| /*- |
| * Copyright (c) 2004 Lev Walkin <vlm@lionet.info>. All rights reserved. |
| * Redistribution and modifications are permitted subject to BSD license. |
| */ |
| #include <REAL.h> |
| #include <INTEGER.h> |
| #include <stdlib.h> /* for strtod(3) */ |
| #include <math.h> |
| #include <errno.h> |
| #include <assert.h> |
| |
| #undef INT_MAX |
| #define INT_MAX ((int)(((unsigned int)-1) >> 1)) |
| |
| #ifndef INFINITY |
| #define INFINITY HUGE_VAL |
| #endif |
| |
| #ifndef NAN |
| static const double nan0; |
| #define NAN (nan0/nan0) |
| #endif |
| |
| /* |
| * REAL basic type description. |
| */ |
| static ber_tlv_tag_t asn1_DEF_REAL_tags[] = { |
| (ASN_TAG_CLASS_UNIVERSAL | (9 << 2)) |
| }; |
| asn1_TYPE_descriptor_t asn1_DEF_REAL = { |
| "REAL", |
| asn_generic_no_constraint, |
| INTEGER_decode_ber, /* Implemented in terms of INTEGER type */ |
| INTEGER_encode_der, |
| REAL_print, |
| INTEGER_free, |
| 0, /* Use generic outmost tag fetcher */ |
| asn1_DEF_REAL_tags, |
| sizeof(asn1_DEF_REAL_tags) / sizeof(asn1_DEF_REAL_tags[0]), |
| asn1_DEF_REAL_tags, /* Same as above */ |
| sizeof(asn1_DEF_REAL_tags) / sizeof(asn1_DEF_REAL_tags[0]), |
| 0, /* Always in primitive form */ |
| 0, 0, /* No members */ |
| 0 /* No specifics */ |
| }; |
| |
| int |
| REAL_print(asn1_TYPE_descriptor_t *td, const void *sptr, int ilevel, |
| asn_app_consume_bytes_f *cb, void *app_key) { |
| const REAL_t *st = (const REAL_t *)sptr; |
| char buf[128]; |
| double d; |
| int ret; |
| |
| (void)td; /* Unused argument */ |
| (void)ilevel; /* Unused argument */ |
| |
| if(!st) |
| return cb("<absent>", 8, app_key); |
| |
| if(asn1_REAL2double(st, &d)) |
| return cb("<error>", 7, app_key); |
| |
| ret = snprintf(buf, sizeof(buf), "%f", d); |
| if(ret < 0 || ret >= sizeof(buf)) |
| return cb("<error>", 7, app_key); |
| |
| return cb(buf, ret, app_key); |
| } |
| |
| int |
| asn1_REAL2double(const REAL_t *st, double *dbl_value) { |
| unsigned long octv; |
| |
| if(!st || !st->buf) { |
| errno = EINVAL; |
| return -1; |
| } |
| |
| if(st->size == 0) { |
| *dbl_value = 0; |
| return 0; |
| } |
| |
| octv = st->buf[0]; /* unsigned byte */ |
| |
| switch(octv & 0xC0) { |
| case 0x40: /* X.690: 8.5.8 */ |
| /* "SpecialRealValue" */ |
| |
| /* Be liberal in what you accept... |
| if(st->size != 1) ... |
| */ |
| |
| switch(st->buf[0]) { |
| case 0x40: /* 01000000: PLUS-INFINITY */ |
| *dbl_value = INFINITY; |
| return 0; |
| case 0x41: /* 01000001: MINUS-INFINITY */ |
| *dbl_value = -INFINITY; |
| return 0; |
| /* |
| * The following cases are defined by |
| * X.690 Amendment 1 (10/03) |
| */ |
| case 0x42: /* 01000010: NOT-A-NUMBER */ |
| *dbl_value = NAN; |
| return 0; |
| case 0x43: /* 01000011: minus zero */ |
| *dbl_value = NAN; |
| return 0; |
| } |
| |
| errno = EINVAL; |
| return -1; |
| case 0x00: { /* X.690: 8.5.6 */ |
| /* |
| * Decimal. NR{1,2,3} format. |
| */ |
| double d; |
| |
| assert(st->buf[st->size - 1] == 0); /* Security, vashu mat' */ |
| |
| d = strtod((char *)st->buf, 0); |
| if(finite(d)) { |
| *dbl_value = d; |
| return 0; |
| } else { |
| errno = ERANGE; |
| return 0; |
| } |
| } |
| } |
| |
| /* |
| * Binary representation. |
| */ |
| { |
| double m; |
