  lt  4      input 1   amp  0xF0   gt  gt  4        output 2      input 1   amp  0x0F   lt  lt  2      input 2   amp  0xC0   gt  gt  6        output 3    input 2   amp  0x3F       ctcopy   4       switch  ctremaining            case 1              ctcopy   2              break           case 2              ctcopy   3              break             for  i   0  i  lt  ctcopy  i             result appendString   NSString stringWithFormat     c   base64EncodingTable output i           for  i   ctcopy  i  lt  4  i             result appendString              ixtext    3       charsonline    4       if   length  gt  0   amp  amp   charsonline  gt   length           charsonline   0    return result     end   While calling call     Base64Converter base64StringFromData dataval length lengthval     That s it

User · Answer

At the time this question was originally posted  people were understandably directing you to third-party base 64 libraries because of the lack of any native routines  But iOS 7 introduced base 64 encoding routines  which actually simply just exposes private methods iOS had going back to iOS 4   So  you can use the NSData method base64EncodedStringWithOptions  to create a base-64 string from a NSData  NSString  string    data base64EncodedStringWithOptions kNilOptions    And you can use initWithBase64EncodedString options  to convert a base-64 string back to a NSData  NSData  data     NSData alloc  initWithBase64EncodedString string options kNilOptions     Or  in Swift  let string   data base64EncodedString    And let data   Data base64Encoded  string

User · Answer

For an update to use the NSData  NSDataBase64Encoding  category methods in iOS7 see my answer here  https   stackoverflow com a 18927627 1602729

User · Answer

Here s a compact Objective-C version as a Category on NSData  It takes some thinking about      implementation NSData  DataUtils   static char base64      ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789      -  NSString   newStringInBase64FromData    NSMutableString  dest     NSMutableString alloc  initWithString        unsigned char   working    unsigned char    self bytes    int srcLen    self length        tackle the source in 3 s as conveniently 4 Base64 nibbles fit into 3 bytes  for  int i 0  i lt srcLen  i    3          for each output nibble   for  int nib 0  nib lt 4  nib              nibble nib from char byt    int byt    nib    0  0 nib-1     int ix    nib 1  2      if  i byt  gt   srcLen  break         extract the top bits of the nibble  if valid    unsigned char curr     working i byt   lt  lt   8-ix    amp  0x3F          extract the bottom bits of the nibble  if valid    if  i nib  lt  srcLen  curr      working i nib   gt  gt  ix   amp  0x3F        dest appendFormat    c   base64 curr             return dest      end   Padding can be added if required by making the scope of  byt  wider and appending  dest  with  2-byt      characters before returning   A Category can then be added to NSString  thus    implementation NSString  StringUtils   -  NSString   newStringInBase64FromString    NSData  theData    NSData dataWithBytes  self UTF8String  length  self length       return  theData newStringInBase64FromData       end

User · Answer

In mvds s excellent improvement  there are two problems  Change code to this   raw   tmpbuf  inp   0  outbuf outp      base64EncodingTable  raw inp   amp  0xFC   gt  gt  2   outbuf outp      base64EncodingTable   raw inp   amp  0x03   lt  lt  4      raw inp 1   amp  0xF0   gt  gt  4    if   left    2   outbuf outp      base64EncodingTable   raw inp 1   amp  0x0F   lt  lt  2      raw inp 2   amp  0xC0   gt  gt  6    else outbuf outp           outbuf outp

User · Answer

iOS has had built-in Base64 encoding and decoding methods  without using libresolv  since iOS 4  However  it was only declared in the iOS 7 SDK  Apple documentation states that you can use it when targeting iOS 4 and above   NSData  myData       some data NSString  base64String    myData base64Encoding   NSData  decodedData     NSData alloc  initWithBase64Encoding base64String

User · Answer

Download Base64  Do following code to convert an image to base64  NSString  base64String  UIImagePNGRepresentation image  base64Encoding

User · Answer

iOS includes built in support for base64 encoding and decoding  If you look at resolv h you should see the two functions b64 ntop and b64 pton   The Square SocketRocket library provides a reasonable example of how to use these functions from objective-c   These functions are pretty well tested and reliable - unlike many of the implementations you may find in random internet postings  Don t forget to link against libresolv dylib

