[babeltrace.git] / formats / ctf / types / float.c

/*
 * Common Trace Format
 *
 * Floating point read/write functions.
 *
 * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
 *
 * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * Reference: ISO C99 standard 5.2.4
 */

#include <babeltrace/ctf/types.h>
#include <glib.h>
#include <float.h>	/* C99 floating point definitions */
#include <limits.h>	/* C99 limits */
#include <babeltrace/endian.h>

/*
 * This library is limited to binary representation of floating point values.
 * We use hardware support for conversion between 32 and 64-bit floating
 * point values.
 */

/*
 * Aliasing float/double and unsigned long is not strictly permitted by strict
 * aliasing, but in practice declaration 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 vd;
	float vf;
#ifdef HAS_TYPE_PRUNING
	unsigned long bits[(sizeof(double) + sizeof(unsigned long) - 1) / sizeof(unsigned long)];
#else
	unsigned char bits[sizeof(double)];
#endif
};

static struct declaration_float *static_float_declaration,
		*static_double_declaration;

struct pos_len {
	size_t sign_start, exp_start, mantissa_start, len;
};

int _ctf_float_copy(struct stream_pos *destp,
		    struct definition_float *dest_definition,
		    struct stream_pos *srcp,
		    const struct definition_float *src_definition)
{
	int ret;

	/* We only support copy of same-size floats for now */
	assert(src_definition->declaration->sign->len ==
		dest_definition->declaration->sign->len);
	assert(src_definition->declaration->exp->len ==
		dest_definition->declaration->exp->len);
	assert(src_definition->declaration->mantissa->len ==
		dest_definition->declaration->mantissa->len);
	/* Read */
	if (src_definition->declaration->byte_order == LITTLE_ENDIAN) {
		ret = ctf_integer_read(srcp, &src_definition->mantissa->p);
		if (ret)
			return ret;
		ret = ctf_integer_read(srcp, &src_definition->exp->p);
		if (ret)
			return ret;
		ret = ctf_integer_read(srcp, &src_definition->sign->p);
		if (ret)
			return ret;
	} else {
		ret = ctf_integer_read(srcp, &src_definition->sign->p);
		if (ret)
			return ret;
		ret = ctf_integer_read(srcp, &src_definition->exp->p);
		if (ret)
			return ret;
		ret = ctf_integer_read(srcp, &src_definition->mantissa->p);
		if (ret)
			return ret;
	}

	dest_definition->mantissa->value._unsigned =
		src_definition->mantissa->value._unsigned;
	dest_definition->exp->value._signed =
		src_definition->exp->value._signed;
	dest_definition->sign->value._unsigned =
		src_definition->sign->value._unsigned;

	/* Write */
	if (dest_definition->declaration->byte_order == LITTLE_ENDIAN) {
		ret = ctf_integer_write(destp, &dest_definition->mantissa->p);
		if (ret)
			return ret;
		ret = ctf_integer_write(destp, &dest_definition->exp->p);
		if (ret)
			return ret;
		ret = ctf_integer_write(destp, &dest_definition->sign->p);
		if (ret)
			return ret;
	} else {
		ret = ctf_integer_write(destp, &dest_definition->sign->p);
		if (ret)
			return ret;
		ret = ctf_integer_write(destp, &dest_definition->exp->p);
		if (ret)
			return ret;
		ret = ctf_integer_write(destp, &dest_definition->mantissa->p);
		if (ret)
			return ret;
	}
	return 0;
}

int ctf_float_read(struct stream_pos *ppos, struct definition *definition)
{
	struct definition_float *float_definition =
		container_of(definition, struct definition_float, p);
	const struct declaration_float *float_declaration =
		float_definition->declaration;
	struct ctf_stream_pos *pos = ctf_pos(ppos);
	union doubleIEEE754 u;
	struct definition *tmpdef;
	struct definition_float *tmpfloat;
	struct ctf_stream_pos destp;
	struct mmap_align mma;
	int ret;

