[libsigrok.git] / src / analog.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2014 Bert Vermeulen <bert@biot.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <ctype.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"

/** @cond PRIVATE */
#define LOG_PREFIX "analog"
/** @endcond */

/**
 * @file
 *
 * Handling and converting analog data.
 */

/**
 * @defgroup grp_analog Analog data handling
 *
 * Handling and converting analog data.
 *
 * @{
 */

struct unit_mq_string {
	uint64_t value;
	const char *str;
};

/* Please use the same order as in enum sr_unit (libsigrok.h). */
static struct unit_mq_string unit_strings[] = {
	{ SR_UNIT_VOLT, "V" },
	{ SR_UNIT_AMPERE, "A" },
	{ SR_UNIT_OHM, "\xe2\x84\xa6" },
	{ SR_UNIT_FARAD, "F" },
	{ SR_UNIT_KELVIN, "K" },
	{ SR_UNIT_CELSIUS, "\xc2\xb0""C" },
	{ SR_UNIT_FAHRENHEIT, "\xc2\xb0""F" },
	{ SR_UNIT_HERTZ, "Hz" },
	{ SR_UNIT_PERCENTAGE, "%" },
	{ SR_UNIT_BOOLEAN, "" },
	{ SR_UNIT_SECOND, "s" },
	{ SR_UNIT_SIEMENS, "S" },
	{ SR_UNIT_DECIBEL_MW, "dBu" },
	{ SR_UNIT_DECIBEL_VOLT, "dBv" },
	{ SR_UNIT_UNITLESS, "" },
	{ SR_UNIT_DECIBEL_SPL, "dB" },
	{ SR_UNIT_CONCENTRATION, "ppm" },
	{ SR_UNIT_REVOLUTIONS_PER_MINUTE, "RPM" },
	{ SR_UNIT_VOLT_AMPERE, "VA" },
	{ SR_UNIT_WATT, "W" },
	{ SR_UNIT_WATT_HOUR, "Wh" },
	{ SR_UNIT_METER_SECOND, "m/s" },
	{ SR_UNIT_HECTOPASCAL, "hPa" },
	{ SR_UNIT_HUMIDITY_293K, "%rF" },
	{ SR_UNIT_DEGREE, "\xc2\xb0" },
	{ SR_UNIT_HENRY, "H" },
	{ SR_UNIT_GRAM, "g" },
	{ SR_UNIT_CARAT, "ct" },
	{ SR_UNIT_OUNCE, "oz" },
	{ SR_UNIT_TROY_OUNCE, "oz t" },
	{ SR_UNIT_POUND, "lb" },
	{ SR_UNIT_PENNYWEIGHT, "dwt" },
	{ SR_UNIT_GRAIN, "gr" },
	{ SR_UNIT_TAEL, "tael" },
	{ SR_UNIT_MOMME, "momme" },
	{ SR_UNIT_TOLA, "tola" },
	{ SR_UNIT_PIECE, "pcs" },
	ALL_ZERO
};

/* Please use the same order as in enum sr_mqflag (libsigrok.h). */
static struct unit_mq_string mq_strings[] = {
	{ SR_MQFLAG_AC, " AC" },
	{ SR_MQFLAG_DC, " DC" },
	{ SR_MQFLAG_RMS, " RMS" },
	{ SR_MQFLAG_DIODE, " DIODE" },
	{ SR_MQFLAG_HOLD, " HOLD" },
	{ SR_MQFLAG_MAX, " MAX" },
	{ SR_MQFLAG_MIN, " MIN" },
	{ SR_MQFLAG_AUTORANGE, " AUTO" },
	{ SR_MQFLAG_RELATIVE, " REL" },
	{ SR_MQFLAG_SPL_FREQ_WEIGHT_A, "(A)" },
	{ SR_MQFLAG_SPL_FREQ_WEIGHT_C, "(C)" },
	{ SR_MQFLAG_SPL_FREQ_WEIGHT_Z, "(Z)" },
	{ SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT, "(SPL)" },
	{ SR_MQFLAG_SPL_TIME_WEIGHT_S, " S" },
	{ SR_MQFLAG_SPL_TIME_WEIGHT_F, " F" },
	{ SR_MQFLAG_SPL_LAT, " LAT" },
	/* Not a standard function for SLMs, so this is a made-up notation. */
	{ SR_MQFLAG_SPL_PCT_OVER_ALARM, "%oA" },
	{ SR_MQFLAG_DURATION, " DURATION" },
	{ SR_MQFLAG_AVG, " AVG" },
	{ SR_MQFLAG_REFERENCE, " REF" },
	{ SR_MQFLAG_UNSTABLE, " UNSTABLE" },
	ALL_ZERO
};

