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今天给大家提供base64编码的代码，base64不是加密方案，只能说是编码方案，通过将数据转成base64，可以使之进行网络传输，很多公司基本上都是用base64进行网络数据传输。
NSString+YYBase64.h
#import <Foundation/Foundation.h>
/**
Base64编码
*/
@interface NSString (YYBase64)
/**
编码
@return 编码后的字符串
*/
- (NSString *)encodeBase64;
/**
解码
@return 解码后的字符串
*/
- (NSString *)decodeBase64;
+ (NSString *)base64StringFromData:(NSData *)data;
+ (NSData *)dataWithBase64EncodedString:(NSString *)strBase64;
@end
NSString+YYBase64.m
#import "NSString+YYBase64.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', '+', '/'
};
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
};
@implementation NSString (YYBase64)
- (NSString *)encodeBase64 {
NSData *dataString = [self dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [NSString base64StringFromData:dataString];
return base64String;
}
+ (NSString *)base64StringFromData:(NSData *)data {
NSUInteger lentext = [data length];
if (lentext < 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;
NSUInteger do_now = lentext - (lentext%3);
for (outp = 0, inp = 0; inp < do_now; inp += 3) {
outbuf[outp++] = base64EncodingTable[(raw[inp] & 0xFC) >> 2];
outbuf[outp++] = base64EncodingTable[((raw[inp] & 0x03) << 4) | ((raw[inp+1] & 0xF0) >> 4)];
outbuf[outp++] = base64EncodingTable[((raw[inp+1] & 0x0F) << 2) | ((raw[inp+2] & 0xC0) >> 6)];
outbuf[outp++] = base64EncodingTable[raw[inp+2] & 0x3F];
}
if (do_now < lentext) {
char tmpbuf[2] = {0, 0};
int left = lentext%3;
for (int i=0; i < left; i++) {
tmpbuf[i] = raw[do_now+i];
}
inp = 0;
outbuf[outp++] = base64EncodingTable[(tmpbuf[inp] & 0xFC) >> 2];
outbuf[outp++] = base64EncodingTable[((tmpbuf[inp] & 0x03) << 4) | ((tmpbuf[inp+1] & 0xF0) >> 4)];
if (left == 2) {
outbuf[outp++] = base64EncodingTable[((tmpbuf[inp+1] & 0x0F) << 2)];
}
else
outbuf[outp++] = '=';
outbuf[outp++] = '=';
}
NSString *ret = [[NSString alloc] initWithBytes:outbuf length:outp encoding:NSASCIIStringEncoding];
free(outbuf);
return ret;
}
- (NSString *)decodeBase64 {
if ([self isEqualToString:@""]) {
return @"";
} else {
NSData *data = [NSString dataWithBase64EncodedString:self];
return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
}
}
+ (NSData *)dataWithBase64EncodedString:(NSString *)strBase64 {
const char * objPointer = [strBase64 cStringUsingEncoding:NSASCIIStringEncoding];
int intLength = (int)strlen(objPointer);
int intCurrent;
int i = 0, j = 0, k;
unsigned char * objResult;
objResult = calloc(intLength, sizeof(char));
// Run through the whole string, converting as we go
while ( ((intCurrent = *objPointer++) != '\0') && (intLength-- > 0) ) {
if (intCurrent == '=') {
if (*objPointer != '=' && ((i % 4) == 1)) {// || (intLength > 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 << 2;
break;
case 1:
objResult[j++] |= intCurrent >> 4;
objResult[j] = (intCurrent & 0x0f) << 4;
break;
case 2:
objResult[j++] |= intCurrent >>2;
objResult[j] = (intCurrent & 0x03) << 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];
free(objResult);
return objData;
}
@end
如何使用？base64编码：
科技小弟(https://www.jianshu.com/u/23c527245f22)
1
base64解码：
2
需要的自取。
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