summaryrefslogtreecommitdiff
path: root/src/od.c
blob: 4ea27206758313ac8a59ec9589c42877e901abff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
/* od -- dump files in octal and other formats
   Copyright (C) 1992-2016 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/>.  */

/* Written by Jim Meyering.  */

#include <config.h>

#include <stdio.h>
#include <assert.h>
#include <getopt.h>
#include <sys/types.h>
#include "system.h"
#include "argmatch.h"
#include "die.h"
#include "error.h"
#include "ftoastr.h"
#include "quote.h"
#include "stat-size.h"
#include "xfreopen.h"
#include "xprintf.h"
#include "xstrtol.h"

/* The official name of this program (e.g., no 'g' prefix).  */
#define PROGRAM_NAME "od"

#define AUTHORS proper_name ("Jim Meyering")

/* The default number of input bytes per output line.  */
#define DEFAULT_BYTES_PER_BLOCK 16

#if HAVE_UNSIGNED_LONG_LONG_INT
typedef unsigned long long int unsigned_long_long_int;
#else
/* This is just a place-holder to avoid a few '#if' directives.
   In this case, the type isn't actually used.  */
typedef unsigned long int unsigned_long_long_int;
#endif

enum size_spec
  {
    NO_SIZE,
    CHAR,
    SHORT,
    INT,
    LONG,
    LONG_LONG,
    /* FIXME: add INTMAX support, too */
    FLOAT_SINGLE,
    FLOAT_DOUBLE,
    FLOAT_LONG_DOUBLE,
    N_SIZE_SPECS
  };

enum output_format
  {
    SIGNED_DECIMAL,
    UNSIGNED_DECIMAL,
    OCTAL,
    HEXADECIMAL,
    FLOATING_POINT,
    NAMED_CHARACTER,
    CHARACTER
  };

#define MAX_INTEGRAL_TYPE_SIZE sizeof (unsigned_long_long_int)

/* The maximum number of bytes needed for a format string, including
   the trailing nul.  Each format string expects a variable amount of
   padding (guaranteed to be at least 1 plus the field width), then an
   element that will be formatted in the field.  */
enum
  {
    FMT_BYTES_ALLOCATED =
           (sizeof "%*.99" - 1
            + MAX (sizeof "ld",
                   MAX (sizeof PRIdMAX,
                        MAX (sizeof PRIoMAX,
                             MAX (sizeof PRIuMAX,
                                  sizeof PRIxMAX)))))
  };

/* Ensure that our choice for FMT_BYTES_ALLOCATED is reasonable.  */
verify (MAX_INTEGRAL_TYPE_SIZE * CHAR_BIT / 3 <= 99);

/* Each output format specification (from '-t spec' or from
   old-style options) is represented by one of these structures.  */
struct tspec
  {
    enum output_format fmt;
    enum size_spec size; /* Type of input object.  */
    /* FIELDS is the number of fields per line, BLANK is the number of
       fields to leave blank.  WIDTH is width of one field, excluding
       leading space, and PAD is total pad to divide among FIELDS.
       PAD is at least as large as FIELDS.  */
    void (*print_function) (size_t fields, size_t blank, void const *data,
                            char const *fmt, int width, int pad);
    char fmt_string[FMT_BYTES_ALLOCATED]; /* Of the style "%*d".  */
    bool hexl_mode_trailer;
    int field_width; /* Minimum width of a field, excluding leading space.  */
    int pad_width; /* Total padding to be divided among fields.  */
  };

/* Convert the number of 8-bit bytes of a binary representation to
   the number of characters (digits + sign if the type is signed)
   required to represent the same quantity in the specified base/type.
   For example, a 32-bit (4-byte) quantity may require a field width
   as wide as the following for these types:
   11	unsigned octal
   11	signed decimal
   10	unsigned decimal
   8	unsigned hexadecimal  */

static unsigned int const bytes_to_oct_digits[] =
{0, 3, 6, 8, 11, 14, 16, 19, 22, 25, 27, 30, 32, 35, 38, 41, 43};

static unsigned int const bytes_to_signed_dec_digits[] =
{1, 4, 6, 8, 11, 13, 16, 18, 20, 23, 25, 28, 30, 33, 35, 37, 40};

static unsigned int const bytes_to_unsigned_dec_digits[] =
{0, 3, 5, 8, 10, 13, 15, 17, 20, 22, 25, 27, 29, 32, 34, 37, 39};

static unsigned int const bytes_to_hex_digits[] =
{0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32};

/* It'll be a while before we see integral types wider than 16 bytes,
   but if/when it happens, this check will catch it.  Without this check,
   a wider type would provoke a buffer overrun.  */
verify (MAX_INTEGRAL_TYPE_SIZE < ARRAY_CARDINALITY (bytes_to_hex_digits));

/* Make sure the other arrays have the same length.  */
verify (sizeof bytes_to_oct_digits == sizeof bytes_to_signed_dec_digits);
verify (sizeof bytes_to_oct_digits == sizeof bytes_to_unsigned_dec_digits);
verify (sizeof bytes_to_oct_digits == sizeof bytes_to_hex_digits);

/* Convert enum size_spec to the size of the named type.  */
static const int width_bytes[] =
{
  -1,
  sizeof (char),
  sizeof (short int),
  sizeof (int),
  sizeof (long int),
  sizeof (unsigned_long_long_int),
  sizeof (float),
  sizeof (double),
  sizeof (long double)
};

/* Ensure that for each member of 'enum size_spec' there is an
   initializer in the width_bytes array.  */
verify (ARRAY_CARDINALITY (width_bytes) == N_SIZE_SPECS);

/* Names for some non-printing characters.  */
static char const charname[33][4] =
{
  "nul", "soh", "stx", "etx", "eot", "enq", "ack", "bel",
  "bs", "ht", "nl", "vt", "ff", "cr", "so", "si",
  "dle", "dc1", "dc2", "dc3", "dc4", "nak", "syn", "etb",
  "can", "em", "sub", "esc", "fs", "gs", "rs", "us",
  "sp"
};

/* Address base (8, 10 or 16).  */
static int address_base;

/* The number of octal digits required to represent the largest
   address value.  */
#define MAX_ADDRESS_LENGTH \
  ((sizeof (uintmax_t) * CHAR_BIT + CHAR_BIT - 1) / 3)

/* Width of a normal address.  */
static int address_pad_len;

/* Minimum length when detecting --strings.  */
static size_t string_min;

/* True when in --strings mode.  */
static bool flag_dump_strings;

/* True if we should recognize the older non-option arguments
   that specified at most one file and optional arguments specifying
   offset and pseudo-start address.  */
static bool traditional;

/* True if an old-style 'pseudo-address' was specified.  */
static bool flag_pseudo_start;

/* The difference between the old-style pseudo starting address and
   the number of bytes to skip.  */
static uintmax_t pseudo_offset;

/* Function that accepts an address and an optional following char,
   and prints the address and char to stdout.  */
static void (*format_address) (uintmax_t, char);

/* The number of input bytes to skip before formatting and writing.  */
static uintmax_t n_bytes_to_skip = 0;

/* When false, MAX_BYTES_TO_FORMAT and END_OFFSET are ignored, and all
   input is formatted.  */
static bool limit_bytes_to_format = false;

