src/analog.c

   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         { SR_MQFLAG_FOUR_WIRE, " 4-WIRE" },
 118         ALL_ZERO
 119 };
 120
 121 SR_PRIV int sr_analog_init(struct sr_datafeed_analog *analog,
 122                 struct sr_analog_encoding *encoding,
 123                 struct sr_analog_meaning *meaning,
 124                 struct sr_analog_spec *spec,
 125                 int digits)
 126 {
 127         memset(analog, 0, sizeof(*analog));
 128         memset(encoding, 0, sizeof(*encoding));
 129         memset(meaning, 0, sizeof(*meaning));
 130         memset(spec, 0, sizeof(*spec));
 131
 132         analog->encoding = encoding;
 133         analog->meaning = meaning;
 134         analog->spec = spec;
 135
 136         encoding->unitsize = sizeof(float);
 137         encoding->is_float = TRUE;
 138 #ifdef WORDS_BIGENDIAN
 139         encoding->is_bigendian = TRUE;
 140 #else
 141         encoding->is_bigendian = FALSE;
 142 #endif
 143         encoding->digits = digits;
 144         encoding->is_digits_decimal = TRUE;
 145         encoding->scale.p = 1;
 146         encoding->scale.q = 1;
 147         encoding->offset.p = 0;
 148         encoding->offset.q = 1;
 149
 150         spec->spec_digits = digits;
 151
 152         return SR_OK;
 153 }
 154
 155 /**
 156  * Convert an analog datafeed payload to an array of floats.
 157  *
 158  * @param[in] analog The analog payload to convert. Must not be NULL.
 159  *                   analog->data, analog->meaning, and analog->encoding
 160  *                   must not be NULL.
 161  * @param[out] outbuf Memory where to store the result. Must not be NULL.
 162  *
 163  * Sufficient memory for outbuf must have been pre-allocated by the caller,
 164  * who is also responsible for freeing it when no longer needed.
 165  *
 166  * @retval SR_OK Success.
 167  * @retval SR_ERR Unsupported encoding.
 168  * @retval SR_ERR_ARG Invalid argument.
 169  *
 170  * @since 0.4.0
 171  */
 172 SR_API int sr_analog_to_float(const struct sr_datafeed_analog *analog,
 173                 float *outbuf)
 174 {
 175         float offset;
 176         unsigned int b, i, count;
 177         gboolean bigendian;
 178
 179         if (!analog || !(analog->data) || !(analog->meaning)
 180                         || !(analog->encoding) || !outbuf)
 181                 return SR_ERR_ARG;
 182
 183         count = analog->num_samples * g_slist_length(analog->meaning->channels);
 184
 185 #ifdef WORDS_BIGENDIAN
 186         bigendian = TRUE;
 187 #else
 188         bigendian = FALSE;
 189 #endif
 190         if (!analog->encoding->is_float) {
 191                 float offset = analog->encoding->offset.p / (float)analog->encoding->offset.q;
 192                 float scale = analog->encoding->scale.p / (float)analog->encoding->scale.q;
 193                 gboolean is_signed = analog->encoding->is_signed;
 194                 gboolean is_bigendian = analog->encoding->is_bigendian;
 195                 int8_t *data8 = (int8_t *)(analog->data);
 196                 int16_t *data16 = (int16_t *)(analog->data);
 197                 int32_t *data32 = (int32_t *)(analog->data);
 198
 199                 switch (analog->encoding->unitsize) {
 200                 case 1:
 201                         if (is_signed) {
 202                                 for (unsigned int i = 0; i < count; i++) {
 203                                         outbuf[i] = scale * data8[i];
 204                                         outbuf[i] += offset;
 205                                 }
 206                         } else {
 207                                 for (unsigned int i = 0; i < count; i++) {
 208                                         outbuf[i] = scale * R8(data8 + i);
 209                                         outbuf[i] += offset;
 210                                 }
 211                         }
 212                         break;
 213                 case 2:
 214                         if (is_signed && is_bigendian) {
 215                                 for (unsigned int i = 0; i < count; i++) {
 216                                         outbuf[i] = scale * RB16S(&data16[i]);
 217                                         outbuf[i] += offset;
 218                                 }
 219                         } else if (is_bigendian) {
 220                                 for (unsigned int i = 0; i < count; i++) {
 221                                         outbuf[i] = scale * RB16(&data16[i]);
 222                                         outbuf[i] += offset;
 223                                 }
 224                         } else if (is_signed) {
 225                                 for (unsigned int i = 0; i < count; i++) {
 226                                         outbuf[i] = scale * RL16S(&data16[i]);
 227                                         outbuf[i] += offset;
 228                                 }
 229                         } else {
 230                                 for (unsigned int i = 0; i < count; i++) {
 231                                         outbuf[i] = scale * RL16(&data16[i]);
 232                                         outbuf[i] += offset;
 233                                 }
 234                         }
 235                         break;
 236                 case 4:
