[Pspp-cvs] pspp tests/automake.mk tests/ChangeLog src/libp...

[Ben Pfaff]

CVSROOT:        /cvsroot/pspp
Module name:    pspp
Changes by:     Ben Pfaff <blp> 08/02/03 06:52:13

Modified files:
        tests          : automake.mk ChangeLog 
        src/libpspp    : float-format.c 
Added files:
        tests          : dissect-sysfile.c 

Log message:
        Add new utility "dissect-sysfile".
        
        Patch #6347.

CVSWeb URLs:
http://cvs.savannah.gnu.org/viewcvs/pspp/tests/automake.mk?cvsroot=pspp&r1=1.50&r2=1.51
http://cvs.savannah.gnu.org/viewcvs/pspp/tests/ChangeLog?cvsroot=pspp&r1=1.121&r2=1.122
http://cvs.savannah.gnu.org/viewcvs/pspp/tests/dissect-sysfile.c?cvsroot=pspp&rev=1.1
http://cvs.savannah.gnu.org/viewcvs/pspp/src/libpspp/float-format.c?cvsroot=pspp&r1=1.7&r2=1.8

Patches:
Index: tests/automake.mk
===================================================================
RCS file: /cvsroot/pspp/pspp/tests/automake.mk,v
retrieving revision 1.50
retrieving revision 1.51
diff -u -b -r1.50 -r1.51
--- tests/automake.mk   2 Feb 2008 06:58:13 -0000       1.50
+++ tests/automake.mk   3 Feb 2008 06:52:13 -0000       1.51
@@ -255,6 +255,13 @@
 
 tests_formats_inexactify_SOURCES = tests/formats/inexactify.c
 
+noinst_PROGRAMS += tests/dissect-sysfile
+tests_dissect_sysfile_SOURCES = \
+       src/libpspp/integer-format.c \
+       src/libpspp/float-format.c \
+       tests/dissect-sysfile.c
+tests_dissect_sysfile_LDADD = gl/libgl.la @LIBINTL@
+
 EXTRA_DIST += \
        $(dist_TESTS) \
         tests/Book1.gnm.unzipped \

Index: tests/ChangeLog
===================================================================
RCS file: /cvsroot/pspp/pspp/tests/ChangeLog,v
retrieving revision 1.121
retrieving revision 1.122
diff -u -b -r1.121 -r1.122
--- tests/ChangeLog     2 Feb 2008 06:58:13 -0000       1.121
+++ tests/ChangeLog     3 Feb 2008 06:52:13 -0000       1.122
@@ -1,3 +1,9 @@
+2008-02-02  Ben Pfaff  <address@hidden>
+
+       * automake.mk: Add target for dissect-sysfile.
+
+       * dissect-sysfile.c: New program.
+
 2008-02-01  Ben Pfaff  <address@hidden>
 
        * automake.mk: Add new test.

Index: src/libpspp/float-format.c
===================================================================
RCS file: /cvsroot/pspp/pspp/src/libpspp/float-format.c,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -b -r1.7 -r1.8
--- src/libpspp/float-format.c  25 Nov 2007 19:11:40 -0000      1.7
+++ src/libpspp/float-format.c  3 Feb 2008 06:52:13 -0000       1.8
@@ -21,10 +21,10 @@
 #include <ctype.h>
 #include <inttypes.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include <libpspp/assertion.h>
 #include <libpspp/integer-format.h>
-#include <libpspp/str.h>
 