	switch (float_declaration->mantissa->len + 1) {
	case FLT_MANT_DIG:
		tmpdef = static_float_declaration->p.definition_new(
				&static_float_declaration->p,
				NULL, 0, 0, "__tmpfloat");
		break;
	case DBL_MANT_DIG:
		tmpdef = static_double_declaration->p.definition_new(
				&static_double_declaration->p,
				NULL, 0, 0, "__tmpfloat");
		break;
	default:
		return -EINVAL;
	}
	tmpfloat = container_of(tmpdef, struct definition_float, p);
	memset(&destp, 0, sizeof(destp));
	ctf_init_pos(&destp, -1, O_RDWR);
	mmap_align_set_addr(&mma, (char *) u.bits);
	destp.base_mma = &mma;
	destp.packet_size = sizeof(u) * CHAR_BIT;
	ctf_align_pos(pos, float_declaration->p.alignment);
	ret = _ctf_float_copy(&destp.parent, tmpfloat, ppos, float_definition);
	switch (float_declaration->mantissa->len + 1) {
	case FLT_MANT_DIG:
		float_definition->value = u.vf;
		break;
	case DBL_MANT_DIG:
		float_definition->value = u.vd;
		break;
	default:
		return -EINVAL;
	}
	definition_unref(tmpdef);
	return ret;
}

int ctf_float_write(struct stream_pos *ppos, struct definition *definition)
{
	struct definition_float *float_definition =
		container_of(definition, struct definition_float, p);
	const struct declaration_float *float_declaration =
		float_definition->declaration;
	struct ctf_stream_pos *pos = ctf_pos(ppos);
	union doubleIEEE754 u;
	struct definition *tmpdef;
	struct definition_float *tmpfloat;
	struct ctf_stream_pos srcp;
	struct mmap_align mma;
	int ret;

	switch (float_declaration->mantissa->len + 1) {
	case FLT_MANT_DIG:
		tmpdef = static_float_declaration->p.definition_new(
				&static_float_declaration->p,
				NULL, 0, 0, "__tmpfloat");
		break;
	case DBL_MANT_DIG:
		tmpdef = static_double_declaration->p.definition_new(
				&static_double_declaration->p,
				NULL, 0, 0, "__tmpfloat");
		break;
	default:
		return -EINVAL;
	}
	tmpfloat = container_of(tmpdef, struct definition_float, p);
	ctf_init_pos(&srcp, -1, O_RDONLY);
	mmap_align_set_addr(&mma, (char *) u.bits);
	srcp.base_mma = &mma;
	srcp.packet_size = sizeof(u) * CHAR_BIT;
	switch (float_declaration->mantissa->len + 1) {
	case FLT_MANT_DIG:
		u.vf = float_definition->value;
		break;
	case DBL_MANT_DIG:
		u.vd = float_definition->value;
		break;
	default:
		return -EINVAL;
	}
	ctf_align_pos(pos, float_declaration->p.alignment);
	ret = _ctf_float_copy(ppos, float_definition, &srcp.parent, tmpfloat);
	definition_unref(tmpdef);
	return ret;
}

void __attribute__((constructor)) ctf_float_init(void)
{
	static_float_declaration =
		float_declaration_new(FLT_MANT_DIG,
				sizeof(float) * CHAR_BIT - FLT_MANT_DIG,
				BYTE_ORDER,
				__alignof__(float));
	static_double_declaration =
		float_declaration_new(DBL_MANT_DIG,
				sizeof(double) * CHAR_BIT - DBL_MANT_DIG,
				BYTE_ORDER,
				__alignof__(double));
}