/* The maximum number of bytes that will be formatted.  */
static uintmax_t max_bytes_to_format;

/* The offset of the first byte after the last byte to be formatted.  */
static uintmax_t end_offset;

/* When true and two or more consecutive blocks are equal, format
   only the first block and output an asterisk alone on the following
   line to indicate that identical blocks have been elided.  */
static bool abbreviate_duplicate_blocks = true;

/* An array of specs describing how to format each input block.  */
static struct tspec *spec;

/* The number of format specs.  */
static size_t n_specs;

/* The allocated length of SPEC.  */
static size_t n_specs_allocated;

/* The number of input bytes formatted per output line.  It must be
   a multiple of the least common multiple of the sizes associated with
   the specified output types.  It should be as large as possible, but
   no larger than 16 -- unless specified with the -w option.  */
static size_t bytes_per_block;

/* Human-readable representation of *file_list (for error messages).
   It differs from file_list[-1] only when file_list[-1] is "-".  */
static char const *input_filename;

/* A NULL-terminated list of the file-arguments from the command line.  */
static char const *const *file_list;

/* Initializer for file_list if no file-arguments
   were specified on the command line.  */
static char const *const default_file_list[] = {"-", NULL};

/* The input stream associated with the current file.  */
static FILE *in_stream;

/* If true, at least one of the files we read was standard input.  */
static bool have_read_stdin;

/* Map the size in bytes to a type identifier.  */
static enum size_spec integral_type_size[MAX_INTEGRAL_TYPE_SIZE + 1];

#define MAX_FP_TYPE_SIZE sizeof (long double)
static enum size_spec fp_type_size[MAX_FP_TYPE_SIZE + 1];

#ifndef WORDS_BIGENDIAN
# define WORDS_BIGENDIAN 0
#endif

/* Use native endianess by default.  */
static bool input_swap;

static char const short_options[] = "A:aBbcDdeFfHhIij:LlN:OoS:st:vw::Xx";

/* For long options that have no equivalent short option, use a
   non-character as a pseudo short option, starting with CHAR_MAX + 1.  */
enum
{
  TRADITIONAL_OPTION = CHAR_MAX + 1,
  ENDIAN_OPTION,
};

enum endian_type
{
  endian_little,
  endian_big
};

static char const *const endian_args[] =
{
  "little", "big", NULL
};

static enum endian_type const endian_types[] =
{
  endian_little, endian_big
};

static struct option const long_options[] =
{
  {"skip-bytes", required_argument, NULL, 'j'},
  {"address-radix", required_argument, NULL, 'A'},
  {"read-bytes", required_argument, NULL, 'N'},
  {"format", required_argument, NULL, 't'},
  {"output-duplicates", no_argument, NULL, 'v'},
  {"strings", optional_argument, NULL, 'S'},
  {"traditional", no_argument, NULL, TRADITIONAL_OPTION},
  {"width", optional_argument, NULL, 'w'},
  {"endian", required_argument, NULL, ENDIAN_OPTION },

  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {NULL, 0, NULL, 0}
};

void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    emit_try_help ();
  else
    {
      printf (_("\
Usage: %s [OPTION]... [FILE]...\n\
  or:  %s [-abcdfilosx]... [FILE] [[+]OFFSET[.][b]]\n\
  or:  %s --traditional [OPTION]... [FILE] [[+]OFFSET[.][b] [+][LABEL][.][b]]\n\
"),
              program_name, program_name, program_name);
      fputs (_("\n\
Write an unambiguous representation, octal bytes by default,\n\
of FILE to standard output.  With more than one FILE argument,\n\
concatenate them in the listed order to form the input.\n\
"), stdout);

      emit_stdin_note ();

      fputs (_("\
\n\
If first and second call formats both apply, the second format is assumed\n\
if the last operand begins with + or (if there are 2 operands) a digit.\n\
An OFFSET operand means -j OFFSET.  LABEL is the pseudo-address\n\
at first byte printed, incremented when dump is progressing.\n\
For OFFSET and LABEL, a 0x or 0X prefix indicates hexadecimal;\n\
suffixes may be . for octal and b for multiply by 512.\n\
"), stdout);

      emit_mandatory_arg_note ();

      fputs (_("\
  -A, --address-radix=RADIX   output format for file offsets; RADIX is one\n\
                                of [doxn], for Decimal, Octal, Hex or None\n\
      --endian={big|little}   swap input bytes according the specified order\n\
  -j, --skip-bytes=BYTES      skip BYTES input bytes first\n\
"), stdout);
      fputs (_("\
  -N, --read-bytes=BYTES      limit dump to BYTES input bytes\n\
  -S BYTES, --strings[=BYTES]  output strings of at least BYTES graphic chars;\
\n\
                                3 is implied when BYTES is not specified\n\
  -t, --format=TYPE           select output format or formats\n\
  -v, --output-duplicates     do not use * to mark line suppression\n\
  -w[BYTES], --width[=BYTES]  output BYTES bytes per output line;\n\
                                32 is implied when BYTES is not specified\n\
      --traditional           accept arguments in third form above\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      fputs (_("\
\n\
\n\
Traditional format specifications may be intermixed; they accumulate:\n\
  -a   same as -t a,  select named characters, ignoring high-order bit\n\
  -b   same as -t o1, select octal bytes\n\
  -c   same as -t c,  select printable characters or backslash escapes\n\
  -d   same as -t u2, select unsigned decimal 2-byte units\n\
"), stdout);
      fputs (_("\
  -f   same as -t fF, select floats\n\
  -i   same as -t dI, select decimal ints\n\
  -l   same as -t dL, select decimal longs\n\
  -o   same as -t o2, select octal 2-byte units\n\
  -s   same as -t d2, select decimal 2-byte units\n\
  -x   same as -t x2, select hexadecimal 2-byte units\n\
"), stdout);
      fputs (_("\
\n\
\n\
TYPE is made up of one or more of these specifications:\n\
  a          named character, ignoring high-order bit\n\
  c          printable character or backslash escape\n\
"), stdout);
      fputs (_("\
  d[SIZE]    signed decimal, SIZE bytes per integer\n\
  f[SIZE]    floating point, SIZE bytes per integer\n\
  o[SIZE]    octal, SIZE bytes per integer\n\
  u[SIZE]    unsigned decimal, SIZE bytes per integer\n\
  x[SIZE]    hexadecimal, SIZE bytes per integer\n\
"), stdout);
      fputs (_("\
\n\
SIZE is a number.  For TYPE in [doux], SIZE may also be C for\n\
sizeof(char), S for sizeof(short), I for sizeof(int) or L for\n\
sizeof(long).  If TYPE is f, SIZE may also be F for sizeof(float), D\n\
for sizeof(double) or L for sizeof(long double).\n\
"), stdout);
      fputs (_("\
\n\
Adding a z suffix to any type displays printable characters at the end of\n\
each output line.\n\
"), stdout);
      fputs (_("\
\n\
\n\
BYTES is hex with 0x or 0X prefix, and may have a multiplier suffix:\n\
  b    512\n\
  KB   1000\n\
  K    1024\n\
  MB   1000*1000\n\
  M    1024*1024\n\
and so on for G, T, P, E, Z, Y.\n\
"), stdout);
      emit_ancillary_info (PROGRAM_NAME);
    }
  exit (status);
}