 237                         if (is_signed && is_bigendian) {
 238                                 for (unsigned int i = 0; i < count; i++) {
 239                                         outbuf[i] = scale * RB32S(&data32[i]);
 240                                         outbuf[i] += offset;
 241                                 }
 242                         } else if (is_bigendian) {
 243                                 for (unsigned int i = 0; i < count; i++) {
 244                                         outbuf[i] = scale * RB32(&data32[i]);
 245                                         outbuf[i] += offset;
 246                                 }
 247                         } else if (is_signed) {
 248                                 for (unsigned int i = 0; i < count; i++) {
 249                                         outbuf[i] = scale * RL32S(&data32[i]);
 250                                         outbuf[i] += offset;
 251                                 }
 252                         } else {
 253                                 for (unsigned int i = 0; i < count; i++) {
 254                                         outbuf[i] = scale * RL32(&data32[i]);
 255                                         outbuf[i] += offset;
 256                                 }
 257                         }
 258                         break;
 259                 default:
 260                         sr_err("Unsupported unit size '%d' for analog-to-float conversion.",
 261                                 analog->encoding->unitsize);
 262                         return SR_ERR;
 263                 }
 264                 return SR_OK;
 265         }
 266
 267         if (analog->encoding->unitsize == sizeof(float)
 268                         && analog->encoding->is_bigendian == bigendian
 269                         && analog->encoding->scale.p == 1
 270                         && analog->encoding->scale.q == 1
 271                         && analog->encoding->offset.p / (float)analog->encoding->offset.q == 0) {
 272                 /* The data is already in the right format. */
 273                 memcpy(outbuf, analog->data, count * sizeof(float));
 274         } else {
 275                 for (i = 0; i < count; i += analog->encoding->unitsize) {
 276                         for (b = 0; b < analog->encoding->unitsize; b++) {
 277                                 if (analog->encoding->is_bigendian == bigendian)
 278                                         ((uint8_t *)outbuf)[i + b] =
 279                                                 ((uint8_t *)analog->data)[i * analog->encoding->unitsize + b];
 280                                 else
 281                                         ((uint8_t *)outbuf)[i + (analog->encoding->unitsize - b)] =
 282                                                 ((uint8_t *)analog->data)[i * analog->encoding->unitsize + b];
 283                         }
 284                         if (analog->encoding->scale.p != 1
 285                                         || analog->encoding->scale.q != 1)
 286                                 outbuf[i] = (outbuf[i] * analog->encoding->scale.p) / analog->encoding->scale.q;
 287                         offset = ((float)analog->encoding->offset.p / (float)analog->encoding->offset.q);
 288                         outbuf[i] += offset;
 289                 }
 290         }
 291
 292         return SR_OK;
 293 }
 294
 295 /**
 296  * Convert the unit/MQ/MQ flags in the analog struct to a string.
 297  *
 298  * @param[in] analog Struct containing the unit, MQ and MQ flags.
 299  *                   Must not be NULL. analog->meaning must not be NULL.
 300  * @param[out] result Pointer to store result. Must not be NULL.
 301  *
 302  * The string is allocated by the function and must be freed by the caller
 303  * after use by calling g_free().
 304  *
 305  * @retval SR_OK Success.
 306  * @retval SR_ERR_ARG Invalid argument.
 307  *
 308  * @since 0.4.0
 309  */
 310 SR_API int sr_analog_unit_to_string(const struct sr_datafeed_analog *analog,
 311                 char **result)
 312 {
 313         int i;
 314         GString *buf;
 315
 316         if (!analog || !(analog->meaning) || !result)
 317                 return SR_ERR_ARG;
 318
 319         buf = g_string_new(NULL);
 320
 321         for (i = 0; unit_strings[i].value; i++) {
 322                 if (analog->meaning->unit == unit_strings[i].value) {
 323                         g_string_assign(buf, unit_strings[i].str);
 324                         break;
 325                 }
 326         }
 327
 328         /* More than one MQ flag may apply. */
 329         for (i = 0; mq_strings[i].value; i++)
 330                 if (analog->meaning->mqflags & mq_strings[i].value)
 331                         g_string_append(buf, mq_strings[i].str);
 332
 333         *result = buf->str;
 334         g_string_free(buf, FALSE);
 335
 336         return SR_OK;
 337 }
 338
 339 /**
 340  * Set sr_rational r to the given value.
 341  *
 342  * @param[out] r Rational number struct to set. Must not be NULL.
 343  * @param[in] p Numerator.
 344  * @param[in] q Denominator.
 345  *
 346  * @since 0.4.0
 347  */
 348 SR_API void sr_rational_set(struct sr_rational *r, int64_t p, uint64_t q)
 349 {
 350         if (!r)
 351                 return;
 352
 353         r->p = p;
 354         r->q = q;
 355 }
 356
 357 /** @} */