2009-04-05 Daniel Kraft <d@domob.eu>

	PR fortran/38654
	* io/read.c (read_f): Reworked to speed up floating point parsing.
	(convert_real): Use pointer-casting instead of memcpy and temporaries.

2009-04-05  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR libfortran/37754
	* io/io.h (format_hash_entry): New structure for hash table.
	(format_hash_table): The hash table itself.
	(free_format_data): Revise function prototype.
	(free_format_hash_table, init_format_hash,
	free_format_hash): New function prototypes.
	* io/unit.c (close_unit_1): Use free_format_hash_table.
	* io/transfer.c (st_read_done, st_write_done): Free format data if
	internal unit.
	* io/format.c (free_format_hash_table): New function that frees any
	memory allocated previously for cached format data.
	(reset_node): New static helper function to reset the format counters
	for a format node.
	(reset_fnode_counters): New static function recursively calls reset_node
	to traverse the	fnode tree.
	(format_hash): New simple hash function based on XOR, probabalistic,
	tosses collisions.
	(save_parsed_format): New static function to save the parsed format
	data to use again.
	(find_parsed_format): New static function searches the hash table
	looking for a match.
	(free_format_data): Revised to accept pointer to format data rather than
	the dtp pointer so that the function can be used in more places.
	(format_lex): Editorial.
	(parse_format_list): Set flag used to determine of format data hashing
	is to be used.  Internal units are not persistent enough for this.
	(revert): Move to ne location in file.
	(parse_format): Use new functions to look for previously parsed
	format strings and use them rather than re-parse.  If not found, saves
	the parsed format data for later use.
	
2009-04-05  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

        PR libfortran/37754
	* io/transfer.c (formatted_transfer_scalar): Remove this function by
	factoring it into two new functions, one for read and one for write,
	eliminating all the conditionals for read or write mode.
	(formatted transfer_scalar_read): New function.
	(formatted transfer_scalar_write): New function.
	(formatted_transfer): Use new functions.