void __attribute__((destructor)) ctf_float_fini(void)
{
	declaration_unref(&static_float_declaration->p);
	declaration_unref(&static_double_declaration->p);
}
Commit	Line	Data
6dc2ca62 MD	1	/*
	2	* Common Trace Format
	3	*
	4	* Floating point read/write functions.
	5	*
64fa3fec MD	6	* Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
	7	*
	8	* Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6dc2ca62	9	*
ccd7e1c8 MD	10	* Permission is hereby granted, free of charge, to any person obtaining a copy
	11	* of this software and associated documentation files (the "Software"), to deal
	12	* in the Software without restriction, including without limitation the rights
	13	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	14	* copies of the Software, and to permit persons to whom the Software is
	15	* furnished to do so, subject to the following conditions:
de0ba614	16	*
ccd7e1c8 MD	17	* The above copyright notice and this permission notice shall be included in
ccd7e1c8 MD	18	* all copies or substantial portions of the Software.
6dc2ca62	19	*
de0ba614	20	* Reference: ISO C99 standard 5.2.4
6dc2ca62 MD	21	*/
6dc2ca62 MD	22
d79865b9	23	#include <babeltrace/ctf/types.h>
6dc2ca62	24	#include <glib.h>
de0ba614	25	#include <float.h> /* C99 floating point definitions */
a3dbc794	26	#include <limits.h> /* C99 limits */
9b0422a0	27	#include <babeltrace/endian.h>
6dc2ca62	28
de0ba614 MD	29	/*
de0ba614 MD	30	* This library is limited to binary representation of floating point values.
f72803ca MD	31	* We use hardware support for conversion between 32 and 64-bit floating
f72803ca MD	32	* point values.
de0ba614 MD	33	*/
de0ba614 MD	34
6dc2ca62 MD	35	/*
6dc2ca62 MD	36	* Aliasing float/double and unsigned long is not strictly permitted by strict
f6625916	37	* aliasing, but in practice declaration prunning is well supported, and this permits
6dc2ca62 MD	38	* us to use per-word read/writes rather than per-byte.
	39	*/
	40
	41	#if defined(__GNUC__) \|\| defined(__MINGW32__) \|\| defined(_MSC_VER)
	42	#define HAS_TYPE_PRUNING
	43	#endif
	44
de0ba614 MD	45	#if (FLT_RADIX != 2)
	46
	47	#error "Unsupported floating point radix"
	48
6dc2ca62	49	#endif
6dc2ca62 MD	50
6dc2ca62 MD	51	union doubleIEEE754 {
f72803ca MD	52	double vd;
f72803ca MD	53	float vf;
6dc2ca62 MD	54	#ifdef HAS_TYPE_PRUNING
	55	unsigned long bits[(sizeof(double) + sizeof(unsigned long) - 1) / sizeof(unsigned long)];
	56	#else
	57	unsigned char bits[sizeof(double)];
	58	#endif
	59	};
	60
f72803ca MD	61	static struct declaration_float *static_float_declaration,
f72803ca MD	62	*static_double_declaration;
d11e9c49	63
de0ba614 MD	64	struct pos_len {
	65	size_t sign_start, exp_start, mantissa_start, len;
	66	};
	67
c5e74408 MD	68	int _ctf_float_copy(struct stream_pos *destp,
	69	struct definition_float *dest_definition,
	70	struct stream_pos *srcp,
	71	const struct definition_float *src_definition)
6dc2ca62	72	{
c5e74408 MD	73	int ret;
c5e74408 MD	74
f72803ca MD	75	/* We only support copy of same-size floats for now */
	76	assert(src_definition->declaration->sign->len ==
	77	dest_definition->declaration->sign->len);
