[TIMOB-1611] iOS: base64 encoding/decoding of Blob cannot be round-tripped successfully

Hi, I'm an end user of Titanium that had some trouble with this recently.

The problem on iPhone is that the TiBlob is converted to a String first using UtilsModule.convertToString grabbing the TiBlob.text field. If the TiBlob is an image or file you need to use the TiBlob.data field.

I managed to get it to work using the attached code. I figured it was better to use the TiBlob.data rather than TiBlob.text always, as if you really must base64 encode a String from a blob you can change your Javascript to Ti.Utils.base64encode(blob.text) and it will still encode it.

-(TiBlob*)base64encode:(id)args {

   ENSURE_SINGLE_ARG(args,NSObject);
   const char *data;
   size_t len;
   if ([args isKindOfClass:[NSString class]])
   {
       data = [args UTF8String];
       len = [args length];
   }
   else if ([args isKindOfClass:[TiBlob class]])
   {
       data = [[(TiBlob*)args data] bytes];
       len = [[(TiBlob*)args data] length];
   }
   else
   {
       THROW_INVALID_ARG(@"invalid type");
   }
   
   size_t outsize = EstimateBas64EncodedDataSize(len);
   char *base64Result = malloc(sizeof(char)*outsize);
   size_t theResultLength = outsize;
   
   bool result = Base64EncodeData(data, len, base64Result, &theResultLength);
   if (result)
   {
       NSData *theData = [NSData dataWithBytes:base64Result length:theResultLength];
       free(base64Result);
       return [[[TiBlob alloc] initWithData:theData mimetype:@"application/octet-stream"] autorelease];
   }    
   free(base64Result);
   return nil;
   

}

I also created this function because I wanted the TiBlob I created to be an Image with width/height attributes. Is it possible to
1) Add it to UtilsModule.m
or
2) Have an optional parameter that determines the type of TiBlob to return
or
3) Maybe even better have an TiBlob be able to create another TiBlob of type TiBlobTypeImage from the data within it. Maybe at the same time you could provide a constructor in Javascript to let us create our own TiBlobs from our own data.

-(TiBlob*)base64decodeImage:(id)args {

   ENSURE_SINGLE_ARG(args,NSObject);
   
   NSString *str = [self convertToString:args];
   
   const char *data = [str UTF8String];
   size_t len = [str length];
   
   size_t outsize = EstimateBas64DecodedDataSize(len);
   char *base64Result = malloc(sizeof(char)*outsize);
   size_t theResultLength = outsize;
   
   bool result = Base64DecodeData(data, len, base64Result, &theResultLength);
   if (result)
   {
       NSData *theData = [NSData dataWithBytes:base64Result length:theResultLength];
       free(base64Result);
       return [[[TiBlob alloc] initWithImage:[UIImage imageWithData:theData]] autorelease];
   }    
   free(base64Result);
   return nil;
   

}