2009-04-05  Janne Blomqvist  <jb@gcc.gnu.org>

        PR libfortran/25561 libfortran/37754
	* io/io.h (struct stream): Define new stream interface function
	pointers, and inline functions for accessing it.
	(struct fbuf): Use int instead of size_t, remove flushed element.
	(mem_alloc_w): New prototype.
	(mem_alloc_r): New prototype.
	(stream_at_bof): Remove prototype.
	(stream_at_eof): Remove prototype.
	(file_position): Remove prototype.
	(flush): Remove prototype.
	(stream_offset): Remove prototype.
	(unit_truncate): New prototype.
	(read_block_form): Change to return pointer, int* argument.
	(hit_eof): New prototype.
	(fbuf_init): Change prototype.
	(fbuf_reset): Change prototype.
	(fbuf_alloc): Change prototype.
	(fbuf_flush): Change prototype.
	(fbuf_seek): Change prototype.
	(fbuf_read): New prototype.
	(fbuf_getc_refill): New prototype.
	(fbuf_getc): New inline function.
        * io/fbuf.c (fbuf_init): Use int, get rid of flushed.
	(fbuf_debug): New function.
	(fbuf_reset): Flush, and return position offset.
	(fbuf_alloc): Simplify, don't flush, just realloc.
	(fbuf_flush): Make usable for read mode, salvage remaining bytes.
	(fbuf_seek): New whence argument.
	(fbuf_read): New function.
	(fbuf_getc_refill): New function.
	* io/file_pos.c (formatted_backspace): Use new stream interface.
	(unformatted_backspace): Likewise.
	(st_backspace): Make sure format buffer is reset, use new stream
	interface, use unit_truncate.
	(st_endfile): Likewise.
	(st_rewind): Likewise.
	* io/intrinsics.c: Use new stream interface.
	* io/list_read.c (push_char): Don't use u.p.scratch, use realloc
	to resize.
	(free_saved): Don't check u.p.scratch.
	(next_char): Use new stream interface, use fbuf_getc() for external files.
	(finish_list_read): flush format buffer.
	(nml_query): Update to use modified interface:s
	* io/open.c (test_endfile): Use new stream interface.
	(edit_modes): Likewise.
	(new_unit): Likewise, set bytes_left to 1 for stream files.
	* io/read.c (read_l): Use new read_block_form interface.
	(read_utf8): Likewise.
	(read_utf8_char1): Likewise.
	(read_default_char1): Likewise.
	(read_utf8_char4): Likewise.
	(read_default_char4): Likewise.
	(read_a): Likewise.
	(read_a_char4): Likewise.
	(read_decimal): Likewise.
	(read_radix): Likewise.
	(read_f): Likewise.
	* io/transfer.c (read_sf): Use fbuf_read and mem_alloc_r, remove
	usage of u.p.line_buffer.
	(read_block_form): Update interface to return pointer, use
	fbuf_read for direct access.
	(read_block_direct): Update to new stream interface.
	(write_block): Use mem_alloc_w for internal I/O.
	(write_buf): Update to new stream interface.
	(formatted_transfer_scalar): Don't use u.p.line_buffer, use
	fbuf_seek for external files.
	(us_read): Update to new stream interface.
	(us_write): Likewise.
	(data_transfer_init): Always check if we switch modes and flush.
	(skip_record): Use new stream interface, fix comparison.
	(next_record_r): Check for and reset u.p.at_eof, use new stream
	interface, use fbuf_getc for spacing.
	(write_us_marker): Update to new stream interface, don't inline.
	(next_record_w_unf): Likewise.
	(sset): New function.
	(next_record_w): Use new stream interface, use fbuf for printing
	newline.
	(next_record): Use new stream interface.
	(finalize_transfer): Remove sfree call, use new stream interface.
	(st_iolength_done): Don't use u.p.scratch.
	(st_read): Don't check for end of file.
	(st_read_done): Don't use u.p.scratch, use unit_truncate.
	(hit_eof): New function.
	* io/unit.c (init_units): Always init fbuf for formatted units.
	(update_position): Use new stream interface.
	(unit_truncate): New function.
	(finish_last_advance_record): Use fbuf to print newline.
	* io/unix.c: Remove unused SSIZE_MAX macro.
	(BUFFER_SIZE): Make static const variable rather than macro.
	(struct unix_stream): Remove dirty_offset, len, method,
	small_buffer. Order elements by decreasing size.
	(struct int_stream): Remove.
	(move_pos_offset): Remove usage of dirty_offset.
	(reset_stream): Remove.
	(do_read): Rename to raw_read, update to match new stream
	interface.
	(do_write): Rename to raw_write, update to new stream interface.
	(raw_seek): New function.
	(raw_tell): New function.
	(raw_truncate): New function.
	(raw_close): New function.
	(raw_flush): New function.
	(raw_init): New function.
	(fd_alloc): Remove.
	(fd_alloc_r_at): Remove.
	(fd_alloc_w_at): Remove.
	(fd_sfree): Remove.
	(fd_seek): Remove.
	(fd_truncate): Remove.
	(fd_sset): Remove.
	(fd_read): Remove.
	(fd_write): Remove.
	(fd_close): Remove.
	(fd_open): Remove.
	(fd_flush): Rename to buf_flush, update to new stream interface
	and unix_stream.
	(buf_read): New function.
	(buf_write): New function.
	(buf_seek): New function.
	(buf_tell): New function.
	(buf_truncate): New function.
	(buf_close): New function.
	(buf_init): New function.
	(mem_alloc_r_at): Rename to mem_alloc_r, change prototype.
	(mem_alloc_w_at): Rename to mem_alloc_w, change prototype.
	(mem_read): Change to match new stream interface.
	(mem_write): Likewise.
	(mem_seek): Likewise.
	(mem_tell): Likewise.
	(mem_truncate): Likewise.
	(mem_close): Likewise.
	(mem_flush): New function.
	(mem_sfree): Remove.
	(empty_internal_buffer): Cast to correct type.
	(open_internal): Use correct type, init function pointers.
	(fd_to_stream): Test whether to open file as buffered or raw.
	(output_stream): Remove mode set.
	(error_stream): Likewise.
	(flush_all_units_1): Use new stream interface.
	(flush_all_units): Likewise.
	(stream_at_bof): Remove.
	(stream_at_eof): Remove.
	(file_position): Remove.
	(file_length): Update logic to use stream interface.
	(flush): Remove.
	(stream_offset): Remove.
	* io/write.c (write_utf8_char4): Use int instead of size_t.
	(write_x): Extra safety check.
	(namelist_write_newline): Use new stream interface.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@145571 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 221 insertions, 269 deletions

