/* 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 <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <float.h>

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

/* Error conditions.  The tricky part here is printing a message when
 * it is the I/O subsystem that is severely wounded.  Our goal is to
 * try and print something making the fewest assumptions possible,
 * then try to clean up before actually exiting.
 *
 * The following exit conditions are defined:
 * 0    Normal program exit.
 * 1    Terminated because of operating system error.
 * 2    Error in the runtime library
 * 3    Internal error in runtime library
 * 4    Error during error processing (very bad)
 *
 * Other error returns are reserved for the STOP statement with a numeric code.
 */

/* locus variables.  These are optionally set by a caller before a
 * library subroutine is called.  They are always cleared on exit so
 * that files that report loci and those that do not can be linked
 * together without reporting an erroneous position. */

char *filename;
unsigned line;

static char buffer[32];		/* buffer for integer/ascii conversions */


/* Returns a pointer to a static buffer. */

char *
itoa (int64_t n)
{
  int negative;
  char *p;
  uint64_t t;

  if (n == 0)
    {
      buffer[0] = '0';
      buffer[1] = '\0';
      return buffer;
    }

  negative = 0;
  t = n;
  if (n < 0)
    {
      negative = 1;
      t = -n; /*must use unsigned to protect from overflow*/
    }

  p = buffer + sizeof (buffer) - 1;
  *p-- = '\0';

  while (t != 0)
    {
      *p-- = '0' + (t % 10);
      t /= 10;
    }

  if (negative)
    *p-- = '-';
  return ++p;
}


/* xtoa()-- Integer to hexadecimal conversion.  Returns a pointer to a
 * static buffer. */

char *
xtoa (uint64_t n)
{
  int digit;
  char *p;

  if (n == 0)
    {
      buffer[0] = '0';
      buffer[1] = '\0';
      return buffer;
    }

  p = buffer + sizeof (buffer) - 1;
  *p-- = '\0';

  while (n != 0)
    {
      digit = n & 0xF;
      if (digit > 9)
	digit += 'A' - '0' - 10;

      *p-- = '0' + digit;
      n >>= 4;
    }

  return ++p;
}


/* st_printf()-- simple printf() function for streams that handles the
 * formats %d, %s and %c.  This function handles printing of error
 * messages that originate within the library itself, not from a user
 * program. */

int
st_printf (const char *format, ...)
{
  int count, total;
  va_list arg;
  char *p, *q;
  stream *s;

  total = 0;
  s = init_error_stream ();
  va_start (arg, format);

  for (;;)
    {
      count = 0;

      while (format[count] != '%' && format[count] != '\0')
	count++;

      if (count != 0)
	{
	  p = salloc_w (s, &count);
	  memmove (p, format, count);
	  sfree (s);
	}

      total += count;
      format += count;
      if (*format++ == '\0')
	break;

      switch (*format)
	{
	case 'c':
	  count = 1;

	  p = salloc_w (s, &count);
	  *p = (char) va_arg (arg, int);

	  sfree (s);
	  break;

	case 'd':
	  q = itoa (va_arg (arg, int));
	  count = strlen (q);

	  p = salloc_w (s, &count);
	  memmove (p, q, count);
	  sfree (s);
	  break;

	case 'x':
	  q = xtoa (va_arg (arg, unsigned));
	  count = strlen (q);

	  p = salloc_w (s, &count);
	  memmove (p, q, count);
	  sfree (s);
	  break;

	case 's':
	  q = va_arg (arg, char *);
	  count = strlen (q);

	  p = salloc_w (s, &count);
	  memmove (p, q, count);
	  sfree (s);
	  break;

	case '\0':
	  return total;

	default:
	  count = 2;
	  p = salloc_w (s, &count);
	  p[0] = format[-1];
	  p[1] = format[0];
	  sfree (s);
	  break;
	}

      total += count;
      format++;
    }

  va_end (arg);
  return total;
}


/* st_sprintf()-- Simple sprintf() for formatting memory buffers. */

void
st_sprintf (char *buffer, const char *format, ...)
{
  va_list arg;
  char c, *p;
  int count;

  va_start (arg, format);

  for (;;)
    {
      c = *format++;
      if (c != '%')
	{
	  *buffer++ = c;
	  if (c == '\0')
	    break;
	  continue;
	}

      c = *format++;
      switch (c)
	{
	case 'c':
	  *buffer++ = (char) va_arg (arg, int);
	  break;