 #include "error.h"
 #include <byteswap.h>

Index: tests/dissect-sysfile.c
===================================================================
RCS file: tests/dissect-sysfile.c
diff -N tests/dissect-sysfile.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ tests/dissect-sysfile.c     3 Feb 2008 06:52:12 -0000       1.1
@@ -0,0 +1,834 @@
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2007 Free Software Foundation, Inc.
+
+   This program 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 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <data/val-type.h>
+#include <libpspp/compiler.h>
+#include <libpspp/float-format.h>
+#include <libpspp/integer-format.h>
+#include <libpspp/misc.h>
+
+#include "error.h"
+#include "minmax.h"
+#include "progname.h"
+#include "xalloc.h"
+
+#include "gettext.h"
+#define _(msgid) gettext (msgid)
+
+struct sfm_reader
+  {
+    const char *file_name;
+    FILE *file;
+
+    int n_variable_records, n_variables;
+
+    enum integer_format integer_format;
+    enum float_format float_format;
+  };
+
+static void read_header (struct sfm_reader *);
+static void read_variable_record (struct sfm_reader *);
+static void read_value_label_record (struct sfm_reader *);
+static void read_document_record (struct sfm_reader *);
+static void read_extension_record (struct sfm_reader *);
+static void read_machine_integer_info (struct sfm_reader *,
+                                       size_t size, size_t count);
+static void read_machine_float_info (struct sfm_reader *,
+                                     size_t size, size_t count);
+static void read_display_parameters (struct sfm_reader *,
+                                     size_t size, size_t count);
+static void read_long_var_name_map (struct sfm_reader *r,
+                                    size_t size, size_t count);
+static void read_long_string_map (struct sfm_reader *r,
+                                  size_t size, size_t count);
+
+static struct variable_to_value_map *open_variable_to_value_map (
+  struct sfm_reader *, size_t size);
+static void close_variable_to_value_map (struct variable_to_value_map *);
+static bool read_variable_to_value_map (struct variable_to_value_map *,
+                                        char **key, char **value);
+
+static void usage (int exit_code);
+static void sys_warn (struct sfm_reader *, const char *, ...)
+     PRINTF_FORMAT (2, 3);
+static void sys_error (struct sfm_reader *, const char *, ...)
+     PRINTF_FORMAT (2, 3)
+     NO_RETURN;
+
+static void read_bytes (struct sfm_reader *, void *, size_t);
+static int read_int (struct sfm_reader *);
+static double read_float (struct sfm_reader *);
+static void read_string (struct sfm_reader *, char *, size_t);
+static void skip_bytes (struct sfm_reader *, size_t);
+static void trim_spaces (char *);
+
+int
+main (int argc, char *argv[])
+{
+  struct sfm_reader r;
+  int rec_type;
+
+  set_program_name (argv[0]);
+  if (argc != 2)
+    usage (EXIT_FAILURE);
+
+  r.file_name = argv[1];
+  r.file = fopen (r.file_name, "rb");
+  if (r.file == NULL)
+    error (EXIT_FAILURE, errno, "error opening \"%s\"", r.file_name);
+  r.n_variable_records = 0;
+  r.n_variables = 0;
+
+  read_header (&r);
+  while ((rec_type = read_int (&r)) != 999)
+    {
+      switch (rec_type)
+        {
+        case 2:
+          read_variable_record (&r);
+          break;
+
+        case 3:
+          read_value_label_record (&r);
+          break;
+
+        case 4:
+          sys_error (&r, _("Misplaced type 4 record."));
+
+        case 6:
+          read_document_record (&r);
+          break;
+
+        case 7:
+          read_extension_record (&r);
+          break;
+
+        default:
+          sys_error (&r, _("Unrecognized record type %d."), rec_type);
+        }
+    }
+  printf ("%08lx: end-of-dictionary record (first byte of data at %08lx)\n",
+          ftell (r.file), ftell (r.file) + 4);
+
+  return 0;
+}
+
+static void
+read_header (struct sfm_reader *r)
+{
+  char rec_type[5];
+  char eye_catcher[61];
+  uint8_t raw_layout_code[4];
+  int32_t layout_code;
+  int32_t nominal_case_size;
+  int32_t compressed;
+  int32_t weight_index;