	78	assert(src_definition->declaration->exp->len ==
	79	dest_definition->declaration->exp->len);
	80	assert(src_definition->declaration->mantissa->len ==
	81	dest_definition->declaration->mantissa->len);
11d43b90	82	/* Read */
d11e9c49	83	if (src_definition->declaration->byte_order == LITTLE_ENDIAN) {
c5e74408 MD	84	ret = ctf_integer_read(srcp, &src_definition->mantissa->p);
	85	if (ret)
	86	return ret;
	87	ret = ctf_integer_read(srcp, &src_definition->exp->p);
	88	if (ret)
	89	return ret;
	90	ret = ctf_integer_read(srcp, &src_definition->sign->p);
	91	if (ret)
	92	return ret;
de0ba614	93	} else {
c5e74408 MD	94	ret = ctf_integer_read(srcp, &src_definition->sign->p);
	95	if (ret)
	96	return ret;
	97	ret = ctf_integer_read(srcp, &src_definition->exp->p);
	98	if (ret)
	99	return ret;
	100	ret = ctf_integer_read(srcp, &src_definition->mantissa->p);
	101	if (ret)
	102	return ret;
6dc2ca62	103	}
d11e9c49 MD	104
	105	dest_definition->mantissa->value._unsigned =
	106	src_definition->mantissa->value._unsigned;
	107	dest_definition->exp->value._signed =
	108	src_definition->exp->value._signed;
	109	dest_definition->sign->value._unsigned =
	110	src_definition->sign->value._unsigned;
	111
11d43b90	112	/* Write */
d11e9c49	113	if (dest_definition->declaration->byte_order == LITTLE_ENDIAN) {
c5e74408 MD	114	ret = ctf_integer_write(destp, &dest_definition->mantissa->p);
	115	if (ret)
	116	return ret;
	117	ret = ctf_integer_write(destp, &dest_definition->exp->p);
	118	if (ret)
	119	return ret;
	120	ret = ctf_integer_write(destp, &dest_definition->sign->p);
	121	if (ret)
	122	return ret;
de0ba614	123	} else {
c5e74408 MD	124	ret = ctf_integer_write(destp, &dest_definition->sign->p);
	125	if (ret)
	126	return ret;
	127	ret = ctf_integer_write(destp, &dest_definition->exp->p);
	128	if (ret)
	129	return ret;
	130	ret = ctf_integer_write(destp, &dest_definition->mantissa->p);
	131	if (ret)
	132	return ret;
6dc2ca62	133	}
c5e74408	134	return 0;
11d43b90	135	}
de0ba614	136
c5e74408	137	int ctf_float_read(struct stream_pos ppos, struct definition definition)
6dc2ca62	138	{
d11e9c49 MD	139	struct definition_float *float_definition =
	140	container_of(definition, struct definition_float, p);
	141	const struct declaration_float *float_declaration =
	142	float_definition->declaration;
	143	struct ctf_stream_pos *pos = ctf_pos(ppos);
f72803ca MD	144	union doubleIEEE754 u;
	145	struct definition *tmpdef;
	146	struct definition_float *tmpfloat;
46322b33	147	struct ctf_stream_pos destp;
aee35fcc	148	struct mmap_align mma;
c5e74408	149	int ret;
11d43b90	150
f72803ca MD	151	switch (float_declaration->mantissa->len + 1) {
	152	case FLT_MANT_DIG:
	153	tmpdef = static_float_declaration->p.definition_new(
	154	&static_float_declaration->p,
	155	NULL, 0, 0, "__tmpfloat");
	156	break;
	157	case DBL_MANT_DIG:
	158	tmpdef = static_double_declaration->p.definition_new(
	159	&static_double_declaration->p,
	160	NULL, 0, 0, "__tmpfloat");
	161	break;
	162	default:
	163	return -EINVAL;
	164	}
	165	tmpfloat = container_of(tmpdef, struct definition_float, p);
86b06ede	166	memset(&destp, 0, sizeof(destp));
989c73bc	167	ctf_init_pos(&destp, -1, O_RDWR);