	case 'd':
	  p = itoa (va_arg (arg, int));
	  count = strlen (p);

	  memcpy (buffer, p, count);
	  buffer += count;
	  break;

	case 's':
	  p = va_arg (arg, char *);
	  count = strlen (p);

	  memcpy (buffer, p, count);
	  buffer += count;
	  break;

	default:
	  *buffer++ = c;
	}
    }

  va_end (arg);
}


/* show_locus()-- Print a line number and filename describing where
 * something went wrong */

void
show_locus (void)
{

  if (!options.locus || filename == NULL)
    return;

  st_printf ("At line %d of file %s\n", line, filename);
}


/* recursion_check()-- It's possible for additional errors to occur
 * during fatal error processing.  We detect this condition here and
 * exit with code 4 immediately. */

#define MAGIC 0x20DE8101

static void
recursion_check (void)
{
  static int magic = 0;

  if (magic == MAGIC)
    sys_exit (4);		/* Don't even try to print something at this point */

  magic = MAGIC;
}


/* os_error()-- Operating system error.  We get a message from the
 * operating system, show it and leave.  Some operating system errors
 * are caught and processed by the library.  If not, we come here. */

void
os_error (const char *message)
{

  recursion_check ();

  show_locus ();
  st_printf ("Operating system error: %s\n%s\n", get_oserror (), message);

  sys_exit (1);
}


/* void runtime_error()-- These are errors associated with an
 * invalid fortran program. */

void
runtime_error (const char *message)
{

  recursion_check ();

  show_locus ();
  st_printf ("Fortran runtime error: %s\n", message);

  sys_exit (2);
}


/* void internal_error()-- These are this-can't-happen errors
 * that indicate something deeply wrong. */

void
internal_error (const char *message)
{

  recursion_check ();

  show_locus ();
  st_printf ("Internal Error: %s\n", message);
  sys_exit (3);
}


/* translate_error()-- Given an integer error code, return a string
 * describing the error. */

const char *
translate_error (int code)
{
  const char *p;

  switch (code)
    {
    case ERROR_EOR:
      p = "End of record";
      break;

    case ERROR_END:
      p = "End of file";
      break;

    case ERROR_OK:
      p = "Successful return";
      break;

    case ERROR_OS:
      p = "Operating system error";
      break;

    case ERROR_BAD_OPTION:
      p = "Bad statement option";
      break;

    case ERROR_MISSING_OPTION:
      p = "Missing statement option";
      break;

    case ERROR_OPTION_CONFLICT:
      p = "Conflicting statement options";
      break;

    case ERROR_ALREADY_OPEN:
      p = "File already opened in another unit";
      break;

    case ERROR_BAD_UNIT:
      p = "Unattached unit";
      break;

    case ERROR_FORMAT:
      p = "FORMAT error";
      break;

    case ERROR_BAD_ACTION:
      p = "Incorrect ACTION specified";
      break;

    case ERROR_ENDFILE:
      p = "Read past ENDFILE record";
      break;

    case ERROR_BAD_US:
      p = "Corrupt unformatted sequential file";
      break;

    case ERROR_READ_VALUE:
      p = "Bad value during read";
      break;

    case ERROR_READ_OVERFLOW:
      p = "Numeric overflow on read";
      break;

    default:
      p = "Unknown error code";
      break;
    }

  return p;
}


/* generate_error()-- Come here when an error happens.  This
 * subroutine is called if it is possible to continue on after the
 * error.  If an IOSTAT variable exists, we set it.  If the IOSTAT or
 * ERR label is present, we return, otherwise we terminate the program
 * after print a message.  The error code is always required but the
 * message parameter can be NULL, in which case a string describing
 * the most recent operating system error is used. */

void
generate_error (int family, const char *message)
{

  if (ioparm.iostat != NULL)
    {
      *ioparm.iostat = family;
      return;
    }

  switch (family)
    {
    case ERROR_EOR:
      ioparm.library_return = LIBRARY_EOR;
      if (ioparm.eor != 0)
	return;
      break;

    case ERROR_END:
      ioparm.library_return = LIBRARY_END;
      if (ioparm.end != 0)
	return;
      break;

    default:
      ioparm.library_return = LIBRARY_ERROR;
      break;
    }

  if (ioparm.err != 0)
    return;

  /* Terminate the program */

  if (message == NULL)
    message =
      (family == ERROR_OS) ? get_oserror () : translate_error (family);

  runtime_error (message);
}