ios - 从 nsdata 获取字节附加额外的垃圾字符

Question

我试图从 nsdata 中获取字节到 char* 中，但是 char* 的长度超过了 nsdata 的长度，并且在最后附加了额外的垃圾字符。代码:

 NSData * newData=[self dataFromHexString:trimmedHex];
 NSLog(@"new data length %d",[newData length]);
 char * ciphertext=(char*)[newData bytes];
 NSLog(@"length of ciphertext %zd",strlen(ciphertext));

日志:

2013-08-02 17:02:28.175 AES[4187:11303] new data length 128
2013-08-02 17:02:28.176 AES[4187:11303] length of ciphertext 144

从早上就坚持这个。:(

const char * ciphertextTemp=(const char*)[newData bytes];
char ciphertext[[newData length]+1];
for (int len=0; len<[self length];len++) {
    ciphertext[len]=ciphertextTemp[len];
}
ciphertext[[self length]]='\0';

Answer 1

是否是 char 的 ciphertext 指向的序列缺少 0 终止符？

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更新:

代替

for (int len=0; len<[self length];len++) {
  ciphertext[len]=ciphertextTemp[len];
}
ciphertext[[self length]]='\0';

你可以简单地这样做:

strncpy(ciphertext, ciphertextTemp, [newData length]);
ciphertext[[self length] - 1]='\0';