+  int32_t ncases;
+  uint8_t raw_bias[8];
+  double bias;
+  char creation_date[10];
+  char creation_time[9];
+  char file_label[65];
+
+  read_string (r, rec_type, sizeof rec_type);
+  read_string (r, eye_catcher, sizeof eye_catcher);
+
+  if (strcmp ("$FL2", rec_type) != 0)
+    sys_error (r, _("This is not an SPSS system file."));
+
+  /* Identify integer format. */
+  read_bytes (r, raw_layout_code, sizeof raw_layout_code);
+  if ((!integer_identify (2, raw_layout_code, sizeof raw_layout_code,
+                          &r->integer_format)
+       && !integer_identify (3, raw_layout_code, sizeof raw_layout_code,
+                             &r->integer_format))
+      || (r->integer_format != INTEGER_MSB_FIRST
+          && r->integer_format != INTEGER_LSB_FIRST))
+    sys_error (r, _("This is not an SPSS system file."));
+  layout_code = integer_get (r->integer_format,
+                             raw_layout_code, sizeof raw_layout_code);
+
+  nominal_case_size = read_int (r);
+  compressed = read_int (r) != 0;
+  weight_index = read_int (r);
+  ncases = read_int (r);
+
+  /* Identify floating-point format and obtain compression bias. */
+  read_bytes (r, raw_bias, sizeof raw_bias);
+  if (float_identify (100.0, raw_bias, sizeof raw_bias, &r->float_format) == 0)
+    {
+      sys_warn (r, _("Compression bias is not the usual "
+                     "value of 100, or system file uses unrecognized "
+                     "floating-point format."));
+      if (r->integer_format == INTEGER_MSB_FIRST)
+        r->float_format = FLOAT_IEEE_DOUBLE_BE;
+      else
+        r->float_format = FLOAT_IEEE_DOUBLE_LE;
+    }
+  bias = float_get_double (r->float_format, raw_bias);
+
+  read_string (r, creation_date, sizeof creation_date);
+  read_string (r, creation_time, sizeof creation_time);
+  read_string (r, file_label, sizeof file_label);
+  trim_spaces (file_label);
+  skip_bytes (r, 3);
+
+  printf ("File header record:\n");
+  printf ("\t%17s: %s\n", "Product name", eye_catcher);
+  printf ("\t%17s: %"PRId32"\n", "Layout code", layout_code);
+  printf ("\t%17s: %"PRId32"\n", "Compressed", compressed);
+  printf ("\t%17s: %"PRId32"\n", "Weight index", weight_index);
+  printf ("\t%17s: %"PRId32"\n", "Number of cases", ncases);
+  printf ("\t%17s: %g\n", "Compression bias", bias);
+  printf ("\t%17s: %s\n", "Creation date", creation_date);
+  printf ("\t%17s: %s\n", "Creation time", creation_time);
+  printf ("\t%17s: \"%s\"\n", "File label", file_label);
+}
+
+static const char *
+format_name (int format)
+{
+  switch ((format >> 16) & 0xff)
+    {
+    case 1: return "A";
+    case 2: return "AHEX";
+    case 3: return "COMMA";
+    case 4: return "DOLLAR";
+    case 5: return "F";
+    case 6: return "IB";
+    case 7: return "PIBHEX";
+    case 8: return "P";
+    case 9: return "PIB";
+    case 10: return "PK";
+    case 11: return "RB";
+    case 12: return "RBHEX";
+    case 15: return "Z";
+    case 16: return "N";
+    case 17: return "E";
+    case 20: return "DATE";
+    case 21: return "TIME";
+    case 22: return "DATETIME";
+    case 23: return "ADATE";
+    case 24: return "JDATE";
+    case 25: return "DTIME";
+    case 26: return "WKDAY";
+    case 27: return "MONTH";
+    case 28: return "MOYR";
+    case 29: return "QYR";
+    case 30: return "WKYR";
+    case 31: return "PCT";
+    case 32: return "DOT";
+    case 33: return "CCA";
+    case 34: return "CCB";
+    case 35: return "CCC";
+    case 36: return "CCD";
+    case 37: return "CCE";
+    case 38: return "EDATE";
+    case 39: return "SDATE";
+    default: return "invalid";
+    }
+}
+
+/* Reads a variable (type 2) record from R and adds the
+   corresponding variable to DICT.
+   Also skips past additional variable records for long string
+   variables. */
+static void
+read_variable_record (struct sfm_reader *r)
+{
+  int width;
+  int has_variable_label;
+  int missing_value_code;
+  int print_format;
+  int write_format;
+  char name[9];
+
+  printf ("%08lx: variable record #%d\n",
+          ftell (r->file), r->n_variable_records++);
+
+  width = read_int (r);
+  has_variable_label = read_int (r);
+  missing_value_code = read_int (r);