SR_PRIV int sr_analog_init(struct sr_datafeed_analog *analog,
		struct sr_analog_encoding *encoding,
		struct sr_analog_meaning *meaning,
		struct sr_analog_spec *spec,
		int digits)
{
	memset(analog, 0, sizeof(*analog));
	memset(encoding, 0, sizeof(*encoding));
	memset(meaning, 0, sizeof(*meaning));
	memset(spec, 0, sizeof(*spec));

	analog->encoding = encoding;
	analog->meaning = meaning;
	analog->spec = spec;

	encoding->unitsize = sizeof(float);
	encoding->is_float = TRUE;
#ifdef WORDS_BIGENDIAN
	encoding->is_bigendian = TRUE;
#else
	encoding->is_bigendian = FALSE;
#endif
	encoding->digits = digits;
	encoding->is_digits_decimal = TRUE;
	encoding->scale.p = 1;
	encoding->scale.q = 1;
	encoding->offset.p = 0;
	encoding->offset.q = 1;

	spec->spec_digits = digits;

	return SR_OK;
}

/**
 * Convert an analog datafeed payload to an array of floats.
 *
 * @param[in] analog The analog payload to convert. Must not be NULL.
 *                   analog->data, analog->meaning, and analog->encoding
 *                   must not be NULL.
 * @param[out] outbuf Memory where to store the result. Must not be NULL.
 *
 * Sufficient memory for outbuf must have been pre-allocated by the caller,
 * who is also responsible for freeing it when no longer needed.
 *
 * @retval SR_OK Success.
 * @retval SR_ERR Unsupported encoding.
 * @retval SR_ERR_ARG Invalid argument.
 *
 * @since 0.4.0
 */
SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
		float *outbuf)
{
	float offset;
	unsigned int b, i, count;
	gboolean bigendian;

	if (!analog || !(analog->data) || !(analog->meaning)
			|| !(analog->encoding) || !outbuf)
		return SR_ERR_ARG;

	count = analog->num_samples * g_slist_length(analog->meaning->channels);

#ifdef WORDS_BIGENDIAN
	bigendian = TRUE;
#else
	bigendian = FALSE;
#endif
	if (!analog->encoding->is_float) {
		float offset = analog->encoding->offset.p / (float)analog->encoding->offset.q;
		float scale = analog->encoding->scale.p / (float)analog->encoding->scale.q;
		gboolean is_signed = analog->encoding->is_signed;
		gboolean is_bigendian = analog->encoding->is_bigendian;
		int8_t *data8 = (int8_t *)(analog->data);
		int16_t *data16 = (int16_t *)(analog->data);
		int32_t *data32 = (int32_t *)(analog->data);

		switch (analog->encoding->unitsize) {
		case 1:
			if (is_signed) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * data8[i];
					outbuf[i] += offset;
				}
			} else {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * R8(data8 + i);
					outbuf[i] += offset;
				}
			}
			break;
		case 2:
			if (is_signed && is_bigendian) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RB16S(&data16[i]);
					outbuf[i] += offset;
				}
			} else if (is_bigendian) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RB16(&data16[i]);
					outbuf[i] += offset;
				}
			} else if (is_signed) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RL16S(&data16[i]);
					outbuf[i] += offset;
				}
			} else {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RL16(&data16[i]);
					outbuf[i] += offset;
				}
			}
			break;
		case 4:
			if (is_signed && is_bigendian) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RB32S(&data32[i]);
					outbuf[i] += offset;
				}
			} else if (is_bigendian) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RB32(&data32[i]);
					outbuf[i] += offset;
				}
			} else if (is_signed) {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RL32S(&data32[i]);
					outbuf[i] += offset;
				}
			} else {
				for (unsigned int i = 0; i < count; i++) {
					outbuf[i] = scale * RL32(&data32[i]);
					outbuf[i] += offset;
				}
			}
			break;
		default:
			sr_err("Unsupported unit size '%d' for analog-to-float conversion.",
				analog->encoding->unitsize);
			return SR_ERR;
		}
		return SR_OK;
	}

