/* Written by Jarett Stevens
   Program to convert log files beginning with an epoch time-stamp
   (space delimited) to begin with localtime (YYYY-MM-DD HH:MM:SS)
   Compiles equally well under Unix with gcc or Windows (MinGW)
   Usage: fix-time input-file.log > output-file.log
*/

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

int main(int argc, char **argv) {

        long epoch_time ;
	int buffct ;
	FILE *input_file ;
	char line_buffer[2048] ;
	char epoch_buff[32] ;
	char out_time_buff[32] ;
	char c ;

	epoch_time = buffct = c = 0 ;
	input_file = NULL ;

        if ( argc != 2 ) return 1 ;

	if ( (input_file = fopen(argv[1], "r")) != NULL) {
	
		while ( (fgets(line_buffer, 2048, input_file)) != NULL ) {
			buffct = 0 ;
			for ( buffct = 0 ; buffct < 32 ; buffct++ ) {
				if ( (c = line_buffer[buffct]) == ' ' )  {
					epoch_buff[buffct] = 0 ;
					break ;

				} else {
					epoch_buff[buffct] = c ;
				}
			}

			epoch_time = atoi(epoch_buff) ;
			(void) strftime(out_time_buff, 32, "%Y-%m-%d %H:%M:%S", localtime(&epoch_time)) ;
	       		printf("%s%s", out_time_buff, (line_buffer + buffct)) ;
		} 

		fclose(input_file) ;

	} else { 
		perror(argv[1]) ;
		return 1; 
	}

return 0 ;
}