+++ /dev/null
-/*
- * Common Trace Format
- *
- * Floating point read/write functions.
- *
- * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * 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
- *
- * 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
- * us to use per-word read/writes rather than per-byte.
- */
-
-#if defined(__GNUC__) || defined(__MINGW32__) || defined(_MSC_VER)
-#define HAS_TYPE_PRUNING
-#endif
-
-#if (FLT_RADIX != 2)
-
-#error "Unsupported floating point radix"
-
-#endif
-
-union doubleIEEE754 {
- double v;
-#ifdef HAS_TYPE_PRUNING
- unsigned long bits[(sizeof(double) + sizeof(unsigned long) - 1) / sizeof(unsigned long)];
-#else
- unsigned char bits[sizeof(double)];
-#endif
-};
-
-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)
-{
- 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;
- }
-
- 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);
-}
-
-double ctf_double_read(const unsigned char *ptr, const struct ctf_float *src)
-{
- 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;
-}
-
-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;
-}
projects / babeltrace.git / blobdiff