/* Define the print functions.  */

#define PRINT_FIELDS(N, T, FMT_STRING, ACTION)                          \
static void                                                             \
N (size_t fields, size_t blank, void const *block,                      \
   char const *FMT_STRING, int width, int pad)                          \
{                                                                       \
  T const *p = block;                                                   \
  uintmax_t i;                                                          \
  int pad_remaining = pad;                                              \
  for (i = fields; blank < i; i--)                                      \
    {                                                                   \
      int next_pad = pad * (i - 1) / fields;                            \
      int adjusted_width = pad_remaining - next_pad + width;            \
      T x;                                                              \
      if (input_swap && sizeof (T) > 1)                                 \
        {                                                               \
          size_t j;                                                     \
          union {                                                       \
            T x;                                                        \
            char b[sizeof (T)];                                         \
          } u;                                                          \
          for (j = 0; j < sizeof (T); j++)                              \
            u.b[j] = ((const char *) p)[sizeof (T) - 1 - j];            \
          x = u.x;                                                      \
        }                                                               \
      else                                                              \
        x = *p;                                                         \
      p++;                                                              \
      ACTION;                                                           \
      pad_remaining = next_pad;                                         \
    }                                                                   \
}

#define PRINT_TYPE(N, T)                                                \
  PRINT_FIELDS (N, T, fmt_string, xprintf (fmt_string, adjusted_width, x))

#define PRINT_FLOATTYPE(N, T, FTOASTR, BUFSIZE)                         \
  PRINT_FIELDS (N, T, fmt_string _GL_UNUSED,                      \
                char buf[BUFSIZE];                                      \
                FTOASTR (buf, sizeof buf, 0, 0, x);                     \
                xprintf ("%*s", adjusted_width, buf))

PRINT_TYPE (print_s_char, signed char)
PRINT_TYPE (print_char, unsigned char)
PRINT_TYPE (print_s_short, short int)
PRINT_TYPE (print_short, unsigned short int)
PRINT_TYPE (print_int, unsigned int)
PRINT_TYPE (print_long, unsigned long int)
PRINT_TYPE (print_long_long, unsigned_long_long_int)

PRINT_FLOATTYPE (print_float, float, ftoastr, FLT_BUFSIZE_BOUND)
PRINT_FLOATTYPE (print_double, double, dtoastr, DBL_BUFSIZE_BOUND)
PRINT_FLOATTYPE (print_long_double, long double, ldtoastr, LDBL_BUFSIZE_BOUND)

#undef PRINT_TYPE
#undef PRINT_FLOATTYPE

static void
dump_hexl_mode_trailer (size_t n_bytes, const char *block)
{
  size_t i;
  fputs ("  >", stdout);
  for (i = n_bytes; i > 0; i--)
    {
      unsigned char c = *block++;
      unsigned char c2 = (isprint (c) ? c : '.');
      putchar (c2);
    }
  putchar ('<');
}

static void
print_named_ascii (size_t fields, size_t blank, void const *block,
                   const char *unused_fmt_string _GL_UNUSED,
                   int width, int pad)
{
  unsigned char const *p = block;
  uintmax_t i;
  int pad_remaining = pad;
  for (i = fields; blank < i; i--)
    {
      int next_pad = pad * (i - 1) / fields;
      int masked_c = *p++ & 0x7f;
      const char *s;
      char buf[2];

      if (masked_c == 127)
        s = "del";
      else if (masked_c <= 040)
        s = charname[masked_c];
      else
        {
          buf[0] = masked_c;
          buf[1] = 0;
          s = buf;
        }

      xprintf ("%*s", pad_remaining - next_pad + width, s);
      pad_remaining = next_pad;
    }
}

static void
print_ascii (size_t fields, size_t blank, void const *block,
             const char *unused_fmt_string _GL_UNUSED, int width,
             int pad)
{
  unsigned char const *p = block;
  uintmax_t i;
  int pad_remaining = pad;
  for (i = fields; blank < i; i--)
    {
      int next_pad = pad * (i - 1) / fields;
      unsigned char c = *p++;
      const char *s;
      char buf[4];

      switch (c)
        {
        case '\0':
          s = "\\0";
          break;

        case '\a':
          s = "\\a";
          break;

        case '\b':
          s = "\\b";
          break;

        case '\f':
          s = "\\f";
          break;

        case '\n':
          s = "\\n";
          break;

        case '\r':
          s = "\\r";
          break;

        case '\t':
          s = "\\t";
          break;

        case '\v':
          s = "\\v";
          break;

        default:
          sprintf (buf, (isprint (c) ? "%c" : "%03o"), c);
          s = buf;
        }

      xprintf ("%*s", pad_remaining - next_pad + width, s);
      pad_remaining = next_pad;
    }
}

/* Convert a null-terminated (possibly zero-length) string S to an
   unsigned long integer value.  If S points to a non-digit set *P to S,
   *VAL to 0, and return true.  Otherwise, accumulate the integer value of
   the string of digits.  If the string of digits represents a value
   larger than ULONG_MAX, don't modify *VAL or *P and return false.
   Otherwise, advance *P to the first non-digit after S, set *VAL to
   the result of the conversion and return true.  */

static bool
simple_strtoul (const char *s, const char **p, unsigned long int *val)
{
  unsigned long int sum;

  sum = 0;
  while (ISDIGIT (*s))
    {
      int c = *s++ - '0';
      if (sum > (ULONG_MAX - c) / 10)
        return false;
      sum = sum * 10 + c;
    }
  *p = s;
  *val = sum;
  return true;
}

/* If S points to a single valid modern od format string, put
   a description of that format in *TSPEC, make *NEXT point at the
   character following the just-decoded format (if *NEXT is non-NULL),
   and return true.  If S is not valid, don't modify *NEXT or *TSPEC,
   give a diagnostic, and return false.  For example, if S were
   "d4afL" *NEXT would be set to "afL" and *TSPEC would be
     {
       fmt = SIGNED_DECIMAL;
       size = INT or LONG; (whichever integral_type_size[4] resolves to)
       print_function = print_int; (assuming size == INT)
       field_width = 11;
       fmt_string = "%*d";
      }
   pad_width is determined later, but is at least as large as the
   number of fields printed per row.
   S_ORIG is solely for reporting errors.  It should be the full format
   string argument.
   */

static bool
decode_one_format (const char *s_orig, const char *s, const char **next,
                   struct tspec *tspec)
{
  enum size_spec size_spec;
  unsigned long int size;
  enum output_format fmt;
  void (*print_function) (size_t, size_t, void const *, char const *,
                          int, int);
  const char *p;
  char c;
  int field_width;

  assert (tspec != NULL);

  switch (*s)
    {
    case 'd':
    case 'o':
    case 'u':
    case 'x':
      c = *s;
      ++s;
      switch (*s)
        {
        case 'C':
          ++s;
          size = sizeof (char);
          break;

        case 'S':
          ++s;
          size = sizeof (short int);
          break;

        case 'I':
          ++s;
          size = sizeof (int);
          break;

        case 'L':
          ++s;
          size = sizeof (long int);
          break;

        default:
          if (! simple_strtoul (s, &p, &size))
            {
              /* The integer at P in S would overflow an unsigned long int.
                 A digit string that long is sufficiently odd looking
                 that the following diagnostic is sufficient.  */
              error (0, 0, _("invalid type string %s"), quote (s_orig));
              return false;
            }
          if (p == s)
            size = sizeof (int);
          else
            {
              if (MAX_INTEGRAL_TYPE_SIZE < size
                  || integral_type_size[size] == NO_SIZE)
                {
                  error (0, 0, _("invalid type string %s;\nthis system"
                                 " doesn't provide a %lu-byte integral type"),
                         quote (s_orig), size);
                  return false;
                }
              s = p;
            }
          break;
        }