diff --git a/libgfortran/io/read.c b/libgfortran/io/read.c
index a8ae3d73f53..b651665944f 100644
--- a/libgfortran/io/read.c
+++ b/libgfortran/io/read.c
@@ -33,6 +33,7 @@ Boston, MA 02110-1301, USA.  */
 #include <errno.h>
 #include <ctype.h>
 #include <stdlib.h>
+#include <assert.h>
 
 typedef unsigned char uchar;
 
@@ -141,38 +142,30 @@ convert_real (st_parameter_dt *dtp, void *dest, const char *buffer, int length)
   switch (length)
     {
     case 4:
-      {
-	GFC_REAL_4 tmp =
+      *((GFC_REAL_4*) dest) =
 #if defined(HAVE_STRTOF)
-	  strtof (buffer, NULL);
+	strtof (buffer, NULL);
 #else
-	  (GFC_REAL_4) strtod (buffer, NULL);
+	(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);
-      }
+      *((GFC_REAL_8*) dest) = strtod (buffer, NULL);
       break;
+
 #if defined(HAVE_GFC_REAL_10) && defined (HAVE_STRTOLD)
     case 10:
-      {
-	GFC_REAL_10 tmp = strtold (buffer, NULL);
-	memcpy (dest, (void *) &tmp, length);
-      }
+      *((GFC_REAL_10*) dest) = strtold (buffer, NULL);
       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);
-      }
+      *((GFC_REAL_16*) dest) = strtold (buffer, NULL);
       break;
 #endif
+
     default:
       internal_error (&dtp->common, "Unsupported real kind during IO");
     }
@@ -195,13 +188,13 @@ void
 read_l (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
 {
   char *p;
-  size_t w;
+  int w;
 
   w = f->u.w;
 
-  p = gfc_alloca (w);
+  p = read_block_form (dtp, &w);
 
-  if (read_block_form (dtp, p, &w) == FAILURE)
+  if (p == NULL)
     return;
 
   while (*p == ' ')
@@ -238,28 +231,26 @@ read_l (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
 }
 
 
-static inline gfc_char4_t
-read_utf8 (st_parameter_dt *dtp, size_t *nbytes) 
+static gfc_char4_t
+read_utf8 (st_parameter_dt *dtp, int *nbytes) 
 {
   static const uchar masks[6] = { 0x7F, 0x1F, 0x0F, 0x07, 0x02, 0x01 };
   static const uchar patns[6] = { 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };
-  static uchar buffer[6];
-  size_t i, nb, nread;
+  int i, nb, nread;
   gfc_char4_t c;
-  int status;
   char *s;
 
   *nbytes = 1;
-  s = (char *) &buffer[0];
-  status = read_block_form (dtp, s, nbytes);
-  if (status == FAILURE)
+
+  s = read_block_form (dtp, nbytes);
+  if (s == NULL)
     return 0;
 
   /* If this is a short read, just return.  */
   if (*nbytes == 0)
     return 0;
 
-  c = buffer[0];
+  c = (uchar) s[0];
   if (c < 0x80)
     return c;
 
@@ -274,9 +265,8 @@ read_utf8 (st_parameter_dt *dtp, size_t *nbytes)
   c = (c & masks[nb-1]);
   nread = nb - 1;
 
