harvey/sys/src/cmd/gs/src/gp_dosfs.c

/* Copyright (C) 1992, 1993, 1996, 1998 Aladdin Enterprises.  All rights reserved.
  
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  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
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*/

/*$Id: gp_dosfs.c,v 1.2.6.1 2002/01/25 06:33:09 rayjj Exp $ */
/* Common routines for MS-DOS (any compiler) and DesqView/X, */
/* which has a MS-DOS-like file system. */
#include "dos_.h"
#include "gx.h"
#include "gp.h"

/* ------ Printer accessing ------ */

/* Put a printer file (which might be stdout) into binary or text mode. */
/* This is not a standard gp procedure, */
/* but all MS-DOS configurations need it. */
void
gp_set_file_binary(int prnfno, bool binary)
{
    union REGS regs;

    regs.h.ah = 0x44;		/* ioctl */
    regs.h.al = 0;		/* get device info */
    regs.rshort.bx = prnfno;
    intdos(&regs, &regs);
    if (regs.rshort.cflag != 0 || !(regs.h.dl & 0x80))
	return;			/* error, or not a device */
    if (binary)
	regs.h.dl |= 0x20;	/* binary (no ^Z intervention) */
    else
	regs.h.dl &= ~0x20;	/* text */
    regs.h.dh = 0;
    regs.h.ah = 0x44;		/* ioctl */
    regs.h.al = 1;		/* set device info */
    intdos(&regs, &regs);
}

/* ------ File accessing ------ */

/* Set a file into binary or text mode. */
int
gp_setmode_binary(FILE * pfile, bool binary)
{
    gp_set_file_binary(fileno(pfile), binary);
    return 0;			/* Fake out dos return status */
}

/* ------ File names ------ */

/* Define the character used for separating file names in a list. */
const char gp_file_name_list_separator = ';';

/* Define the string to be concatenated with the file mode */
/* for opening files without end-of-line conversion. */
const char gp_fmode_binary_suffix[] = "b";

/* Define the file modes for binary reading or writing. */
const char gp_fmode_rb[] = "rb";
const char gp_fmode_wb[] = "wb";

/* Answer whether a file name contains a directory/device specification, */
/* i.e. is absolute (not directory- or device-relative). */
bool
gp_file_name_is_absolute(const char *fname, unsigned len)
{
    /* A file name is absolute if it contains a drive specification */
    /* (second character is a :) or if it start with 0 or more .s */
    /* followed by a / or \. */
    if (len >= 2 && fname[1] == ':')
	return true;
    while (len && *fname == '.')
	++fname, --len;
    return (len && (*fname == '/' || *fname == '\\'));
}

/* Answer whether the file_name references the directory	*/
/* containing the specified path (parent). 			*/
bool
gp_file_name_references_parent(const char *fname, unsigned len)
{
    int i = 0, last_sep_pos = -1;

    /* A file name references its parent directory if it starts */
    /* with ../ or ..\  or if one of these strings follows / or \ */
    while (i < len) {
	if (fname[i] == '/' || fname[i] == '\\') {
	    last_sep_pos = i++;
	    continue;
	}
	if (fname[i++] != '.')
	    continue;
        if (i > last_sep_pos + 2 || (i < len && fname[i] != '.'))
	    continue;
	i++;
	/* have separator followed by .. */
	if (i < len && (fname[i] == '/' || fname[i++] == '\\'))
	    return true;
    }
    return false;
}


/* Answer the string to be used for combining a directory/device prefix */
/* with a base file name. The prefix directory/device is examined to	*/
/* determine if a separator is needed and may return an empty string	*/
const char *
gp_file_name_concat_string(const char *prefix, unsigned plen)
{
    if (plen > 0)
	switch (prefix[plen - 1]) {
	    case ':':
	    case '/':
	    case '\\':
		return "";
	};
    return "/";
}