2 * Copyright (c) 2010, 2017 Craig A. Berry
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 * The above copyright notice and this permission notice shall be included in
11 * all copies or substantial portions of the Software.
13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 * This program provides shortening of long symbols (> 31 characters) using the
25 * same mechanism as the OpenVMS C compiler. The basic procedure is to compute
26 * an AUTODIN II checksum of the entire symbol, encode the checksum in base32,
27 * and glue together a shortened symbol from the first 23 characters of the
28 * original symbol plus the encoded checksum appended. The output format is
29 * the same used in the name mangler database, stored by default in
30 * [.CXX_REPOSITORY]CXX$DEMANGLER_DB.
32 * To obtain the same result as CC/NAMES=SHORTENED, run like so:
34 * $ mcr []vms_shorten_symbol "Please_forgive_this_absurdly_long_symbol_name"
35 * PLEASE_FORGIVE_THIS_ABS1ARO4QU$Please_forgive_this_absurdly_long_symbol_name
37 * To obtain the same result as CC/NAMES=(SHORTENED,AS_IS), pass a non-zero
38 * value as the second argument, like so:
40 * $ mcr []vms_shorten_symbol "Please_forgive_this_absurdly_long_symbol_name" 1
41 * Please_forgive_this_abs3rv8rnn$Please_forgive_this_absurdly_long_symbol_name
50 #define UINT32 unsigned int
53 #define UINT32 uint32_t
56 extern UINT32 crc32(const char *input_string);
57 extern int u32_to_base32(UINT32 input, char *output);
58 extern int vms_shorten_symbol(const char *symbol, char *shortened, char as_is_flag);
61 * This routine implements the AUTODIN II polynomial.
65 crc32(const char *input_string)
69 * CRC code and data based partly on FreeBSD implementation, which
72 * The crc32 functions and data was originally written by Spencer
73 * Garrett <srg@quick.com> and was cleaned from the PostgreSQL source
74 * tree via the files contrib/ltree/crc32.[ch]. No license was
75 * included, therefore it is assumed that this code is public
76 * domain. Attribution still noted.
78 * (I think they mean "gleaned" not "cleaned".)
81 static const UINT32 autodin_ii_table[256] = {
82 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
83 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
84 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
85 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
86 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
87 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
88 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
89 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
90 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
91 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
92 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
93 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
94 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
95 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
96 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
97 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
98 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
99 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
100 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
101 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
102 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
103 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
104 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
105 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
106 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
107 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
108 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
109 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
110 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
111 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
112 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
113 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
114 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
115 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
116 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
117 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
118 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
119 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
120 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
121 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
122 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
123 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
124 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
129 for (c = (char *)input_string; *c; ++c)
130 crc = (crc >> 8) ^ autodin_ii_table[(crc ^ *c) & 0xff];
135 * This is the RFC2938 variant of base32, not RFC3548, Crockford's, or
136 * other newer variant. It produces an 8-byte encoded character string
137 * (plus trailing null) from a 32-bit integer input.
141 u32_to_base32(UINT32 input, char *output)
143 static const char base32hex_table[32] = {
144 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
145 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
146 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
152 * Grab lowest 5 bits and look up conversion in table. Lather, rinse,
153 * repeat for a total of 7, 5-bit chunks to accommodate 32 bits of input.
155 for (i = 0; i < 7; i++) {
156 output[6 - i] = base32hex_table[input & 0x1f];
157 input >>= 5; /* position to look at next 5 */
159 output[7] = '$'; /* It's DEC, so use '$' not '=' to pad. */
165 * Take an input symbol name of arbitrary length and produce a symbol shortened
166 * to 31 characters. The shortened symbol consists of the first 23 characters
167 * of the original symbol plus the 8 characters of the encoded checksum. The
168 * third argument is a boolean indicating whether to emulate the compiler's
169 * /NAMES=AS_IS option. When false (the compiler's default), the shortened
170 * symbol will be upper cased. When the original symbol is 31 characters or
171 * fewer in length, no checksum will be appended and the original symbol is
172 * returned verbatim (though upper cased if the as_is_flag is false).
176 vms_shorten_symbol(const char *input_symbol, char *shortened, char as_is_flag)
183 symlen = strlen(input_symbol);
184 symbol = (char *)malloc(symlen + 1);
188 strncpy(symbol, input_symbol, symlen);
189 symbol[symlen] = '\0';
192 for (c = symbol; *c; c++)
197 strncpy(shortened, symbol, symlen);
198 shortened[symlen] = '\0';
204 * Compute the checksum on the whole symbol.
209 /* The compiler does not use the inverted checksum, so we invert it
210 * back before encoding in base32.
213 if (u32_to_base32(~crc, (char *)&b32str) == -1) {
219 for (c = (char *)&b32str; *c; c++)
223 sprintf(shortened, "%.23s%.8s", symbol, b32str);
224 shortened[31] = '\0';
231 main(int argc, char **argv)
233 char short_symbol[32];
237 fprintf(stderr, "Usage: %s <symbol name> [<AS_IS flag>]\n", argv[0]);
243 if (vms_shorten_symbol(argv[1], (char *)&short_symbol, as_is_flag) == -1) {
244 fprintf(stderr, "Symbol shortening failed\n");
248 printf("%s%s\n", (char *)&short_symbol, argv[1]);