| int expval; /* exponent value */ |
| unsigned int elen; /* exponent value length, in octets */ |
| unsigned int scaleF; |
| unsigned int baseF; |
| uint8_t *ptr; |
| uint8_t *end; |
| int sign; |
| |
| switch((octv & 0x30) >> 4) { |
| case 0x00: baseF = 1; break; /* base 2 */ |
| case 0x01: baseF = 3; break; /* base 8 */ |
| case 0x02: baseF = 4; break; /* base 16 */ |
| default: |
| /* Reserved field, can't parse now. */ |
| errno = EINVAL; |
| return -1; |
| } |
| |
| sign = (octv & 0x40); /* bit 7 */ |
| scaleF = (octv & 0x0C) >> 2; /* bits 4 to 3 */ |
| |
| if(st->size <= (1 + (octv & 0x03))) { |
| errno = EINVAL; |
| return -1; |
| } |
| |
| if((octv & 0x03) == 0x11) { |
| /* 8.5.6.4, case d) */ |
| elen = st->buf[1]; /* unsigned binary number */ |
| if(elen == 0 || st->size <= (2 + elen)) { |
| errno = EINVAL; |
| return -1; |
| } |
| ptr = &st->buf[2]; |
| } else { |
| elen = (octv & 0x03); |
| ptr = &st->buf[1]; |
| } |
| |
| /* Fetch the multibyte exponent */ |
| expval = (int)(*(int8_t *)ptr); |
| end = ptr + elen + 1; |
| for(ptr++; ptr < end; ptr++) |
| expval = (expval * 256) + *ptr; |
| |
| m = 0.0; /* Initial mantissa value */ |
| |
| /* Okay, the exponent is here. Now, what about mantissa? */ |
| end = st->buf + st->size; |
| if(ptr < end) { |
| for(; ptr < end; ptr++) |
| m = scalbn(m, 8) + *ptr; |
| } |
| |
| ASN_DEBUG("m=%.10f, scF=%d, bF=%d, expval=%d, ldexp()=%f, scalbn()=%f", |
| m, scaleF, baseF, expval, |
| ldexp(m, expval * baseF + scaleF), |
| scalbn(m, scaleF) * pow(pow(2, baseF), expval) |
| ); |
| |
| /* |
| * (S * N * 2^F) * B^E |
| * Essentially: |
| m = scalbn(m, scaleF) * pow(pow(2, base), expval); |
| */ |
| m = ldexp(m, expval * baseF + scaleF); |
| if(finite(m)) { |
| *dbl_value = sign ? -m : m; |
| } else { |
| errno = ERANGE; |
| return -1; |
| } |
| |
| } /* if(binary_format) */ |
| |
| return 0; |
| } |
| |
| /* |
| * Assume IEEE 754 floating point: standard 64 bit double. |
| * [1 bit sign] [11 bits exponent] [52 bits mantissa] |
| */ |
| int |
| asn1_double2REAL(REAL_t *st, double dbl_value) { |
| #ifdef WORDS_BIGENDIAN /* Known to be big-endian */ |
| int littleEndian = 0; |
| #else /* need to test: have no explicit information */ |
| unsigned int LE = 1; |
| int littleEndian = *(unsigned char *)&LE; |
| #endif |
| uint8_t buf[16]; /* More than enough for 8-byte dbl_value */ |
| uint8_t dscr[sizeof(dbl_value)]; /* double value scratch pad */ |
| /* Assertion guards: won't even compile, if unexpected double size */ |
| char assertion_buffer1[9 - sizeof(dbl_value)] __attribute__((unused)); |
| char assertion_buffer2[sizeof(dbl_value) - 7] __attribute__((unused)); |
| uint8_t *ptr = buf; |
| uint8_t *mstop; /* Last byte of mantissa */ |
| unsigned int mval; /* Value of the last byte of mantissa */ |
| unsigned int bmsign; /* binary mask with sign */ |
| unsigned int buflen; |
| unsigned int accum; |
| int expval; |
| |
| if(!st) { |
| errno = EINVAL; |
| return -1; |
| } |
| |
| expval = ilogb(dbl_value); |
| |
| if(expval == -INT_MAX /* Also catches (dbl_value == 0) */ |
| || expval == INT_MAX /* catches finite() which catches isnan() */ |
| ) { |
| if(!st->buf || st->size < 2) { |
| (void *)ptr = MALLOC(2); |