User · Answer

As per your requirement i have created a sample demo using Swift 4 in which you can encode decode string and image as per your requirement    I have also added sample methods of relevant operations          Base64VC swift     SOF SortArrayOfCustomObject        Created by Test User on 09 01 18      Copyright    2018 Test User  All rights reserved      import UIKit import Foundation  class Base64VC  NSObject          ----------------------------------------------------------------        MARK -        MARK - String to Base64 Encode Methods       ----------------------------------------------------------------      func sampleStringEncodingAndDecoding             if let base64String   self base64Encode string   TestString                 print  Base64 Encoded String   n  base64String                if let originalString   self base64Decode base64String  base64String                    print  Base64 Decoded String   n  originalString                                          ----------------------------------------------------------------      func base64Encode string  String  - gt  String            if let stringData   string data using   utf8                return stringData base64EncodedString                     return nil              ----------------------------------------------------------------      func base64Decode base64String  String  - gt  String            if let base64Data   Data base64Encoded  base64String                return String data  base64Data  encoding   utf8                    return nil               ----------------------------------------------------------------        MARK -        MARK - Image to Base64 Encode  Methods       ----------------------------------------------------------------      func sampleImageEncodingAndDecoding             if let base64ImageString   self base64Encode image  UIImage init named   yourImageName                   print  Base64 Encoded Image   n  base64ImageString                if let originaImage   self base64Decode base64ImageString  base64ImageString                    print  originalImageData  n  originaImage                                         ----------------------------------------------------------------      func base64Encode image  UIImage  - gt  String            if let imageData   UIImagePNGRepresentation image                return imageData base64EncodedString                     return nil              ----------------------------------------------------------------      func base64Decode base64ImageString  String  - gt  UIImage            if let base64Data   Data base64Encoded  base64ImageString                return UIImage data  base64Data                     return nil

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This is a good use case for Objective C categories   For Base64 encoding    import  lt Foundation NSString h gt    interface NSString  NSStringAdditions      NSString    base64StringFromData  NSData   data length  int length    end  -------------------------------------------   import  NSStringAdditions h   static char base64EncodingTable 64         A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P      Q    R    S    T    U    V    W    X    Y    Z    a    b    c    d    e    f      g    h    i    j    k    l    m    n    o    p    q    r    s    t    u    v      w    x    y    z    0    1    2    3    4    5    6    7    8    9                 implementation NSString  NSStringAdditions      NSString    base64StringFromData   NSData   data length   int length     unsigned long ixtext  lentext    long ctremaining    unsigned char input 3   output 4     short i  charsonline   0  ctcopy    const unsigned char  raw    NSMutableString  result     lentext    data length      if  lentext  lt  1      return        result    NSMutableString stringWithCapacity  lentext     raw    data bytes     ixtext   0      while  true        ctremaining   lentext - ixtext      if  ctremaining  lt   0          break              for  i   0  i  lt  3  i              unsigned long ix   ixtext   i         if  ix  lt  lentext            input i    raw ix          else   input i    0        output 0     input 0   amp  0xFC   gt  gt  2    output 1      input 0   amp  0x03   lt  lt  4      input 1   amp  0xF0   gt  gt  4     output 2      input 1   amp  0x0F   lt  lt  2      input 2   amp  0xC0   gt  gt  6     output 3    input 2   amp  0x3F    ctcopy   4    switch  ctremaining        case 1         ctcopy   2         break      case 2         ctcopy   3         break         for  i   0  i  lt  ctcopy  i          result appendString   NSString stringWithFormat     c   base64EncodingTable output i         for  i   ctcopy  i  lt  4  i          result appendString            ixtext    3    charsonline    4     if   length  gt  0   amp  amp   charsonline  gt   length       charsonline   0             return result      end   For Base64 decoding    import  lt Foundation Foundation h gt    class NSString    interface NSData  NSDataAdditions      NSData    base64DataFromString  NSString   string    end  -------------------------------------------   import  NSDataAdditions h    implementation NSData  NSDataAdditions      NSData   base64DataFromString   NSString   string       unsigned long ixtext  lentext      unsigned char ch  inbuf 4   outbuf 3       short i  ixinbuf      Boolean flignore  flendtext   false      const unsigned char  tempcstring      NSMutableData  theData       if  string    nil                return  NSData data              ixtext   0       tempcstring    const unsigned char    string UTF8String        lentext    string length        theData    NSMutableData dataWithCapacity  lentext        ixinbuf   0       while  true                if  ixtext  gt   lentext                        break                     ch   tempcstring  ixtext              flignore   false           if   ch  gt    A    amp  amp   ch  lt    Z                          ch   ch -  A                     else if   ch  gt    a    amp  amp   ch  lt    z                          ch   ch -  a    26                    else if   ch  gt    0    amp  amp   ch  lt    9                          ch   ch -  0    52                    else if  ch                               ch   62                    else if  ch                               flendtext   true                    else if  ch                               ch   63                    else                       flignore   true                      if   flignore                        short ctcharsinbuf   3              Boolean flbreak   false               if  flendtext                                if  ixinbuf    0                                        break                                     if   ixinbuf    1      ixinbuf    2                                         ctcharsinbuf   1                                    else                                       ctcharsinbuf   2                                     ixinbuf   3                   flbreak   true                             inbuf  ixinbuf      ch               if  ixinbuf    4                                ixinbuf   0                   outbuf 0     inbuf 0   lt  lt  2      inbuf 1   amp  0x30   gt  gt  4                   outbuf 1      inbuf 1   amp  0x0F   lt  lt  4      inbuf 2   amp  0x3C   gt  gt  2                   outbuf 2      inbuf 2   amp  0x03   lt  lt  6     inbuf 3   amp  0x3F                    for  i   0  i  lt  ctcharsinbuf  i                                           theData appendBytes   amp outbuf i  length  1                                                if  flbreak                                break                                     return theData          end

