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gcc/libgfortran/io/read.c

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/* Copyright (C) 2002-2003 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.
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, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, 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, int64_t value, int length)
{
switch (length)
{
case 8:
*((int64_t *) dest) = value;
break;
case 4:
*((int32_t *) dest) = value;
break;
case 2:
*((int16_t *) dest) = value;
break;
case 1:
*((int8_t *) dest) = value;
break;
default:
internal_error ("Bad integer kind");
}
}
/* max_value()-- Given a length (kind), return the maximum signed or
* unsigned value */
uint64_t
max_value (int length, int signed_flag)
{
uint64_t value;
switch (length)
{
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 ("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 (void *dest, const char *buffer, int length)
{
errno = 0;
switch (length)
{
case 4:
*((float *) dest) =
#if defined(HAVE_STRTOF)
strtof (buffer, NULL);
#else
(float) strtod (buffer, NULL);
#endif
break;
case 8:
*((double *) dest) = strtod (buffer, NULL);
break;
default:
internal_error ("Unsupported real kind during IO");
}
if (errno != 0)
{
generate_error (ERROR_READ_VALUE,
"Range error during floating point read");
return 1;
}
return 0;
}
/* read_l()-- Read a logical value */
void
read_l (fnode * f, char *dest, int length)
{
char *p;
int w;
w = f->u.w;
p = read_block (&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, 1, length);
break;
case 'f':
case 'F':
set_integer (dest, 0, length);
break;
default:
bad:
generate_error (ERROR_READ_VALUE, "Bad value on logical read");
break;
}
}
/* read_a()-- Read a character record. This one is pretty easy. */
void
read_a (fnode * f, char *p, int length)
{
char *source;
int w, m, n;
w = f->u.w;
if (w == -1) /* '(A)' edit descriptor */
w = length;
source = read_block (&w);
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 (char **p, int *w)
{
char c, *q;
if (*w == 0)
return '\0';
q = *p;
c = *q++;
*p = q;
(*w)--;
if (c != ' ')
return c;
if (g.blank_status == BLANK_ZERO)
return '0';
/* 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 (fnode * f, char *dest, int length)
{
unsigned value, maxv, maxv_10;
int v, w, negative;
char c, *p;
w = f->u.w;
p = read_block (&w);
if (p == NULL)
return;
p = eat_leading_spaces (&w, p);
if (w == 0)
{
set_integer (dest, 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 (&p, &w);
if (c == '\0')
break;
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 = (signed int) value;
if (negative)
v = -v;
set_integer (dest, v, length);
return;
bad:
generate_error (ERROR_READ_VALUE, "Bad value during integer read");
return;
overflow:
generate_error (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 (fnode * f, char *dest, int length, int radix)
{
unsigned value, maxv, maxv_r;
int v, w, negative;
char c, *p;
w = f->u.w;
p = read_block (&w);
if (p == NULL)
return;
p = eat_leading_spaces (&w, p);
if (w == 0)
{
set_integer (dest, 0, length);
return;
}
maxv = max_value (length, 0);
maxv_r = maxv / radix;
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 (&p, &w);
if (c == '\0')
break;
switch (radix)
{
case 2:
if (c < '0' || c > '1')
goto bad;
break;
case 8:
if (c < '0' || c > '7')
goto bad;
break;
case 16:
switch (c)
{
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
break;
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
c = c - 'a' + '9' + 1;
break;
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
c = c - 'A' + '9' + 1;
break;
default:
goto bad;
}
break;
}
if (value > maxv_r)
goto overflow;
c -= '0';
value = radix * value;
if (maxv - c < value)
goto overflow;
value += c;
}
v = (signed int) value;
if (negative)
v = -v;
set_integer (dest, v, length);
return;
bad:
generate_error (ERROR_READ_VALUE, "Bad value during integer read");
return;
overflow:
generate_error (ERROR_READ_OVERFLOW,
"Value overflowed during integer read");
return;
}
/* read_f()-- Read a floating point number with F-style editing, which
is what all of the other floating point descriptors behave as. The
tricky part is that optional spaces are allowed after an E or D,
and the implicit decimal point if a decimal point is not present in
the input. */
void
read_f (fnode * f, char *dest, int length)
{
int w, seen_dp, exponent;
int exponent_sign, val_sign;
int ndigits;
int edigits;
int i;
char *p, *buffer;
char *digits;
val_sign = 1;
seen_dp = 0;
w = f->u.w;
p = read_block (&w);
if (p == NULL)
return;
p = eat_leading_spaces (&w, p);
if (w == 0)
{
switch (length)
{
case 4:
*((float *) dest) = 0.0f;
break;
case 8:
*((double *) dest) = 0.0;
break;
default:
internal_error ("Unsupported real kind during IO");
}
return;
}
/* Optional sign */
if (*p == '-' || *p == '+')
{
if (*p == '-')
val_sign = -1;
p++;
if (--w == 0)
goto bad_float;
}
exponent_sign = 1;
/* A digit (or a '.') is required at this point */
if (!isdigit (*p) && *p != '.')