-  s = (char *) &buffer[1];
-  status = read_block_form (dtp, s, &nread);
-  if (status == FAILURE)
+  s = read_block_form (dtp, &nread);
+  if (s == NULL)
     return 0;
   /* Decode the bytes read.  */
   for (i = 1; i < nb; i++)
@@ -309,14 +299,14 @@ read_utf8 (st_parameter_dt *dtp, size_t *nbytes)
 
 
 static void
-read_utf8_char1 (st_parameter_dt *dtp, char *p, int len, size_t width)
+read_utf8_char1 (st_parameter_dt *dtp, char *p, int len, int width)
 {
   gfc_char4_t c;
   char *dest;
-  size_t nbytes;
+  int nbytes;
   int i, j;
 
-  len = ((int) width < len) ? len : (int) width;
+  len = (width < len) ? len : width;
 
   dest = (char *) p;
 
@@ -339,21 +329,19 @@ read_utf8_char1 (st_parameter_dt *dtp, char *p, int len, size_t width)
 }
 
 static void
-read_default_char1 (st_parameter_dt *dtp, char *p, int len, size_t width)
+read_default_char1 (st_parameter_dt *dtp, char *p, int len, int width)
 {
   char *s;
-  int m, n, status;
+  int m, n;
 
-  s = gfc_alloca (width);
-
-  status = read_block_form (dtp, s, &width);
+  s = read_block_form (dtp, &width);
   
-  if (status == FAILURE)
+  if (s == NULL)
     return;
-  if (width > (size_t) len)
+  if (width > len)
      s += (width - len);
 
-  m = ((int) width > len) ? len : (int) width;
+  m = (width > len) ? len : width;
   memcpy (p, s, m);
 
   n = len - width;
@@ -363,13 +351,13 @@ read_default_char1 (st_parameter_dt *dtp, char *p, int len, size_t width)
 
 
 static void
-read_utf8_char4 (st_parameter_dt *dtp, void *p, int len, size_t width)
+read_utf8_char4 (st_parameter_dt *dtp, void *p, int len, int width)
 {
   gfc_char4_t *dest;
-  size_t nbytes;
+  int nbytes;
   int i, j;
 
-  len = ((int) width < len) ? len : (int) width;
+  len = (width < len) ? len : width;
 
   dest = (gfc_char4_t *) p;
 
@@ -391,19 +379,17 @@ read_utf8_char4 (st_parameter_dt *dtp, void *p, int len, size_t width)
 
 
 static void
-read_default_char4 (st_parameter_dt *dtp, char *p, int len, size_t width)
+read_default_char4 (st_parameter_dt *dtp, char *p, int len, int width)
 {
   char *s;
   gfc_char4_t *dest;
-  int m, n, status;
-
-  s = gfc_alloca (width);
+  int m, n;
 
-  status = read_block_form (dtp, s, &width);
+  s = read_block_form (dtp, &width);
   
-  if (status == FAILURE)
+  if (s == NULL)
     return;
-  if (width > (size_t) len)
+  if (width > len)
      s += (width - len);
 
   m = ((int) width > len) ? len : (int) width;
@@ -425,7 +411,7 @@ void
 read_a (st_parameter_dt *dtp, const fnode *f, char *p, int length)
 {
   int wi;
-  size_t w;
+  int w;
 
   wi = f->u.w;
   if (wi == -1) /* '(A)' edit descriptor  */
@@ -451,13 +437,11 @@ read_a (st_parameter_dt *dtp, const fnode *f, char *p, int length)
 void
 read_a_char4 (st_parameter_dt *dtp, const fnode *f, char *p, int length)
 {
-  int wi;
-  size_t w;
+  int w;
 
-  wi = f->u.w;
-  if (wi == -1) /* '(A)' edit descriptor  */
-    wi = length;
-  w = wi;
+  w = f->u.w;
+  if (w == -1) /* '(A)' edit descriptor  */
+    w = length;
 
   /* Read in w characters, treating comma as not a separator.  */
   dtp->u.p.sf_read_comma = 0;
@@ -532,18 +516,15 @@ 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; 
-  size_t wu;
   char c, *p;
 
-  wu = f->u.w;
+  w = f->u.w;
 
-  p = gfc_alloca (wu);
+  p = read_block_form (dtp, &w);
 
