/* Copyright (C) 2002-2003 Free Software Foundation, Inc.
   Contributed by Andy Vaught

This file is part of the GNU Fortran 95 runtime library (libgfor).

Libgfor 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, or (at your option)
any later version.

Libgfor 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 libgfor; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include <string.h>
#include <stdlib.h>
#include <ctype.h>

#include "libgfortran.h"
#include "../io/io.h"


/* Environment scanner.  Examine the environment for controlling minor
 * aspects of the program's execution.  Our philosophy here that the
 * environment should not prevent the program from running, so an
 * environment variable with a messed-up value will be interpreted in
 * the default way.
 *
 * Most of the environment is checked early in the startup sequence,
 * but other variables are checked during execution of the user's
 * program. */

options_t options;

extern char **environ;

typedef struct variable
{
  const char *name;
  int value, *var;
  void (*init) (struct variable *);
  void (*show) (struct variable *);
  const char *desc;
  int bad;
}
variable;


/* print_spaces()-- Print a particular number of spaces */

static void
print_spaces (int n)
{
  char buffer[80];
  int i;

  if (n <= 0)
    return;

  for (i = 0; i < n; i++)
    buffer[i] = ' ';

  buffer[i] = '\0';

  st_printf (buffer);
}


/* var_source()-- Return a string that describes where the value of a
 * variable comes from */

static const char *
var_source (variable * v)
{
  if (getenv (v->name) == NULL)
    return "Default";

  if (v->bad)
    return "Bad    ";

  return "Set    ";
}


/* init_integer()-- Initialize an integer environment variable */

static void
init_integer (variable * v)
{
  char *p, *q;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  for (q = p; *q; q++)
    if (!isdigit (*q))
      {
	v->bad = 1;
	goto set_default;
      }

  *v->var = atoi (p);
  return;

 set_default:
  *v->var = v->value;
  return;
}


/* show_integer()-- Show an integer environment variable */

static void
show_integer (variable * v)
{
  st_printf ("%s  %d\n", var_source (v), *v->var);
}


/* init_boolean()-- Initialize a boolean environment variable.  We
 * only look at the first letter of the variable. */

static void
init_boolean (variable * v)
{
  char *p;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  if (*p == '1' || *p == 'Y' || *p == 'y')
    {
      *v->var = 1;
      return;
    }

  if (*p == '0' || *p == 'N' || *p == 'n')
    {
      *v->var = 0;
      return;
    }

  v->bad = 1;

set_default:
  *v->var = v->value;
  return;
}


/* show_boolean()-- Show a boolean environment variable */

static void
show_boolean (variable * v)
{
  st_printf ("%s  %s\n", var_source (v), *v->var ? "Yes" : "No");
}


/* init_mem()-- Initialize environment variables that have to do with
 * how memory from an ALLOCATE statement is filled.  A single flag
 * enables filling and a second variable gives the value that is used
 * to initialize the memory. */

static void
init_mem (variable * v)
{
  int offset, n;
  char *p;

  p = getenv (v->name);

  options.allocate_init_flag = 0;	/* The default */

  if (p == NULL)
    return;

  if (strcasecmp (p, "NONE") == 0)
    return;

  /* IEEE-754 Quiet Not-a-Number that will work for single and double
   * precision.  Look for the 'f95' mantissa in debug dumps. */

  if (strcasecmp (p, "NaN") == 0)
    {
      options.allocate_init_flag = 1;
      options.allocate_init_value = 0xfff80f95;
      return;
    }

  /* Interpret the string as a hexadecimal constant */

  n = 0;
  while (*p)
    {
      if (!isxdigit (*p))
	{
	  v->bad = 1;
	  return;
	}

      offset = '0';
      if (islower (*p))
	offset = 'a';
      if (isupper (*p))
	offset = 'A';

      n = (n << 4) | (*p++ - offset);
    }

  options.allocate_init_flag = 1;
  options.allocate_init_value = n;
}


static void
show_mem (variable * v)
{
  char *p;

  p = getenv (v->name);

  st_printf ("%s  ", var_source (v));

  if (options.allocate_init_flag)
    st_printf ("0x%x", options.allocate_init_value);

  st_printf ("\n");
}


static void
init_sep (variable * v)
{
  int seen_comma;
  char *p;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  v->bad = 1;
  options.separator = p;
  options.separator_len = strlen (p);