	if (analog->encoding->unitsize == sizeof(float)
			&& analog->encoding->is_bigendian == bigendian
			&& analog->encoding->scale.p == 1
			&& analog->encoding->scale.q == 1
			&& analog->encoding->offset.p / (float)analog->encoding->offset.q == 0) {
		/* The data is already in the right format. */
		memcpy(outbuf, analog->data, count * sizeof(float));
	} else {
		for (i = 0; i < count; i += analog->encoding->unitsize) {
			for (b = 0; b < analog->encoding->unitsize; b++) {
				if (analog->encoding->is_bigendian == bigendian)
					((uint8_t *)outbuf)[i + b] =
						((uint8_t *)analog->data)[i * analog->encoding->unitsize + b];
				else
					((uint8_t *)outbuf)[i + (analog->encoding->unitsize - b)] =
						((uint8_t *)analog->data)[i * analog->encoding->unitsize + b];
			}
			if (analog->encoding->scale.p != 1
					|| analog->encoding->scale.q != 1)
				outbuf[i] = (outbuf[i] * analog->encoding->scale.p) / analog->encoding->scale.q;
			offset = ((float)analog->encoding->offset.p / (float)analog->encoding->offset.q);
			outbuf[i] += offset;
		}
	}

	return SR_OK;
}

/**
 * Convert the unit/MQ/MQ flags in the analog struct to a string.
 *
 * @param[in] analog Struct containing the unit, MQ and MQ flags.
 *                   Must not be NULL. analog->meaning must not be NULL.
 * @param[out] result Pointer to store result. Must not be NULL.
 *
 * The string is allocated by the function and must be freed by the caller
 * after use by calling g_free().
 *
 * @retval SR_OK Success.
 * @retval SR_ERR_ARG Invalid argument.
 *
 * @since 0.4.0
 */
SR_API int sr_analog_unit_to_string(const struct sr_datafeed_analog *analog,
		char **result)
{
	int i;
	GString *buf;

	if (!analog || !(analog->meaning) || !result)
		return SR_ERR_ARG;

	buf = g_string_new(NULL);

	for (i = 0; unit_strings[i].value; i++) {
		if (analog->meaning->unit == unit_strings[i].value) {
			g_string_assign(buf, unit_strings[i].str);
			break;
		}
	}

	/* More than one MQ flag may apply. */
	for (i = 0; mq_strings[i].value; i++)
		if (analog->meaning->mqflags & mq_strings[i].value)
			g_string_append(buf, mq_strings[i].str);

	*result = buf->str;
	g_string_free(buf, FALSE);

	return SR_OK;
}

/**
 * Set sr_rational r to the given value.
 *
 * @param[out] r Rational number struct to set. Must not be NULL.
 * @param[in] p Numerator.
 * @param[in] q Denominator.
 *
 * @since 0.4.0
 */
SR_API void sr_rational_set(struct sr_rational *r, int64_t p, uint64_t q)
{
	if (!r)
		return;

