崩潰的基地64編碼

Question

您好我使用base 64編碼爲我的字符串，但我有時崩潰。它不是經常複製。我嘗試了不同的方式，但沒有取得成功。

這裏是崩潰：

的malloc：*錯誤對象0x6880830：不正確的校驗和釋放對象 - 對象被釋放後，可能被修改。 *設置malloc_error_break斷點調試

這裏是代碼片段：

-(NSString *)Base64Encode:(NSData *)data{ 

     if([data length]) 
    { 
    //Point to start of the data and set buffer sizes 
int inLength = [data length]; 
int outLength = ((((inLength * 4)/3)/4)*4) + (((inLength * 4)/3)%4 ? 4 : 0); 
const char *inputBuffer = [data bytes]; 
char *outputBuffer = malloc(outLength); 
outputBuffer[outLength] = 0; 
//64 digit code 
static char Encode[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz/"; 
//start the count 
int cycle = 0; 
int inpos = 0; 
int outpos = 0; 
char temp; 

//Pad the last to bytes, the outbuffer must always be a multiple of 4 
outputBuffer[outLength-1] = '='; 
outputBuffer[outLength-2] = '='; 

/* 
Text content M   a   n 
ASCII   77   97   110 
8 Bit pattern 01001101 01100001 01101110 

6 Bit pattern 010011 010110 000101 101110 
Index   19  22  5  46 
Base64-encoded T  W  F  u 
*/ 


while (inpos < inLength){ 
    switch (cycle) { 
     case 0: 
      outputBuffer[outpos++] = Encode[(inputBuffer[inpos]&0xFC)>>2]; 
      cycle = 1; 
      break; 
     case 1: 
      temp = (inputBuffer[inpos++]&0x03)<<4; 
      outputBuffer[outpos] = Encode[temp]; 
      cycle = 2; 
      break; 
     case 2: 
      outputBuffer[outpos++] = Encode[temp|(inputBuffer[inpos]&0xF0)>> 4]; 
      temp = (inputBuffer[inpos++]&0x0F)<<2; 
      outputBuffer[outpos] = Encode[temp]; 
      cycle = 3;     
      break; 
     case 3: 
      outputBuffer[outpos++] = Encode[temp|(inputBuffer[inpos]&0xC0)>>6]; 
      cycle = 4; 
      break; 
     case 4: 
      outputBuffer[outpos++] = Encode[inputBuffer[inpos++]&0x3f]; 
      cycle = 0; 
      break;       
     default: 
      cycle = 0; 
      break; 
    } 
} 
NSString *pictemp = [NSString stringWithUTF8String:outputBuffer]; 
free(outputBuffer); 
return pictemp; 

} 
else { 
    return @""; 
} 

} 

Answer 1

你正在編寫超出你的輸出緩衝區的末尾：

char *outputBuffer = malloc(outLength); 
outputBuffer[outLength] = 0; 

如果分配outLength + 1字節你應該沒問題。