  /* Make sure the separator is valid */

  if (options.separator_len == 0)
    goto set_default;
  seen_comma = 0;

  while (*p)
    {
      if (*p == ',')
	{
	  if (seen_comma)
	    goto set_default;
	  seen_comma = 1;
	  p++;
	  continue;
	}

      if (*p++ != ' ')
	goto set_default;
    }

  v->bad = 0;
  return;

set_default:
  options.separator = " ";
  options.separator_len = 1;
}


static void
show_sep (variable * v)
{
  st_printf ("%s  \"%s\"\n", var_source (v), options.separator);
}


static void
init_string (variable * v)
{
}

static void
show_string (variable * v)
{
  const char *p;

  p = getenv (v->name);
  if (p == NULL)
    p = "";

  st_printf ("%s  \"%s\"\n", var_source (v), p);
}


/* Structure for associating names and values.  */

typedef struct
{
  const char *name;
  int value;
}
choice;


enum
{ FP_ROUND_NEAREST, FP_ROUND_UP, FP_ROUND_DOWN, FP_ROUND_ZERO };

static choice rounding[] = {
  {"NEAREST", FP_ROUND_NEAREST},
  {"UP", FP_ROUND_UP},
  {"DOWN", FP_ROUND_DOWN},
  {"ZERO", FP_ROUND_ZERO},
  {NULL}
};

static choice precision[] =
{
  { "24", 1},
  { "53", 2},
  { "64", 0},
  { NULL}
};

static choice signal_choices[] =
{
  { "IGNORE", 1},
  { "ABORT", 0},
  { NULL}
};


static void
init_choice (variable * v, choice * c)
{
  char *p;

  p = getenv (v->name);
  if (p == NULL)
    goto set_default;

  for (; c->name; c++)
    if (strcasecmp (c->name, p) == 0)
      break;

  if (c->name == NULL)
    {
      v->bad = 1;
      goto set_default;
    }

  *v->var = c->value;
  return;

 set_default:
  *v->var = v->value;
}


static void
show_choice (variable * v, choice * c)
{
  st_printf ("%s  ", var_source (v));

  for (; c->name; c++)
    if (c->value == *v->var)
      break;

  if (c->name)
    st_printf ("%s\n", c->name);
  else
    st_printf ("(Unknown)\n");
}


static void
init_round (variable * v)
{
  init_choice (v, rounding);
}

static void
show_round (variable * v)
{
  show_choice (v, rounding);
}

static void
init_precision (variable * v)
{
  init_choice (v, precision);
}

static void
show_precision (variable * v)
{
  show_choice (v, precision);
}

static void
init_signal (variable * v)
{
  init_choice (v, signal_choices);
}

static void
show_signal (variable * v)
{
  show_choice (v, signal_choices);
}


static variable variable_table[] = {
  {"GFORTRAN_STDIN_UNIT", 5, &options.stdin_unit, init_integer, show_integer,
   "Unit number that will be preconnected to standard input\n"
   "(No preconnection if negative)"},

  {"GFORTRAN_STDOUT_UNIT", 6, &options.stdout_unit, init_integer,
   show_integer,
   "Unit number that will be preconnected to standard output\n"
   "(No preconnection if negative)"},

  {"GFORTRAN_USE_STDERR", 1, &options.use_stderr, init_boolean,
   show_boolean,
   "Sends library output to standard error instead of standard output."},

  {"GFORTRAN_TMPDIR", 0, NULL, init_string, show_string,
   "Directory for scratch files.  Overrides the TMP environment variable\n"
   "If TMP is not set " DEFAULT_TEMPDIR " is used."},

  {"GFORTRAN_UNBUFFERED_ALL", 0, &options.all_unbuffered, init_boolean,
   show_boolean,
   "If TRUE, all output is unbuffered.  This will slow down large writes "
   "but can be\nuseful for forcing data to be displayed immediately."},

  {"GFORTRAN_SHOW_LOCUS", 1, &options.locus, init_boolean, show_boolean,
   "If TRUE, print filename and line number where runtime errors happen."},

/* GFORTRAN_NAME_xx (where xx is a unit number) gives the names of files
 * preconnected to those units. */

/* GFORTRAN_UNBUFFERED_xx (where xx is a unit number) gives a boolean that is used
 * to turn off buffering for that unit. */

  {"GFORTRAN_OPTIONAL_PLUS", 0, &options.optional_plus, init_boolean, show_boolean,
   "Print optional plus signs in numbers where permitted.  Default FALSE."},

  {"GFORTRAN_DEFAULT_RECL", DEFAULT_RECL, &options.default_recl,
   init_integer, show_integer,
   "Default maximum record length for sequential files.  Most useful for\n"
   "adjusting line length of preconnected units.  Default "
   stringize (DEFAULT_RECL)},

  {"GFORTRAN_LIST_SEPARATOR", 0, NULL, init_sep, show_sep,
   "Separatator to use when writing list output.  May contain any number of "
   "spaces\nand at most one comma.  Default is a single space."},

  /* Memory related controls */

  {"GFORTRAN_MEM_INIT", 0, NULL, init_mem, show_mem,
   "How to initialize allocated memory.  Default value is NONE for no "
   "initialization\n(faster), NAN for a Not-a-Number with the mantissa "
   "0x40f95 or a custom\nhexadecimal value"},

  {"GFORTRAN_MEM_CHECK", 0, &options.mem_check, init_boolean, show_boolean,
   "Whether memory still allocated will be reported when the program ends."},

  /* Signal handling (Unix).  */

  {"GFORTRAN_SIGHUP", 0, &options.sighup, init_signal, show_signal,
   "Whether the program will IGNORE or ABORT on SIGHUP."},