+  print_format = read_int (r);
+  write_format = read_int (r);
+  read_string (r, name, sizeof name);
+  name[strcspn (name, " ")] = '\0';
+
+  if (width >= 0)
+    r->n_variables++;
+
+  printf ("\tWidth: %d (%s)\n",
+          width,
+          width > 0 ? "string"
+          : width == 0 ? "numeric"
+          : "long string continuation record");
+  printf ("\tVariable label: %d\n", has_variable_label);
+  printf ("\tMissing values code: %d (%s)\n", missing_value_code,
+          (missing_value_code == 0 ? "no missing values"
+           : missing_value_code == 1 ? "one missing value"
+           : missing_value_code == 2 ? "two missing values"
+           : missing_value_code == 3 ? "three missing values"
+           : missing_value_code == -2 ? "one missing value range"
+           : missing_value_code == -3 ? "one missing value, one range"
+           : "bad value"));
+  printf ("\tPrint format: %06x (%s%d.%d)\n",
+          print_format, format_name (print_format),
+          (print_format >> 8) & 0xff, print_format & 0xff);
+  printf ("\tWrite format: %06x (%s%d.%d)\n",
+          write_format, format_name (write_format),
+          (write_format >> 8) & 0xff, write_format & 0xff);
+  printf ("\tName: %s\n", name);
+
+  /* Get variable label, if any. */
+  if (has_variable_label != 0 && has_variable_label != 1)
+    sys_error (r, _("Variable label indicator field is not 0 or 1."));
+  if (has_variable_label == 1)
+    {
+      long int offset = ftell (r->file);
+      size_t len;
+      char label[255 + 1];
+
+      len = read_int (r);
+      if (len >= sizeof label)
+        sys_error (r, _("Variable %s has label of invalid length %zu."),
+                   name, len);
+      read_string (r, label, len + 1);
+      printf("\t%08lx Variable label: \"%s\"\n", offset, label);
+
+      skip_bytes (r, ROUND_UP (len, 4) - len);
+    }
+
+  /* Set missing values. */
+  if (missing_value_code != 0)
+    {
+      int i;
+
+      printf ("\t%08lx Missing values:", ftell (r->file));
+      if (!width)
+        {
+          if (missing_value_code < -3 || missing_value_code > 3
+              || missing_value_code == -1)
+            sys_error (r, _("Numeric missing value indicator field is not "
+                            "-3, -2, 0, 1, 2, or 3."));
+          if (missing_value_code < 0)
+            {
+              double low = read_float (r);
+              double high = read_float (r);
+              printf (" %g...%g", low, high);
+              missing_value_code = -missing_value_code - 2;
+            }
+          for (i = 0; i < missing_value_code; i++)
+            printf (" %g", read_float (r));
+        }
+      else if (width > 0)
+        {
+          if (missing_value_code < 1 || missing_value_code > 3)
+            sys_error (r, _("String missing value indicator field is not "
+                            "0, 1, 2, or 3."));
+          for (i = 0; i < missing_value_code; i++)
+            {
+              char string[9];
+              read_string (r, string, sizeof string);
+              printf (" \"%s\"", string);
+            }
+        }
+      putchar ('\n');
+    }
+}
+
+/* Reads value labels from sysfile R and inserts them into the
+   associated dictionary. */
+static void
+read_value_label_record (struct sfm_reader *r)
+{
+  int label_cnt, var_cnt;
+  int i;
+
+  printf ("%08lx: value labels record\n", ftell (r->file));
+
+  /* Read number of labels. */
+  label_cnt = read_int (r);
+  for (i = 0; i < label_cnt; i++)
+    {
+      char raw_value[8];
+      double value;
+      int n_printable;
+      unsigned char label_len;
+      size_t padded_len;
+      char label[256];
+
+      read_bytes (r, raw_value, sizeof raw_value);
+      value = float_get_double (r->float_format, raw_value);
+      for (n_printable = 0; n_printable < sizeof raw_value; n_printable++)
+        if (!isprint (raw_value[n_printable]))
+          break;
+
+      /* Read label length. */
+      read_bytes (r, &label_len, sizeof label_len);
+      padded_len = ROUND_UP (label_len + 1, 8);
+
+      /* Read label, padding. */
+      read_bytes (r, label, padded_len - 1);
+      label[label_len] = 0;
+