#define ISPEC_TO_FORMAT(Spec, Min_format, Long_format, Max_format)	\
  ((Spec) == LONG_LONG ? (Max_format)					\
   : ((Spec) == LONG ? (Long_format)					\
      : (Min_format)))							\

      size_spec = integral_type_size[size];

      switch (c)
        {
        case 'd':
          fmt = SIGNED_DECIMAL;
          field_width = bytes_to_signed_dec_digits[size];
          sprintf (tspec->fmt_string, "%%*%s",
                   ISPEC_TO_FORMAT (size_spec, "d", "ld", PRIdMAX));
          break;

        case 'o':
          fmt = OCTAL;
          sprintf (tspec->fmt_string, "%%*.%d%s",
                   (field_width = bytes_to_oct_digits[size]),
                   ISPEC_TO_FORMAT (size_spec, "o", "lo", PRIoMAX));
          break;

        case 'u':
          fmt = UNSIGNED_DECIMAL;
          field_width = bytes_to_unsigned_dec_digits[size];
          sprintf (tspec->fmt_string, "%%*%s",
                   ISPEC_TO_FORMAT (size_spec, "u", "lu", PRIuMAX));
          break;

        case 'x':
          fmt = HEXADECIMAL;
          sprintf (tspec->fmt_string, "%%*.%d%s",
                   (field_width = bytes_to_hex_digits[size]),
                   ISPEC_TO_FORMAT (size_spec, "x", "lx", PRIxMAX));
          break;

        default:
          abort ();
        }

      assert (strlen (tspec->fmt_string) < FMT_BYTES_ALLOCATED);

      switch (size_spec)
        {
        case CHAR:
          print_function = (fmt == SIGNED_DECIMAL
                            ? print_s_char
                            : print_char);
          break;

        case SHORT:
          print_function = (fmt == SIGNED_DECIMAL
                            ? print_s_short
                            : print_short);
          break;

        case INT:
          print_function = print_int;
          break;

        case LONG:
          print_function = print_long;
          break;

        case LONG_LONG:
          print_function = print_long_long;
          break;

        default:
          abort ();
        }
      break;

    case 'f':
      fmt = FLOATING_POINT;
      ++s;
      switch (*s)
        {
        case 'F':
          ++s;
          size = sizeof (float);
          break;

        case 'D':
          ++s;
          size = sizeof (double);
          break;

        case 'L':
          ++s;
          size = sizeof (long double);
          break;

        default:
          if (! simple_strtoul (s, &p, &size))
            {
              /* The integer at P in S would overflow an unsigned long int.
                 A digit string that long is sufficiently odd looking
                 that the following diagnostic is sufficient.  */
              error (0, 0, _("invalid type string %s"), quote (s_orig));
              return false;
            }
          if (p == s)
            size = sizeof (double);
          else
            {
              if (size > MAX_FP_TYPE_SIZE
                  || fp_type_size[size] == NO_SIZE)
                {
                  error (0, 0,
                         _("invalid type string %s;\n"
                           "this system doesn't provide a %lu-byte"
                           " floating point type"),
                         quote (s_orig), size);
                  return false;
                }
              s = p;
            }
          break;
        }
      size_spec = fp_type_size[size];

      {
        struct lconv const *locale = localeconv ();
        size_t decimal_point_len =
          (locale->decimal_point[0] ? strlen (locale->decimal_point) : 1);

        switch (size_spec)
          {
          case FLOAT_SINGLE:
            print_function = print_float;
            field_width = FLT_STRLEN_BOUND_L (decimal_point_len);
            break;

          case FLOAT_DOUBLE:
            print_function = print_double;
            field_width = DBL_STRLEN_BOUND_L (decimal_point_len);
            break;

          case FLOAT_LONG_DOUBLE:
            print_function = print_long_double;
            field_width = LDBL_STRLEN_BOUND_L (decimal_point_len);
            break;

          default:
            abort ();
          }

        break;
      }

    case 'a':
      ++s;
      fmt = NAMED_CHARACTER;
      size_spec = CHAR;
      print_function = print_named_ascii;
      field_width = 3;
      break;

    case 'c':
      ++s;
      fmt = CHARACTER;
      size_spec = CHAR;
      print_function = print_ascii;
      field_width = 3;
      break;

    default:
      error (0, 0, _("invalid character '%c' in type string %s"),
             *s, quote (s_orig));
      return false;
    }

  tspec->size = size_spec;
  tspec->fmt = fmt;
  tspec->print_function = print_function;

  tspec->field_width = field_width;
  tspec->hexl_mode_trailer = (*s == 'z');
  if (tspec->hexl_mode_trailer)
    s++;

  if (next != NULL)
    *next = s;

  return true;
}

/* Given a list of one or more input filenames FILE_LIST, set the global
   file pointer IN_STREAM and the global string INPUT_FILENAME to the
   first one that can be successfully opened. Modify FILE_LIST to
   reference the next filename in the list.  A file name of "-" is
   interpreted as standard input.  If any file open fails, give an error
   message and return false.  */

static bool
open_next_file (void)
{
  bool ok = true;

  do
    {
      input_filename = *file_list;
      if (input_filename == NULL)
        return ok;
      ++file_list;

      if (STREQ (input_filename, "-"))
        {
          input_filename = _("standard input");
          in_stream = stdin;
          have_read_stdin = true;
          if (O_BINARY && ! isatty (STDIN_FILENO))
            xfreopen (NULL, "rb", stdin);
        }
      else
        {
          in_stream = fopen (input_filename, (O_BINARY ? "rb" : "r"));
          if (in_stream == NULL)
            {
              error (0, errno, "%s", quotef (input_filename));
              ok = false;
            }
        }
    }
  while (in_stream == NULL);

  if (limit_bytes_to_format && !flag_dump_strings)
    setvbuf (in_stream, NULL, _IONBF, 0);

  return ok;
}

/* Test whether there have been errors on in_stream, and close it if
   it is not standard input.  Return false if there has been an error
   on in_stream or stdout; return true otherwise.  This function will
   report more than one error only if both a read and a write error
   have occurred.  IN_ERRNO, if nonzero, is the error number
   corresponding to the most recent action for IN_STREAM.  */

static bool
check_and_close (int in_errno)
{
  bool ok = true;

