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我有一個網絡字節順序的字符數組。我試圖將存儲在索引[4-7]中的字符轉換爲主機順序,並將其分配給unsigned int。我有以下功能:C++從網絡到主機順序轉換char []並分配給unsigned int
unsigned int parse_num_bytes(char buf[]){
unsigned int num_bytes = ((unsigned int)buf[7] << 24) | ((unsigned int)buf[6] << 16) | ((unsigned int)buf[5] << 8) | (unsigned int)buf[4];
return num_bytes;
}
從GDB(實際上可以LLDB因爲我在Mac上)我可以看到,運算,產生正確的結果,但轉讓之後,該值是錯誤的:
81
82 unsigned int parse_num_bytes(char buf[]){
83 unsigned int num_bytes = ((unsigned int)buf[7] << 24) | ((unsigned int)buf[6] << 16) | ((unsigned int)buf[5] << 8) | (unsigned int)buf[4];
-> 84 return num_bytes;
85 }
(lldb) p num_bytes
(unsigned int) $0 = 4294967170
(lldb) p ((unsigned int)buf[7] << 24) | ((unsigned int)buf[6] << 16) | ((unsigned int)buf[5] << 8) | (unsigned int)buf[4]
(unsigned int) $1 = 2434
爲了澄清,2434
是正確的值。
這裏就是我產生了網絡訂購(在服務器應用程序):
return_buf[4] = index & 0xff;
return_buf[5] = (index >> 8) & 0xff;
return_buf[6] = (index >> 16) & 0xff;
return_buf[7] = (index >> 24) & 0xff;
而且從GDB我可以告訴你指數的值(它是一個unsigned int
)
142 return_buf[4] = index & 0xff;
143 return_buf[5] = (index >> 8) & 0xff;
144 return_buf[6] = (index >> 16) & 0xff;
-> 145 return_buf[7] = (index >> 24) & 0xff;
146
147 in_file.close();
148 Rio_writen(connfd, return_buf, MAXLINE);
(lldb) p index
(unsigned int) $0 = 2434