vlm | 785435b | 2004-09-14 12:46:35 +0000 | [diff] [blame] | 1 | /*- |
| 2 | * Copyright (c) 2004 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| 3 | * Redistribution and modifications are permitted subject to BSD license. |
| 4 | */ |
| 5 | #include <REAL.h> |
| 6 | #include <INTEGER.h> |
| 7 | #include <stdlib.h> /* for strtod(3) */ |
| 8 | #include <math.h> |
| 9 | #include <errno.h> |
| 10 | #include <assert.h> |
| 11 | |
| 12 | #undef INT_MAX |
| 13 | #define INT_MAX ((int)(((unsigned int)-1) >> 1)) |
| 14 | |
vlm | 1d3ed28 | 2004-09-14 13:40:42 +0000 | [diff] [blame] | 15 | #ifndef INFINITY |
| 16 | #define INFINITY HUGE_VAL |
| 17 | #endif |
| 18 | |
| 19 | #ifndef NAN |
| 20 | static const double nan0; |
| 21 | #define NAN (nan0/nan0) |
| 22 | #endif |
| 23 | |
vlm | 785435b | 2004-09-14 12:46:35 +0000 | [diff] [blame] | 24 | /* |
| 25 | * REAL basic type description. |
| 26 | */ |
| 27 | static ber_tlv_tag_t asn1_DEF_REAL_tags[] = { |
| 28 | (ASN_TAG_CLASS_UNIVERSAL | (9 << 2)) |
| 29 | }; |
| 30 | asn1_TYPE_descriptor_t asn1_DEF_REAL = { |
| 31 | "REAL", |
| 32 | asn_generic_no_constraint, |
| 33 | INTEGER_decode_ber, /* Implemented in terms of INTEGER type */ |
| 34 | INTEGER_encode_der, |
| 35 | REAL_print, |
| 36 | INTEGER_free, |
| 37 | 0, /* Use generic outmost tag fetcher */ |
| 38 | asn1_DEF_REAL_tags, |
| 39 | sizeof(asn1_DEF_REAL_tags) / sizeof(asn1_DEF_REAL_tags[0]), |
| 40 | asn1_DEF_REAL_tags, /* Same as above */ |
| 41 | sizeof(asn1_DEF_REAL_tags) / sizeof(asn1_DEF_REAL_tags[0]), |
| 42 | 0, /* Always in primitive form */ |
| 43 | 0, 0, /* No members */ |
| 44 | 0 /* No specifics */ |
| 45 | }; |
| 46 | |
| 47 | int |
| 48 | REAL_print(asn1_TYPE_descriptor_t *td, const void *sptr, int ilevel, |
| 49 | asn_app_consume_bytes_f *cb, void *app_key) { |
| 50 | const REAL_t *st = (const REAL_t *)sptr; |
| 51 | char buf[128]; |
| 52 | double d; |
| 53 | int ret; |
| 54 | |
| 55 | (void)td; /* Unused argument */ |
| 56 | (void)ilevel; /* Unused argument */ |
| 57 | |
| 58 | if(!st) |
| 59 | return cb("<absent>", 8, app_key); |
| 60 | |
| 61 | if(asn1_REAL2double(st, &d)) |
| 62 | return cb("<error>", 7, app_key); |
| 63 | |
| 64 | ret = snprintf(buf, sizeof(buf), "%f", d); |
| 65 | if(ret < 0 || ret >= sizeof(buf)) |
| 66 | return cb("<error>", 7, app_key); |
| 67 | |
| 68 | return cb(buf, ret, app_key); |
| 69 | } |
| 70 | |
| 71 | int |
| 72 | asn1_REAL2double(const REAL_t *st, double *dbl_value) { |
| 73 | unsigned long octv; |
| 74 | |
| 75 | if(!st || !st->buf) { |
| 76 | errno = EINVAL; |
| 77 | return -1; |
| 78 | } |
| 79 | |
| 80 | if(st->size == 0) { |
| 81 | *dbl_value = 0; |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | octv = st->buf[0]; /* unsigned byte */ |
| 86 | |
| 87 | switch(octv & 0xC0) { |
| 88 | case 0x40: /* X.690: 8.5.8 */ |
| 89 | /* "SpecialRealValue" */ |
| 90 | |
| 91 | /* Be liberal in what you accept... |
| 92 | if(st->size != 1) ... |
| 93 | */ |
| 94 | |
| 95 | switch(st->buf[0]) { |
| 96 | case 0x40: /* 01000000: PLUS-INFINITY */ |
| 97 | *dbl_value = INFINITY; |
