[英]the issue convert buffer to hex string in c
I'm trying to convert buffer to hex string in c as the below, the below image is the input file 我正在尝试将缓冲区转换为c中的十六进制字符串,如下所示,下图是输入文件
it's a binary file.
这是一个二进制文件。
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "fcntl.h"
#if defined(_MSC_VER)
#include <BaseTsd.h>
typedef SSIZE_T ssize_t;
#endif
#define BUFF_SIZE 5
int main()
{
char buff[BUFF_SIZE];
int fd;
ssize_t rd_size;
FILE *rfp;
FILE *ofp;
ofp = fopen("output.txt", "w");
rfp = fopen("test.bin", "rb");
while ( 4== (fread(buff, 1, 4, rfp)))
{
fprintf(ofp, "%02X%02X%02X%02X \n", buff[0], buff[1], buff[2], buff[3]);
}
fclose(ofp);
fclose(rfp);
return 0;
}
then I use above code, I've got bin to hex file but I've got the problem at result. 然后我使用上面的代码,我将bin放入了十六进制文件,但是结果出了问题。
04002B2B
000001FFFFFFFF
00030003
00000000
00000000
00000000
00000300
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00500050
00500050
00500050
00500050
00000000
FFFFFF80002000
00000000
08700F00
00000000
00000000
00000001
00000002
00000003
00000004
00000005
00000006
00000007
FFFFFF800FFFFFFFF01E
087007FFFFFF80
00320032
0BFFFFFFB80820
00050005
2DFFFFFFC7114D
00FFFFFFC20118
00001B58
As you can see that the above file, especially I don't want to "000001FFFFFFFF " this output. 如您所见,上面的文件,特别是我不想“ 000001FFFFFFFF”此输出。 But I don't know what am I supposed to do
但是我不知道该怎么办
I want to run in the linux. 我想在linux中运行。 but if I make a execute file, I got the segmant error.
但是,如果我创建了一个执行文件,则会收到segmant错误。 Can you let me know what am I supposed to do?
你能让我知道我该怎么办吗?
The major problem here is that your char
type seems to be signed
(if char
is signed
or unsigned
is implementation specific). 这里的主要问题是您的
char
类型似乎是带signed
(如果char
是带signed
还是unsigned
是实现特定的)。 That means that values larger equal or larger than 0x80
will be treated as negative values (with two's complement systems). 这意味着大于或等于
0x80
值将被视为负值(使用二进制补码系统)。
And when you pass such a value to printf
and the value is promoted to an int
it is sign-extended. 并且,当您将这样的值传递给
printf
并将该值提升为int
它将被符号扩展。 So 0xff
becomes 0xffffffff
, which is then printed. 因此
0xff
变为0xffffffff
,然后将其打印出来。
If you use unsigned char
for your values instead, then values like 0xff
are not extended when being promoted to unsigned int
. 如果改为使用
unsigned char
作为值,则当提升为unsigned int
时,不会扩展0xff
类的值。 So 0xff
is promoted to 0x000000ff
, and the leading zeroes are not printed. 因此,将
0xff
提升为0x000000ff
,并且不打印前导零。
Another issue is that you are using the wrong format for printf
. 另一个问题是您为
printf
使用了错误的格式。 The format "%x"
is for unsigned int
and not unsigned char
. 格式
"%x"
用于unsigned int
而非unsigned char
。 If you read eg this printf
(and family) reference you will see a big table with all the formatting code and the different size prefixes for different types. 如果您阅读此
printf
(和系列)参考,您将看到一个大表,其中包含所有格式代码和不同类型的不同大小前缀。 To print an unsigned char
you should use the hh
prefix, as in "%hhx"
. 要打印
unsigned char
,应使用hh
前缀,如"%hhx"
。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.