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HEX File Data Display

Displays bytes in a file from an optional offset to an optional maximum value of bytes to show to the terminal. I made this for Linux but it will work in Windows.

Submitted By: WolfCoder

Actions:

Rating:

Views: 453

Language: C

Last Modified: July 1, 2009

Instructions: Just compile and run. Program has it's own instructions inside for usage. For Windows, you *might* have to change the file operations to use their _s forms (ex: fopen_s) for it to compile in MSVS.

Snippet

/*
Cat-HEX
written by WolfCoder (2009)
Displays the contents of a file in HEX format and ASCII characters.
*/
/* Defines */
#define DEFAULT_LINES 12
#define WIDE_DIVISOR 16
#define CATHEX_OK 0
#define WRONG_ARG_ERR 1
#define FILE_ERR 2
/* Includes */
#include <stdlib.h>
#include <stdio.h>
/* Globals */
FILE *showfile;
int num_show = DEFAULT_LINES*WIDE_DIVISOR;
int offset = 0;
unsigned char hex[WIDE_DIVISOR];
int num_read = 0;
int so_far_read = 0;
int max_show = 0;
/* Display a line of 8 hex digits */
void display_line()
{
int i;
/* Display */
for(i = 0;i < WIDE_DIVISOR;i++)
{
/* Read data? */
if(i < num_read)
{
/* Small? */
if(hex[i] <= 0xF)
printf("0%x ",hex[i]);
else
printf("%x ",hex[i]); /* Large */
}
else
{
/* Spacers */
printf(" ");
}
}
}
/* Display a line of characters */
void display_ascii_line()
{
int i;
/* Display */
for(i = 0;i < num_read;i++)
{
/* Visible character? */
if(hex[i] >= 0x20 && hex[i] < 0x7F)
printf("%c",(char)hex[i]);
else
printf("."); /* Not visible */
}
}
/* Program Entry */
int main(int argn,char **argv)
{
int i;
/* No options */
if(argn == 1)
{
printf("Usage: cathex [filename] [bytes to display] [offset to start from]\n");
return CATHEX_OK;
}
/* Illegal options */
if(argn > 4)
{
fprintf(stderr,"Wrong number of arguments passed.\n");
return WRONG_ARG_ERR;
}
/* Open file */
showfile = fopen(argv[1],"rb");
if(!showfile)
{
fprintf(stderr,"Could not open %s.\n",argv[1]);
return FILE_ERR;
}
/* Set maximum */
if(argn > 2)
max_show = atoi(argv[2]);
/* Set offset */
if(argn > 3)
offset = atoi(argv[3]);
/* Seek */
fseek(showfile,offset,SEEK_SET);
/* Begin reading lines */
while(1)
{
/* Read */
num_read = fread(hex,1,WIDE_DIVISOR,showfile);
/* Show */
display_line();
printf("\t");
display_ascii_line();
/* Return */
printf("\n");
/* Advance */
so_far_read += num_read;
/* Check for ending */
if(num_read != WIDE_DIVISOR)
break;
if(max_show != 0 && so_far_read >= max_show)
break;
}
/* Everything is alright */
return CATHEX_OK;
}

Copy & Paste

/*
	Cat-HEX
	written by WolfCoder (2009)

Displays the contents of a file in HEX format and ASCII characters.
*/

/* Defines */
#define DEFAULT_LINES 12
#define WIDE_DIVISOR 16

#define CATHEX_OK 0
#define WRONG_ARG_ERR 1
#define FILE_ERR 2

/* Includes */
#include <stdlib.h>
#include <stdio.h>

/* Globals */
FILE *showfile;
int num_show = DEFAULT_LINES*WIDE_DIVISOR;
int offset = 0;
unsigned char hex[WIDE_DIVISOR];
int num_read = 0;
int so_far_read = 0;
int max_show = 0;

/* Display a line of 8 hex digits */
void display_line()
{
	int i;
	/* Display */
	for(i = 0;i < WIDE_DIVISOR;i++)
	{
		/* Read data? */
		if(i < num_read)
		{
			/* Small? */
			if(hex[i] <= 0xF)
				printf("0%x ",hex[i]);
			else
				printf("%x ",hex[i]); /* Large */
		}
		else
		{
			/* Spacers */
			printf("   ");
		}
	}
}

/* Display a line of characters */
void display_ascii_line()
{
	int i;
	/* Display */
	for(i = 0;i < num_read;i++)
	{
		/* Visible character? */
		if(hex[i] >= 0x20 && hex[i] < 0x7F)
			printf("%c",(char)hex[i]);
		else
			printf("."); /* Not visible */
	}
}

/* Program Entry */
int main(int argn,char **argv)
{
	int i;
	/* No options */
	if(argn == 1)
	{
		printf("Usage: cathex [filename] [bytes to display] [offset to start from]\n");
		return CATHEX_OK;
	}
	/* Illegal options */
	if(argn > 4)
	{
		fprintf(stderr,"Wrong number of arguments passed.\n");
		return WRONG_ARG_ERR;
	}
	/* Open file */
	showfile = fopen(argv[1],"rb");
	if(!showfile)
	{
		fprintf(stderr,"Could not open %s.\n",argv[1]);
		return FILE_ERR;
	}
	/* Set maximum */
	if(argn > 2)
		max_show = atoi(argv[2]);
	/* Set offset */
	if(argn > 3)
		offset = atoi(argv[3]);
	/* Seek */
	fseek(showfile,offset,SEEK_SET);
	/* Begin reading lines */
	while(1)
	{
		/* Read */
		num_read = fread(hex,1,WIDE_DIVISOR,showfile);
		/* Show */
		display_line();
		printf("\t");
		display_ascii_line();
		/* Return */
		printf("\n");
		/* Advance */
		so_far_read += num_read;
		/* Check for ending */
		if(num_read != WIDE_DIVISOR)
			break;
		if(max_show != 0 && so_far_read >= max_show)
			break;
	}
	/* Everything is alright */
	return CATHEX_OK;
}