diff --git a/media/libnblog/Reader.cpp b/media/libnblog/Reader.cpp
new file mode 100644
index 0000000..f86bb99
--- /dev/null
+++ b/media/libnblog/Reader.cpp
@@ -0,0 +1,421 @@
+/*
+ * Copyright (C) 2018 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 LOG_TAG "NBLog"
+//#define LOG_NDEBUG 0
+
+#include <memory>
+#include <stddef.h>
+#include <string>
+#include <unordered_set>
+
+#include <audio_utils/fifo.h>
+#include <binder/IMemory.h>
+#include <media/nblog/Entry.h>
+#include <media/nblog/Events.h>
+#include <media/nblog/Reader.h>
+#include <media/nblog/Timeline.h>
+#include <utils/Log.h>
+#include <utils/String8.h>
+
+namespace android {
+namespace NBLog {
+
+Reader::Reader(const void *shared, size_t size, const std::string &name)
+    : mName(name),
+      mShared((/*const*/ Shared *) shared), /*mIMemory*/
+      mFifo(mShared != NULL ?
+        new audio_utils_fifo(size, sizeof(uint8_t),
+            mShared->mBuffer, mShared->mRear, NULL /*throttlesFront*/) : NULL),
+      mFifoReader(mFifo != NULL ? new audio_utils_fifo_reader(*mFifo) : NULL)
+{
+}
+
+Reader::Reader(const sp<IMemory>& iMemory, size_t size, const std::string &name)
+    : Reader(iMemory != 0 ? (Shared *) iMemory->pointer() : NULL, size, name)
+{
+    mIMemory = iMemory;
+}
+
+Reader::~Reader()
+{
+    delete mFifoReader;
+    delete mFifo;
+}
+
+// Copies content of a Reader FIFO into its Snapshot
+// The Snapshot has the same raw data, but represented as a sequence of entries
+// and an EntryIterator making it possible to process the data.
+std::unique_ptr<Snapshot> Reader::getSnapshot()
+{
+    if (mFifoReader == NULL) {
+        return std::unique_ptr<Snapshot>(new Snapshot());
+    }
+
+    // This emulates the behaviour of audio_utils_fifo_reader::read, but without incrementing the
+    // reader index. The index is incremented after handling corruption, to after the last complete
+    // entry of the buffer
+    size_t lost = 0;
+    audio_utils_iovec iovec[2];
+    const size_t capacity = mFifo->capacity();
+    ssize_t availToRead;
+    // A call to audio_utils_fifo_reader::obtain() places the read pointer one buffer length
+    // before the writer's pointer (since mFifoReader was constructed with flush=false). The
+    // do while loop is an attempt to read all of the FIFO's contents regardless of how behind
+    // the reader is with respect to the writer. However, the following scheduling sequence is
+    // possible and can lead to a starvation situation:
+    // - Writer T1 writes, overrun with respect to Reader T2
+    // - T2 calls obtain() and gets EOVERFLOW, T2 ptr placed one buffer size behind T1 ptr
+    // - T1 write, overrun
+    // - T2 obtain(), EOVERFLOW (and so on...)
+    // To address this issue, we limit the number of tries for the reader to catch up with
+    // the writer.
+    int tries = 0;
+    size_t lostTemp;
+    do {
+        availToRead = mFifoReader->obtain(iovec, capacity, NULL /*timeout*/, &lostTemp);
+        lost += lostTemp;
+    } while (availToRead < 0 || ++tries <= kMaxObtainTries);
+
+    if (availToRead <= 0) {
+        ALOGW_IF(availToRead < 0, "NBLog Reader %s failed to catch up with Writer", mName.c_str());
+        return std::unique_ptr<Snapshot>(new Snapshot());
+    }
+
+    // Change to #if 1 for debugging. This statement is useful for checking buffer fullness levels
+    // (as seen by reader) and how much data was lost. If you find that the fullness level is
+    // getting close to full, or that data loss is happening to often, then you should
+    // probably try some of the following:
+    // - log less data
+    // - log less often
+    // - increase the initial shared memory allocation for the buffer
+#if 0
+    ALOGD("getSnapshot name=%s, availToRead=%zd, capacity=%zu, fullness=%.3f, lost=%zu",
+            name().c_str(), availToRead, capacity, (double)availToRead / (double)capacity, lost);
+#endif
+    std::unique_ptr<Snapshot> snapshot(new Snapshot(availToRead));
+    memcpy(snapshot->mData, (const char *) mFifo->buffer() + iovec[0].mOffset, iovec[0].mLength);
+    if (iovec[1].mLength > 0) {
+        memcpy(snapshot->mData + (iovec[0].mLength),
+                (const char *) mFifo->buffer() + iovec[1].mOffset, iovec[1].mLength);
+    }
+
+    // Handle corrupted buffer
+    // Potentially, a buffer has corrupted data on both beginning (due to overflow) and end
+    // (due to incomplete format entry). But even if the end format entry is incomplete,
+    // it ends in a complete entry (which is not an FMT_END). So is safe to traverse backwards.