  if (in_stream != NULL)
    {
      if (ferror (in_stream))
        {
          error (0, in_errno, _("%s: read error"), quotef (input_filename));
          if (! STREQ (file_list[-1], "-"))
            fclose (in_stream);
          ok = false;
        }
      else if (! STREQ (file_list[-1], "-") && fclose (in_stream) != 0)
        {
          error (0, errno, "%s", quotef (input_filename));
          ok = false;
        }

      in_stream = NULL;
    }

  if (ferror (stdout))
    {
      error (0, 0, _("write error"));
      ok = false;
    }

  return ok;
}

/* Decode the modern od format string S.  Append the decoded
   representation to the global array SPEC, reallocating SPEC if
   necessary.  Return true if S is valid.  */

static bool
decode_format_string (const char *s)
{
  const char *s_orig = s;
  assert (s != NULL);

  while (*s != '\0')
    {
      const char *next;

      if (n_specs_allocated <= n_specs)
        spec = X2NREALLOC (spec, &n_specs_allocated);

      if (! decode_one_format (s_orig, s, &next, &spec[n_specs]))
        return false;

      assert (s != next);
      s = next;
      ++n_specs;
    }

  return true;
}

/* Given a list of one or more input filenames FILE_LIST, set the global
   file pointer IN_STREAM to position N_SKIP in the concatenation of
   those files.  If any file operation fails or if there are fewer than
   N_SKIP bytes in the combined input, give an error message and return
   false.  When possible, use seek rather than read operations to
   advance IN_STREAM.  */

static bool
skip (uintmax_t n_skip)
{
  bool ok = true;
  int in_errno = 0;

  if (n_skip == 0)
    return true;

  while (in_stream != NULL)	/* EOF.  */
    {
      struct stat file_stats;

      /* First try seeking.  For large offsets, this extra work is
         worthwhile.  If the offset is below some threshold it may be
         more efficient to move the pointer by reading.  There are two
         issues when trying to seek:
           - the file must be seekable.
           - before seeking to the specified position, make sure
             that the new position is in the current file.
             Try to do that by getting file's size using fstat.
             But that will work only for regular files.  */

      if (fstat (fileno (in_stream), &file_stats) == 0)
        {
          /* The st_size field is valid for regular files.
             If the number of bytes left to skip is larger than
             the size of the current file, we can decrement n_skip
             and go on to the next file.  Skip this optimization also
             when st_size is no greater than the block size, because
             some kernels report nonsense small file sizes for
             proc-like file systems.  */
          if (usable_st_size (&file_stats)
              && ST_BLKSIZE (file_stats) < file_stats.st_size)
            {
              if ((uintmax_t) file_stats.st_size < n_skip)
                n_skip -= file_stats.st_size;
              else
                {
                  if (fseeko (in_stream, n_skip, SEEK_CUR) != 0)
                    {
                      in_errno = errno;
                      ok = false;
                    }
                  n_skip = 0;
                }
            }

          /* If it's not a regular file with nonnegative size,
             or if it's so small that it might be in a proc-like file system,
             position the file pointer by reading.  */

          else
            {
              char buf[BUFSIZ];
              size_t n_bytes_read, n_bytes_to_read = BUFSIZ;

              while (0 < n_skip)
                {
                  if (n_skip < n_bytes_to_read)
                    n_bytes_to_read = n_skip;
                  n_bytes_read = fread (buf, 1, n_bytes_to_read, in_stream);
                  n_skip -= n_bytes_read;
                  if (n_bytes_read != n_bytes_to_read)
                    {
                      if (ferror (in_stream))
                        {
                          in_errno = errno;
                          ok = false;
                          n_skip = 0;
                          break;
                        }
                      if (feof (in_stream))
                        break;
                    }
                }
            }

          if (n_skip == 0)
            break;
        }

      else   /* cannot fstat() file */
        {
          error (0, errno, "%s", quotef (input_filename));
          ok = false;
        }

      ok &= check_and_close (in_errno);

      ok &= open_next_file ();
    }

  if (n_skip != 0)
    die (EXIT_FAILURE, 0, _("cannot skip past end of combined input"));

  return ok;
}

static void
format_address_none (uintmax_t address _GL_UNUSED,
                     char c _GL_UNUSED)
{
}

static void
format_address_std (uintmax_t address, char c)
{
  char buf[MAX_ADDRESS_LENGTH + 2];
  char *p = buf + sizeof buf;
  char const *pbound;

  *--p = '\0';
  *--p = c;
  pbound = p - address_pad_len;

  /* Use a special case of the code for each base.  This is measurably
     faster than generic code.  */
  switch (address_base)
    {
    case 8:
      do
        *--p = '0' + (address & 7);
      while ((address >>= 3) != 0);
      break;

    case 10:
      do
        *--p = '0' + (address % 10);
      while ((address /= 10) != 0);
      break;

    case 16:
      do
        *--p = "0123456789abcdef"[address & 15];
      while ((address >>= 4) != 0);
      break;
    }

  while (pbound < p)
    *--p = '0';

  fputs (p, stdout);
}

static void
format_address_paren (uintmax_t address, char c)
{
  putchar ('(');
  format_address_std (address, ')');
  if (c)
    putchar (c);
}

static void
format_address_label (uintmax_t address, char c)
{
  format_address_std (address, ' ');
  format_address_paren (address + pseudo_offset, c);
}

/* Write N_BYTES bytes from CURR_BLOCK to standard output once for each
   of the N_SPEC format specs.  CURRENT_OFFSET is the byte address of
   CURR_BLOCK in the concatenation of input files, and it is printed
   (optionally) only before the output line associated with the first
   format spec.  When duplicate blocks are being abbreviated, the output
   for a sequence of identical input blocks is the output for the first
   block followed by an asterisk alone on a line.  It is valid to compare
   the blocks PREV_BLOCK and CURR_BLOCK only when N_BYTES == BYTES_PER_BLOCK.
   That condition may be false only for the last input block.  */

static void
write_block (uintmax_t current_offset, size_t n_bytes,
             const char *prev_block, const char *curr_block)
{
  static bool first = true;
  static bool prev_pair_equal = false;

#define EQUAL_BLOCKS(b1, b2) (memcmp (b1, b2, bytes_per_block) == 0)

  if (abbreviate_duplicate_blocks
      && !first && n_bytes == bytes_per_block
      && EQUAL_BLOCKS (prev_block, curr_block))
    {
      if (prev_pair_equal)
        {
          /* The two preceding blocks were equal, and the current
             block is the same as the last one, so print nothing.  */
        }
      else
        {
          printf ("*\n");
          prev_pair_equal = true;
        }
    }
  else
    {
      size_t i;

      prev_pair_equal = false;
      for (i = 0; i < n_specs; i++)
        {
          int datum_width = width_bytes[spec[i].size];
          int fields_per_block = bytes_per_block / datum_width;
          int blank_fields = (bytes_per_block - n_bytes) / datum_width;
          if (i == 0)
            format_address (current_offset, '\0');
          else
            printf ("%*s", address_pad_len, "");
          (*spec[i].print_function) (fields_per_block, blank_fields,
                                     curr_block, spec[i].fmt_string,
                                     spec[i].field_width, spec[i].pad_width);
          if (spec[i].hexl_mode_trailer)
            {
              /* space-pad out to full line width, then dump the trailer */
              int field_width = spec[i].field_width;
              int pad_width = (spec[i].pad_width * blank_fields
                               / fields_per_block);
              printf ("%*s", blank_fields * field_width + pad_width, "");
              dump_hexl_mode_trailer (n_bytes, curr_block);
            }
          putchar ('\n');
        }
    }
  first = false;
}

