1 files changed, 150 insertions, 0 deletions
diff --git a/hal-volume.c b/hal-volume.c
new file mode 100644
index 0000000..997ce98
--- /dev/null
+++ b/hal-volume.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2016 "IoT.bzh"
+ * Author Fulup Ar Foll <fulup@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * references:
+ *   alsa-util/amixer.c + alsa-lib/simple.c
+ *   snd_tlv_convert_from_dB
+ *   nt snd_tlv_convert_to_dB
+ *   snd_tlv_get_dB_range
+ */
+
+#define _GNU_SOURCE  // needed for vasprintf
+#include <math.h>
+#include "hal-interface.h"
+
+typedef enum {
+    NORMALIZE_NONE = 0,
+    NORMALIZE_DB_LINEAR,
+    NORMALIZE_DB_MATH,
+    NORMALIZE_LINEAR,
+} enumRandeModeDB_T;
+
+
+// Return Value express from 0-100%
+
+STATIC int dbNormalizeVal(enumRandeModeDB_T normaliseMode, const alsaHalDBscaleT *dbscale, int value) {
+    double normalized, min_norm;
+
+    // To get real DB from TLV DB values should be divided by 100
+    switch (normaliseMode) {
+        case NORMALIZE_DB_LINEAR:
+            normalized = ((double) (value - dbscale->min) / (double) (dbscale->max - dbscale->min));
+            break;
+
+        case NORMALIZE_DB_MATH:
+            normalized = exp10((double) (value - dbscale->max) / 6000.0);
+            if (dbscale->min != SND_CTL_TLV_DB_GAIN_MUTE) {
+                min_norm = exp10((double) (dbscale->min - dbscale->max) / 20);
+                normalized = (normalized - min_norm) / (1 - min_norm);
+            }
+
+            break;
+
+        default:
+            normalized = 0;
+    }
+
+    return (int) round(normalized * 100);
+}
+
+// HAL normalise volume values to 0-100%
+
+PUBLIC json_object *volumeNormalise(ActionSetGetT action, const alsaHalCtlMapT *halCtls, json_object *valuesJ) {
+    enumRandeModeDB_T useNormalizeDB;
+    int length;
+
+    // If Integer look for DBscale
+    if (halCtls->type == SND_CTL_ELEM_TYPE_INTEGER) {
+
+        // If not valid db_scale let's use raw_scale
+        if (!halCtls->dbscale || (halCtls->dbscale->min >= halCtls->dbscale->max)) {
+
+            // dbscale is invalid let's try raw range
+            if (halCtls->minval >= halCtls->maxval) goto ExitOnError;
+
+            // Use Raw Scale Model
+            useNormalizeDB = NORMALIZE_LINEAR;
+
+        } else { // db_scale looks OK let's use it
+            if ((halCtls->dbscale->max - halCtls->dbscale->min) <= MAX_LINEAR_DB_SCALE * 100) useNormalizeDB = NORMALIZE_DB_LINEAR;
+            else useNormalizeDB = NORMALIZE_LINEAR; // Fulup not sure how to handle this useNormalizeDB=NORMALIZE_DB_MATH;
+        }
+    } else useNormalizeDB = NORMALIZE_NONE;
+
+
+    // loop on values to normalise
+    enum json_type jtype = json_object_get_type(valuesJ);
+    if (jtype == json_type_array) length = json_object_array_length(valuesJ);
+    else length = 1;
+
+    json_object *normalisedJ = json_object_new_array();
+    for (int idx = 0; idx < length; idx++) {
+        int value;
+
+        if (jtype == json_type_array) {
+            json_object *valueJ = json_object_array_get_idx(valuesJ, idx);
+            value = json_object_get_int(valueJ);
+        } else {
+            value = json_object_get_int(valuesJ);
+        }
+
+        // If Integer scale to 0/100
+        if (halCtls->type == SND_CTL_ELEM_TYPE_INTEGER) {
+
+            switch (action) {
+
+                case ACTION_GET:
+                    switch (useNormalizeDB) {
+                        case NORMALIZE_LINEAR:
+                            value = 100 * (value - halCtls->minval) / (halCtls->maxval - halCtls->minval);
+                            break;
+                        case NORMALIZE_DB_MATH: //ToBeDone
+                            value = dbNormalizeVal(useNormalizeDB, halCtls->dbscale, value);
+                            break;
+                        case NORMALIZE_NONE:
+                        default:
+                            value = value;
+                    }
+                    break;
+
+                case ACTION_SET:
+                    switch (useNormalizeDB) {
+                        case NORMALIZE_LINEAR:
+                            value = (value * (halCtls->maxval - halCtls->minval)) / 100;
+                            break;
+                        case NORMALIZE_DB_MATH: //ToBeDone
+                            value = dbNormalizeVal(useNormalizeDB, halCtls->dbscale, value);
+                            break;
+                        case NORMALIZE_NONE:
+                        default:
+                            value = value;
+                    }
+                    break;
+
+                default:
+                    AFB_NOTICE("volumeNormalise: invalid action value=%d", (int) action);
+                    goto ExitOnError;
+            }
+        }
+
+        json_object_array_add(normalisedJ, json_object_new_int(value));
+    }
+
+    return (normalisedJ);
+
+ExitOnError:
+    return NULL;
+}