aee35fcc MD	168	mmap_align_set_addr(&mma, (char *) u.bits);
aee35fcc MD	169	destp.base_mma = &mma;
f72803ca	170	destp.packet_size = sizeof(u) * CHAR_BIT;
d11e9c49	171	ctf_align_pos(pos, float_declaration->p.alignment);
c5e74408	172	ret = _ctf_float_copy(&destp.parent, tmpfloat, ppos, float_definition);
f72803ca MD	173	switch (float_declaration->mantissa->len + 1) {
	174	case FLT_MANT_DIG:
	175	float_definition->value = u.vf;
	176	break;
	177	case DBL_MANT_DIG:
	178	float_definition->value = u.vd;
	179	break;
	180	default:
	181	return -EINVAL;
	182	}
d11e9c49	183	definition_unref(tmpdef);
c5e74408	184	return ret;
de0ba614 MD	185	}
de0ba614 MD	186
c5e74408	187	int ctf_float_write(struct stream_pos ppos, struct definition definition)
de0ba614	188	{
d11e9c49 MD	189	struct definition_float *float_definition =
	190	container_of(definition, struct definition_float, p);
	191	const struct declaration_float *float_declaration =
	192	float_definition->declaration;
	193	struct ctf_stream_pos *pos = ctf_pos(ppos);
f72803ca MD	194	union doubleIEEE754 u;
	195	struct definition *tmpdef;
	196	struct definition_float *tmpfloat;
46322b33	197	struct ctf_stream_pos srcp;
aee35fcc	198	struct mmap_align mma;
c5e74408	199	int ret;
11d43b90	200
f72803ca MD	201	switch (float_declaration->mantissa->len + 1) {
	202	case FLT_MANT_DIG:
	203	tmpdef = static_float_declaration->p.definition_new(
	204	&static_float_declaration->p,
	205	NULL, 0, 0, "__tmpfloat");
	206	break;
	207	case DBL_MANT_DIG:
	208	tmpdef = static_double_declaration->p.definition_new(
	209	&static_double_declaration->p,
	210	NULL, 0, 0, "__tmpfloat");
	211	break;
	212	default:
	213	return -EINVAL;
	214	}
	215	tmpfloat = container_of(tmpdef, struct definition_float, p);
8563e754	216	ctf_init_pos(&srcp, -1, O_RDONLY);
aee35fcc MD	217	mmap_align_set_addr(&mma, (char *) u.bits);
aee35fcc MD	218	srcp.base_mma = &mma;
f72803ca MD	219	srcp.packet_size = sizeof(u) * CHAR_BIT;
	220	switch (float_declaration->mantissa->len + 1) {
	221	case FLT_MANT_DIG:
	222	u.vf = float_definition->value;
	223	break;
	224	case DBL_MANT_DIG:
	225	u.vd = float_definition->value;
	226	break;
	227	default:
	228	return -EINVAL;
	229	}
d11e9c49	230	ctf_align_pos(pos, float_declaration->p.alignment);
c5e74408	231	ret = _ctf_float_copy(ppos, float_definition, &srcp.parent, tmpfloat);
d11e9c49	232	definition_unref(tmpdef);
c5e74408	233	return ret;
de0ba614	234	}
6dc2ca62	235
d11e9c49	236	void __attribute__((constructor)) ctf_float_init(void)
de0ba614	237	{
f72803ca MD	238	static_float_declaration =
	239	float_declaration_new(FLT_MANT_DIG,
	240	sizeof(float) * CHAR_BIT - FLT_MANT_DIG,
	241	BYTE_ORDER,
	242	__alignof__(float));
	243	static_double_declaration =
	244	float_declaration_new(DBL_MANT_DIG,
	245	sizeof(double) * CHAR_BIT - DBL_MANT_DIG,
11d43b90	246	BYTE_ORDER,
f72803ca	247	__alignof__(double));
de0ba614 MD	248	}
de0ba614 MD	249
d11e9c49	250	void __attribute__((destructor)) ctf_float_fini(void)
de0ba614	251	{
f72803ca MD	252	declaration_unref(&static_float_declaration->p);
f72803ca MD	253	declaration_unref(&static_double_declaration->p);
6dc2ca62	254	}