base64 on iphone-sdk

For Base64 encoding:

#import <Foundation/NSString.h>@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 < 1)    return @"";  result = [NSMutableString stringWithCapacity: lentext];  raw = [data bytes];  ixtext = 0;   while (true) {    ctremaining = lentext - ixtext;    if (ctremaining <= 0)        break;            for (i = 0; i < 3; i++) {        unsigned long ix = ixtext + i;       if (ix < lentext)          input[i] = raw[ix];       else  input[i] = 0;  }  output[0] = (input[0] & 0xFC) >> 2;  output[1] = ((input[0] & 0x03) << 4) | ((input[1] & 0xF0) >> 4);  output[2] = ((input[1] & 0x0F) << 2) | ((input[2] & 0xC0) >> 6);  output[3] = input[2] & 0x3F;  ctcopy = 4;  switch (ctremaining) {    case 1:       ctcopy = 2;       break;    case 2:       ctcopy = 3;       break;  }  for (i = 0; i < ctcopy; i++)     [result appendString: [NSString stringWithFormat: @"%c", base64EncodingTable[output[i]]]];  for (i = ctcopy; i < 4; i++)     [result appendString: @"="];  ixtext += 3;  charsonline += 4;  if ((length > 0) && (charsonline >= length))    charsonline = 0;  }       return result;}@end

For Base64 decoding:

#import <Foundation/Foundation.h>@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 >= lentext)        {            break;        }        ch = tempcstring [ixtext++];        flignore = false;        if ((ch >= 'A') && (ch <= 'Z'))        {            ch = ch - 'A';        }        else if ((ch >= 'a') && (ch <= 'z'))        {            ch = ch - 'a' + 26;        }        else if ((ch >= '0') && (ch <= '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] << 2) | ((inbuf[1] & 0x30) >> 4);                outbuf[1] = ((inbuf[1] & 0x0F) << 4) | ((inbuf[2] & 0x3C) >> 2);                outbuf[2] = ((inbuf[2] & 0x03) << 6) | (inbuf[3] & 0x3F);                for (i = 0; i < ctcharsinbuf; i++)                {                    [theData appendBytes: &outbuf[i] length: 1];                }            }            if (flbreak)            {                break;            }        }    }    return theData;}@end

转帖：http://stackoverflow.com/questions/392464/any-base64-library-on-iphone-sdk