| if(!ptr) return -1; |
| st->buf = ptr; |
| } |
| /* fpclassify(3) is not portable yet */ |
| if(expval == -INT_MAX) { |
| if(signbit(dbl_value)) { |
| st->buf[0] = 0x80 | 0x40; |
| st->buf[1] = 0; |
| st->size = 2; |
| } else { |
| st->buf[0] = 0; /* JIC */ |
| st->size = 0; |
| } |
| } else if(isinf(dbl_value)) { |
| if(signbit(dbl_value)) { |
| st->buf[0] = 0x41; /* MINUS-INFINITY */ |
| } else { |
| st->buf[0] = 0x40; /* PLUS-INFINITY */ |
| } |
| st->buf[1] = 0; |
| st->size = 1; |
| } else { |
| st->buf[0] = 0x42; /* NaN */ |
| st->buf[1] = 0; |
| st->size = 1; |
| } |
| return 0; |
| } |
| |
| if(littleEndian) { |
| uint8_t *s = ((uint8_t *)&dbl_value) + sizeof(dbl_value) - 2; |
| uint8_t *d; |
| |
| bmsign = 0x80 | ((s[1] >> 1) & 0x40); /* binary mask & - */ |
| for(mstop = d = dscr; s >= (uint8_t *)&dbl_value; d++, s--) { |
| *d = *s; |
| if(*d) mstop = d; |
| } |
| } else { |
| uint8_t *s = ((uint8_t *)&dbl_value) + 1; |
| uint8_t *end = ((uint8_t *)&dbl_value) + sizeof(double); |
| uint8_t *d; |
| |
| bmsign = 0x80 | ((s[-1] >> 1) & 0x40); /* binary mask & - */ |
| for(mstop = d = dscr; s < end; d++, s++) { |
| *d = *s; |
| if(*d) mstop = d; |
| } |
| } |
| |
| /* Remove parts of the exponent, leave mantissa and explicit 1. */ |
| dscr[0] = 0x10 | (dscr[0] & 0x0f); |
| |
| /* Adjust exponent in a very unobvious way */ |
| expval -= 8 * ((mstop - dscr) + 1) - 4; |
| |
| /* This loop ensures DER conformance by forcing mantissa odd: 11.3.1 */ |
| mval = *mstop; |
| if(mval && !(mval & 1)) { |
| unsigned int shift_count = 1; |
| unsigned int ishift; |
| uint8_t *mptr; |
| |
| /* |
| * Figure out what needs to be done to make mantissa odd. |
| */ |
| if(!(mval & 0x0f)) /* Speed-up a little */ |
| shift_count = 4; |
| while(((mval >> shift_count) & 1) == 0) |
| shift_count++; |
| |
| ishift = 8 - shift_count; |
| accum = 0; |
| |
| /* Go over the buffer, shifting it shift_count bits right. */ |
| for(mptr = dscr; mptr <= mstop; mptr++) { |
| mval = *mptr; |
| *mptr = accum | (mval >> shift_count); |
| accum = mval << ishift; |
| } |
| |
| /* Adjust mantissa appropriately. */ |
| expval += shift_count; |
| } |
| |
| if(expval < 0) { |
| if((expval >> 7) == -1) { |
| *ptr++ = bmsign | 0x00; |
| *ptr++ = expval; |
| } else if((expval >> 15) == -1) { |
| *ptr++ = bmsign | 0x01; |
| *ptr++ = expval >> 8; |
| *ptr++ = expval; |
| } else { |
| assert((expval >> 23) == -1); |
| *ptr++ = bmsign | 0x02; |
| *ptr++ = expval >> 16; |
| *ptr++ = expval >> 8; |
| *ptr++ = expval; |
| } |
| } else if(expval <= 0x7f) { |
| *ptr++ = bmsign | 0x00; |
| *ptr++ = expval; |
| } else if(expval <= 0x7fff) { |
| *ptr++ = bmsign | 0x01; |
| *ptr++ = expval >> 8; |
| *ptr++ = expval; |
| } else { |
| assert(expval <= 0x7fffff); |
| *ptr++ = bmsign | 0x02; |
| *ptr++ = expval >> 16; |
| *ptr++ = expval >> 8; |
| *ptr++ = expval; |
| } |
| |
| buflen = (mstop - dscr) + 1; |
| memcpy(ptr, dscr, buflen); |
| ptr += buflen; |
| buflen = ptr - buf; |
| |
| (void *)ptr = MALLOC(buflen + 1); |
| if(!ptr) return -1; |
| |
| memcpy(ptr, buf, buflen); |
| buf[buflen] = 0; /* JIC */ |
| |
| if(st->buf) FREEMEM(st->buf); |
| st->buf = ptr; |
| st->size = buflen; |
| |
| return 0; |
| } |