| 98 | return 0; |
| 99 | case 0x41: /* 01000001: MINUS-INFINITY */ |
| 100 | *dbl_value = -INFINITY; |
| 101 | return 0; |
| 102 | /* |
| 103 | * The following cases are defined by |
| 104 | * X.690 Amendment 1 (10/03) |
| 105 | */ |
| 106 | case 0x42: /* 01000010: NOT-A-NUMBER */ |
| 107 | *dbl_value = NAN; |
| 108 | return 0; |
| 109 | case 0x43: /* 01000011: minus zero */ |
| 110 | *dbl_value = NAN; |
| 111 | return 0; |
| 112 | } |
| 113 | |
| 114 | errno = EINVAL; |
| 115 | return -1; |
| 116 | case 0x00: { /* X.690: 8.5.6 */ |
| 117 | /* |
| 118 | * Decimal. NR{1,2,3} format. |
| 119 | */ |
| 120 | double d; |
| 121 | |
| 122 | assert(st->buf[st->size - 1] == 0); /* Security, vashu mat' */ |
| 123 | |
| 124 | d = strtod((char *)st->buf, 0); |
| 125 | if(finite(d)) { |
| 126 | *dbl_value = d; |
| 127 | return 0; |
| 128 | } else { |
| 129 | errno = ERANGE; |
| 130 | return 0; |
| 131 | } |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | /* |
| 136 | * Binary representation. |
| 137 | */ |
| 138 | { |
| 139 | double m; |
| 140 | int expval; /* exponent value */ |
| 141 | unsigned int elen; /* exponent value length, in octets */ |
| 142 | unsigned int scaleF; |
| 143 | unsigned int baseF; |
| 144 | uint8_t *ptr; |
| 145 | uint8_t *end; |
| 146 | int sign; |
| 147 | |
| 148 | switch((octv & 0x30) >> 4) { |
| 149 | case 0x00: baseF = 1; break; /* base 2 */ |
| 150 | case 0x01: baseF = 3; break; /* base 8 */ |
| 151 | case 0x02: baseF = 4; break; /* base 16 */ |
| 152 | default: |
| 153 | /* Reserved field, can't parse now. */ |
| 154 | errno = EINVAL; |
| 155 | return -1; |
| 156 | } |
| 157 | |
| 158 | sign = (octv & 0x40); /* bit 7 */ |
| 159 | scaleF = (octv & 0x0C) >> 2; /* bits 4 to 3 */ |
| 160 | |
| 161 | if(st->size <= (1 + (octv & 0x03))) { |
| 162 | errno = EINVAL; |
| 163 | return -1; |
| 164 | } |
| 165 | |
| 166 | if((octv & 0x03) == 0x11) { |
| 167 | /* 8.5.6.4, case d) */ |
| 168 | elen = st->buf[1]; /* unsigned binary number */ |
| 169 | if(elen == 0 || st->size <= (2 + elen)) { |
| 170 | errno = EINVAL; |
| 171 | return -1; |
| 172 | } |
| 173 | ptr = &st->buf[2]; |
| 174 | } else { |
| 175 | elen = (octv & 0x03); |
| 176 | ptr = &st->buf[1]; |
| 177 | } |
| 178 | |
| 179 | /* Fetch the multibyte exponent */ |
| 180 | expval = (int)(*(int8_t *)ptr); |
| 181 | end = ptr + elen + 1; |
| 182 | for(ptr++; ptr < end; ptr++) |
| 183 | expval = (expval * 256) + *ptr; |
| 184 | |
| 185 | m = 0.0; /* Initial mantissa value */ |
| 186 | |
| 187 | /* Okay, the exponent is here. Now, what about mantissa? */ |
| 188 | end = st->buf + st->size; |
| 189 | if(ptr < end) { |
| 190 | for(; ptr < end; ptr++) |
| 191 | m = scalbn(m, 8) + *ptr; |
| 192 | } |
| 193 | |
| 194 | ASN_DEBUG("m=%.10f, scF=%d, bF=%d, expval=%d, ldexp()=%f, scalbn()=%f", |
| 195 | m, scaleF, baseF, expval, |
| 196 | ldexp(m, expval * baseF + scaleF), |
| 197 | scalbn(m, scaleF) * pow(pow(2, baseF), expval) |
| 198 | ); |
| 199 | |
| 200 | /* |
| 201 | * (S * N * 2^F) * B^E |
| 202 | * Essentially: |
| 203 | m = scalbn(m, scaleF) * pow(pow(2, base), expval); |