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A really  really fast implementation which was ported  and modified improved  from the PHP Core library into native Objective-C code is available in the QSStrings Class from the QSUtilities Library   I did a quick benchmark  a 5 3MB image  JPEG  file took  lt  50ms to encode  and about 140ms to decode   The code for the entire library  including the Base64 Methods  are available on GitHub   Or alternatively  if you want the code to just the Base64 methods themselves  I ve posted it here   First  you need the mapping tables   static const char  base64EncodingTable 64     ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789     static const short  base64DecodingTable 256          -2  -2  -2  -2  -2  -2  -2  -2  -2  -1  -1  -2  -1  -1  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -1  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  62  -2  -2  -2  63      52  53  54  55  56  57  58  59  60  61  -2  -2  -2  -2  -2  -2      -2   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14      15  16  17  18  19  20  21  22  23  24  25  -2  -2  -2  -2  -2      -2  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40      41  42  43  44  45  46  47  48  49  50  51  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2  -2      To Encode      NSString   encodeBase64WithString  NSString   strData       return  QSStrings encodeBase64WithData  strData dataUsingEncoding NSUTF8StringEncoding          NSString   encodeBase64WithData  NSData   objData       const unsigned char   objRawData    objData bytes       char   objPointer      char   strResult          Get the Raw Data length and ensure we actually have data     int intLength    objData length       if  intLength    0  return nil          Setup the String-based Result placeholder and pointer within that placeholder     strResult    char   calloc    intLength   2    3    4    1  sizeof char        objPointer   strResult          Iterate through everything     while  intLength  gt  2       keep going until we have less than 24 bits          objPointer      base64EncodingTable objRawData 0   gt  gt  2            objPointer      base64EncodingTable   objRawData 0   amp  0x03   lt  lt  4     objRawData 1   gt  gt  4             objPointer      base64EncodingTable   objRawData 1   amp  0x0f   lt  lt  2     objRawData 2   gt  gt  6             objPointer      base64EncodingTable objRawData 2   amp  0x3f               we just handled 3 octets  24 bits  of data         objRawData    3          intLength -  3                 now deal with the tail end of things     if  intLength    0             objPointer      base64EncodingTable objRawData 0   gt  gt  2           if  intLength  gt  1                 objPointer      base64EncodingTable   objRawData 0   amp  0x03   lt  lt  4     objRawData 1   gt  gt  4                 objPointer      base64EncodingTable  objRawData 1   amp  0x0f   lt  lt  2                objPointer                    else                objPointer      base64EncodingTable  objRawData 0   amp  0x03   lt  lt  4                objPointer                       objPointer                                  Terminate the string-based result      objPointer     0           Create result NSString object     NSString  base64String    NSString stringWithCString strResult encoding NSASCIIStringEncoding           Free memory     free strResult        return base64String      To Decode      NSData   decodeBase64WithString  NSString   strBase64       const char  objPointer    strBase64 cStringUsingEncoding NSASCIIStringEncoding       size t intLength   strlen objPointer       int intCurrent      int i   0  j   0  k       unsigned char  objResult   calloc intLength  sizeof unsigned char            Run through the whole string  converting as we go     while     intCurrent    objPointer         0    amp  amp   intLength--  gt  0              if  intCurrent                       if   objPointer         amp  amp    i   4     1           intLength  gt  0                        the padding character is invalid at this point -- so this entire string is invalid                 free objResult                   return nil                            continue                     intCurrent    base64DecodingTable intCurrent           if  intCurrent    -1                   we re at a whitespace -- simply skip over             continue            else if  intCurrent    -2                   we re at an invalid character             free objResult               return nil                     switch  i   4                case 0                  objResult j    intCurrent  lt  lt  2                  break               case 1                  objResult j       intCurrent  gt  gt  4                  objResult j     intCurrent  amp  0x0f   lt  lt  4                  break               case 2                  objResult j       intCurrent  gt  gt 2                  objResult j     intCurrent  amp  0x03   lt  lt  6                  break               case 3                  objResult j       intCurrent                  break                    i                  mop things up if we ended on a boundary     k   j      if  intCurrent                   switch  i   4                case 1                     Invalid state                 free objResult                   return nil               case 2                  k                       flow through             case 3                  objResult k    0                          Cleanup and setup the return NSData     NSData   objData      NSData alloc  initWithBytes objResult length j  autorelease       free objResult       return objData