-  if (read_block_form (dtp, p, &wu) == FAILURE)
+  if (p == NULL)
     return;
 
-  w = wu;
-
   p = eat_leading_spaces (&w, p);
   if (w == 0)
     {
@@ -636,17 +617,14 @@ read_radix (st_parameter_dt *dtp, const fnode *f, char *dest, int length,
   GFC_INTEGER_LARGEST v;
   int w, negative;
   char c, *p;
-  size_t wu;
 
-  wu = f->u.w;
+  w = f->u.w;
 
-  p = gfc_alloca (wu);
+  p = read_block_form (dtp, &w);
 
-  if (read_block_form (dtp, p, &wu) == FAILURE)
+  if (p == NULL)
     return;
 
-  w = wu;
-
   p = eat_leading_spaces (&w, p);
   if (w == 0)
     {
@@ -783,75 +761,83 @@ read_radix (st_parameter_dt *dtp, const fnode *f, char *dest, int length,
 void
 read_f (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
 {
-  size_t wu;
   int w, seen_dp, exponent;
-  int exponent_sign, val_sign;
-  int ndigits;
-  int edigits;
-  int i;
-  char *p, *buffer;
-  char *digits;
-  char scratch[SCRATCH_SIZE];
-
-  val_sign = 1;
-  seen_dp = 0;
-  wu = f->u.w;
+  int exponent_sign;
+  const char *p;
+  char *buffer;
+  char *out;
+  int seen_int_digit; /* Seen a digit before the decimal point?  */
+  int seen_dec_digit; /* Seen a digit after the decimal point?  */
 
-  p = gfc_alloca (wu);
+  seen_dp = 0;
+  seen_int_digit = 0;
+  seen_dec_digit = 0;
+  exponent_sign = 1;
+  exponent = 0;
+  w = f->u.w;
 
-  if (read_block_form (dtp, p, &wu) == FAILURE)
+  /* Read in the next block.  */
+  p = read_block_form (dtp, &w);
+  if (p == NULL)
     return;
-
-  w = wu;
-
-  p = eat_leading_spaces (&w, p);
+  p = eat_leading_spaces (&w, (char*) p);
   if (w == 0)
     goto zero;
 
-  /* Optional sign */
+  /* In this buffer we're going to re-format the number cleanly to be parsed
+     by convert_real in the end; this assures we're using strtod from the
+     C library for parsing and thus probably get the best accuracy possible.
+     This process may add a '+0.0' in front of the number as well as change the
+     exponent because of an implicit decimal point or the like.  Thus allocating
+     strlen ("+0.0e-1000") == 10 characters plus one for NUL more than the
+     original buffer had should be enough.  */
+  buffer = gfc_alloca (w + 11);
+  out = buffer;
 
+  /* Optional sign */
   if (*p == '-' || *p == '+')
     {
       if (*p == '-')
-        val_sign = -1;
-      p++;
-      w--;
+	*(out++) = '-';
+      ++p;
+      --w;
     }
 
-  exponent_sign = 1;
-  p = eat_leading_spaces (&w, p);
+  p = eat_leading_spaces (&w, (char*) p);
   if (w == 0)
     goto zero;
 
-  /* A digit, a '.' or a exponent character ('e', 'E', 'd' or 'D')
-     is required at this point */
-
-  if (!isdigit (*p) && *p != '.' && *p != ',' && *p != 'd' && *p != 'D'
-      && *p != 'e' && *p != 'E')
-    goto bad_float;
-
-  /* Remember the position of the first digit.  */
-  digits = p;
-  ndigits = 0;
-
-  /* Scan through the string to find the exponent.  */
+  /* Process the mantissa string.  */
   while (w > 0)
     {
       switch (*p)
 	{
 	case ',':
-	  if (dtp->u.p.current_unit->decimal_status == DECIMAL_COMMA
-               && *p == ',')
-	    *p = '.';
-	  else
+	  if (dtp->u.p.current_unit->decimal_status != DECIMAL_COMMA)
 	    goto bad_float;
-	  /* Fall through */
+	  /* Fall through.  */
 	case '.':
 	  if (seen_dp)
 	    goto bad_float;
+	  if (!seen_int_digit)
+	    *(out++) = '0';
+	  *(out++) = '.';
 	  seen_dp = 1;
-	  /* Fall through */
+	  break;
 