	r->p = p;
	r->q = q;
}

/** @} */
Commit	Line	Data
	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2014 Bert Vermeulen <bert@biot.com>
	5	*
	6	* This program is free software: you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation, either version 3 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	#include <config.h>
	21	#include <stdio.h>
	22	#include <stdint.h>
	23	#include <string.h>
	24	#include <ctype.h>
	25	#include <libsigrok/libsigrok.h>
	26	#include "libsigrok-internal.h"
	27
	28	/** @cond PRIVATE */
	29	#define LOG_PREFIX "analog"
	30	/** @endcond */
	31
	32	/**
	33	* @file
	34	*
	35	* Handling and converting analog data.
	36	*/
	37
	38	/**
	39	* @defgroup grp_analog Analog data handling
	40	*
	41	* Handling and converting analog data.
	42	*
	43	* @{
	44	*/
	45
	46	struct unit_mq_string {
	47	uint64_t value;
	48	const char *str;
	49	};
	50
	51	/* Please use the same order as in enum sr_unit (libsigrok.h). */
	52	static struct unit_mq_string unit_strings[] = {
	53	{ SR_UNIT_VOLT, "V" },
	54	{ SR_UNIT_AMPERE, "A" },
	55	{ SR_UNIT_OHM, "\xe2\x84\xa6" },
	56	{ SR_UNIT_FARAD, "F" },
	57	{ SR_UNIT_KELVIN, "K" },
	58	{ SR_UNIT_CELSIUS, "\xc2\xb0""C" },
	59	{ SR_UNIT_FAHRENHEIT, "\xc2\xb0""F" },
	60	{ SR_UNIT_HERTZ, "Hz" },
	61	{ SR_UNIT_PERCENTAGE, "%" },
	62	{ SR_UNIT_BOOLEAN, "" },
	63	{ SR_UNIT_SECOND, "s" },
	64	{ SR_UNIT_SIEMENS, "S" },
	65	{ SR_UNIT_DECIBEL_MW, "dBu" },
	66	{ SR_UNIT_DECIBEL_VOLT, "dBv" },
	67	{ SR_UNIT_UNITLESS, "" },
	68	{ SR_UNIT_DECIBEL_SPL, "dB" },
	69	{ SR_UNIT_CONCENTRATION, "ppm" },
	70	{ SR_UNIT_REVOLUTIONS_PER_MINUTE, "RPM" },
	71	{ SR_UNIT_VOLT_AMPERE, "VA" },
	72	{ SR_UNIT_WATT, "W" },
	73	{ SR_UNIT_WATT_HOUR, "Wh" },
	74	{ SR_UNIT_METER_SECOND, "m/s" },
	75	{ SR_UNIT_HECTOPASCAL, "hPa" },
	76	{ SR_UNIT_HUMIDITY_293K, "%rF" },
	77	{ SR_UNIT_DEGREE, "\xc2\xb0" },
	78	{ SR_UNIT_HENRY, "H" },
	79	{ SR_UNIT_GRAM, "g" },
	80	{ SR_UNIT_CARAT, "ct" },
	81	{ SR_UNIT_OUNCE, "oz" },
	82	{ SR_UNIT_TROY_OUNCE, "oz t" },
	83	{ SR_UNIT_POUND, "lb" },
	84	{ SR_UNIT_PENNYWEIGHT, "dwt" },
	85	{ SR_UNIT_GRAIN, "gr" },
	86	{ SR_UNIT_TAEL, "tael" },
	87	{ SR_UNIT_MOMME, "momme" },
	88	{ SR_UNIT_TOLA, "tola" },
	89	{ SR_UNIT_PIECE, "pcs" },
	90	ALL_ZERO
	91	};
	92
	93	/* Please use the same order as in enum sr_mqflag (libsigrok.h). */
	94	static struct unit_mq_string mq_strings[] = {
	95	{ SR_MQFLAG_AC, " AC" },
	96	{ SR_MQFLAG_DC, " DC" },
	97	{ SR_MQFLAG_RMS, " RMS" },
	98	{ SR_MQFLAG_DIODE, " DIODE" },
	99	{ SR_MQFLAG_HOLD, " HOLD" },
	100	{ SR_MQFLAG_MAX, " MAX" },
	101	{ SR_MQFLAG_MIN, " MIN" },
	102	{ SR_MQFLAG_AUTORANGE, " AUTO" },
	103	{ SR_MQFLAG_RELATIVE, " REL" },
	104	{ SR_MQFLAG_SPL_FREQ_WEIGHT_A, "(A)" },
	105	{ SR_MQFLAG_SPL_FREQ_WEIGHT_C, "(C)" },
	106	{ SR_MQFLAG_SPL_FREQ_WEIGHT_Z, "(Z)" },
	107	{ SR_MQFLAG_SPL_FREQ_WEIGHT_FLAT, "(SPL)" },
	108	{ SR_MQFLAG_SPL_TIME_WEIGHT_S, " S" },
	109	{ SR_MQFLAG_SPL_TIME_WEIGHT_F, " F" },
	110	{ SR_MQFLAG_SPL_LAT, " LAT" },
	111	/* Not a standard function for SLMs, so this is a made-up notation. */
	112	{ SR_MQFLAG_SPL_PCT_OVER_ALARM, "%oA" },
	113	{ SR_MQFLAG_DURATION, " DURATION" },
	114	{ SR_MQFLAG_AVG, " AVG" },
	115	{ SR_MQFLAG_REFERENCE, " REF" },
	116	{ SR_MQFLAG_UNSTABLE, " UNSTABLE" },
	117	ALL_ZERO
	118	};
	119
	120	SR_PRIV int sr_analog_init(struct sr_datafeed_analog *analog,
	121	struct sr_analog_encoding *encoding,
	122	struct sr_analog_meaning *meaning,
	123	struct sr_analog_spec *spec,
	124	int digits)
