如何将base64string解码/转换为NSData？

你好我想弄清楚如何转换/解码一个iOS应用程序中的base64string到NSData，所以我可以解密我encryption的数据。

我用于将NSData转换为基础64string的方法可以在这里find有没有类似的方法来创build方法来解码/基地64string转换为NSData？

Answer 1

这是我正在寻找的。

+ (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; }