+	case ' ':
+	  if (dtp->u.p.blank_status == BLANK_ZERO)
+	    {
+	      *(out++) = '0';
+	      goto found_digit;
+	    }
+	  else if (dtp->u.p.blank_status == BLANK_NULL)
+	    break;
+	  else
+	    /* TODO: Should we check instead that there are only trailing
+	       blanks here, as is done below for exponents?  */
+	    goto done;
+	  /* Fall through.  */
 	case '0':
 	case '1':
 	case '2':
@@ -862,207 +848,173 @@ read_f (st_parameter_dt *dtp, const fnode *f, char *dest, int length)
 	case '7':
 	case '8':
 	case '9':
-	case ' ':
-	  ndigits++;
-	  p++;
-	  w--;
+	  *(out++) = *p;
+found_digit:
+	  if (!seen_dp)
+	    seen_int_digit = 1;
+	  else
+	    seen_dec_digit = 1;
 	  break;
 
 	case '-':
-	  exponent_sign = -1;
-	  /* Fall through */
-
 	case '+':
-	  p++;
-	  w--;
-	  goto exp2;
+	  goto exponent;
 
-	case 'd':
 	case 'e':
-	case 'D':
 	case 'E':
-	  p++;
-	  w--;
-	  goto exp1;
+	case 'd':
+	case 'D':
+	  ++p;
+	  --w;
+	  goto exponent;
 
 	default:
 	  goto bad_float;
 	}
-    }
 
-  /* No exponent has been seen, so we use the current scale factor */
-  exponent = -dtp->u.p.scale_factor;
-  goto done;
-
- bad_float:
-  generate_error (&dtp->common, LIBERROR_READ_VALUE,
-		  "Bad value during floating point read");
-  next_record (dtp, 1);
-  return;
-
-  /* The value read is zero */
- zero:
-  switch (length)
-    {
-      case 4:
-	*((GFC_REAL_4 *) dest) = 0;
-	break;
-
-      case 8:
-	*((GFC_REAL_8 *) dest) = 0;
-	break;
-
-#ifdef HAVE_GFC_REAL_10
-      case 10:
-	*((GFC_REAL_10 *) dest) = 0;
-	break;
-#endif
-
-#ifdef HAVE_GFC_REAL_16
-      case 16:
-	*((GFC_REAL_16 *) dest) = 0;
-	break;
-#endif
-
-      default:
-	internal_error (&dtp->common, "Unsupported real kind during IO");
+      ++p;
+      --w;
     }
-  return;
+  
+  /* No exponent has been seen, so we use the current scale factor.  */
+  exponent = - dtp->u.p.scale_factor;
+  goto done;
 
-  /* At this point the start of an exponent has been found */
- exp1:
-  while (w > 0 && *p == ' ')
+  /* At this point the start of an exponent has been found.  */
+exponent:
+  p = eat_leading_spaces (&w, (char*) p);
+  if (*p == '-' || *p == '+')
     {
-      w--;
-      p++;
+      if (*p == '-')
+	exponent_sign = -1;
+      ++p;
+      --w;
     }
 
-  switch (*p)
-    {
-    case '-':
-      exponent_sign = -1;
-      /* Fall through */
-
-    case '+':
-      p++;
-      w--;
-      break;
-    }
+  /* 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.  */
 
