read.c

gcc-fortran,linux使用fortran的编译软件。很好用的。

/* Copyright (C) 2002, 2003, 2005 Free Software Foundation, Inc.
   Contributed by Andy Vaught

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

Libgfortran 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.

In addition to the permissions in the GNU General Public License, the
Free Software Foundation gives you unlimited permission to link the
compiled version of this file into combinations with other programs,
and to distribute those combinations without any restriction coming
from the use of this file.  (The General Public License restrictions
do apply in other respects; for example, they cover modification of
the file, and distribution when not linked into a combine
executable.)

Libgfortran 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 Libgfortran; see the file COPYING.  If not, write to
the Free Software Foundation, 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.  */


#include "config.h"
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include "libgfortran.h"
#include "io.h"

/* read.c -- Deal with formatted reads */

/* set_integer()-- All of the integer assignments come here to
 * actually place the value into memory.  */

void
set_integer (void *dest, GFC_INTEGER_LARGEST value, int length)
{
  switch (length)
    {
#ifdef HAVE_GFC_INTEGER_16
    case 16:
      {
	GFC_INTEGER_16 tmp = value;
	memcpy (dest, (void *) &tmp, length);
      }
      break;
#endif
    case 8:
      {
	GFC_INTEGER_8 tmp = value;
	memcpy (dest, (void *) &tmp, length);
      }
      break;
    case 4:
      {
	GFC_INTEGER_4 tmp = value;
	memcpy (dest, (void *) &tmp, length);
      }
      break;
    case 2:
      {
	GFC_INTEGER_2 tmp = value;
	memcpy (dest, (void *) &tmp, length);
      }
      break;
    case 1:
      {
	GFC_INTEGER_1 tmp = value;
	memcpy (dest, (void *) &tmp, length);
      }
      break;
    default:
      internal_error (NULL, "Bad integer kind");
    }
}


/* max_value()-- Given a length (kind), return the maximum signed or
 * unsigned value */

GFC_UINTEGER_LARGEST
max_value (int length, int signed_flag)
{
  GFC_UINTEGER_LARGEST value;
  int n;

  switch (length)
    {
#if defined HAVE_GFC_REAL_16 || defined HAVE_GFC_REAL_10
    case 16:
    case 10:
      value = 1;
      for (n = 1; n < 4 * length; n++)
        value = (value << 2) + 3;
      if (! signed_flag)
        value = 2*value+1;
      break;
#endif
    case 8:
      value = signed_flag ? 0x7fffffffffffffff : 0xffffffffffffffff;
      break;
    case 4:
      value = signed_flag ? 0x7fffffff : 0xffffffff;
      break;
    case 2:
      value = signed_flag ? 0x7fff : 0xffff;
      break;
    case 1:
      value = signed_flag ? 0x7f : 0xff;
      break;
    default:
      internal_error (NULL, "Bad integer kind");
    }

  return value;
}


/* convert_real()-- Convert a character representation of a floating
 * point number to the machine number.  Returns nonzero if there is a
 * range problem during conversion.  TODO: handle not-a-numbers and
 * infinities.  */

int
convert_real (st_parameter_dt *dtp, void *dest, const char *buffer, int length)
{
  errno = 0;

  switch (length)
    {
    case 4:
      {
	GFC_REAL_4 tmp =
#if defined(HAVE_STRTOF)
	  strtof (buffer, NULL);
#else
	  (GFC_REAL_4) strtod (buffer, NULL);
#endif
	memcpy (dest, (void *) &tmp, length);
      }
      break;
    case 8:
      {
	GFC_REAL_8 tmp = strtod (buffer, NULL);
	memcpy (dest, (void *) &tmp, length);
      }
      break;
#if defined(HAVE_GFC_REAL_10) && defined (HAVE_STRTOLD)
    case 10:
      {
	GFC_REAL_10 tmp = strtold (buffer, NULL);
	memcpy (dest, (void *) &tmp, length);
      }
      break;
#endif
#if defined(HAVE_GFC_REAL_16) && defined (HAVE_STRTOLD)
    case 16:
      {
	GFC_REAL_16 tmp = strtold (buffer, NULL);
	memcpy (dest, (void *) &tmp, length);
      }
      break;
#endif
    default:
      internal_error (&dtp->common, "Unsupported real kind during IO");
    }

  if (errno != 0 && errno != EINVAL)
    {
      generate_error (&dtp->common, ERROR_READ_VALUE,
		      "Range error during floating point read");
      return 1;
    }

  return 0;
}


/* read_l()-- Read a logical value */

void
read_l (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
{
  char *p;
  int w;

  w = f->u.w;
  p = read_block (dtp, &w);
  if (p == NULL)
    return;

  while (*p == ' ')
    {
      if (--w == 0)
	goto bad;
      p++;
    }

  if (*p == '.')
    {
      if (--w == 0)
	goto bad;
      p++;
    }

  switch (*p)
    {
    case 't':
    case 'T':
      set_integer (dest, (GFC_INTEGER_LARGEST) 1, length);
      break;
    case 'f':
    case 'F':
      set_integer (dest, (GFC_INTEGER_LARGEST) 0, length);
      break;
    default:
    bad:
      generate_error (&dtp->common, ERROR_READ_VALUE,
		      "Bad value on logical read");
      break;
    }
}


