Backport recent changes from mainline.

[libsigrok.git] / src / conversion.c

diff --git a/src/conversion.c b/src/conversion.c
new file mode 100644 (file)
index 0000000..3d96930
--- /dev/null
+++ b/src/conversion.c
@@ -0,0 +1,107 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2017 Soeren Apel <soeren@apelpie.net>
+ *
+ * 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 2 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/>.
+ */
+
+/**
+ * @file
+ *
+ * Conversion helper functions.
+ */
+
+#include <libsigrok/libsigrok.h>
+#include "libsigrok-internal.h"
+
+#define LOG_PREFIX "conv"
+
+/**
+ * Convert analog values to logic values by using a fixed threshold.
+ *
+ * @param[in] analog The analog input values.
+ * @param[in] threshold The threshold to use.
+ * @param[out] output The converted output values; either 0 or 1. Must provide
+ *                    space for count bytes.
+ * @param[in] count The number of samples to process.
+ *
+ * @return SR_OK on success or SR_ERR on failure.
+ */
+SR_API int sr_a2l_threshold(const struct sr_datafeed_analog *analog,
+               float threshold, uint8_t *output, uint64_t count)
+{
+       float *input;
+
+       if (!analog->encoding->is_float) {
+               input = g_try_malloc(sizeof(float) * count);
+               if (!input)
+                       return SR_ERR;
+
+               sr_analog_to_float(analog, input);
+       } else
+               input = analog->data;
+
+       for (uint64_t i = 0; i < count; i++)
+               output[i] = (input[i] >= threshold) ? 1 : 0;
+
+       if (!analog->encoding->is_float)
+               g_free(input);
+
+       return SR_OK;
+}
+
+/**
+ * Convert analog values to logic values by using a Schmitt-trigger algorithm.
+ *
+ * @param analog The analog input values.
+ * @param lo_thr The low threshold - result becomes 0 below it.
+ * @param lo_thr The high threshold - result becomes 1 above it.
+ * @param state The internal converter state. Must contain the state of logic
+ *        sample n-1, will contain the state of logic sample n+count upon exit.
+ * @param output The converted output values; either 0 or 1. Must provide
+ *        space for count bytes.
+ * @param count The number of samples to process.
+ *
+ * @return SR_OK on success or SR_ERR on failure.
+ */
+SR_API int sr_a2l_schmitt_trigger(const struct sr_datafeed_analog *analog,
+               float lo_thr, float hi_thr, uint8_t *state, uint8_t *output,
+               uint64_t count)
+{
+       float *input;
+
+       if (!analog->encoding->is_float) {
+               input = g_try_malloc(sizeof(float) * count);
+               if (!input)
+                       return SR_ERR;
+
+               sr_analog_to_float(analog, input);
+       } else
+               input = analog->data;
+
+       for (uint64_t i = 0; i < count; i++) {
+               if (input[i] < lo_thr)
+                       *state = 0;
+               else if (input[i] > hi_thr)
+                       *state = 1;
+
+               output[i] = *state;
+       }
+
+       if (!analog->encoding->is_float)
+               g_free(input);
+
+       return SR_OK;
+}