/* Read a single byte into *C from the concatenation of the input files
   named in the global array FILE_LIST.  On the first call to this
   function, the global variable IN_STREAM is expected to be an open
   stream associated with the input file INPUT_FILENAME.  If IN_STREAM
   is at end-of-file, close it and update the global variables IN_STREAM
   and INPUT_FILENAME so they correspond to the next file in the list.
   Then try to read a byte from the newly opened file.  Repeat if
   necessary until EOF is reached for the last file in FILE_LIST, then
   set *C to EOF and return.  Subsequent calls do likewise.  Return
   true if successful.  */

static bool
read_char (int *c)
{
  bool ok = true;

  *c = EOF;

  while (in_stream != NULL)	/* EOF.  */
    {
      *c = fgetc (in_stream);

      if (*c != EOF)
        break;

      ok &= check_and_close (errno);

      ok &= open_next_file ();
    }

  return ok;
}

/* Read N bytes into BLOCK from the concatenation of the input files
   named in the global array FILE_LIST.  On the first call to this
   function, the global variable IN_STREAM is expected to be an open
   stream associated with the input file INPUT_FILENAME.  If all N
   bytes cannot be read from IN_STREAM, close IN_STREAM and update
   the global variables IN_STREAM and INPUT_FILENAME.  Then try to
   read the remaining bytes from the newly opened file.  Repeat if
   necessary until EOF is reached for the last file in FILE_LIST.
   On subsequent calls, don't modify BLOCK and return true.  Set
   *N_BYTES_IN_BUFFER to the number of bytes read.  If an error occurs,
   it will be detected through ferror when the stream is about to be
   closed.  If there is an error, give a message but continue reading
   as usual and return false.  Otherwise return true.  */

static bool
read_block (size_t n, char *block, size_t *n_bytes_in_buffer)
{
  bool ok = true;

  assert (0 < n && n <= bytes_per_block);

  *n_bytes_in_buffer = 0;

  while (in_stream != NULL)	/* EOF.  */
    {
      size_t n_needed;
      size_t n_read;

      n_needed = n - *n_bytes_in_buffer;
      n_read = fread (block + *n_bytes_in_buffer, 1, n_needed, in_stream);

      *n_bytes_in_buffer += n_read;

      if (n_read == n_needed)
        break;

      ok &= check_and_close (errno);

      ok &= open_next_file ();
    }

  return ok;
}

/* Return the least common multiple of the sizes associated
   with the format specs.  */

static int _GL_ATTRIBUTE_PURE
get_lcm (void)
{
  size_t i;
  int l_c_m = 1;

  for (i = 0; i < n_specs; i++)
    l_c_m = lcm (l_c_m, width_bytes[spec[i].size]);
  return l_c_m;
}

/* If S is a valid traditional offset specification with an optional
   leading '+' return true and set *OFFSET to the offset it denotes.  */

static bool
parse_old_offset (const char *s, uintmax_t *offset)
{
  int radix;

  if (*s == '\0')
    return false;

  /* Skip over any leading '+'. */
  if (s[0] == '+')
    ++s;

  /* Determine the radix we'll use to interpret S.  If there is a '.',
     it's decimal, otherwise, if the string begins with '0X'or '0x',
     it's hexadecimal, else octal.  */
  if (strchr (s, '.') != NULL)
    radix = 10;
  else
    {
      if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
        radix = 16;
      else
        radix = 8;
    }

  return xstrtoumax (s, NULL, radix, offset, "Bb") == LONGINT_OK;
}

/* Read a chunk of size BYTES_PER_BLOCK from the input files, write the
   formatted block to standard output, and repeat until the specified
   maximum number of bytes has been read or until all input has been
   processed.  If the last block read is smaller than BYTES_PER_BLOCK
   and its size is not a multiple of the size associated with a format
   spec, extend the input block with zero bytes until its length is a
   multiple of all format spec sizes.  Write the final block.  Finally,
   write on a line by itself the offset of the byte after the last byte
   read.  Accumulate return values from calls to read_block and
   check_and_close, and if any was false, return false.
   Otherwise, return true.  */

static bool
dump (void)
{
  char *block[2];
  uintmax_t current_offset;
  bool idx = false;
  bool ok = true;
  size_t n_bytes_read;

  block[0] = xnmalloc (2, bytes_per_block);
  block[1] = block[0] + bytes_per_block;

  current_offset = n_bytes_to_skip;

  if (limit_bytes_to_format)
    {
      while (1)
        {
          size_t n_needed;
          if (current_offset >= end_offset)
            {
              n_bytes_read = 0;
              break;
            }
          n_needed = MIN (end_offset - current_offset,
                          (uintmax_t) bytes_per_block);
          ok &= read_block (n_needed, block[idx], &n_bytes_read);
          if (n_bytes_read < bytes_per_block)
            break;
          assert (n_bytes_read == bytes_per_block);
          write_block (current_offset, n_bytes_read,
                       block[!idx], block[idx]);
          current_offset += n_bytes_read;
          idx = !idx;
        }
    }
  else
    {
      while (1)
        {
          ok &= read_block (bytes_per_block, block[idx], &n_bytes_read);
          if (n_bytes_read < bytes_per_block)
            break;
          assert (n_bytes_read == bytes_per_block);
          write_block (current_offset, n_bytes_read,
                       block[!idx], block[idx]);
          current_offset += n_bytes_read;
          idx = !idx;
        }
    }

  if (n_bytes_read > 0)
    {
      int l_c_m;
      size_t bytes_to_write;

      l_c_m = get_lcm ();

      /* Ensure zero-byte padding up to the smallest multiple of l_c_m that
         is at least as large as n_bytes_read.  */
      bytes_to_write = l_c_m * ((n_bytes_read + l_c_m - 1) / l_c_m);

      memset (block[idx] + n_bytes_read, 0, bytes_to_write - n_bytes_read);
      write_block (current_offset, n_bytes_read, block[!idx], block[idx]);
      current_offset += n_bytes_read;
    }

  format_address (current_offset, '\n');

  if (limit_bytes_to_format && current_offset >= end_offset)
    ok &= check_and_close (0);

  free (block[0]);

  return ok;
}

/* STRINGS mode.  Find each "string constant" in the input.
   A string constant is a run of at least 'string_min' ASCII
   graphic (or formatting) characters terminated by a null.
   Based on a function written by Richard Stallman for a
   traditional version of od.  Return true if successful.  */

static bool
dump_strings (void)
{
  size_t bufsize = MAX (100, string_min);
  char *buf = xmalloc (bufsize);
  uintmax_t address = n_bytes_to_skip;
  bool ok = true;

  while (1)
    {
      size_t i;
      int c;

      /* See if the next 'string_min' chars are all printing chars.  */
    tryline:

      if (limit_bytes_to_format
          && (end_offset < string_min || end_offset - string_min <= address))
        break;

      for (i = 0; i < string_min; i++)
        {
          ok &= read_char (&c);
          address++;
          if (c < 0)
            {
              free (buf);
              return ok;
            }
          if (! isprint (c))
            /* Found a non-printing.  Try again starting with next char.  */
            goto tryline;
          buf[i] = c;
        }