| 204 | */ |
| 205 | m = ldexp(m, expval * baseF + scaleF); |
| 206 | if(finite(m)) { |
| 207 | *dbl_value = sign ? -m : m; |
| 208 | } else { |
| 209 | errno = ERANGE; |
| 210 | return -1; |
| 211 | } |
| 212 | |
| 213 | } /* if(binary_format) */ |
| 214 | |
| 215 | return 0; |
| 216 | } |
| 217 | |
| 218 | /* |
| 219 | * Assume IEEE 754 floating point: standard 64 bit double. |
| 220 | * [1 bit sign] [11 bits exponent] [52 bits mantissa] |
| 221 | */ |
| 222 | int |
| 223 | asn1_double2REAL(REAL_t *st, double dbl_value) { |
| 224 | #ifdef WORDS_BIGENDIAN /* Known to be big-endian */ |
| 225 | int littleEndian = 0; |
| 226 | #else /* need to test: have no explicit information */ |
| 227 | unsigned int LE = 1; |
| 228 | int littleEndian = *(unsigned char *)&LE; |
| 229 | #endif |
| 230 | uint8_t buf[16]; /* More than enough for 8-byte dbl_value */ |
| 231 | uint8_t dscr[sizeof(dbl_value)]; /* double value scratch pad */ |
| 232 | /* Assertion guards: won't even compile, if unexpected double size */ |
| 233 | char assertion_buffer1[9 - sizeof(dbl_value)] __attribute__((unused)); |
| 234 | char assertion_buffer2[sizeof(dbl_value) - 7] __attribute__((unused)); |
| 235 | uint8_t *ptr = buf; |
| 236 | uint8_t *mstop; /* Last byte of mantissa */ |
| 237 | unsigned int mval; /* Value of the last byte of mantissa */ |
| 238 | unsigned int bmsign; /* binary mask with sign */ |
| 239 | unsigned int buflen; |
| 240 | unsigned int accum; |
| 241 | int expval; |
| 242 | |
| 243 | if(!st) { |
| 244 | errno = EINVAL; |
| 245 | return -1; |
| 246 | } |
| 247 | |
| 248 | expval = ilogb(dbl_value); |
| 249 | |
| 250 | if(expval == -INT_MAX /* Also catches (dbl_value == 0) */ |
| 251 | || expval == INT_MAX /* catches finite() which catches isnan() */ |
| 252 | ) { |
| 253 | if(!st->buf || st->size < 2) { |
| 254 | (void *)ptr = MALLOC(2); |
| 255 | if(!ptr) return -1; |
| 256 | st->buf = ptr; |
| 257 | } |
| 258 | /* fpclassify(3) is not portable yet */ |
| 259 | if(expval == -INT_MAX) { |
vlm | b02ccb2 | 2004-09-14 13:50:21 +0000 | [diff] [blame^] | 260 | if(copysign(1.0, dbl_value) < 0.0) { |
vlm | 785435b | 2004-09-14 12:46:35 +0000 | [diff] [blame] | 261 | st->buf[0] = 0x80 | 0x40; |
| 262 | st->buf[1] = 0; |
| 263 | st->size = 2; |
| 264 | } else { |
| 265 | st->buf[0] = 0; /* JIC */ |
| 266 | st->size = 0; |
| 267 | } |
| 268 | } else if(isinf(dbl_value)) { |
vlm | b02ccb2 | 2004-09-14 13:50:21 +0000 | [diff] [blame^] | 269 | if(copysign(1.0, dbl_value) < 0.0) { |
vlm | 785435b | 2004-09-14 12:46:35 +0000 | [diff] [blame] | 270 | st->buf[0] = 0x41; /* MINUS-INFINITY */ |
| 271 | } else { |
| 272 | st->buf[0] = 0x40; /* PLUS-INFINITY */ |
| 273 | } |
| 274 | st->buf[1] = 0; |
| 275 | st->size = 1; |
| 276 | } else { |
| 277 | st->buf[0] = 0x42; /* NaN */ |
| 278 | st->buf[1] = 0; |
| 279 | st->size = 1; |
| 280 | } |
| 281 | return 0; |
| 282 | } |
| 283 | |
| 284 | if(littleEndian) { |
| 285 | uint8_t *s = ((uint8_t *)&dbl_value) + sizeof(dbl_value) - 2; |
| 286 | uint8_t *d; |
| 287 | |
