CODEWITHSUNDEEP
chex
AriX
AriX

Reputation: 1697

Convert Hexadecimal String to Data

I have found a whole lot of different solutions to this problem, but not all of them work, and a lot of them seem somewhat hacky and inefficient. Basically I have a string of hexadecimal data (i.e. "55 AA 41 2A 00 94 55 AA BB BB 00 FF") which I would like to convert to raw data. What is the best way to do this?

UPDATE: Vicky's solution worked great for me, but I changed it to work with hexadecimal strings that don't have spaces in between and changed the style a bit.

int i = 0;
char *hexString = "55AA412A009455AABBBB00FF"
char *hexPtr = hexString;
unsigned int *result = calloc(strlen(hexString)/2 + 1, sizeof *result);

while (sscanf(hexPtr, "%02x", &result[i++])) {
    hexPtr += 2;
    if (hexPtr >= hexString + strlen(hexString)) break;
}

return result;

Upvotes: 3

Views: 2657

Answers (5)

ButterCYassine
ButterCYassine

Reputation: 21

 /*
  * copyLeft (ButterC) All Right Changed :)
 */
 void _StackOverFlow(void *data) {

    unsigned char *ButterC = (unsigned char *) data;
    size_t ssize ,size = ssize = 0; 

    int i;

    for (i = 0; ButterC[i] != 0; i++)
    {
            if (ButterC[i] != 32)
                    size++;
    }

    unsigned int *resu = (unsigned int *) malloc((size / 2) + 1);


    while (*ButterC != 0 && resu != NULL && ssize < size) 
    {
            if (*ButterC == 32) 
                    ButterC++;
            else {
                    sscanf(ButterC,"%02x",&resu[ssize++]); ButterC += 2;
            }
    }
    // TEST RESULTE TO => (resu) 
    for (i = 0; i < ssize; i++)
    {
            printf("%02X ",resu[i] & 0xff);
    }

    puts(""); // NEWLINE  
}

int _start() {

    char data[] = "FF 00FF           01";
    _StackOverFlow(data);

    
    _exit(0);
}

Upvotes: 0

Vishwanath Patil
Vishwanath Patil

Reputation: 1

while(input[i]!='\0'){        
    *(temp++) = ((input[i]>='0' && input[i]<='9')?(input[i]-'0'):(input[i]-'a'+10))*16 +( (input[i+1]>='0' && input[i]<='9')?(input[i+1]-'0'):(input[i+1]-'a'+10));
         i+=2;
}

Upvotes: 0

Vicky
Vicky

Reputation: 13244

Is the string always the same length?

If so:

char *buf = "55 AA 41 2A 00 94 55 AA BB BB 00 FF";
sscanf(buf, "%x %x %x [repeat as many times as necessary]", &a, &b, &c [etc]);

If not:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main (int argc, char ** argv)
{
    char *buf = "55 AA 41 2A 00 94 55 AA BB BB 00 FF";
    char *p = buf;
    int i = 0, j;
    unsigned int *result = calloc(strlen(buf)/3 + 1 * sizeof(int), 1);

    if (result)
    {
        while (sscanf(p, "%02x", &result[i++]))
        {
             p += 3;
            if (p > buf + strlen(buf))
            {
             break;
            }
        }

        printf("%s\n", buf);

        for (j = 0; j < i; j++)
        {
            printf("%02X ", result[j]);
        }

        printf("\n");
    }
}

Upvotes: 2

qrdl
qrdl

Reputation: 35008

#define GETBITS(a) (a < 'A' ? a - '0' : toupper(a) - 'A' + 10)

char *cur;
char data;
for (cur = buffer; *cur; cur++) {
    data = GETBITS(cur[0]) << 4 + GETBITS(cur[1]);
    cur += 2;
    printf("%c", data);
}
printf("\n");

Upvotes: 0

ablaeul
ablaeul

Reputation: 2798

Did you try sscanf or scanf? This function processes hexadecimal values to and returns "raw data".

Upvotes: 1

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