*
* Floating point read/write functions.
*
- * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * Reference: ISO C99 standard 5.2.4
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
- * Dual LGPL v2.1/GPL v2 license.
+ * Reference: ISO C99 standard 5.2.4
*/
#include <ctf/ctf-types.h>
#include <glib.h>
+#include <float.h> /* C99 floating point definitions */
#include <endian.h>
+/*
+ * This library is limited to binary representation of floating point values.
+ * Sign-extension of the exponents is assumed to keep the NaN, +inf, -inf
+ * values, but this should be double-checked (TODO).
+ */
+
/*
* Aliasing float/double and unsigned long is not strictly permitted by strict
* aliasing, but in practice type prunning is well supported, and this permits
#define HAS_TYPE_PRUNING
#endif
-union floatIEEE754 {
- float v;
-#ifdef HAS_TYPE_PRUNING
- unsigned long bits[(sizeof(float) + sizeof(unsigned long) - 1) / sizeof(unsigned long)];
-#else
- unsigned char bits[sizeof(float)];
+#if (FLT_RADIX != 2)
+
+#error "Unsupported floating point radix"
+
#endif
-};
union doubleIEEE754 {
double v;
#endif
};
-double float_read(const uint8_t *ptr, size_t len, int byte_order)
+union ldoubleIEEE754 {
+ long double v;
+#ifdef HAS_TYPE_PRUNING
+ unsigned long bits[(sizeof(long double) + sizeof(unsigned long) - 1) / sizeof(unsigned long)];
+#else
+ unsigned char bits[sizeof(long double)];
+#endif
+};
+
+struct pos_len {
+ size_t sign_start, exp_start, mantissa_start, len;
+};
+
+void ctf_float_copy(unsigned char *destp, const struct ctf_float *dest,
+ const unsigned char *src, const struct ctf_float *src)
{
- int rbo = (byte_order != __FLOAT_WORD_ORDER); /* reverse byte order */
-
- switch (len) {
- case 32:
- {
- union floatIEEE754 u;
- uint32_t tmp;
-
- if (!rbo)
- return (double) *(const float *) ptr;
- /*
- * Need to reverse byte order. Read the opposite from our
- * architecture.
- */
- if (__FLOAT_WORD_ORDER == LITTLE_ENDIAN) {
- /* Read big endian */
- tmp = bitfield_unsigned_read(ptr, 0, 1, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 31, 1, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 1, 8, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 23, 8, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 9, 23, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 23, LITTLE_ENDIAN,
- tmp);
- } else {
- /* Read little endian */
- tmp = bitfield_unsigned_read(ptr, 31, 1, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 1, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 23, 8, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 1, 8, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 0, 23, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 9, 23, BIG_ENDIAN,
- tmp);
- }
- return (double) u.v;
- }
- case 64:
- {
- union doubleIEEE754 u;
- uint64_t tmp;
-
- if (!rbo)
- return (double) *(const double *) ptr;
- /*
- * Need to reverse byte order. Read the opposite from our
- * architecture.
- */
- if (__FLOAT_WORD_ORDER == LITTLE_ENDIAN) {
- /* Read big endian */
- tmp = bitfield_unsigned_read(ptr, 0, 1, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 63, 1, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 1, 11, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 52, 11, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 12, 52, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 52, LITTLE_ENDIAN,
- tmp);
- } else {
- /* Read little endian */
- tmp = bitfield_unsigned_read(ptr, 63, 1, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 1, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 52, 11, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 1, 11, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 0, 52, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 12, 52, BIG_ENDIAN,
- tmp);
- }
- return u.v;
+ struct pos_len destpos, srcpos;
+ union {
+ unsigned long long u;
+ long long s;
+ } tmp;
+
+ destpos.len = dest.exp_len + dest.mantissa_len;
+ if (dest.byte_order == LITTLE_ENDIAN) {
+ destpos.sign_start = destpos.len - 1;
+ destpos.exp_start = destpos.sign_start - dest->exp_len;
+ destpos.mantissa_start = 0;
+ } else {
+ destpos.sign_start = 0;
+ destpos.exp_start = 1;
+ destpos.mantissa_start = destpos.exp_start + dest->exp_len;
}
- default:
- printf("float read unavailable for size %u\n", len);
- assert(0);
+
+ srcpos.len = src.exp_len + src.mantissa_len;
+ if (src.byte_order == LITTLE_ENDIAN) {
+ srcpos.sign_start = srcpos.len - 1;
+ srcpos.exp_start = srcpos.sign_start - src->exp_len;
+ srcpos.mantissa_start = 0;
+ } else {