+      printf ("\t%g/\"%.*s\": \"%s\"\n", value, n_printable, raw_value, label);
+    }
+
+  /* Now, read the type 4 record that has the list of variables
+     to which the value labels are to be applied. */
+
+  /* Read record type of type 4 record. */
+  if (read_int (r) != 4)
+    sys_error (r, _("Variable index record (type 4) does not immediately "
+                    "follow value label record (type 3) as it should."));
+
+  /* Read number of variables associated with value label from type 4
+     record. */
+  printf ("\t%08lx: apply to variables", ftell (r->file));
+  var_cnt = read_int (r);
+  for (i = 0; i < var_cnt; i++)
+    printf (" #%d", read_int (r));
+  putchar ('\n');
+}
+
+static void
+read_document_record (struct sfm_reader *r)
+{
+  int n_lines;
+  int i;
+
+  printf ("%08lx: document record\n", ftell (r->file));
+  n_lines = read_int (r);
+  printf ("\t%d lines of documents\n", n_lines);
+
+  for (i = 0; i < n_lines; i++)
+    {
+      char line[81];
+      printf ("\t%08lx: ", ftell (r->file));
+      read_string (r, line, sizeof line);
+      trim_spaces (line);
+      printf ("line %d: \"%s\"\n", i, line);
+    }
+}
+
+static void
+read_extension_record (struct sfm_reader *r)
+{
+  long int offset = ftell (r->file);
+  int subtype = read_int (r);
+  size_t size = read_int (r);
+  size_t count = read_int (r);
+  size_t bytes = size * count;
+
+  printf ("%08lx: Record 7, subtype %d, size=%zu, count=%zu\n",
+          offset, subtype, size, count);
+
+  switch (subtype)
+    {
+    case 3:
+      read_machine_integer_info (r, size, count);
+      return;
+
+    case 4:
+      read_machine_float_info (r, size, count);
+      return;
+
+    case 5:
+      /* Variable sets information.  We don't use these yet.
+         They only apply to GUIs; see VARSETS on the APPLY
+         DICTIONARY command in SPSS documentation. */
+      break;
+
+    case 6:
+      /* DATE variable information.  We don't use it yet, but we
+         should. */
+      break;
+
+    case 7:
+      /* Unknown purpose. */
+      break;
+
+    case 11:
+      read_display_parameters (r, size, count);
+      return;
+
+    case 13:
+      read_long_var_name_map (r, size, count);
+      return;
+
+    case 14:
+      read_long_string_map (r, size, count);
+      return;
+
+    case 16:
+      /* New in SPSS v14?  Unknown purpose.  */
+      break;
+
+    case 17:
+      /* Text field that defines variable attributes.  New in
+         SPSS 14. */
+      break;
+
+    default:
+      sys_warn (r, _("Unrecognized record type 7, subtype %d."), subtype);
+      break;
+    }
+
+  skip_bytes (r, bytes);
+}
+
+static void
+read_machine_integer_info (struct sfm_reader *r, size_t size, size_t count)
+{
+  long int offset = ftell (r->file);
+  int version_major = read_int (r);
+  int version_minor = read_int (r);
+  int version_revision = read_int (r);
+  int machine_code = read_int (r);
+  int float_representation = read_int (r);
+  int compression_code = read_int (r);
+  int integer_representation = read_int (r);
+  int character_code = read_int (r);
+
+  printf ("%08lx: machine integer info\n", offset);
+  if (size != 4 || count != 8)
+    sys_error (r, _("Bad size (%zu) or count (%zu) field on record type 7, "
+                    "subtype 3."),
+                size, count);
+
+  printf ("\tVersion: %d.%d.%d\n",
+          version_major, version_minor, version_revision);
+  printf ("\tMachine code: %d\n", machine_code);
+  printf ("\tFloating point representation: %d (%s)\n",
+          float_representation,
+          float_representation == 1 ? "IEEE 754"
+          : float_representation == 2 ? "IBM 370"
+          : float_representation == 3 ? "DEC VAX"
+          : "unknown");
+  printf ("\tCompression code: %d\n", compression_code);
+  printf ("\tEndianness: %d (%s)\n", integer_representation,
+          integer_representation == 1 ? "big"
+          : integer_representation == 2 ? "little" : "unknown");
+  printf ("\tCharacter code: %d\n", character_code);
+}
+
+/* Read record type 7, subtype 4. */
+static void
+read_machine_float_info (struct sfm_reader *r, size_t size, size_t count)
+{
+  long int offset = ftell (r->file);