+    // TODO: handle client corruption (in the middle of a buffer)
+
+    const uint8_t *back = snapshot->mData + availToRead;
+    const uint8_t *front = snapshot->mData;
+
+    // Find last FMT_END. <back> is sitting on an entry which might be the middle of a FormatEntry.
+    // We go backwards until we find an EVENT_FMT_END.
+    const uint8_t *lastEnd = findLastValidEntry(front, back, invalidEndTypes);
+    if (lastEnd == nullptr) {
+        snapshot->mEnd = snapshot->mBegin = EntryIterator(front);
+    } else {
+        // end of snapshot points to after last FMT_END entry
+        snapshot->mEnd = EntryIterator(lastEnd).next();
+        // find first FMT_START
+        const uint8_t *firstStart = nullptr;
+        const uint8_t *firstStartTmp = snapshot->mEnd;
+        while ((firstStartTmp = findLastValidEntry(front, firstStartTmp, invalidBeginTypes))
+                != nullptr) {
+            firstStart = firstStartTmp;
+        }
+        // firstStart is null if no FMT_START entry was found before lastEnd
+        if (firstStart == nullptr) {
+            snapshot->mBegin = snapshot->mEnd;
+        } else {
+            snapshot->mBegin = EntryIterator(firstStart);
+        }
+    }
+
+    // advance fifo reader index to after last entry read.
+    mFifoReader->release(snapshot->mEnd - front);
+
+    snapshot->mLost = lost;
+    return snapshot;
+}
+
+bool Reader::isIMemory(const sp<IMemory>& iMemory) const
+{
+    return iMemory != 0 && mIMemory != 0 && iMemory->pointer() == mIMemory->pointer();
+}
+
+// We make a set of the invalid types rather than the valid types when aligning
+// Snapshot EntryIterators to valid entries during log corruption checking.
+// This is done in order to avoid the maintenance overhead of adding a new Event
+// type to the two sets below whenever a new Event type is created, as it is
+// very likely that new types added will be valid types.
+// Currently, invalidBeginTypes and invalidEndTypes are used to handle the special
+// case of a Format Entry, which consists of a variable number of simple log entries.
+// If a new Event is added that consists of a variable number of simple log entries,
+// then these sets need to be updated.
+
+// We want the beginning of a Snapshot to point to an entry that is not in
+// the middle of a formatted entry and not an FMT_END.
+const std::unordered_set<Event> Reader::invalidBeginTypes {
+    EVENT_FMT_AUTHOR,
+    EVENT_FMT_END,
+    EVENT_FMT_FLOAT,
+    EVENT_FMT_HASH,
+    EVENT_FMT_INTEGER,
+    EVENT_FMT_PID,
+    EVENT_FMT_STRING,
+    EVENT_FMT_TIMESTAMP,
+};
+
+// We want the end of a Snapshot to point to an entry that is not in
+// the middle of a formatted entry and not a FMT_START.
