show-bytes.c

/* $begin show-bytes */
#include <stdio.h>
/* $end show-bytes */
#include <stdlib.h>
#include <string.h>
/* $begin show-bytes */

typedef unsigned char *byte_pointer;

void show_bytes(byte_pointer start, int len) {
    int i;
    for (i = 0; i < len; i++)
	printf(" %.2x", start[i]);    //line:data:show_bytes_printf
    printf("\n");
}

void show_int(int x) {
    show_bytes((byte_pointer) &x, sizeof(int)); //line:data:show_bytes_amp1
}

void show_short(short x) {
    show_bytes((byte_pointer) &x, sizeof(short)); //line:data:show_bytes_amp1
}

void show_long(long x) {
    show_bytes((byte_pointer) &x, sizeof(long)); //line:data:show_bytes_amp1
}

void show_double(double x) {
    show_bytes((byte_pointer) &x, sizeof(double)); //line:data:show_bytes_amp1
}

void show_float(float x) {
    show_bytes((byte_pointer) &x, sizeof(float)); //line:data:show_bytes_amp2
}

void show_pointer(void *x) {
    show_bytes((byte_pointer) &x, sizeof(void *)); //line:data:show_bytes_amp3
}
/* $end show-bytes */


/* $begin test-show-bytes */
void test_show_bytes(int val) {
    int ival = val;
    float fval = (float) ival;
    short sval = (short) ival;
    long lval = (long) ival;
    double dval = (double) dval;
    int *pval = &ival;
    show_int(ival);
    show_float(fval);
    show_long(lval);
    show_short(sval);
    show_double(dval);
    show_pointer(pval);
}
/* $end test-show-bytes */

void simple_show_a() {
/* $begin simple-show-a */
int val = 0x87654321;
byte_pointer valp = (byte_pointer) &val;
show_bytes(valp, 1); /* A. */
show_bytes(valp, 2); /* B. */
show_bytes(valp, 3); /* C. */
/* $end simple-show-a */
}

void simple_show_b() {
/* $begin simple-show-b */
int val = 0x12345678;
byte_pointer valp = (byte_pointer) &val;
show_bytes(valp, 1); /* A. */
show_bytes(valp, 2); /* B. */
show_bytes(valp, 3); /* C. */
/* $end simple-show-b */
}

void float_eg() {
  int x = 3490593;
  float f = (float) x;
  printf("For x = %d\n", x);
  show_int(x);
  show_float(f);

  x = 3510593;
  f = (float) x;
  printf("For x = %d\n", x);
  show_int(x);
  show_float(f);

}

void string_ueg() {
/* $begin show-ustring */
const char *s = "ABCDEF";
show_bytes((byte_pointer) s, strlen(s)); 
/* $end show-ustring */
}

void string_leg() {
/* $begin show-lstring */
const char *s = "abcdef";
show_bytes((byte_pointer) s, strlen(s)); 
/* $end show-lstring */
}

void show_twocomp() 
{
/* $begin show-twocomp */
    short x = 12345; 
    short mx = -x; 
    
    show_bytes((byte_pointer) &x, sizeof(short)); 
    show_bytes((byte_pointer) &mx, sizeof(short)); 
/* $end show-twocomp */
}

int main(int argc, char *argv[])
{
    int val = 12345;

    if (argc > 1) {
	if (argc > 1) {
	    val = strtol(argv[1], NULL, 0);
	}
	printf("calling test_show_bytes\n");
	test_show_bytes(val);
    } else {
	printf("calling show_twocomp\n");
	show_twocomp();
	printf("Calling simple_show_a\n");
	simple_show_a();
	printf("Calling simple_show_b\n");
	simple_show_b();
	printf("Calling float_eg\n");
	float_eg();
	printf("Calling string_ueg\n");
	string_ueg();
	printf("Calling string_leg\n");
	string_leg();
    }
    return 0;
}