   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:
-  /* Normal processing of exponent */
-  exponent = 0;
   if (dtp->u.p.blank_status == BLANK_UNSPECIFIED)
     {
       while (w > 0 && isdigit (*p))
-        {
-          exponent = 10 * exponent + *p - '0';
-          p++;
-          w--;
-        }
-        
-      /* Only allow trailing blanks */
-
+	{
+	  exponent *= 10;
+	  exponent += *p - '0';
+	  ++p;
+	  --w;
+	}
+	
+      /* Only allow trailing blanks.  */
       while (w > 0)
-        {
-          if (*p != ' ')
+	{
+	  if (*p != ' ')
 	    goto bad_float;
-          p++;
-          w--;
-        }
+	  ++p;
+	  --w;
+	}
     }    
-  else  /* BZ or BN status is enabled */
+  else  /* BZ or BN status is enabled.  */
     {
       while (w > 0)
-        {
-          if (*p == ' ')
-            {
-	      if (dtp->u.p.blank_status == BLANK_ZERO) *p = '0';
-	      if (dtp->u.p.blank_status == BLANK_NULL)
-                {
-                  p++;
-                  w--;
-                  continue;
-                }
-            }
-          else if (!isdigit (*p))
-            goto bad_float;
-
-          exponent = 10 * exponent + *p - '0';
-          p++;
-          w--;
-        }
+	{
+	  if (*p == ' ')
+	    {
+	      if (dtp->u.p.blank_status == BLANK_ZERO)
+		exponent *= 10;
+	      else
+		assert (dtp->u.p.blank_status == BLANK_NULL);
+	    }
+	  else if (!isdigit (*p))
+	    goto bad_float;
+	  else
+	    {
+	      exponent *= 10;
+	      exponent += *p - '0';
+	    }
+
+	  ++p;
+	  --w;
+	}
     }
 
-  exponent = exponent * exponent_sign;
+  exponent *= exponent_sign;
 
- done:
+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;
-    }
+  /* Output a trailing '0' after decimal point if not yet found.  */
+  if (seen_dp && !seen_dec_digit)
+    *(out++) = '0';
 
-  while (i >= 10)
+  /* Print out the exponent to finish the reformatted number.  Maximum 4
+     digits for the exponent.  */
+  if (exponent != 0)
     {
-      i /= 10;
-      edigits++;
-    }
+      int dig;
 
-  i = ndigits + edigits + 1;
-  if (val_sign < 0)
-    i++;
+      *(out++) = 'e';
+      if (exponent < 0)
+	{
+	  *(out++) = '-';
+	  exponent = - exponent;
+	}
 
-  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 decimal point in place.  */
-  p = buffer;
-  if (val_sign < 0)
-    *(p++) = '-';
-  for (; ndigits > 0; ndigits--)
-    {
-      if (*digits == ' ')
-        {
-	  if (dtp->u.p.blank_status == BLANK_ZERO) *digits = '0';
-	  if (dtp->u.p.blank_status == BLANK_NULL)
-            {
-              digits++;
-              continue;
-            } 
-        }
-      *p = *digits;
-      p++;
-      digits++;
+      assert (exponent < 10000);
+      for (dig = 3; dig >= 0; --dig)
+	{
+	  out[dig] = (char) ('0' + exponent % 10);
+	  exponent /= 10;
+	}
+      out += 4;
     }
-  *(p++) = 'e';
-  sprintf (p, "%d", exponent);
+  *(out++) = '\0';
 
   /* Do the actual conversion.  */
   convert_real (dtp, dest, buffer, length);
 
-  if (buffer != scratch)
-     free_mem (buffer);
+  return;
 
+  /* The value read is zero.  */
+zero:
+  switch (length)
+    {
+      case 4:
+	*((GFC_REAL_4 *) dest) = 0.0;
+	break;
+
+      case 8:
+	*((GFC_REAL_8 *) dest) = 0.0;
+	break;
+
+#ifdef HAVE_GFC_REAL_10
+      case 10:
+	*((GFC_REAL_10 *) dest) = 0.0;
+	break;
+#endif
+
+#ifdef HAVE_GFC_REAL_16
+      case 16:
+	*((GFC_REAL_16 *) dest) = 0.0;
+	break;
+#endif
+
+      default:
+	internal_error (&dtp->common, "Unsupported real kind during IO");
+    }
+  return;
+
+bad_float:
+  generate_error (&dtp->common, LIBERROR_READ_VALUE,
+		  "Bad value during floating point read");
+  next_record (dtp, 1);
+  return;
 }