transform: Add an "invert" transform module.

This inverts the data values:

 - An analog value of x becomes 1/x.

 - A digital value of 0 becomes 1 (and vice versa).

diff --git a/Makefile.am b/Makefile.am
index c68ceeb3a9e06521df5be6252b7ff3e436200c8b..16cd288d877b788ec59275824b865c0a28e60bb9 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -72,7 +72,8 @@ libsigrok_la_SOURCES += \
 libsigrok_la_SOURCES += \
        src/transform/transform.c \
        src/transform/nop.c \
-       src/transform/scale.c
+       src/transform/scale.c \
+       src/transform/invert.c
 
 # SCPI support
 libsigrok_la_SOURCES += \

diff --git a/src/transform/invert.c b/src/transform/invert.c
new file mode 100644 (file)
index 0000000..9f4dcea
--- /dev/null
+++ b/src/transform/invert.c
@@ -0,0 +1,87 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2015 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <string.h>
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+
+#define LOG_PREFIX "transform/invert"
+
+static int receive(const struct sr_transform *t,
+               struct sr_datafeed_packet *packet_in,
+               struct sr_datafeed_packet **packet_out)
+{
+       const struct sr_datafeed_logic *logic;
+       const struct sr_datafeed_analog *analog;
+       struct sr_channel *ch;
+       GSList *l;
+       float *fdata, *f;
+       int si, num_channels, c;
+       uint8_t *b;
+       uint64_t i, j;
+
+       if (!t || !t->sdi || !packet_in || !packet_out)
+               return SR_ERR_ARG;
+
+       switch (packet_in->type) {
+       case SR_DF_LOGIC:
+               logic = packet_in->payload;
+               for (i = 0; i <= logic->length - logic->unitsize; i += logic->unitsize) {
+                       for (j = 0; j < logic->unitsize; j++) {
+                               /* For now invert every bit in every byte. */
+                               b = (uint8_t *)logic->data + i + logic->unitsize - 1 - j;
+                               *b = ~(*b);
+                       }
+               }
+               break;
+       case SR_DF_ANALOG:
+               analog = packet_in->payload;
+               fdata = (float *)analog->data;
+               num_channels = g_slist_length(analog->channels);
+               for (si = 0; si < analog->num_samples; si++) {
+                       /* For now invert all values in all channels. */
+                       for (l = analog->channels, c = 0; l; l = l->next, c++) {
+                               ch = l->data;
+                               (void)ch;
+                               f = &fdata[si * num_channels + c];
+                               *f = 1.0 / *f;
+                       }
+               }
+               break;
+       default:
+               sr_spew("Unsupported packet type %d, ignoring.", packet_in->type);
+               break;
+       }
+
+       /* Return the in-place-modified packet. */
+       *packet_out = packet_in;
+
+       return SR_OK;
+}
+
+SR_PRIV struct sr_transform_module transform_invert = {
+       .id = "invert",
+       .name = "Invert",
+       .desc = "Invert values",
+       .options = NULL,
+       .init = NULL,
+       .receive = receive,
+       .cleanup = NULL,
+};

diff --git a/src/transform/transform.c b/src/transform/transform.c
index f4166dde18c0a35ad97a92c0e6564b0f7d8ca00b..3a422597bdb953859ce2b1137c6c603beb30e697 100644 (file)
--- a/src/transform/transform.c
+++ b/src/transform/transform.c
@@ -41,11 +41,13 @@
 /** @cond PRIVATE */
 extern SR_PRIV struct sr_transform_module transform_nop;
 extern SR_PRIV struct sr_transform_module transform_scale;
+extern SR_PRIV struct sr_transform_module transform_invert;
 /* @endcond */
 
 static const struct sr_transform_module *transform_module_list[] = {
        &transform_nop,
        &transform_scale,
+       &transform_invert,
        NULL,
 };