	125	{
	126	memset(analog, 0, sizeof(*analog));
	127	memset(encoding, 0, sizeof(*encoding));
	128	memset(meaning, 0, sizeof(*meaning));
	129	memset(spec, 0, sizeof(*spec));
	130
	131	analog->encoding = encoding;
	132	analog->meaning = meaning;
	133	analog->spec = spec;
	134
	135	encoding->unitsize = sizeof(float);
	136	encoding->is_float = TRUE;
	137	#ifdef WORDS_BIGENDIAN
	138	encoding->is_bigendian = TRUE;
	139	#else
	140	encoding->is_bigendian = FALSE;
	141	#endif
	142	encoding->digits = digits;
	143	encoding->is_digits_decimal = TRUE;
	144	encoding->scale.p = 1;
	145	encoding->scale.q = 1;
	146	encoding->offset.p = 0;
	147	encoding->offset.q = 1;
	148
	149	spec->spec_digits = digits;
	150
	151	return SR_OK;
	152	}
	153
	154	/**
	155	* Convert an analog datafeed payload to an array of floats.
	156	*
	157	* @param[in] analog The analog payload to convert. Must not be NULL.
	158	* analog->data, analog->meaning, and analog->encoding
	159	* must not be NULL.
	160	* @param[out] outbuf Memory where to store the result. Must not be NULL.
	161	*
	162	* Sufficient memory for outbuf must have been pre-allocated by the caller,
	163	* who is also responsible for freeing it when no longer needed.
	164	*
	165	* @retval SR_OK Success.
	166	* @retval SR_ERR Unsupported encoding.
	167	* @retval SR_ERR_ARG Invalid argument.
	168	*
	169	* @since 0.4.0
	170	*/
	171	SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
	172	float *outbuf)
	173	{
	174	float offset;
	175	unsigned int b, i, count;
	176	gboolean bigendian;
	177
	178	if (!analog \|\| !(analog->data) \|\| !(analog->meaning)
	179	\|\| !(analog->encoding) \|\| !outbuf)
	180	return SR_ERR_ARG;
	181
	182	count = analog->num_samples * g_slist_length(analog->meaning->channels);
	183
	184	#ifdef WORDS_BIGENDIAN
	185	bigendian = TRUE;
	186	#else
	187	bigendian = FALSE;
	188	#endif
	189	if (!analog->encoding->is_float) {
	190	float offset = analog->encoding->offset.p / (float)analog->encoding->offset.q;
	191	float scale = analog->encoding->scale.p / (float)analog->encoding->scale.q;
	192	gboolean is_signed = analog->encoding->is_signed;
	193	gboolean is_bigendian = analog->encoding->is_bigendian;
	194	int8_t data8 = (int8_t )(analog->data);
	195	int16_t data16 = (int16_t )(analog->data);
	196	int32_t data32 = (int32_t )(analog->data);
	197
	198	switch (analog->encoding->unitsize) {
	199	case 1:
	200	if (is_signed) {
	201	for (unsigned int i = 0; i < count; i++) {
	202	outbuf[i] = scale * data8[i];
	203	outbuf[i] += offset;
	204	}
	205	} else {
	206	for (unsigned int i = 0; i < count; i++) {
	207	outbuf[i] = scale * R8(data8 + i);
	208	outbuf[i] += offset;
	209	}
	210	}
	211	break;
	212	case 2:
	213	if (is_signed && is_bigendian) {
	214	for (unsigned int i = 0; i < count; i++) {
	215	outbuf[i] = scale * RB16S(&data16[i]);
	216	outbuf[i] += offset;
	217	}
	218	} else if (is_bigendian) {
	219	for (unsigned int i = 0; i < count; i++) {
	220	outbuf[i] = scale * RB16(&data16[i]);
	221	outbuf[i] += offset;
	222	}
	223	} else if (is_signed) {
	224	for (unsigned int i = 0; i < count; i++) {
	225	outbuf[i] = scale * RL16S(&data16[i]);
	226	outbuf[i] += offset;
	227	}
	228	} else {
	229	for (unsigned int i = 0; i < count; i++) {
	230	outbuf[i] = scale * RL16(&data16[i]);
	231	outbuf[i] += offset;
	232	}
	233	}
	234	break;
	235	case 4:
	236	if (is_signed && is_bigendian) {
	237	for (unsigned int i = 0; i < count; i++) {
	238	outbuf[i] = scale * RB32S(&data32[i]);
	239	outbuf[i] += offset;
