/* given a list of filenames in input (one per line), and a set of
   directories; for each filename, compare the versions in the directories. 
   If they are the same, copy one of them to dest; otherwise, copy all
   of them with appropriate prefixes */

#include <stdio.h>
#include <varargs.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <errno.h>

#define MAX_DIRS 100
#define BUFF_SIZE 8192
#define MAXPATHLEN 10000
#define MAX_BUFFERS 1000

extern char *malloc ();
extern char *strchr ();
extern int system ();
extern int errno;

int  nb_dirs;
char *dir    [MAX_DIRS];
char *suffix [MAX_DIRS];

int  nb_buffs;
char *buffer [MAX_BUFFERS];
int   size [MAX_BUFFERS];

char line [MAXPATHLEN];
char filename [MAXPATHLEN];
char command [MAXPATHLEN];
char *output;

int verbose;

void error (va_alist)
     va_dcl
{
  va_list args;
  char *fmt;

  fprintf (stderr, "merge2: ");

  va_start (args);
  fmt = va_arg (args, char*);
  vfprintf (stderr, fmt, args);
  va_end (args);

  fprintf (stderr, "\n");
  fflush (stderr);

  perror ("");
  exit (1);
}

char read_line (dest)
     char *dest;
{
  char c;
  while (((c = getchar ()) != '\n') && (c != EOF)) { *dest++ = c; }
  *dest = '\0';
  return c;
}


void protected_system (command)
     char * command;
{
  int i;

  errno = 0;

  if ((i = system (command)) != 0) {
    error ("system exited with 0x%x", i); }
}

main (argc, argv)
     int argc;
     char **argv;
{
  int bad_usage;
  char *c;
  int i, j, n, b;
  int f;
  int output_length = 0;

  argc--; argv++;

  while ((argc > 0) && (argv[0][0] == '-')) {
    switch (argv[0][1]) {
      case 'v': verbose = 1; break;
      case 'o': output = argv[0] + 2; break;
      default:
        bad_usage = 1; break; }
    argv++; argc--; }

  while (argc > 0) {
    c = strchr (argv[0], '=');
    if (c == 0) {
      bad_usage = 1; break; }
    else {
      dir[nb_dirs] = c + 1;
      suffix[nb_dirs] = argv[0];
      *c = '\0';
      nb_dirs++; }
    argc--; argv++; }

  if (bad_usage) {
    fprintf (stderr, "usage: merge2 [-v] [-odest] suffix=dir ...\n"); 
    exit (1); }

  
  buffer [0] = malloc (BUFF_SIZE);

  while (read_line (line) != EOF) {
    /* read in the first file */
    sprintf (filename, "%s/%s", dir[0], line);
    if ((f = open (filename, O_RDONLY, 0)) <= -1) {
      if (errno == ENOENT) {
	goto diff; }
      error ("opening %s\n", filename); }
    
    nb_buffs = 0;
    while (1) {
      nb_buffs++;
      if (buffer [nb_buffs] == 0) { buffer [nb_buffs] = malloc (BUFF_SIZE); }
      size [nb_buffs] = read (f, buffer[nb_buffs], BUFF_SIZE);
      if (size [nb_buffs] < 0) { error ("reading  %s\n", filename); }
      if (size [nb_buffs] == 0) {
	if (close (f) != 0) {
	  error ("closing %s\n", filename); }
	break; }}

    /* compare each of the other files */
    for (j = 1; j < nb_dirs; j++) {
      sprintf (filename, "%s/%s", dir[j], line); 
      if ((f = open (filename, O_RDONLY, 0)) <= -1) {
	if (errno == ENOENT) {
	  goto diff; }
	error ("opening %s\n", filename); }
      b = 1;
      while (b <= nb_buffs) {
	n = read (f, buffer [0], BUFF_SIZE);
	if (n < 0) { error ("reading %s", filename); }
	if (n != size [b]) {
	  goto diff; }
	if (memcmp (buffer[0], buffer [b], n) != 0) {
	  goto diff; }
	b ++; }
      if (close (f) != 0) {
	error ("closing %s\n", filename); }}

    /* they are the same */
    if (verbose) {
      fprintf (stderr, "same %s\n", line); }
    else {
      if (output_length > 70) {
	printf ("\n"); 
	output_length = 0; }
      output_length++;
      printf (".");
      fflush (stdout); }
    sprintf (command, "cp %s/%s %s/%s\n", dir[0], line, output, line);
    protected_system (command);
    continue;

  diff:
    /* they differ */
    if (close (f) != 0) {
      error ("closing %s\n", filename); }

    if (output_length != 0) {
      printf ("\n"); }
    fprintf (stderr, "#### %s\n", line);
    output_length = 0;
   
    for (j = 0; j < nb_dirs; j++) {
      sprintf (command, "touch %s/%s; cp %s/%s %s/%s.%s\n", 
	       dir[j], line, dir[j], line, output, line, suffix[j]);
      protected_system (command); }
    continue; }
  exit (0);
}