/* This file is extracted from sash-3.4/util.c */

/*
 * Copyright (c) 1999 by David I. Bell
 * Permission is granted to use, distribute, or modify this source,
 * provided that this copyright notice remains intact.
 *
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <utime.h>

typedef int     BOOL;
#define FALSE   ((BOOL) 0)
#define TRUE    ((BOOL) 1)
#define EXPAND_ALLOC    1024
#define PATH_LEN        1024

/*
 * A chunk of data.
 * Chunks contain data which is allocated as needed, but which is
 * not freed until all of the data needs freeing, such as at
 * the beginning of the next command.
 */
typedef	struct	chunk	CHUNK;
#define	CHUNK_INIT_SIZE	4

struct	chunk
{
	CHUNK *	next;
	char	data[CHUNK_INIT_SIZE];	/* actually of varying length */
};

static	CHUNK *	chunkList;

/*
 * Allocate a chunk of memory (like malloc).
 * The difference, though, is that the memory allocated is put on a
 * list of chunks which can be freed all at one time.  You CAN NOT free
 * an individual chunk.
 */
static char *getChunk(int size)
{
	CHUNK *	chunk;

	if (size < CHUNK_INIT_SIZE)
		size = CHUNK_INIT_SIZE;

	chunk = (CHUNK *) malloc(size + sizeof(CHUNK) - CHUNK_INIT_SIZE);

	if (chunk == NULL)
		return NULL;

	chunk->next = chunkList;
	chunkList = chunk;

	return chunk->data;
}

/*
 * Sort routine for list of fileNames.
 */
static int nameSort(const void * p1, const void * p2)
{
	const char **	s1;
	const char **	s2;

	s1 = (const char **) p1;
	s2 = (const char **) p2;

	return strcmp(*s1, *s2);
}

/*
 * Routine to see if a text string is matched by a wildcard pattern.
 * Returns TRUE if the text is matched, or FALSE if it is not matched
 * or if the pattern is invalid.
 *  *		matches zero or more characters
 *  ?		matches a single character
 *  [abc]	matches 'a', 'b' or 'c'
 *  \c		quotes character c
 *  Adapted from code written by Ingo Wilken.
 */
static BOOL match(const char * text, const char * pattern)
{
	const char *	retryPat;
	const char *	retryText;
	int		ch;
	BOOL		found;

	retryPat = NULL;
	retryText = NULL;

	while (*text || *pattern)
	{
		ch = *pattern++;

		switch (ch)
		{
			case '*':
				retryPat = pattern;
				retryText = text;
				break;

			case '[':
				found = FALSE;

				while ((ch = *pattern++) != ']')
				{
					if (ch == '\\')
						ch = *pattern++;

					if (ch == '\0')
						return FALSE;

					if (*text == ch)
						found = TRUE;
				}

				if (!found)
				{
					pattern = retryPat;
					text = ++retryText;
				}

				/* fall into next case */

			case '?':
				if (*text++ == '\0')
					return FALSE;

				break;

			case '\\':
				ch = *pattern++;

				if (ch == '\0')
					return FALSE;

				/* fall into next case */

			default:
				if (*text == ch)
				{
					if (*text)
						text++;
					break;
				}

				if (*text)
				{
					pattern = retryPat;
					text = ++retryText;
					break;
				}

				return FALSE;
		}

		if (pattern == NULL)
			return FALSE;
	}

	return TRUE;
}


/*
 * Utility routines.
 *
 * Expand the wildcards in a fileName wildcard pattern, if any.
 * Returns an argument list with matching fileNames in sorted order.
 * The expanded names are stored in memory chunks which can later all
 * be freed at once.  The returned list is only valid until the next
 * call or until the next command.  Returns zero if the name is not a
 * wildcard, or returns the count of matched files if the name is a
 * wildcard and there was at least one match, or returns -1 if either
 * no fileNames matched or there was an allocation error.
 */
int expandWildCards(const char * fileNamePattern, const char *** retFileTable)
{
	const char *	last;
	const char *	cp1;
	const char *	cp2;
	const char *	cp3;
	char *		str;
	DIR *		dirp;
	struct dirent *	dp;
	int		dirLen;
	int		newFileTableSize;
	char **		newFileTable;
	char		dirName[PATH_LEN];

	static int	fileCount;
	static int	fileTableSize;
	static char **	fileTable;

	/*
	 * Clear the return values until we know their final values.
	 */
	fileCount = 0;
	*retFileTable = NULL;

	/*
	 * Scan the file name pattern for any wildcard characters.
	 */
	cp1 = strchr(fileNamePattern, '*');
	cp2 = strchr(fileNamePattern, '?');
	cp3 = strchr(fileNamePattern, '[');