goto bad_float;
/* Remember the position of the first digit. */
digits = p;
ndigits = 0;
/* Scan through the string to find the exponent. */
while (w > 0)
{
switch (*p)
{
case '.':
if (seen_dp)
goto bad_float;
seen_dp = 1;
/* Fall through */
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case ' ':
ndigits++;
*p++;
w--;
break;
case '-':
exponent_sign = -1;
/* Fall through */
case '+':
p++;
w--;
goto exp2;
case 'd':
case 'e':
case 'D':
case 'E':
p++;
w--;
goto exp1;
default:
goto bad_float;
}
}
/* No exponent has been seen, so we use the current scale factor */
exponent = -g.scale_factor;
goto done;
bad_float:
generate_error (ERROR_READ_VALUE, "Bad value during floating point read");
if (buffer != scratch)
free_mem (buffer);
return;
/* At this point the start of an exponent has been found */
exp1:
while (w > 0 && *p == ' ')
{
w--;
p++;
}
switch (*p)
{
case '-':
exponent_sign = -1;
/* Fall through */
case '+':
p++;
w--;
break;
}
if (w == 0)
goto bad_float;
/* At this point a digit string is required. We calculate the value
of the exponent in order to take account of the scale factor and
the d parameter before explict conversion takes place. */
exp2:
if (!isdigit (*p))
goto bad_float;
exponent = *p - '0';
p++;
w--;
while (w > 0 && isdigit (*p))
{
exponent = 10 * exponent + *p - '0';
p++;
w--;
}
/* Only allow trailing blanks */
while (w > 0)
{
if (*p != ' ')
goto bad_float;
p++;
w--;
}
exponent = exponent * exponent_sign;
done:
/* Use the precision specified in the format if no decimal point has been
seen. */
if (!seen_dp)
exponent -= f->u.real.d;
if (exponent > 0)
{
edigits = 2;
i = exponent;
}
else
{
edigits = 3;
i = -exponent;
}
while (i >= 10)
{
i /= 10;
edigits++;
}
i = ndigits + edigits + 1;
if (val_sign < 0)
i++;
if (i < SCRATCH_SIZE)
buffer = scratch;
else
buffer = get_mem (i);
/* Reformat the string into a temporary buffer. As we're using atof it's
easiest to just leave the dcimal point in place. */
p = buffer;
if (val_sign < 0)
*(p++) = '-';
for (; ndigits > 0; ndigits--)
{
if (*digits == ' ' && g.blank_status == BLANK_ZERO)
*p = '0';
else
*p = *digits;
p++;
digits++;
}
*(p++) = 'e';
sprintf (p, "%d", exponent);
/* Do the actual conversion. */
convert_real (dest, buffer, length);
if (buffer != scratch)
free_mem (buffer);
return;
}
/* read_x()-- Deal with the X/TR descriptor. We just read some data
* and never look at it. */
void
read_x (fnode * f)
{
int n;
n = f->u.n;
read_block (&n);
}
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