	240	}
	241	} else if (is_bigendian) {
	242	for (unsigned int i = 0; i < count; i++) {
	243	outbuf[i] = scale * RB32(&data32[i]);
	244	outbuf[i] += offset;
	245	}
	246	} else if (is_signed) {
	247	for (unsigned int i = 0; i < count; i++) {
	248	outbuf[i] = scale * RL32S(&data32[i]);
	249	outbuf[i] += offset;
	250	}
	251	} else {
	252	for (unsigned int i = 0; i < count; i++) {
	253	outbuf[i] = scale * RL32(&data32[i]);
	254	outbuf[i] += offset;
	255	}
	256	}
	257	break;
	258	default:
	259	sr_err("Unsupported unit size '%d' for analog-to-float conversion.",
	260	analog->encoding->unitsize);
	261	return SR_ERR;
	262	}
	263	return SR_OK;
	264	}
	265
	266	if (analog->encoding->unitsize == sizeof(float)
	267	&& analog->encoding->is_bigendian == bigendian
	268	&& analog->encoding->scale.p == 1
	269	&& analog->encoding->scale.q == 1
	270	&& analog->encoding->offset.p / (float)analog->encoding->offset.q == 0) {
	271	/* The data is already in the right format. */
	272	memcpy(outbuf, analog->data, count * sizeof(float));
	273	} else {
	274	for (i = 0; i < count; i += analog->encoding->unitsize) {
	275	for (b = 0; b < analog->encoding->unitsize; b++) {
	276	if (analog->encoding->is_bigendian == bigendian)
	277	((uint8_t *)outbuf)[i + b] =
	278	((uint8_t )analog->data)[i analog->encoding->unitsize + b];
	279	else
	280	((uint8_t *)outbuf)[i + (analog->encoding->unitsize - b)] =
	281	((uint8_t )analog->data)[i analog->encoding->unitsize + b];
	282	}
	283	if (analog->encoding->scale.p != 1
	284	\|\| analog->encoding->scale.q != 1)
	285	outbuf[i] = (outbuf[i] * analog->encoding->scale.p) / analog->encoding->scale.q;
	286	offset = ((float)analog->encoding->offset.p / (float)analog->encoding->offset.q);
	287	outbuf[i] += offset;
	288	}
	289	}
	290
	291	return SR_OK;
	292	}
	293
	294	/**
	295	* Convert the unit/MQ/MQ flags in the analog struct to a string.
	296	*
	297	* @param[in] analog Struct containing the unit, MQ and MQ flags.
	298	* Must not be NULL. analog->meaning must not be NULL.
	299	* @param[out] result Pointer to store result. Must not be NULL.
	300	*
	301	* The string is allocated by the function and must be freed by the caller
	302	* after use by calling g_free().
	303	*
	304	* @retval SR_OK Success.
	305	* @retval SR_ERR_ARG Invalid argument.
	306	*
	307	* @since 0.4.0
	308	*/
	309	SR_API int sr_analog_unit_to_string(const struct sr_datafeed_analog *analog,
	310	char **result)
	311	{
	312	int i;
	313	GString *buf;
	314
	315	if (!analog \|\| !(analog->meaning) \|\| !result)
	316	return SR_ERR_ARG;
	317
	318	buf = g_string_new(NULL);
	319
	320	for (i = 0; unit_strings[i].value; i++) {
	321	if (analog->meaning->unit == unit_strings[i].value) {
	322	g_string_assign(buf, unit_strings[i].str);
	323	break;
	324	}
	325	}
	326
	327	/* More than one MQ flag may apply. */
	328	for (i = 0; mq_strings[i].value; i++)
	329	if (analog->meaning->mqflags & mq_strings[i].value)
	330	g_string_append(buf, mq_strings[i].str);
	331
	332	*result = buf->str;
	333	g_string_free(buf, FALSE);
	334
	335	return SR_OK;
	336	}
	337
	338	/**
	339	* Set sr_rational r to the given value.
	340	*
	341	* @param[out] r Rational number struct to set. Must not be NULL.
	342	* @param[in] p Numerator.
	343	* @param[in] q Denominator.
	344	*
	345	* @since 0.4.0
	346	*/
	347	SR_API void sr_rational_set(struct sr_rational *r, int64_t p, uint64_t q)
	348	{
	349	if (!r)
	350	return;
	351
	352	r->p = p;
	353	r->q = q;
	354	}
	355
	356	/** @} */