1 files changed, 150 insertions, 0 deletions
diff --git a/libs/common_time/common_clock.cpp b/libs/common_time/common_clock.cpp
new file mode 100644
index 0000000..c9eb388
--- /dev/null
+++ b/libs/common_time/common_clock.cpp
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#define __STDC_LIMIT_MACROS
+
+#define LOG_TAG "common_time"
+#include <utils/Log.h>
+
+#include <stdint.h>
+
+#include <utils/Errors.h>
+#include <utils/LinearTransform.h>
+
+#include "common_clock.h"
+
+namespace android {
+
+CommonClock::CommonClock() {
+    cur_slew_        = 0;
+    cur_trans_valid_ = false;
+
+    cur_trans_.a_zero = 0;
+    cur_trans_.b_zero = 0;
+    cur_trans_.a_to_b_numer = local_to_common_freq_numer_ = 1;
+    cur_trans_.a_to_b_denom = local_to_common_freq_denom_ = 1;
+    duration_trans_ = cur_trans_;
+}
+
+bool CommonClock::init(uint64_t local_freq) {
+    Mutex::Autolock lock(&lock_);
+
+    if (!local_freq)
+        return false;
+
+    uint64_t numer = kCommonFreq;
+    uint64_t denom = local_freq;
+
+    LinearTransform::reduce(&numer, &denom);
+    if ((numer > UINT32_MAX) || (denom > UINT32_MAX)) {
+        ALOGE("Overflow in CommonClock::init while trying to reduce %lld/%lld",
+             kCommonFreq, local_freq);
+        return false;
+    }
+
+    cur_trans_.a_to_b_numer = local_to_common_freq_numer_ =
+        static_cast<uint32_t>(numer);
+    cur_trans_.a_to_b_denom = local_to_common_freq_denom_ =
+        static_cast<uint32_t>(denom);
+    duration_trans_ = cur_trans_;
+
+    return true;
+}
+
+status_t CommonClock::localToCommon(int64_t local, int64_t *common_out) const {
+    Mutex::Autolock lock(&lock_);
+
+    if (!cur_trans_valid_)
+        return INVALID_OPERATION;
+
+    if (!cur_trans_.doForwardTransform(local, common_out))
+        return INVALID_OPERATION;
+
+    return OK;
+}
+
+status_t CommonClock::commonToLocal(int64_t common, int64_t *local_out) const {
+    Mutex::Autolock lock(&lock_);
+
+    if (!cur_trans_valid_)
+        return INVALID_OPERATION;
+
+    if (!cur_trans_.doReverseTransform(common, local_out))
+        return INVALID_OPERATION;
+
+    return OK;
+}
+
+int64_t CommonClock::localDurationToCommonDuration(int64_t localDur) const {
+    int64_t ret;
+    duration_trans_.doForwardTransform(localDur, &ret);
+    return ret;
+}
+
+void CommonClock::setBasis(int64_t local, int64_t common) {
+    Mutex::Autolock lock(&lock_);
+
+    cur_trans_.a_zero = local;
+    cur_trans_.b_zero = common;
+    cur_trans_valid_ = true;
+}
+
+void CommonClock::resetBasis() {
+    Mutex::Autolock lock(&lock_);
+
+    cur_trans_.a_zero = 0;
+    cur_trans_.b_zero = 0;
+    cur_trans_valid_ = false;
+}
+
+status_t CommonClock::setSlew(int64_t change_time, int32_t ppm) {
+    Mutex::Autolock lock(&lock_);
+
+    int64_t new_local_basis;
+    int64_t new_common_basis;
+
+    if (cur_trans_valid_) {
+        new_local_basis = change_time;
+        if (!cur_trans_.doForwardTransform(change_time, &new_common_basis)) {
+            ALOGE("Overflow when attempting to set slew rate to %d", ppm);
+            return INVALID_OPERATION;
+        }
+    } else {
+        new_local_basis = 0;
+        new_common_basis = 0;
+    }
+
+    cur_slew_ = ppm;
+    uint32_t n1 = local_to_common_freq_numer_;
+    uint32_t n2 = 1000000 + cur_slew_;
+
+    uint32_t d1 = local_to_common_freq_denom_;
+    uint32_t d2 = 1000000;
+
+    // n1/d1 has already been reduced, no need to do so here.
+    LinearTransform::reduce(&n1, &d2);
+    LinearTransform::reduce(&n2, &d1);
+    LinearTransform::reduce(&n2, &d2);
+
+    cur_trans_.a_zero = new_local_basis;
+    cur_trans_.b_zero = new_common_basis;
+    cur_trans_.a_to_b_numer = n1 * n2;
+    cur_trans_.a_to_b_denom = d1 * d2;
+
+    return OK;
+}
+
+}  // namespace android