#if 0
	/*
	 * If there are no wildcard characters then return zero to
	 * indicate that there was actually no wildcard pattern.
	 */
	if ((cp1 == NULL) && (cp2 == NULL) && (cp3 == NULL))
		return 0;
#endif

	/*
	 * There are wildcards in the specified filename.
	 * Get the last component of the file name.
	 */
	last = strrchr(fileNamePattern, '/');

	if (last)
		last++;
	else
		last = fileNamePattern;

	/*
	 * If any wildcards were found before the last filename component
	 * then return an error.
	 */
	if ((cp1 && (cp1 < last)) || (cp2 && (cp2 < last)) ||
		(cp3 && (cp3 < last)))
	{
		fprintf(stderr,
		"Wildcards only implemented for last file name component\n");

		return -1;
	}

	/*
	 * Assume at first that we are scanning the current directory.
	 */
	dirName[0] = '.';
	dirName[1] = '\0';

	/*
	 * If there was a directory given as part of the file name then
	 * copy it and null terminate it.
	 */
	if (last != fileNamePattern)
	{
		memcpy(dirName, fileNamePattern, last - fileNamePattern);
		dirName[last - fileNamePattern - 1] = '\0';

		if (dirName[0] == '\0')
		{
			dirName[0] = '/';
			dirName[1] = '\0';
		}
	}

	/*
	 * Open the directory containing the files to be checked.
	 */
	dirp = opendir(dirName);

	if (dirp == NULL)
	{
		perror(dirName);

		return -1;
	}

	/*
	 * Prepare the directory name for use in making full path names.
	 */
	dirLen = strlen(dirName);

	if (last == fileNamePattern)
	{
		dirLen = 0;
		dirName[0] = '\0';
	}
	else if (dirName[dirLen - 1] != '/')
	{
		dirName[dirLen++] = '/';
		dirName[dirLen] = '\0';
	}

	/*
	 * Find all of the files in the directory and check them against
	 * the wildcard pattern.
	 */
	while ((dp = readdir(dirp)) != NULL)
	{
		/*
		 * Skip the current and parent directories.
		 */
		if ((strcmp(dp->d_name, ".") == 0) ||
			(strcmp(dp->d_name, "..") == 0))
		{
			continue;
		}

		/*
		 * If the file name doesn't match the pattern then skip it.
		 */
		if (!match(dp->d_name, last))
			continue;

		/*
		 * This file name is selected.
		 * See if we need to reallocate the file name table.
		 */
		if (fileCount >= fileTableSize)
		{
			/*
			 * Increment the file table size and reallocate it.
			 */
			newFileTableSize = fileTableSize + EXPAND_ALLOC;

			newFileTable = (char **) realloc((char *) fileTable,
				(newFileTableSize * sizeof(char *)));

			if (newFileTable == NULL)
			{
				fprintf(stderr, "Cannot allocate file list\n");
				closedir(dirp);

				return -1;
			}

			fileTable = newFileTable;
			fileTableSize = newFileTableSize;
		}

		/*
		 * Allocate space for storing the file name in a chunk.
		 */
		str = getChunk(dirLen + strlen(dp->d_name) + 1);

		if (str == NULL)
		{
#if 0
			fprintf(stderr, "No memory for file name\n");
#endif
			closedir(dirp);

			return -1;
		}

		/*
		 * Save the file name in the chunk.
		 */
		if (dirLen)
			memcpy(str, dirName, dirLen);

		strcpy(str + dirLen, dp->d_name);

		/*
		 * Save the allocated file name into the file table.
		 */
		fileTable[fileCount++] = str;
	}

	/*
	 * Close the directory and check for any matches.
	 */
	closedir(dirp);

	if (fileCount == 0)
	{
#if 0
		fprintf(stderr, "No matches\n");
#endif

		return -1;
	}

	/*
	 * Sort the list of file names.
	 */
	qsort((void *) fileTable, fileCount, sizeof(char *), nameSort);

	/*
	 * Return the file list and count.
	 */
	*retFileTable = (const char **) fileTable;

	return fileCount;
}

#ifdef TEST
int main(int argc, char *argv[])
{
    const char **fileTable;
    int  fileCount, i, j;

    for (j=1; j<argc; j++) {
	printf("============argv[%d]=%s\n", j, argv[j]);
	fileCount=expandWildCards(argv[j], &fileTable);
	for (i=0; i<fileCount; i++) {
            printf("%s\n", fileTable[i]);
	}
    }

    return 0;
}
#endif