| 288 | bmsign = 0x80 | ((s[1] >> 1) & 0x40); /* binary mask & - */ |
| 289 | for(mstop = d = dscr; s >= (uint8_t *)&dbl_value; d++, s--) { |
| 290 | *d = *s; |
| 291 | if(*d) mstop = d; |
| 292 | } |
| 293 | } else { |
| 294 | uint8_t *s = ((uint8_t *)&dbl_value) + 1; |
| 295 | uint8_t *end = ((uint8_t *)&dbl_value) + sizeof(double); |
| 296 | uint8_t *d; |
| 297 | |
| 298 | bmsign = 0x80 | ((s[-1] >> 1) & 0x40); /* binary mask & - */ |
| 299 | for(mstop = d = dscr; s < end; d++, s++) { |
| 300 | *d = *s; |
| 301 | if(*d) mstop = d; |
| 302 | } |
| 303 | } |
| 304 | |
| 305 | /* Remove parts of the exponent, leave mantissa and explicit 1. */ |
| 306 | dscr[0] = 0x10 | (dscr[0] & 0x0f); |
| 307 | |
| 308 | /* Adjust exponent in a very unobvious way */ |
| 309 | expval -= 8 * ((mstop - dscr) + 1) - 4; |
| 310 | |
| 311 | /* This loop ensures DER conformance by forcing mantissa odd: 11.3.1 */ |
| 312 | mval = *mstop; |
| 313 | if(mval && !(mval & 1)) { |
| 314 | unsigned int shift_count = 1; |
| 315 | unsigned int ishift; |
| 316 | uint8_t *mptr; |
| 317 | |
| 318 | /* |
| 319 | * Figure out what needs to be done to make mantissa odd. |
| 320 | */ |
| 321 | if(!(mval & 0x0f)) /* Speed-up a little */ |
| 322 | shift_count = 4; |
| 323 | while(((mval >> shift_count) & 1) == 0) |
| 324 | shift_count++; |
| 325 | |
| 326 | ishift = 8 - shift_count; |
| 327 | accum = 0; |
| 328 | |
| 329 | /* Go over the buffer, shifting it shift_count bits right. */ |
| 330 | for(mptr = dscr; mptr <= mstop; mptr++) { |
| 331 | mval = *mptr; |
| 332 | *mptr = accum | (mval >> shift_count); |
| 333 | accum = mval << ishift; |
| 334 | } |
| 335 | |
| 336 | /* Adjust mantissa appropriately. */ |
| 337 | expval += shift_count; |
| 338 | } |
| 339 | |
| 340 | if(expval < 0) { |
| 341 | if((expval >> 7) == -1) { |
| 342 | *ptr++ = bmsign | 0x00; |
| 343 | *ptr++ = expval; |
| 344 | } else if((expval >> 15) == -1) { |
| 345 | *ptr++ = bmsign | 0x01; |
| 346 | *ptr++ = expval >> 8; |
| 347 | *ptr++ = expval; |
| 348 | } else { |
| 349 | assert((expval >> 23) == -1); |
| 350 | *ptr++ = bmsign | 0x02; |
| 351 | *ptr++ = expval >> 16; |
| 352 | *ptr++ = expval >> 8; |
| 353 | *ptr++ = expval; |
| 354 | } |
| 355 | } else if(expval <= 0x7f) { |
| 356 | *ptr++ = bmsign | 0x00; |
| 357 | *ptr++ = expval; |
| 358 | } else if(expval <= 0x7fff) { |
| 359 | *ptr++ = bmsign | 0x01; |
| 360 | *ptr++ = expval >> 8; |
| 361 | *ptr++ = expval; |
| 362 | } else { |
| 363 | assert(expval <= 0x7fffff); |
| 364 | *ptr++ = bmsign | 0x02; |
| 365 | *ptr++ = expval >> 16; |
| 366 | *ptr++ = expval >> 8; |
| 367 | *ptr++ = expval; |
| 368 | } |
| 369 | |
| 370 | buflen = (mstop - dscr) + 1; |
| 371 | memcpy(ptr, dscr, buflen); |
| 372 | ptr += buflen; |
| 373 | buflen = ptr - buf; |
| 374 | |
| 375 | (void *)ptr = MALLOC(buflen + 1); |
| 376 | if(!ptr) return -1; |
| 377 | |
| 378 | memcpy(ptr, buf, buflen); |
| 379 | buf[buflen] = 0; /* JIC */ |
| 380 | |
| 381 | if(st->buf) FREEMEM(st->buf); |
| 382 | st->buf = ptr; |
| 383 | st->size = buflen; |
| 384 | |
| 385 | return 0; |
| 386 | } |