+  double sysmis = read_float (r);
+  double highest = read_float (r);
+  double lowest = read_float (r);
+
+  printf ("%08lx: machine float info\n", offset);
+  if (size != 8 || count != 3)
+    sys_error (r, _("Bad size (%zu) or count (%zu) on extension 4."),
+               size, count);
+
+  printf ("\tsysmis: %g\n", sysmis);
+  if (sysmis != SYSMIS)
+    sys_warn (r, _("File specifies unexpected value %g as SYSMIS."), sysmis);
+  printf ("\thighest: %g\n", highest);
+  if (highest != HIGHEST)
+    sys_warn (r, _("File specifies unexpected value %g as HIGHEST."), highest);
+  printf ("\tlowest: %g\n", lowest);
+  if (lowest != LOWEST)
+    sys_warn (r, _("File specifies unexpected value %g as LOWEST."), lowest);
+}
+
+/* Read record type 7, subtype 11. */
+static void
+read_display_parameters (struct sfm_reader *r, size_t size, size_t count)
+{
+  size_t n_vars;
+  bool includes_width;
+  size_t i;
+
+  printf ("%08lx: variable display parameters\n", ftell (r->file));
+  if (size != 4)
+    {
+      sys_warn (r, _("Bad size %zu on extension 11."), size);
+      skip_bytes (r, size * count);
+      return;
+    }
+
+  n_vars = r->n_variables;
+  if (count == 3 * n_vars)
+    includes_width = true;
+  else if (count == 2 * n_vars)
+    includes_width = false;
+  else
+    {
+      sys_warn (r, _("Extension 11 has bad count %zu (for %zu variables)."),
+                count, n_vars);
+      skip_bytes (r, size * count);
+      return;
+    }
+
+  for (i = 0; i < n_vars; ++i)
+    {
+      int measure = read_int (r);
+      int width = includes_width ? read_int (r) : 0;
+      int align = read_int (r);
+
+      printf ("\tVar #%zu: measure=%d (%s)", i, measure,
+              (measure == 1 ? "nominal"
+               : measure == 2 ? "ordinal"
+               : measure == 3 ? "scale"
+               : "invalid"));
+      if (includes_width)
+        printf (", width=%d", width);
+      printf (", align=%d (%s)\n", align,
+              (align == 0 ? "left"
+               : align == 1 ? "right"
+               : align == 2 ? "centre"
+               : "invalid"));
+    }
+}
+
+/* Reads record type 7, subtype 13, which gives the long name
+   that corresponds to each short name.  */
+static void
+read_long_var_name_map (struct sfm_reader *r, size_t size, size_t count)
+{
+  struct variable_to_value_map *map;
+  char *var;
+  char *long_name;
+
+  printf ("%08lx: long variable names (short => long)\n", ftell (r->file));
+  map = open_variable_to_value_map (r, size * count);
+  while (read_variable_to_value_map (map, &var, &long_name))
+    printf ("\t%s => %s\n", var, long_name);
+  close_variable_to_value_map (map);
+}
+
+/* Reads record type 7, subtype 14, which gives the real length
+   of each very long string.  Rearranges DICT accordingly. */
+static void
+read_long_string_map (struct sfm_reader *r, size_t size, size_t count)
+{
+  struct variable_to_value_map *map;
+  char *var;
+  char *length_s;
+
+  printf ("%08lx: very long strings (variable => length)\n", ftell (r->file));
+  map = open_variable_to_value_map (r, size * count);
+  while (read_variable_to_value_map (map, &var, &length_s))
+    printf ("\t%s => %d\n", var, atoi (length_s));
+  close_variable_to_value_map (map);
+}
+
+/* Helpers for reading records that contain "variable=value"
+   pairs. */
+
+/* State. */
+struct variable_to_value_map
+  {
+    char *buffer;               /* Record contents. */
+    size_t size;                /* Size of buffer. */
+    size_t pos;                 /* Current position in buffer. */
+  };
+
+/* Reads SIZE bytes into a "variable=value" map for R,
+   and returns the map. */
+static struct variable_to_value_map *
+open_variable_to_value_map (struct sfm_reader *r, size_t size)
+{
+  struct variable_to_value_map *map = xmalloc (sizeof *map);
+  char *buffer = xmalloc (size + 1);
+  read_bytes (r, buffer, size);
+  map->buffer = buffer;
+  map->size = size;
+  map->pos = 0;
+  return map;
+}
+
+/* Closes MAP and frees its storage.
+   Not really needed, because the pool will free the map anyway,
+   but can be used to free it earlier. */
+static void
+close_variable_to_value_map (struct variable_to_value_map *map)
