/****************************************************/
/*                                                  */
/* For Win32 that lacks Unix direct support.        */
/*    - avoids including "windows.h"                */
/*                                                  */
/* Copyright (c) 2002 John Popplewell               */
/* john@johnnypops.demon.co.uk                      */
/*                                                  */
/* Version 1.0.1 - fixed bug in opendir()           */
/* Version 1.0.0 - initial version                  */
/*                                                  */
/****************************************************/

/*
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
  
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/* $Id$ */

#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "win32_dirent.h"
#include "debug.h"

/**
 * Open a directory for reading
 *
 * @param pSpec Path of directory to open
 * @return Opened directory, or NULL on failure
 */
DIR *opendir(const char *pSpec)
{
  char pathname[MAX_PATH + 2];

  DIR *pDir = calloc(1, sizeof(DIR));

  if (!pDir)
    return NULL;
  strcpy(pathname, pSpec);
  strcat(pathname, "/*");
  pDir->hFind = FindFirstFile(pathname, &pDir->wfd);
  if (pDir->hFind == INVALID_HANDLE_VALUE)
  {
    free(pDir);
    pDir = NULL;
  }
  return pDir;
}

/**
 * Close an opened directory
 *
 * @param pDir Opened directory to close.
 */
void closedir(DIR *pDir)
{
  assert(pDir != NULL);
  free(pDir);
}

/**
 * Read an entry from an opened directory.
 *
 * @param pDir Opened directory from which to read.
 * @return The next entry from the directory
 */
struct dirent *readdir(struct DIR *pDir)
{
  assert(pDir != NULL);
  if (pDir->hFind)

  {
    strcpy(pDir->de.d_name, (const char *)pDir->wfd.cFileName);
    if (!FindNextFile(pDir->hFind, &pDir->wfd))

    {
      FindClose(pDir->hFind);
      pDir->hFind = NULL;
    }
    return &pDir->de;
  }
  return NULL;
}

/**
 * Callback for sorting directory entries by filenames.
 *
 * @param a Directory entry #1
 * @param b Directory entry #2
 * @return An integer less than, equal to, or greater than zero if the
 *   filename of dir entry 'a' is found, respectively, to be less than,
 *   to match, or be greater than that of 'b'.
 */
int alphasort(const void *a, const void *b)
{
  return (strcmp((*(const struct dirent **)a)->d_name, (*(const struct dirent **)b)->d_name));
}

/**
 * Add directory entry filenames into a list.
 *
 * @param i Incoming count of items
 * @param namelist Pointer to an array of directory entries, which will
 *   be resized as items are added
 * @param entry The directory entry to add to 'namelist'
 * @return New count of items, or -1 on error (e.g., failed malloc())
 */
static int addToList(int i, struct dirent ***namelist, struct dirent *entry)
{
  int size;
  struct dirent *block;

  *namelist = (struct dirent **)realloc((void *)(*namelist), (size_t)((i + 1) * sizeof(struct dirent *)));
  if (*namelist == NULL)
    return -1;
  size = (((char *)&entry->d_name) - ((char *)entry)) + strlen(entry->d_name) + 1;
  block = (struct dirent *)malloc(size);
  if (block == NULL)
    return -1;
  (*namelist)[i] = block;
  memcpy(block, entry, size);
  return ++i;
}

/**
 * Scan a directory
 *
 * @param dir Path to the directory to be scanned.
 * @param namelist Pointer to an array of directory entries, to be filled.
 * @param select Callback function for selecting items to add to the list.
 * @param compar Callback for sorting items in the list (via qsort()).
 * @return Count of items, or -1 on error.
 */
int scandir(const char *dir, struct dirent ***namelist, selectCB select, comparCB compar)
{
  DIR *pDir;
  int count;
  struct dirent *entry;

  assert((dir != NULL) && (namelist != NULL));
  pDir = opendir(dir);
  if (!pDir)
    return -1;
  count = 0;
  while ((entry = readdir(pDir)) != NULL)
  {
    if (select == NULL || (select != NULL && select(entry)))
      if ((count = addToList(count, namelist, entry)) < 0)
        break;
  }
  closedir(pDir);
  if (count <= 0)
    return -1;
  if (compar != NULL)
    qsort((void *)(*namelist), (size_t)count, sizeof(struct dirent *), compar);
  return count;
}