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Here s a compact Objective-C version as a Category on NSData  It takes some thinking about      implementation NSData  DataUtils   static char base64      ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789      -  NSString   newStringInBase64FromData    NSMutableString  dest     NSMutableString alloc  initWithString        unsigned char   working    unsigned char    self bytes    int srcLen    self length        tackle the source in 3 s as conveniently 4 Base64 nibbles fit into 3 bytes  for  int i 0  i lt srcLen  i    3          for each output nibble   for  int nib 0  nib lt 4  nib              nibble nib from char byt    int byt    nib    0  0 nib-1     int ix    nib 1  2      if  i byt  gt   srcLen  break         extract the top bits of the nibble  if valid    unsigned char curr     working i byt   lt  lt   8-ix    amp  0x3F          extract the bottom bits of the nibble  if valid    if  i nib  lt  srcLen  curr      working i nib   gt  gt  ix   amp  0x3F        dest appendFormat    c   base64 curr             return dest      end   Padding can be added if required by making the scope of  byt  wider and appending  dest  with  2-byt      characters before returning   A Category can then be added to NSString  thus    implementation NSString  StringUtils   -  NSString   newStringInBase64FromString    NSData  theData    NSData dataWithBytes  self UTF8String  length  self length       return  theData newStringInBase64FromData       end

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For an update to use the NSData  NSDataBase64Encoding  category methods in iOS7 see my answer here  https   stackoverflow com a 18927627 1602729

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I Think This will be helpful      NSString   toBase64String  NSString   string       NSData  data    string dataUsingEncoding  NSUnicodeStringEncoding        NSString  ret    data base64EncodedStringWithOptions NSDataBase64Encoding64CharacterLineLength        return ret                NSString   fromBase64String  NSString   string   NSData  aData    string dataUsingEncoding NSUTF8StringEncoding   NSData  aDataDecoded     NSData alloc initWithBase64EncodedString string options 0   NSString  decryptedStr     NSString alloc initWithData aDataDecoded encoding NSUTF8StringEncoding    return  decryptedStr autorelease

