/* Copyright (C) 2000 Aladdin Enterprises.  All rights reserved.
  
  This software is provided AS-IS with no warranty, either express or
  implied.
  
  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: ziodevs.c,v 1.9 2004/08/04 19:36:13 stefan Exp $ */
/* %stdxxx IODevice implementation for PostScript interpreter */
#include "stdio_.h"
#include "ghost.h"
#include "gp.h"
#include "gpcheck.h"
#include "oper.h"
#include "stream.h"
#include "gxiodev.h"		/* must come after stream.h */
				/* and before files.h */
#include "files.h"
#include "store.h"

/* Define the special devices. */
const char iodev_dtype_stdio[] = "Special";
#define iodev_special(dname, init, open) {\
    dname, iodev_dtype_stdio,\
	{ init, open, iodev_no_open_file, iodev_no_fopen, iodev_no_fclose,\
	  iodev_no_delete_file, iodev_no_rename_file, iodev_no_file_status,\
	  iodev_no_enumerate_files, NULL, NULL,\
	  iodev_no_get_params, iodev_no_put_params\
	}\
}

/*
 * We need the current context pointer for accessing / opening the %std
 * IODevices.  However, this is not available to the open routine.
 * Therefore, we use the hack of storing this pointer in the IODevice state
 * pointer just before calling the open routines.  We clear the pointer
 * immediately afterwards so as not to wind up with dangling references.
 */

#define STDIN_BUF_SIZE 128

private iodev_proc_init(stdin_init);
private iodev_proc_open_device(stdin_open);
const gx_io_device gs_iodev_stdin =
    iodev_special("%stdin%", stdin_init, stdin_open);

#define STDOUT_BUF_SIZE 128
private iodev_proc_open_device(stdout_open);
const gx_io_device gs_iodev_stdout =
    iodev_special("%stdout%", iodev_no_init, stdout_open);

#define STDERR_BUF_SIZE 128
private iodev_proc_open_device(stderr_open);
const gx_io_device gs_iodev_stderr =
    iodev_special("%stderr%", iodev_no_init, stderr_open);

/* ------- %stdin, %stdout, and %stderr ------ */

/*
 * According to Adobe, it is legal to close the %std... files and then
 * re-open them later.  However, the re-opened file object is not 'eq' to
 * the original file object (in our implementation, it has a different
 * read_id or write_id).
 */

private int
    s_stdin_read_process(stream_state *, stream_cursor_read *,
			 stream_cursor_write *, bool);

private int
stdin_init(gx_io_device * iodev, gs_memory_t * mem)
{
    mem->gs_lib_ctx->stdin_is_interactive = true;
    return 0;
}

/* Read from stdin into the buffer. */
/* If interactive, only read one character. */
private int
s_stdin_read_process(stream_state * st, stream_cursor_read * ignore_pr,
		     stream_cursor_write * pw, bool last)
{
    FILE *file = ((stream *) st)->file;		/* hack for file streams */
    int wcount = (int)(pw->limit - pw->ptr);
    int count;

    if (wcount <= 0)
	return 0;
    count = gp_stdin_read( (char*) pw->ptr + 1, wcount,
			   st->memory->gs_lib_ctx->stdin_is_interactive, file);
    pw->ptr += (count < 0) ? 0 : count;
    return ((count < 0) ? ERRC : (count == 0) ? EOFC : count);
}

private int
stdin_open(gx_io_device * iodev, const char *access, stream ** ps,
	   gs_memory_t * mem)
{
    i_ctx_t *i_ctx_p = (i_ctx_t *)iodev->state;	/* see above */
    stream *s;

    if (!streq1(access, 'r'))
	return_error(e_invalidfileaccess);
    if (file_is_invalid(s, &ref_stdin)) {
	/****** stdin SHOULD NOT LINE-BUFFER ******/
	gs_memory_t *mem = imemory_system;
	byte *buf;

