场景:
1. 在读取文件或内存时，有时候需要输出那段内存的十六或二进制表示进行分析。
2. 标准的printf没有显示二进制的,而%x显示有最大上限，就是8字节，超过8字节就不行了。
test_binary_hex.cpp
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <stdint.h>
#include <iostream>
std::string ToBinaryString(const uint8_t* buf,int len)
{
int output_len = len*8;
std::string output;
const char* m[] = {"0","1"};
for(int i = output_len - 1,j = 0; i >=0 ; --i,++j)
{
output.append(m[((uint8_t)buf[j/8] >> (i % 8)) & 0x01],1);
}
return output;
}
std::string ToHexString(const uint8_t* buf,int len,std::string tok = "")
{
std::string output;
char temp[8];
for (int i = 0; i < len; ++i)
{
sprintf(temp,"0x%.2x",(uint8_t)buf[i]);
output.append(temp,4);
output.append(tok);
}
return output;
}
int main(int argc, char const *argv[])
{
printf("0x%.2x\n",1);
uint8_t buf[] = {0x80,0x0f,0x51,0xEE,0xA7};
std::string output = ToBinaryString(buf,2);
std::string output_hex = ToHexString(buf,2,":");
std::cout << output << std::endl;
std::cout << output_hex << std::endl;
assert(!strcmp(output.c_str(),"1000000000001111"));
output = ToBinaryString(buf,3);
std::cout << output << std::endl;
assert(!strcmp(output.c_str(),"100000000000111101010001"));
output = ToBinaryString(buf,4);
assert(!strcmp(output.c_str(),"10000000000011110101000111101110"));
std::cout << output << std::endl;
output = ToBinaryString(buf,5);
assert(!strcmp(output.c_str(),"1000000000001111010100011110111010100111"));
std::cout << output << std::endl;
return 0;
}
输出:
0x01 1000000000001111 0x80:0x0f: 100000000000111101010001 10000000000011110101000111101110 1000000000001111010100011110111010100111