+const std::unordered_set<Event> Reader::invalidEndTypes {
+    EVENT_FMT_AUTHOR,
+    EVENT_FMT_FLOAT,
+    EVENT_FMT_HASH,
+    EVENT_FMT_INTEGER,
+    EVENT_FMT_PID,
+    EVENT_FMT_START,
+    EVENT_FMT_STRING,
+    EVENT_FMT_TIMESTAMP,
+};
+
+const uint8_t *Reader::findLastValidEntry(const uint8_t *front, const uint8_t *back,
+                                          const std::unordered_set<Event> &invalidTypes) {
+    if (front == nullptr || back == nullptr) {
+        return nullptr;
+    }
+    while (back + Entry::kPreviousLengthOffset >= front) {
+        const uint8_t *prev = back - back[Entry::kPreviousLengthOffset] - Entry::kOverhead;
+        const Event type = (const Event)prev[offsetof(entry, type)];
+        if (prev < front
+                || prev + prev[offsetof(entry, length)] + Entry::kOverhead != back
+                || type <= EVENT_RESERVED || type >= EVENT_UPPER_BOUND) {
+            // prev points to an out of limits or inconsistent entry
+            return nullptr;
+        }
+        // if invalidTypes does not contain the type, then the type is valid.
+        if (invalidTypes.find(type) == invalidTypes.end()) {
+            return prev;
+        }
+        back = prev;
+    }
+    return nullptr; // no entry found
+}
+
+// TODO for future compatibility, would prefer to have a dump() go to string, and then go
+// to fd only when invoked through binder.
+void DumpReader::dump(int fd, size_t indent)
+{
+    if (fd < 0) return;
+    std::unique_ptr<Snapshot> snapshot = getSnapshot();
+    if (snapshot == nullptr) {
+        return;
+    }
+    String8 timestamp, body;
+
+    // TODO all logged types should have a printable format.
+    for (EntryIterator it = snapshot->begin(); it != snapshot->end(); ++it) {
+        switch (it->type) {
+        case EVENT_FMT_START:
+            it = handleFormat(FormatEntry(it), &timestamp, &body);
+            break;
+        case EVENT_WORK_TIME: {
+            const int64_t monotonicNs = it.payload<int64_t>();
+            body.appendFormat("Thread cycle: %ld ns", (long)monotonicNs);
+        } break;
+        case EVENT_LATENCY: {
+            const double latencyMs = it.payload<double>();
+            body.appendFormat("latency: %.3f ms", latencyMs);
+        } break;
+        case EVENT_WARMUP_TIME: {
+            const double timeMs = it.payload<double>();
+            body.appendFormat("warmup time: %.3f ms", timeMs);
+        } break;
+        case EVENT_UNDERRUN:
+            body.appendFormat("underrun");
+            break;
+        case EVENT_OVERRUN:
+            body.appendFormat("overrun");
+            break;
+        case EVENT_FMT_END:
+        case EVENT_RESERVED:
+        case EVENT_UPPER_BOUND:
+            body.appendFormat("warning: unexpected event %d", it->type);
+        default:
+            break;
+        }
+        if (!body.isEmpty()) {
+            dprintf(fd, "%.*s%s %s\n", (int)indent, "", timestamp.string(), body.string());
+            body.clear();
+        }
+        timestamp.clear();
+    }
+}
+
+EntryIterator DumpReader::handleFormat(const FormatEntry &fmtEntry,
+        String8 *timestamp, String8 *body)
+{
+    // log timestamp
+    const int64_t ts = fmtEntry.timestamp();
+    timestamp->clear();
+    timestamp->appendFormat("[%d.%03d]", (int) (ts / (1000 * 1000 * 1000)),
+                    (int) ((ts / (1000 * 1000)) % 1000));
+
+    // log unique hash
+    log_hash_t hash = fmtEntry.hash();
+    // print only lower 16bit of hash as hex and line as int to reduce spam in the log
+    body->appendFormat("%.4X-%d ", (int)(hash >> 16) & 0xFFFF, (int) hash & 0xFFFF);
+
+    // log author (if present)
+    handleAuthor(fmtEntry, body);
+
+    // log string
+    EntryIterator arg = fmtEntry.args();
+
+    const char* fmt = fmtEntry.formatString();
+    size_t fmt_length = fmtEntry.formatStringLength();
+