+{
+  free (map);
+  free (map->buffer);
+}
+
+static char *
+tokenize (struct variable_to_value_map *map, int delimiter)
+{
+  size_t start = map->pos;
+  while (map->pos < map->size
+         && map->buffer[map->pos] != delimiter
+         && map->buffer[map->pos] != '\0')
+    map->pos++;
+  if (map->pos == map->size)
+    return NULL;
+  map->buffer[map->pos++] = '\0';
+  return &map->buffer[start];
+}
+
+/* Reads the next variable=value pair from MAP.
+   Looks up the variable in DICT and stores it into *VAR.
+   Stores a null-terminated value into *VALUE. */
+static bool
+read_variable_to_value_map (struct variable_to_value_map *map,
+                            char **key, char **value)
+{
+  *key = tokenize (map, '=');
+  *value = tokenize (map, '\t');
+  if (!*key || !*value)
+    return false;
+
+  while (map->pos < map->size
+         && (map->buffer[map->pos] == '\t'
+             || map->buffer[map->pos] == '\0'))
+    map->pos++;
+  return true;
+}
+
+static void
+usage (int exit_code)
+{
+  printf ("usage: %s SYSFILE, where SYSFILE is the name of a system file\n",
+          program_name);
+  exit (exit_code);
+}
+
+/* Displays a corruption message. */
+static void
+sys_msg (struct sfm_reader *r, const char *format, va_list args)
+{
+  printf ("\"%s\" near offset 0x%lx: ",
+          r->file_name, (unsigned long) ftell (r->file));
+  vprintf (format, args);
+  putchar ('\n');
+}
+
+/* Displays a warning for the current file position. */
+static void
+sys_warn (struct sfm_reader *r, const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  sys_msg (r, format, args);
+  va_end (args);
+}
+
+/* Displays an error for the current file position,
+   marks it as in an error state,
+   and aborts reading it using longjmp. */
+static void
+sys_error (struct sfm_reader *r, const char *format, ...)
+{
+  va_list args;
+
+  va_start (args, format);
+  sys_msg (r, format, args);
+  va_end (args);
+
+  exit (EXIT_FAILURE);
+}
+
+/* Reads BYTE_CNT bytes into BUF.
+   Returns true if exactly BYTE_CNT bytes are successfully read.
+   Aborts if an I/O error or a partial read occurs.
+   If EOF_IS_OK, then an immediate end-of-file causes false to be
+   returned; otherwise, immediate end-of-file causes an abort
+   too. */
+static inline bool
+read_bytes_internal (struct sfm_reader *r, bool eof_is_ok,
+                     void *buf, size_t byte_cnt)
+{
+  size_t bytes_read = fread (buf, 1, byte_cnt, r->file);
+  if (bytes_read == byte_cnt)
+    return true;
+  else if (ferror (r->file))
+    sys_error (r, _("System error: %s."), strerror (errno));
+  else if (!eof_is_ok || bytes_read != 0)
+    sys_error (r, _("Unexpected end of file."));
+  else
+    return false;
+}
+
+/* Reads BYTE_CNT into BUF.
+   Aborts upon I/O error or if end-of-file is encountered. */
+static void
+read_bytes (struct sfm_reader *r, void *buf, size_t byte_cnt)
+{
+  read_bytes_internal (r, false, buf, byte_cnt);
+}
+
+/* Reads a 32-bit signed integer from R and returns its value in
+   host format. */
+static int
+read_int (struct sfm_reader *r)
+{
+  uint8_t integer[4];
+  read_bytes (r, integer, sizeof integer);
+  return integer_get (r->integer_format, integer, sizeof integer);
+}
+
+/* Reads a 64-bit floating-point number from R and returns its
+   value in host format. */
+static double
+read_float (struct sfm_reader *r)
+{
+  uint8_t number[8];
+  read_bytes (r, number, sizeof number);
+  return float_get_double (r->float_format, number);
+}
+
+/* Reads exactly SIZE - 1 bytes into BUFFER
+   and stores a null byte into BUFFER[SIZE - 1]. */
+static void
+read_string (struct sfm_reader *r, char *buffer, size_t size)
+{
+  assert (size > 0);
+  read_bytes (r, buffer, size - 1);
+  buffer[size - 1] = '\0';
+}
+
+/* Skips BYTES bytes forward in R. */
+static void
+skip_bytes (struct sfm_reader *r, size_t bytes)
+{
+  while (bytes > 0)
+    {
+      char buffer[1024];
+      size_t chunk = MIN (sizeof buffer, bytes);
+      read_bytes (r, buffer, chunk);
+      bytes -= chunk;
+    }
+}
+
+static void
+trim_spaces (char *s)
+{
+  char *end = strchr (s, '\0');
+  while (end > s && end[-1] == ' ')
+    end--;
+  *end = '\0';
+}