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iOS has had built-in Base64 encoding and decoding methods  without using libresolv  since iOS 4  However  it was only declared in the iOS 7 SDK  Apple documentation states that you can use it when targeting iOS 4 and above   NSData  myData       some data NSString  base64String    myData base64Encoding   NSData  decodedData     NSData alloc  initWithBase64Encoding base64String

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This is a good use case for Objective C categories   For Base64 encoding    import  lt Foundation NSString h gt    interface NSString  NSStringAdditions      NSString    base64StringFromData  NSData   data length  int length    end  -------------------------------------------   import  NSStringAdditions h   static char base64EncodingTable 64         A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P      Q    R    S    T    U    V    W    X    Y    Z    a    b    c    d    e    f      g    h    i    j    k    l    m    n    o    p    q    r    s    t    u    v      w    x    y    z    0    1    2    3    4    5    6    7    8    9                 implementation NSString  NSStringAdditions      NSString    base64StringFromData   NSData   data length   int length     unsigned long ixtext  lentext    long ctremaining    unsigned char input 3   output 4     short i  charsonline   0  ctcopy    const unsigned char  raw    NSMutableString  result     lentext    data length      if  lentext  lt  1      return        result    NSMutableString stringWithCapacity  lentext     raw    data bytes     ixtext   0      while  true        ctremaining   lentext - ixtext      if  ctremaining  lt   0          break              for  i   0  i  lt  3  i              unsigned long ix   ixtext   i         if  ix  lt  lentext            input i    raw ix          else   input i    0        output 0     input 0   amp  0xFC   gt  gt  2    output 1      input 0   amp  0x03   lt  lt  4      input 1   amp  0xF0   gt  gt  4     output 2      input 1   amp  0x0F   lt  lt  2      input 2   amp  0xC0   gt  gt  6     output 3    input 2   amp  0x3F    ctcopy   4    switch  ctremaining        case 1         ctcopy   2         break      case 2         ctcopy   3         break         for  i   0  i  lt  ctcopy  i          result appendString   NSString stringWithFormat     c   base64EncodingTable output i         for  i   ctcopy  i  lt  4  i          result appendString            ixtext    3    charsonline    4     if   length  gt  0   amp  amp   charsonline  gt   length       charsonline   0             return result      end   For Base64 decoding    import  lt Foundation Foundation h gt    class NSString    interface NSData  NSDataAdditions      NSData    base64DataFromString  NSString   string    end  -------------------------------------------   import  NSDataAdditions h    implementation NSData  NSDataAdditions      NSData   base64DataFromString   NSString   string       unsigned long ixtext  lentext      unsigned char ch  inbuf 4   outbuf 3       short i  ixinbuf      Boolean flignore  flendtext   false      const unsigned char  tempcstring      NSMutableData  theData       if  string    nil                return  NSData data              ixtext   0       tempcstring    const unsigned char    string UTF8String        lentext    string length        theData    NSMutableData dataWithCapacity  lentext        ixinbuf   0       while  true                if  ixtext  gt   lentext                        break                     ch   tempcstring  ixtext              flignore   false           if   ch  gt    A    amp  amp   ch  lt    Z                          ch   ch -  A                     else if   ch  gt    a    amp  amp   ch  lt    z                          ch   ch -  a    26                    else if   ch  gt    0    amp  amp   ch  lt    9                          ch   ch -  0    52                    else if  ch                               ch   62                    else if  ch                               flendtext   true                    else if  ch                               ch   63                    else                       flignore   true                      if   flignore                        short ctcharsinbuf   3              Boolean flbreak   false               if  flendtext                                if  ixinbuf    0                                        break                                     if   ixinbuf    1      ixinbuf    2                                         ctcharsinbuf   1                                    else                                       ctcharsinbuf   2                                     ixinbuf   3                   flbreak   true                             inbuf  ixinbuf      ch               if  ixinbuf    4                                ixinbuf   0                   outbuf 0     inbuf 0   lt  lt  2      inbuf 1   amp  0x30   gt  gt  4                   outbuf 1      inbuf 1   amp  0x0F   lt  lt  4      inbuf 2   amp  0x3C   gt  gt  2                   outbuf 2      inbuf 2   amp  0x03   lt  lt  6     inbuf 3   amp  0x3F                    for  i   0  i  lt  ctcharsinbuf  i                                           theData appendBytes   amp outbuf i  length  1                                                if  flbreak                                break                                     return theData          end