  {"GFORTRAN_SIGINT", 0, &options.sigint, init_signal, show_signal,
   "Whether the program will IGNORE or ABORT on SIGINT."},

  /* Floating point control */

  {"GFORTRAN_FPU_ROUND", 0, &options.fpu_round, init_round, show_round,
   "Set floating point rounding.  Values are NEAREST, UP, DOWN, ZERO."},

  {"GFORTRAN_FPU_PRECISION", 0, &options.fpu_precision, init_precision,
   show_precision,
   "Precision of intermediate results.  Values are 24, 53 and 64."},

  {"GFORTRAN_FPU_INVALID", 1, &options.fpu_invalid, init_boolean,
   show_boolean,
   "Raise a floating point exception on invalid FP operation."},

  {"GFORTRAN_FPU_DENORMAL", 1, &options.fpu_denormal, init_boolean,
   show_boolean,
   "Raise a floating point exception when denormal numbers are encountered."},

  {"GFORTRAN_FPU_ZERO", 0, &options.fpu_zerodiv, init_boolean, show_boolean,
   "Raise a floating point exception when dividing by zero."},

  {"GFORTRAN_FPU_OVERFLOW", 0, &options.fpu_overflow, init_boolean,
   show_boolean,
   "Raise a floating point exception on overflow."},

  {"GFORTRAN_FPU_UNDERFLOW", 0, &options.fpu_underflow, init_boolean,
   show_boolean,
   "Raise a floating point exception on underflow."},

  {"GFORTRAN_FPU_PRECISION", 0, &options.fpu_precision_loss, init_boolean,
   show_boolean,
   "Raise a floating point exception on precision loss."},

  {NULL}
};


/* init_variables()-- Initialize most runtime variables from
 * environment variables. */

void
init_variables (void)
{
  variable *v;

  for (v = variable_table; v->name; v++)
    v->init (v);
}


/* check_buffered()-- Given an unit number n, determine if an override
 * for the stream exists.  Returns zero for unbuffered, one for
 * buffered or two for not set. */

int
check_buffered (int n)
{
  char name[40];
  variable v;
  int rv;

  if (options.all_unbuffered)
    return 0;

  strcpy (name, "GFORTRAN_UNBUFFERED_");
  strcat (name, itoa (n));

  v.name = name;
  v.value = 2;
  v.var = &rv;

  init_boolean (&v);

  return rv;
}


/* pattern_scan()-- Given an environment string, check that the name
 * has the same name as the pattern followed by an integer.  On a
 * match, a pointer to the value is returned and the integer pointed
 * to by n is updated.  Returns NULL on no match. */

static char *
pattern_scan (char *env, const char *pattern, int *n)
{
  char *p;
  size_t len;

  len = strlen (pattern);
  if (strncasecmp (env, pattern, len) != 0)
    return NULL;
  p = env + len;

  if (!isdigit (*p))
    return NULL;

  while (isdigit (*p))
    p++;

  if (*p != '=')
    return NULL;

  *p = '\0';
  *n = atoi (env + len);
  *p++ = '=';

  return p;
}


void
show_variables (void)
{
  char *p, **e;
  variable *v;
  int n;

  /* TODO: print version number.  */
  st_printf ("GNU Fortran 95 runtime library version "
	     "UNKNOWN" "\n\n");

  st_printf ("Environment variables:\n");
  st_printf ("----------------------\n");

  for (v = variable_table; v->name; v++)
    {
      n = st_printf ("%s", v->name);
      print_spaces (25 - n);

      if (v->show == show_integer)
	st_printf ("Integer ");
      else if (v->show == show_boolean)
	st_printf ("Boolean ");
      else
	st_printf ("String  ");

      v->show (v);
      st_printf ("%s\n\n", v->desc);
    }

  st_printf ("\nDefault unit names (GFORTRAN_NAME_x):\n");

  for (e = environ; *e; e++)
    {
      p = pattern_scan (*e, "GFORTRAN_NAME_", &n);
      if (p == NULL)
	continue;
      st_printf ("GFORTRAN_NAME_%d         %s\n", n, p);
    }

  st_printf ("\nUnit buffering overrides (GFORTRAN_UNBUFFERED_x):\n");
  for (e = environ; *e; e++)
    {
      p = pattern_scan (*e, "GFORTRAN_UNBUFFERED_", &n);
      if (p == NULL)
	continue;

      st_printf ("GFORTRAN_UNBUFFERED_%d = %s\n", n, p);
    }

  /* System error codes */

  st_printf ("\nRuntime error codes:");
  st_printf ("\n--------------------\n");

  for (n = ERROR_FIRST + 1; n < ERROR_LAST; n++)
    if (n < 0 || n > 9)
      st_printf ("%d  %s\n", n, translate_error (n));
    else
      st_printf (" %d  %s\n", n, translate_error (n));

  st_printf ("\nCommand line arguments:\n");
  st_printf ("  --help               Print this list\n");

  /* st_printf("  --resume <dropfile>  Resume program execution from dropfile\n"); */

  sys_exit (0);
}