+ srcpos.sign_start = 0;
+ srcpos.exp_start = 1;
+ srcpos.mantissa_start = srcpos.exp_start + src->exp_len;
}
+
+ /* sign */
+ tmp.u = bitfield_unsigned_read(ptr, srcpos.sign_start, 1,
+ src->byte_order);
+ bitfield_unsigned_write(&u.bits, destpos.sign_start, 1,
+ dest->byte_order, tmp.u);
+
+ /* mantissa (without leading 1). No sign extend. */
+ tmp.u = bitfield_unsigned_read(ptr, srcpos.mantissa_start,
+ src->mantissa_len - 1, src->byte_order);
+ bitfield_unsigned_write(&u.bits, destpos.mantissa_start,
+ dest->mantissa_len - 1, dest->byte_order, tmp.u);
+
+ /* exponent, with sign-extend. */
+ tmp.s = bitfield_signed_read(ptr, srcpos.exp_start, src->exp_len,
+ src->byte_order);
+ bitfield_signed_write(&u.bits, destpos.exp_start, dest->exp_len,
+ dest->byte_order, tmp.s);
}
-size_t float_write(uint8_t *ptr, size_t len, int byte_order, double v)
+double ctf_double_read(const unsigned char *ptr, const struct ctf_float *src)
{
- int rbo = (byte_order != __FLOAT_WORD_ORDER); /* reverse byte order */
+ union doubleIEEE754 u;
+ struct ctf_float dest = {
+ .exp_len = sizeof(double) * CHAR_BIT - DBL_MANT_DIG,
+ .mantissa_len = DBL_MANT_DIG,
+ .byte_order = BYTE_ORDER,
+ };
+
+ float_copy(&u.bits, &dest, ptr, src);
+ return u.v;
+}
+
+size_t ctf_double_write(unsigned char *ptr, const struct ctf_float *dest,
+ double v)
+{
+ union doubleIEEE754 u;
+ struct ctf_float src = {
+ .exp_len = sizeof(double) * CHAR_BIT - DBL_MANT_DIG,
+ .mantissa_len = DBL_MANT_DIG,
+ .byte_order = BYTE_ORDER,
+ };
if (!ptr)
goto end;
+ u.v = v;
+ float_copy(ptr, dest, &u.bits, &src);
+end:
+ return len;
+}
- switch (len) {
- case 32:
- {
- union floatIEEE754 u;
- uint32_t tmp;
-
- if (!rbo) {
- *(float *) ptr = (float) v;
- break;
- }
- u.v = v;
- /*
- * Need to reverse byte order. Write the opposite from our
- * architecture.
- */
- if (__FLOAT_WORD_ORDER == LITTLE_ENDIAN) {
- /* Write big endian */
- tmp = bitfield_unsigned_read(ptr, 31, 1, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 1, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 23, 8, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 1, 8, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 0, 23, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 9, 23, BIG_ENDIAN,
- tmp);
- } else {
- /* Write little endian */
- tmp = bitfield_unsigned_read(ptr, 0, 1, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 31, 1, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 1, 8, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 23, 8, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 9, 23, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 23, LITTLE_ENDIAN,
- tmp);
- }
- break;
- }
- case 64:
- {
- union doubleIEEE754 u;
- uint64_t tmp;
-
- if (!rbo) {
- *(double *) ptr = v;
- break;
- }
- u.v = v;
- /*
- * Need to reverse byte order. Write the opposite from our
- * architecture.
- */
- if (__FLOAT_WORD_ORDER == LITTLE_ENDIAN) {
- /* Write big endian */
- tmp = bitfield_unsigned_read(ptr, 63, 1, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 1, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 52, 11, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 1, 11, BIG_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 0, 52, LITTLE_ENDIAN);
- bitfield_unsigned_write(&u.bits, 12, 52, BIG_ENDIAN,
- tmp);
- } else {
- /* Write little endian */
- tmp = bitfield_unsigned_read(ptr, 0, 1, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 63, 1, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 1, 11, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 52, 11, LITTLE_ENDIAN,
- tmp);
- tmp = bitfield_unsigned_read(ptr, 12, 52, BIG_ENDIAN);
- bitfield_unsigned_write(&u.bits, 0, 52, LITTLE_ENDIAN,
- tmp);
- }
- break;
- }
- default:
- printf("float write unavailable for size %u\n", len);
- assert(0);
- }
+long double ctf_ldouble_read(const unsigned char *ptr,
+ const struct ctf_float *src)
+{
+ union ldoubleIEEE754 u;
+ struct ctf_float dest = {
+ .exp_len = sizeof(double) * CHAR_BIT - LDBL_MANT_DIG,
+ .mantissa_len = LDBL_MANT_DIG,
+ .byte_order = BYTE_ORDER,
+ };
+
+ float_copy(&u.bits, &dest, ptr, src);
+ return u.v;
+}
+
+size_t ctf_ldouble_write(unsigned char *ptr, const struct ctf_float *dest,
+ long double v)
+{
+ union ldoubleIEEE754 u;
+ struct ctf_float src = {
+ .exp_len = sizeof(double) * CHAR_BIT - LDBL_MANT_DIG,
+ .mantissa_len = LDBL_MANT_DIG,
+ .byte_order = BYTE_ORDER,
+ };
+
+ if (!ptr)
+ goto end;
+ u.v = v;
+ float_copy(ptr, dest, &u.bits, &src);
end:
return len;
}
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