	s = file_alloc_stream(mem, "stdin_open(stream)");
	/* We want stdin to read only one character at a time, */
	/* but it must have a substantial buffer, in case it is used */
	/* by a stream that requires more than one input byte */
	/* to make progress. */
	buf = gs_alloc_bytes(mem, STDIN_BUF_SIZE, "stdin_open(buffer)");
	if (s == 0 || buf == 0)
	    return_error(e_VMerror);
	sread_file(s, gs_stdin, buf, STDIN_BUF_SIZE);
	s->procs.process = s_stdin_read_process;
	s->save_close = s_std_null;
	s->procs.close = file_close_file;
	make_file(&ref_stdin, a_readonly | avm_system, s->read_id, s);
	*ps = s;
	return 1;
    }
    *ps = s;
    return 0;
}
/* This is the public routine for getting the stdin stream. */
int
zget_stdin(i_ctx_t *i_ctx_p, stream ** ps)
{
    stream *s;
    gx_io_device *iodev;
    int code;

    if (file_is_valid(s, &ref_stdin)) {
	*ps = s;
	return 0;
    }
    iodev = gs_findiodevice((const byte *)"%stdin", 6);
    iodev->state = i_ctx_p;
    code = (*iodev->procs.open_device)(iodev, "r", ps, imemory_system);
    iodev->state = NULL;
    return min(code, 0);
}
/* Test whether a stream is stdin. */
bool
zis_stdin(const stream *s)
{
    return (s_is_valid(s) && s->procs.process == s_stdin_read_process);
}

private int
stdout_open(gx_io_device * iodev, const char *access, stream ** ps,
	    gs_memory_t * mem)
{
    i_ctx_t *i_ctx_p = (i_ctx_t *)iodev->state;	/* see above */
    stream *s;

    if (!streq1(access, 'w'))
	return_error(e_invalidfileaccess);
    if (file_is_invalid(s, &ref_stdout)) {
	gs_memory_t *mem = imemory_system;
	byte *buf;

	s = file_alloc_stream(mem, "stdout_open(stream)");
	buf = gs_alloc_bytes(mem, STDOUT_BUF_SIZE, "stdout_open(buffer)");
	if (s == 0 || buf == 0)
	    return_error(e_VMerror);
	swrite_file(s, gs_stdout, buf, STDOUT_BUF_SIZE);
	s->save_close = s->procs.flush;
	s->procs.close = file_close_file;
	make_file(&ref_stdout, a_write | avm_system, s->write_id, s);
	*ps = s;
	return 1;
    }
    *ps = s;
    return 0;
}
/* This is the public routine for getting the stdout stream. */
int
zget_stdout(i_ctx_t *i_ctx_p, stream ** ps)
{
    stream *s;
    gx_io_device *iodev;
    int code;

    if (file_is_valid(s, &ref_stdout)) {
	*ps = s;
	return 0;
    }
    iodev = gs_findiodevice((const byte *)"%stdout", 7);
    iodev->state = i_ctx_p;
    code = (*iodev->procs.open_device)(iodev, "w", ps, imemory_system);
    iodev->state = NULL;
    return min(code, 0);
}

private int
stderr_open(gx_io_device * iodev, const char *access, stream ** ps,
	    gs_memory_t * mem)
{
    i_ctx_t *i_ctx_p = (i_ctx_t *)iodev->state;	/* see above */
    stream *s;

    if (!streq1(access, 'w'))
	return_error(e_invalidfileaccess);
    if (file_is_invalid(s, &ref_stderr)) {
	gs_memory_t *mem = imemory_system;
	byte *buf;

	s = file_alloc_stream(mem, "stderr_open(stream)");
	buf = gs_alloc_bytes(mem, STDERR_BUF_SIZE, "stderr_open(buffer)");
	if (s == 0 || buf == 0)
	    return_error(e_VMerror);
	swrite_file(s, gs_stderr, buf, STDERR_BUF_SIZE);
	s->save_close = s->procs.flush;
	s->procs.close = file_close_file;
	make_file(&ref_stderr, a_write | avm_system, s->write_id, s);
	*ps = s;
	return 1;
    }
    *ps = s;
    return 0;
}
/* This is the public routine for getting the stderr stream. */
int
zget_stderr(i_ctx_t *i_ctx_p, stream ** ps)
{
    stream *s;
    gx_io_device *iodev;
    int code;

    if (file_is_valid(s, &ref_stderr)) {
	*ps = s;
	return 0;
    }
    iodev = gs_findiodevice((const byte *)"%stderr", 7);
    iodev->state = i_ctx_p;
    code = (*iodev->procs.open_device)(iodev, "w", ps, imemory_system);
    iodev->state = NULL;
    return min(code, 0);
}