/* Copyright (C) 1994 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
  to anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given
  to you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
*/

/*$RCSfile: gp_dosfe.c,v $ $Revision: 1.2.2.1 $ */
/* MS-DOS file enumeration. */
#include "stdio_.h"
#include <fcntl.h>
#include "dos_.h"
#include "memory_.h"
#include "string_.h"
#include "gstypes.h"
#include "gsmemory.h"
#include "gsstruct.h"
#include "gp.h"
#include "gsutil.h"

struct file_enum_s {
    ff_struct_t ffblk;
    char *pattern;		/* orig pattern + modified pattern */
    int patlen;			/* orig pattern length */
    int pat_size;		/* allocate space for pattern */
    int head_size;		/* pattern length through last */
    /* :, / or \ */
    int first_time;
    gs_memory_t *memory;
};
gs_private_st_ptrs1(st_file_enum, struct file_enum_s, "file_enum",
		    file_enum_enum_ptrs, file_enum_reloc_ptrs, pattern);

/* Initialize an enumeration.  Note that * and ? in a directory */
/* don't work, and \ is taken literally unless a second \ follows. */
file_enum *
gp_enumerate_files_init(const char *pat, uint patlen, gs_memory_t * mem)
{
    file_enum *pfen = gs_alloc_struct(mem, file_enum, &st_file_enum, "gp_enumerate_files");
    int pat_size = 2 * patlen + 1;
    char *pattern;
    char *p;
    int hsize = 0;
    int i;
    int dot = 0;

    if (pfen == 0)
	return 0;

    /* pattern could be allocated as a string, */
    /* but it's simpler for GC and freeing to allocate it as bytes. */

    pattern = (char *)gs_alloc_bytes(mem, pat_size,
				     "gp_enumerate_files(pattern)");
    if (pattern == 0)
	return 0;
    memcpy(pattern, pat, patlen);
    p = pattern + patlen;
    for (i = 0; i < patlen; i++) {
	switch (pat[i]) {
	    case '*':
		/* Skip to . or end of string so DOS can do it. */
		*p++ = '*';
		while (i < patlen && pat[i] != '.')
		    i++;
		if (i == patlen && !dot) {	/* DOS doesn't interpret * alone as */
		    /* matching all files; we need *.*. */
		    *p++ = '.';
		    *p++ = '*';
		}
		i--;
		continue;
	    case '.':
		dot = 1;
		break;
	    case '\\':
		if (i + 1 < patlen && pat[i + 1] == '\\')
		    i++;
		/* falls through */
	    case ':':
	    case '/':
		hsize = p + 1 - (pattern + patlen);
		dot = 0;
	}
	*p++ = pat[i];
    }
    *p = 0;
    pfen->pattern = pattern;
    pfen->patlen = patlen;
    pfen->pat_size = pat_size;
    pfen->head_size = hsize;
    pfen->memory = mem;
    pfen->first_time = 1;
    return pfen;
}

/* Enumerate the next file. */
private const string_match_params smp_file =
{'*', '?', -1, true};

uint
gp_enumerate_files_next(file_enum * pfen, char *ptr, uint maxlen)
{
    int code;
    char *p, *q;
    uint len;
    const char *fpat = pfen->pattern + pfen->patlen;

  top:if (pfen->first_time) {
	code = dos_findfirst(fpat, &pfen->ffblk);
	pfen->first_time = 0;
    } else
	code = dos_findnext(&pfen->ffblk);
    if (code != 0) {		/* All done, clean up. */
	gp_enumerate_files_close(pfen);
	return ~(uint) 0;
    }
    if (maxlen < 13 + pfen->head_size)
	return maxlen + 1;	/* cop out! */
    memcpy(ptr, fpat, pfen->head_size);
    for (p = &pfen->ffblk.ff_name[0], q = ptr + pfen->head_size; *p; p++)
	if (*p != ' ')
	    *q++ = *p;
    len = q - ptr;
    /* Make sure this file really matches the pattern. */
    if (!string_match(ptr, len, pfen->pattern, pfen->patlen, &smp_file))
	goto top;
    return len;
}

/* Clean up the file enumeration. */
void
gp_enumerate_files_close(file_enum * pfen)
{
    gs_memory_t *mem = pfen->memory;

    gs_free_object(mem, pfen->pattern,
		   "gp_enumerate_files_close(pattern)");
    gs_free_object(mem, pfen, "gp_enumerate_files_close");
}