/* read_a()-- Read a character record.  This one is pretty easy. */

void
read_a (st_parameter_dt *dtp, const fnode *f, char *p, int length)
{
  char *source;
  int w, m, n;

  w = f->u.w;
  if (w == -1) /* '(A)' edit descriptor  */
    w = length;

  dtp->u.p.sf_read_comma = 0;
  source = read_block (dtp, &w);
  dtp->u.p.sf_read_comma = 1;
  if (source == NULL)
    return;
  if (w > length)
     source += (w - length);

  m = (w > length) ? length : w;
  memcpy (p, source, m);

  n = length - w;
  if (n > 0)
    memset (p + m, ' ', n);
}


/* eat_leading_spaces()-- Given a character pointer and a width,
 * ignore the leading spaces.  */

static char *
eat_leading_spaces (int *width, char *p)
{
  for (;;)
    {
      if (*width == 0 || *p != ' ')
	break;

      (*width)--;
      p++;
    }

  return p;
}


static char
next_char (st_parameter_dt *dtp, char **p, int *w)
{
  char c, *q;

  if (*w == 0)
    return '\0';

  q = *p;
  c = *q++;
  *p = q;

  (*w)--;

  if (c != ' ')
    return c;
  if (dtp->u.p.blank_status != BLANK_UNSPECIFIED)
    return ' ';  /* return a blank to signal a null */ 

  /* At this point, the rest of the field has to be trailing blanks */

  while (*w > 0)
    {
      if (*q++ != ' ')
	return '?';
      (*w)--;
    }

  *p = q;
  return '\0';
}


/* read_decimal()-- Read a decimal integer value.  The values here are
 * signed values. */

void
read_decimal (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
{
  GFC_UINTEGER_LARGEST value, maxv, maxv_10;
  GFC_INTEGER_LARGEST v;
  int w, negative;
  char c, *p;

  w = f->u.w;
  p = read_block (dtp, &w);
  if (p == NULL)
    return;

  p = eat_leading_spaces (&w, p);
  if (w == 0)
    {
      set_integer (dest, (GFC_INTEGER_LARGEST) 0, length);
      return;
    }

  maxv = max_value (length, 1);
  maxv_10 = maxv / 10;

  negative = 0;
  value = 0;

  switch (*p)
    {
    case '-':
      negative = 1;
      /* Fall through */

    case '+':
      p++;
      if (--w == 0)
	goto bad;
      /* Fall through */

    default:
      break;
    }

  /* At this point we have a digit-string */
  value = 0;

  for (;;)
    {
      c = next_char (dtp, &p, &w);
      if (c == '\0')
	break;
	
      if (c == ' ')
        {
	  if (dtp->u.p.blank_status == BLANK_NULL) continue;
	  if (dtp->u.p.blank_status == BLANK_ZERO) c = '0';
        }
        
      if (c < '0' || c > '9')
	goto bad;

      if (value > maxv_10)
	goto overflow;

      c -= '0';
      value = 10 * value;

      if (value > maxv - c)
	goto overflow;
      value += c;
    }

  v = value;
  if (negative)
    v = -v;

  set_integer (dest, v, length);
  return;

 bad:
  generate_error (&dtp->common, ERROR_READ_VALUE,
		  "Bad value during integer read");
  return;

 overflow:
  generate_error (&dtp->common, ERROR_READ_OVERFLOW,
		  "Value overflowed during integer read");
  return;
}


/* read_radix()-- This function reads values for non-decimal radixes.
 * The difference here is that we treat the values here as unsigned
 * values for the purposes of overflow.  If minus sign is present and
 * the top bit is set, the value will be incorrect. */

void
read_radix (st_parameter_dt *dtp, const fnode *f, char *dest, int length,
	    int radix)
{
  GFC_UINTEGER_LARGEST value, maxv, maxv_r;
  GFC_INTEGER_LARGEST v;
  int w, negative;
  char c, *p;

  w = f->u.w;
  p = read_block (dtp, &w);
  if (p == NULL)
    return;