#include <stdio.h>

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>
#include <sys/time.h>

#define MAX_LEN (2000)

static double RAT( unsigned long long a, unsigned long long b )
{
if( b == 0 )
return 0.0;
else
return ( ( double ) a ) / b;
}

static unsigned long long tdiff(struct timeval *t1, struct timeval *t2)
{
return (t1->tv_sec - t2->tv_sec) * 1000000 + (t1->tv_usec - t2->tv_usec);
}

int main( int argc, char **argv )
{
const char alphabet[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
unsigned long long i;
char name[ MAX_LEN + 1 ];
int min;
int base;
struct timeval start;
struct timeval instant;
unsigned long prev;
unsigned long N;
int ch;
int pad;
unsigned long cycle;
int dodirs;
int writelen;
int reverse;
char *buf;

N = 0;
pad = 0;
dodirs = 0;
cycle = 20000;
writelen = 0;
buf = 0;
reverse = 0;
while( ( ch = getopt( argc, argv, "dn:p:c:w:r" ) ) != -1 )
{
switch( ch )
{
case 'n':
N = atol( optarg );
break;
case 'p':
pad = atoi( optarg );
break;
case 'c':
cycle = atol( optarg );
break;
case 'd':
dodirs = 1;
break;
case 'w':
writelen = atoi( optarg );
break;
case 'r':
reverse = 1;
break;
default:
exit( 0 );
}
}

base = strlen( alphabet );
memset( name, base + 10, MAX_LEN + 1 );
prev = 0;
gettimeofday( &instant, 0 );
start = instant;

if( writelen > 0 )
{
if( dodirs )
{
fprintf( stderr, "Cannot write into directories\n" );
exit( 1 );
}
buf = ( char * )malloc( writelen );
if( buf == NULL )
{
perror( "malloc" );
exit( 1 );
}
}

for( i = 0 ; N && i < N ; ++ i )
{
int j;
int c;
int fd;
int shift;
char fname[ MAX_LEN + 1 ];

for( j = MAX_LEN - 1, c = 1 ; ( j >= 0 ) && c ; -- j )
{
c = 0;
if( name[ j ] == base + 10 )
{
name[ j ] = 1;
min = j;
}
else if( name[ j ] == base - 1 )
{
c = 1;
name[ j ] = 0;
}
else
{
name[ j ] ++;
}
}
if( c == 1 )
{
exit( 1 );
}
if( pad )
{
shift = pad - ( MAX_LEN - min );
if( shift < 0 )
{
shift = 0;
}
for( j = 0 ; j < shift ; ++ j )
{
fname[ j ] = '#';
}
}
else
{
shift = 0;
}
for( j = min ; j < MAX_LEN ; ++ j )
{
fname[ j - min + shift ] = alphabet[ ( int ) name[ j ] ];
}
fname[ MAX_LEN - min + shift ] = 0;
if( reverse )
{
int len;

len = MAX_LEN - min + shift;
for( j = 0 ; j < len / 2 + 1 ; ++ j )
{
char swap;

swap = fname[ j ];
fname[ j ] = fname[ len - j - 1 ];
fname[ len - j - 1 ] = swap;
}
}
if( dodirs )
{
fd = mkdir( fname, 0744 );
}
else
{
fd = open( fname, O_CREAT | O_WRONLY, 0444 );
}
if( fd == -1 )
{
perror( "open" );
printf( "%li files created\n", i );
exit( 2 );
}
if( !dodirs )
{
if( writelen > 0 )
{
int result;

if( write( fd, buf, writelen ) != writelen )
{
perror( "write" );
exit( 3 );
}
}
close( fd );
}
if( ( i % cycle ) == 0 )
{
struct timeval now;

gettimeofday( &now, 0 );
printf( "%lli\t files: %lli (%f/%f), %s\n", i,
tdiff( &now, &instant ),
RAT( i * 1000000, tdiff( &now, &start ) ),
RAT( ( i - prev ) * 1000000, tdiff( &now, &instant ) ),
fname );
gettimeofday( &instant, 0 );
prev = i;
}
}
if( buf != NULL )
free( buf );
}