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I have done it using the following class     implementation Base64Converter static char base64EncodingTable 64       A    B    C    D    E    F    G    H    I    J    K    L     M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z    a    b    c    d    e    f    g    h    i    j    k    l    m    n    o    p    q    r    s    t    u    v    w    x    y    z    0    1    2    3    4    5    6    7       8    9                  NSString    base64StringFromData   NSData   data length   int length    unsigned long ixtext  lentext   long ctremaining   unsigned char input 3   output 4    short i  charsonline   0  ctcopy   const unsigned char  raw   NSMutableString  result   lentext    data length    if  lentext  lt  1      return       result    NSMutableString stringWithCapacity  lentext    raw    data bytes    ixtext   0   while  true         ctremaining   lentext - ixtext       if  ctremaining  lt   0          break       for  i   0  i  lt  3  i              unsigned long ix   ixtext   i          if  ix  lt  lentext              input i    raw ix           else             input i    0             output 0     input 0   amp  0xFC   gt  gt  2       output 1      input 0   amp  0x03   lt  lt  4      input 1   amp  0xF0   gt  gt  4        output 2      input 1   amp  0x0F   lt  lt  2      input 2   amp  0xC0   gt  gt  6        output 3    input 2   amp  0x3F       ctcopy   4       switch  ctremaining            case 1              ctcopy   2              break           case 2              ctcopy   3              break             for  i   0  i  lt  ctcopy  i             result appendString   NSString stringWithFormat     c   base64EncodingTable output i           for  i   ctcopy  i  lt  4  i             result appendString              ixtext    3       charsonline    4       if   length  gt  0   amp  amp   charsonline  gt   length           charsonline   0    return result     end   While calling call     Base64Converter base64StringFromData dataval length lengthval     That s it

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In mvds s excellent improvement  there are two problems  Change code to this   raw   tmpbuf  inp   0  outbuf outp      base64EncodingTable  raw inp   amp  0xFC   gt  gt  2   outbuf outp      base64EncodingTable   raw inp   amp  0x03   lt  lt  4      raw inp 1   amp  0xF0   gt  gt  4    if   left    2   outbuf outp      base64EncodingTable   raw inp 1   amp  0x0F   lt  lt  2      raw inp 2   amp  0xC0   gt  gt  6    else outbuf outp           outbuf outp

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import  NSDataAdditions h   implementation NSData  NSDataAdditions      NSData    base64DataFromString   NSString   string     unsigned long ixtext  lentext    unsigned char ch  input 4   output 3     short i  ixinput    Boolean flignore  flendtext   false    const char  temporary    NSMutableData  result     if   string      return  NSData data      ixtext   0    temporary    string UTF8String     lentext    string length     result    NSMutableData dataWithCapacity  lentext     ixinput   0     while  true        if  ixtext  gt   lentext        break      ch   temporary ixtext         flignore   false       if   ch  gt    A    amp  amp   ch  lt    Z          ch   ch -  A       else if   ch  gt    a    amp  amp   ch  lt    z          ch   ch -  a    26      else if   ch  gt    0    amp  amp   ch  lt    9          ch   ch -  0    52      else if  ch               ch   62      else if  ch               flendtext   true      else if  ch               ch   63      else       flignore   true       if   flignore          short ctcharsinput   3        Boolean flbreak   false         if  flendtext             if  ixinput    0             break                         if   ixinput    1      ixinput    2              ctcharsinput   1           else            ctcharsinput   2           ixinput   3           flbreak   true                 input ixinput      ch         if  ixinput    4           ixinput   0          output 0     input 0   lt  lt  2      input 1   amp  0x30   gt  gt  4           output 1      input 1   amp  0x0F   lt  lt  4      input 2   amp  0x3C   gt  gt  2           output 2      input 2   amp  0x03   lt  lt  6     input 3   amp  0x3F           for  i   0  i  lt  ctcharsinput  i             result appendBytes   amp output i  length  1               if  flbreak        break              return result     end

[ios] How do I do base64 encoding on iOS?

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