      /* We found a run of 'string_min' printable characters.
         Now see if it is terminated with a null byte.  */
      while (!limit_bytes_to_format || address < end_offset)
        {
          if (i == bufsize)
            {
              buf = X2REALLOC (buf, &bufsize);
            }
          ok &= read_char (&c);
          address++;
          if (c < 0)
            {
              free (buf);
              return ok;
            }
          if (c == '\0')
            break;		/* It is; print this string.  */
          if (! isprint (c))
            goto tryline;	/* It isn't; give up on this string.  */
          buf[i++] = c;		/* String continues; store it all.  */
        }

      /* If we get here, the string is all printable and null-terminated,
         so print it.  It is all in 'buf' and 'i' is its length.  */
      buf[i] = 0;
      format_address (address - i - 1, ' ');

      for (i = 0; (c = buf[i]); i++)
        {
          switch (c)
            {
            case '\a':
              fputs ("\\a", stdout);
              break;

            case '\b':
              fputs ("\\b", stdout);
              break;

            case '\f':
              fputs ("\\f", stdout);
              break;

            case '\n':
              fputs ("\\n", stdout);
              break;

            case '\r':
              fputs ("\\r", stdout);
              break;

            case '\t':
              fputs ("\\t", stdout);
              break;

            case '\v':
              fputs ("\\v", stdout);
              break;

            default:
              putc (c, stdout);
            }
        }
      putchar ('\n');
    }

  /* We reach this point only if we search through
     (max_bytes_to_format - string_min) bytes before reaching EOF.  */

  free (buf);

  ok &= check_and_close (0);
  return ok;
}

int
main (int argc, char **argv)
{
  int n_files;
  size_t i;
  int l_c_m;
  size_t desired_width IF_LINT ( = 0);
  bool modern = false;
  bool width_specified = false;
  bool ok = true;
  size_t width_per_block = 0;
  static char const multipliers[] = "bEGKkMmPTYZ0";

  /* The old-style 'pseudo starting address' to be printed in parentheses
     after any true address.  */
  uintmax_t pseudo_start IF_LINT ( = 0);

  initialize_main (&argc, &argv);
  set_program_name (argv[0]);
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  atexit (close_stdout);

  for (i = 0; i <= MAX_INTEGRAL_TYPE_SIZE; i++)
    integral_type_size[i] = NO_SIZE;

  integral_type_size[sizeof (char)] = CHAR;
  integral_type_size[sizeof (short int)] = SHORT;
  integral_type_size[sizeof (int)] = INT;
  integral_type_size[sizeof (long int)] = LONG;
#if HAVE_UNSIGNED_LONG_LONG_INT
  /* If 'long int' and 'long long int' have the same size, it's fine
     to overwrite the entry for 'long' with this one.  */
  integral_type_size[sizeof (unsigned_long_long_int)] = LONG_LONG;
#endif

  for (i = 0; i <= MAX_FP_TYPE_SIZE; i++)
    fp_type_size[i] = NO_SIZE;

  fp_type_size[sizeof (float)] = FLOAT_SINGLE;
  /* The array entry for 'double' is filled in after that for 'long double'
     so that if they are the same size, we avoid any overhead of
     long double computation in libc.  */
  fp_type_size[sizeof (long double)] = FLOAT_LONG_DOUBLE;
  fp_type_size[sizeof (double)] = FLOAT_DOUBLE;

  n_specs = 0;
  n_specs_allocated = 0;
  spec = NULL;

  format_address = format_address_std;
  address_base = 8;
  address_pad_len = 7;
  flag_dump_strings = false;

  while (true)
    {
      uintmax_t tmp;
      enum strtol_error s_err;
      int oi = -1;
      int c = getopt_long (argc, argv, short_options, long_options, &oi);
      if (c == -1)
        break;

      switch (c)
        {
        case 'A':
          modern = true;
          switch (optarg[0])
            {
            case 'd':
              format_address = format_address_std;
              address_base = 10;
              address_pad_len = 7;
              break;
            case 'o':
              format_address = format_address_std;
              address_base = 8;
              address_pad_len = 7;
              break;
            case 'x':
              format_address = format_address_std;
              address_base = 16;
              address_pad_len = 6;
              break;
            case 'n':
              format_address = format_address_none;
              address_pad_len = 0;
              break;
            default:
              die (EXIT_FAILURE, 0,
                   _("invalid output address radix '%c';\
 it must be one character from [doxn]"),
                   optarg[0]);
              break;
            }
          break;

        case 'j':
          modern = true;
          s_err = xstrtoumax (optarg, NULL, 0, &n_bytes_to_skip, multipliers);
          if (s_err != LONGINT_OK)
            xstrtol_fatal (s_err, oi, c, long_options, optarg);
          break;

        case 'N':
          modern = true;
          limit_bytes_to_format = true;

          s_err = xstrtoumax (optarg, NULL, 0, &max_bytes_to_format,
                              multipliers);
          if (s_err != LONGINT_OK)
            xstrtol_fatal (s_err, oi, c, long_options, optarg);
          break;

        case 'S':
          modern = true;
          if (optarg == NULL)
            string_min = 3;
          else
            {
              s_err = xstrtoumax (optarg, NULL, 0, &tmp, multipliers);
              if (s_err != LONGINT_OK)
                xstrtol_fatal (s_err, oi, c, long_options, optarg);

              /* The minimum string length may be no larger than SIZE_MAX,
                 since we may allocate a buffer of this size.  */
              if (SIZE_MAX < tmp)
                die (EXIT_FAILURE, 0, _("%s is too large"), quote (optarg));

              string_min = tmp;
            }
          flag_dump_strings = true;
          break;

        case 't':
          modern = true;
          ok &= decode_format_string (optarg);
          break;

        case 'v':
          modern = true;
          abbreviate_duplicate_blocks = false;
          break;

        case TRADITIONAL_OPTION:
          traditional = true;
          break;

        case ENDIAN_OPTION:
          switch (XARGMATCH ("--endian", optarg, endian_args, endian_types))
            {
              case endian_big:
                  input_swap = ! WORDS_BIGENDIAN;
                  break;
              case endian_little:
                  input_swap = WORDS_BIGENDIAN;
                  break;
            }
          break;

          /* The next several cases map the traditional format
             specification options to the corresponding modern format
             specs.  GNU od accepts any combination of old- and
             new-style options.  Format specification options accumulate.
             The obsolescent and undocumented formats are compatible
             with FreeBSD 4.10 od.  */

#define CASE_OLD_ARG(old_char,new_string)		\
        case old_char:					\
          ok &= decode_format_string (new_string);	\
          break