+    for (size_t fmt_offset = 0; fmt_offset < fmt_length; ++fmt_offset) {
+        if (fmt[fmt_offset] != '%') {
+            body->append(&fmt[fmt_offset], 1); // TODO optimize to write consecutive strings at once
+            continue;
+        }
+        // case "%%""
+        if (fmt[++fmt_offset] == '%') {
+            body->append("%");
+            continue;
+        }
+        // case "%\0"
+        if (fmt_offset == fmt_length) {
+            continue;
+        }
+
+        Event event = (Event) arg->type;
+        size_t length = arg->length;
+
+        // TODO check length for event type is correct
+
+        if (event == EVENT_FMT_END) {
+            break;
+        }
+
+        // TODO: implement more complex formatting such as %.3f
+        const uint8_t *datum = arg->data; // pointer to the current event args
+        switch(fmt[fmt_offset])
+        {
+        case 's': // string
+            ALOGW_IF(event != EVENT_FMT_STRING,
+                "NBLog Reader incompatible event for string specifier: %d", event);
+            body->append((const char*) datum, length);
+            break;
+
+        case 't': // timestamp
+            ALOGW_IF(event != EVENT_FMT_TIMESTAMP,
+                "NBLog Reader incompatible event for timestamp specifier: %d", event);
+            appendTimestamp(body, datum);
+            break;
+
+        case 'd': // integer
+            ALOGW_IF(event != EVENT_FMT_INTEGER,
+                "NBLog Reader incompatible event for integer specifier: %d", event);
+            appendInt(body, datum);
+            break;
+
+        case 'f': // float
+            ALOGW_IF(event != EVENT_FMT_FLOAT,
+                "NBLog Reader incompatible event for float specifier: %d", event);
+            appendFloat(body, datum);
+            break;
+
+        case 'p': // pid
+            ALOGW_IF(event != EVENT_FMT_PID,
+                "NBLog Reader incompatible event for pid specifier: %d", event);
+            appendPID(body, datum, length);
+            break;
+
+        default:
+            ALOGW("NBLog Reader encountered unknown character %c", fmt[fmt_offset]);
+        }
+        ++arg;
+    }
+    ALOGW_IF(arg->type != EVENT_FMT_END, "Expected end of format, got %d", arg->type);
+    return arg;
+}
+
+void DumpReader::appendInt(String8 *body, const void *data)
+{
+    if (body == nullptr || data == nullptr) {
+        return;
+    }
+    //int x = *((int*) data);
+    int x;
+    memcpy(&x, data, sizeof(x));
+    body->appendFormat("<%d>", x);
+}
+
+void DumpReader::appendFloat(String8 *body, const void *data)
+{
+    if (body == nullptr || data == nullptr) {
+        return;
+    }
+    float f;
+    memcpy(&f, data, sizeof(f));
+    body->appendFormat("<%f>", f);
+}
+
+void DumpReader::appendPID(String8 *body, const void* data, size_t length)
+{
+    if (body == nullptr || data == nullptr) {
+        return;
+    }
+    pid_t id = *((pid_t*) data);
+    char * name = &((char*) data)[sizeof(pid_t)];
+    body->appendFormat("<PID: %d, name: %.*s>", id, (int) (length - sizeof(pid_t)), name);
+}
+
+void DumpReader::appendTimestamp(String8 *body, const void *data)
+{
+    if (body == nullptr || data == nullptr) {
+        return;
+    }
+    int64_t ts;
+    memcpy(&ts, data, sizeof(ts));
+    body->appendFormat("[%d.%03d]", (int) (ts / (1000 * 1000 * 1000)),
+                    (int) ((ts / (1000 * 1000)) % 1000));
+}
+
+String8 DumpReader::bufferDump(const uint8_t *buffer, size_t size)
+{
+    String8 str;
+    if (buffer == nullptr) {
+        return str;
+    }
+    str.append("[ ");
+    for(size_t i = 0; i < size; i++) {
+        str.appendFormat("%d ", buffer[i]);
+    }
+    str.append("]");
+    return str;
+}
+
+String8 DumpReader::bufferDump(const EntryIterator &it)
+{
+    return bufferDump(it, it->length + Entry::kOverhead);
+}
+
+}   // namespace NBLog
+}   // namespace android