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#include <stdio.h>
#include <string.h>
#include "dbg.h"
int normal_copy(char * from, char *to, int count)
{
int i = 0;
for(i = 0; i < count; i++) {
to[i] = from[i];
}
return i;
}
int duffs_device(char *from, char *to, int count)
{
{
int n = (count + 7) / 8;
switch(count % 8) {
case 0: do { *to++ = *from++;
case 7: *to++ = *from++;
case 6: *to++ = *from++;
case 5: *to++ = *from++;
case 4: *to++ = *from++;
case 3: *to++ = *from++;
case 2: *to++ = *from++;
case 1: *to++ = *from++;
} while(--n > 0);
}
}
return count;
}
int zeds_device(char *from, char *to, int count)
{
{
int n = (count + 7) / 8;
switch(count % 8) {
case 0:
again: *to++ = *from++;
case 7: *to++ = *from++;
case 6: *to++ = *from++;
case 5: *to++ = *from++;
case 4: *to++ = *from++;
case 3: *to++ = *from++;
case 2: *to++ = *from++;
case 1: *to++ = *from++;
if(--n > 0) goto again;
}
}
return count;
}
int valid_copy(char *data, int count, char expects)
{
int i = 0;
for(i = 0; i < count; i++) {
if(data[i] != expects) {
log_err("[%d] %c != %c", i, data[i], expects);
return 0;
}
}
return 1;
}
int main(int argc, char *argv[])
{
char from[1000] = {'a'};
char to[1000] = {'c'};
int rc = 0;
// setup the from to have some stuff
memset(from, 'x', 1000);
// set it to a failure mode
memset(to, 'y', 1000);
check(valid_copy(to, 1000, 'y'), "Not initialized right");
// use normal copy to
rc = normal_copy(from, to, 1000);
check(rc == 1000, "Normal copy failed: %d", rc);
check(valid_copy(to, 1000, 'x'), "Normal copy failed");
// reset
memset(to, 'y', 1000);
// my version
rc = zeds_device(from, to, 1000);
check(rc = 1000, "Zed's device failed: %d", rc);
check(valid_copy(to, 1000, 'x'), "Zed's device copy failed");
return 0;
error:
return 1;
}
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