          CASE_OLD_ARG ('a', "a");
          CASE_OLD_ARG ('b', "o1");
          CASE_OLD_ARG ('c', "c");
          CASE_OLD_ARG ('D', "u4"); /* obsolescent and undocumented */
          CASE_OLD_ARG ('d', "u2");
        case 'F': /* obsolescent and undocumented alias */
          CASE_OLD_ARG ('e', "fD"); /* obsolescent and undocumented */
          CASE_OLD_ARG ('f', "fF");
        case 'X': /* obsolescent and undocumented alias */
          CASE_OLD_ARG ('H', "x4"); /* obsolescent and undocumented */
          CASE_OLD_ARG ('i', "dI");
        case 'I': case 'L': /* obsolescent and undocumented aliases */
          CASE_OLD_ARG ('l', "dL");
          CASE_OLD_ARG ('O', "o4"); /* obsolesent and undocumented */
        case 'B': /* obsolescent and undocumented alias */
          CASE_OLD_ARG ('o', "o2");
          CASE_OLD_ARG ('s', "d2");
        case 'h': /* obsolescent and undocumented alias */
          CASE_OLD_ARG ('x', "x2");

#undef CASE_OLD_ARG

        case 'w':
          modern = true;
          width_specified = true;
          if (optarg == NULL)
            {
              desired_width = 32;
            }
          else
            {
              uintmax_t w_tmp;
              s_err = xstrtoumax (optarg, NULL, 10, &w_tmp, "");
              if (s_err != LONGINT_OK)
                xstrtol_fatal (s_err, oi, c, long_options, optarg);
              if (SIZE_MAX < w_tmp)
                die (EXIT_FAILURE, 0, _("%s is too large"), quote (optarg));
              desired_width = w_tmp;
            }
          break;

        case_GETOPT_HELP_CHAR;

        case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

        default:
          usage (EXIT_FAILURE);
          break;
        }
    }

  if (!ok)
    return EXIT_FAILURE;

  if (flag_dump_strings && n_specs > 0)
    die (EXIT_FAILURE, 0,
         _("no type may be specified when dumping strings"));

  n_files = argc - optind;

  /* If the --traditional option is used, there may be from
     0 to 3 remaining command line arguments;  handle each case
     separately.
        od [file] [[+]offset[.][b] [[+]label[.][b]]]
     The offset and label have the same syntax.

     If --traditional is not given, and if no modern options are
     given, and if the offset begins with + or (if there are two
     operands) a digit, accept only this form, as per POSIX:
        od [file] [[+]offset[.][b]]
  */

  if (!modern || traditional)
    {
      uintmax_t o1;
      uintmax_t o2;

      switch (n_files)
        {
        case 1:
          if ((traditional || argv[optind][0] == '+')
              && parse_old_offset (argv[optind], &o1))
            {
              n_bytes_to_skip = o1;
              --n_files;
              ++argv;
            }
          break;

        case 2:
          if ((traditional || argv[optind + 1][0] == '+'
               || ISDIGIT (argv[optind + 1][0]))
              && parse_old_offset (argv[optind + 1], &o2))
            {
              if (traditional && parse_old_offset (argv[optind], &o1))
                {
                  n_bytes_to_skip = o1;
                  flag_pseudo_start = true;
                  pseudo_start = o2;
                  argv += 2;
                  n_files -= 2;
                }
              else
                {
                  n_bytes_to_skip = o2;
                  --n_files;
                  argv[optind + 1] = argv[optind];
                  ++argv;
                }
            }
          break;

        case 3:
          if (traditional
              && parse_old_offset (argv[optind + 1], &o1)
              && parse_old_offset (argv[optind + 2], &o2))
            {
              n_bytes_to_skip = o1;
              flag_pseudo_start = true;
              pseudo_start = o2;
              argv[optind + 2] = argv[optind];
              argv += 2;
              n_files -= 2;
            }
          break;
        }

      if (traditional && 1 < n_files)
        {
          error (0, 0, _("extra operand %s"), quote (argv[optind + 1]));
          error (0, 0, "%s",
                 _("compatibility mode supports at most one file"));
          usage (EXIT_FAILURE);
        }
    }

  if (flag_pseudo_start)
    {
      if (format_address == format_address_none)
        {
          address_base = 8;
          address_pad_len = 7;
          format_address = format_address_paren;
        }
      else
        format_address = format_address_label;
    }

  if (limit_bytes_to_format)
    {
      end_offset = n_bytes_to_skip + max_bytes_to_format;
      if (end_offset < n_bytes_to_skip)
        die (EXIT_FAILURE, 0, _("skip-bytes + read-bytes is too large"));
    }

  if (n_specs == 0)
    decode_format_string ("oS");

  if (n_files > 0)
    {
      /* Set the global pointer FILE_LIST so that it
         references the first file-argument on the command-line.  */

      file_list = (char const *const *) &argv[optind];
    }
  else
    {
      /* No files were listed on the command line.
         Set the global pointer FILE_LIST so that it
         references the null-terminated list of one name: "-".  */

      file_list = default_file_list;
    }

  /* open the first input file */
  ok = open_next_file ();
  if (in_stream == NULL)
    goto cleanup;

  /* skip over any unwanted header bytes */
  ok &= skip (n_bytes_to_skip);
  if (in_stream == NULL)
    goto cleanup;

  pseudo_offset = (flag_pseudo_start ? pseudo_start - n_bytes_to_skip : 0);

  /* Compute output block length.  */
  l_c_m = get_lcm ();

  if (width_specified)
    {
      if (desired_width != 0 && desired_width % l_c_m == 0)
        bytes_per_block = desired_width;
      else
        {
          error (0, 0, _("warning: invalid width %lu; using %d instead"),
                 (unsigned long int) desired_width, l_c_m);
          bytes_per_block = l_c_m;
        }
    }
  else
    {
      if (l_c_m < DEFAULT_BYTES_PER_BLOCK)
        bytes_per_block = l_c_m * (DEFAULT_BYTES_PER_BLOCK / l_c_m);
      else
        bytes_per_block = l_c_m;
    }

  /* Compute padding necessary to align output block.  */
  for (i = 0; i < n_specs; i++)
    {
      int fields_per_block = bytes_per_block / width_bytes[spec[i].size];
      int block_width = (spec[i].field_width + 1) * fields_per_block;
      if (width_per_block < block_width)
        width_per_block = block_width;
    }
  for (i = 0; i < n_specs; i++)
    {
      int fields_per_block = bytes_per_block / width_bytes[spec[i].size];
      int block_width = spec[i].field_width * fields_per_block;
      spec[i].pad_width = width_per_block - block_width;
    }

#ifdef DEBUG
  printf ("lcm=%d, width_per_block=%"PRIuMAX"\n", l_c_m,
          (uintmax_t) width_per_block);
  for (i = 0; i < n_specs; i++)
    {
      int fields_per_block = bytes_per_block / width_bytes[spec[i].size];
      assert (bytes_per_block % width_bytes[spec[i].size] == 0);
      assert (1 <= spec[i].pad_width / fields_per_block);
      printf ("%d: fmt=\"%s\" in_width=%d out_width=%d pad=%d\n",
              i, spec[i].fmt_string, width_bytes[spec[i].size],
              spec[i].field_width, spec[i].pad_width);
    }
#endif

  ok &= (flag_dump_strings ? dump_strings () : dump ());

cleanup:

  if (have_read_stdin && fclose (stdin) == EOF)
    die (EXIT_FAILURE, errno, _("standard input"));

  return ok ? EXIT_SUCCESS : EXIT_FAILURE;
}