media/mtp/MtpDataPacket.cpp - android_frameworks_av - Gitiles

 /*
  * Copyright (C) 2010 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 "MtpDataPacket"

 #include "MtpDataPacket.h"

 #include <algorithm>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <usbhost/usbhost.h>
 #include "MtpStringBuffer.h"
 #include "IMtpHandle.h"

 namespace android {

 namespace {
 // Reads the exact |count| bytes from |fd| to |buf|.
 // Returns |count| if it succeed to read the bytes. Otherwise returns -1. If it reaches EOF, the
 // function regards it as an error.
 ssize_t readExactBytes(int fd, void* buf, size_t count) {
     if (count > SSIZE_MAX) {
         return -1;
     }
     size_t read_count = 0;
     while (read_count < count) {
         int result = read(fd, static_cast<int8_t*>(buf) + read_count, count - read_count);
         // Assume that EOF is error.
         if (result <= 0) {
             return -1;
         }
         read_count += result;
     }
     return read_count == count ? count : -1;
 }
 }  // namespace

 MtpDataPacket::MtpDataPacket()
     :   MtpPacket(MTP_BUFFER_SIZE),   // MAX_USBFS_BUFFER_SIZE
         mOffset(MTP_CONTAINER_HEADER_SIZE)
 {
 }

 MtpDataPacket::~MtpDataPacket() {
 }

 void MtpDataPacket::reset() {
     MtpPacket::reset();
     mOffset = MTP_CONTAINER_HEADER_SIZE;
 }

 void MtpDataPacket::setOperationCode(MtpOperationCode code) {
     MtpPacket::putUInt16(MTP_CONTAINER_CODE_OFFSET, code);
 }

 void MtpDataPacket::setTransactionID(MtpTransactionID id) {
     MtpPacket::putUInt32(MTP_CONTAINER_TRANSACTION_ID_OFFSET, id);
 }

 bool MtpDataPacket::getUInt8(uint8_t& value) {
     if (mPacketSize - mOffset < sizeof(value))
         return false;
     value = mBuffer[mOffset++];
     return true;
 }

 bool MtpDataPacket::getUInt16(uint16_t& value) {
     if (mPacketSize - mOffset < sizeof(value))
         return false;
     int offset = mOffset;
     value = (uint16_t)mBuffer[offset] | ((uint16_t)mBuffer[offset + 1] << 8);
     mOffset += sizeof(value);
     return true;
 }

 bool MtpDataPacket::getUInt32(uint32_t& value) {
     if (mPacketSize - mOffset < sizeof(value))
         return false;
     int offset = mOffset;
     value = (uint32_t)mBuffer[offset] | ((uint32_t)mBuffer[offset + 1] << 8) |
            ((uint32_t)mBuffer[offset + 2] << 16)  | ((uint32_t)mBuffer[offset + 3] << 24);
     mOffset += sizeof(value);
     return true;
 }

 bool MtpDataPacket::getUInt64(uint64_t& value) {
     if (mPacketSize - mOffset < sizeof(value))
         return false;
     int offset = mOffset;
     value = (uint64_t)mBuffer[offset] | ((uint64_t)mBuffer[offset + 1] << 8) |
            ((uint64_t)mBuffer[offset + 2] << 16) | ((uint64_t)mBuffer[offset + 3] << 24) |
            ((uint64_t)mBuffer[offset + 4] << 32) | ((uint64_t)mBuffer[offset + 5] << 40) |
            ((uint64_t)mBuffer[offset + 6] << 48)  | ((uint64_t)mBuffer[offset + 7] << 56);
     mOffset += sizeof(value);
     return true;
 }

 bool MtpDataPacket::getUInt128(uint128_t& value) {
     return getUInt32(value[0]) && getUInt32(value[1]) && getUInt32(value[2]) && getUInt32(value[3]);
 }

 bool MtpDataPacket::getString(MtpStringBuffer& string)
 {
     return string.readFromPacket(this);
 }

 Int8List* MtpDataPacket::getAInt8() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     Int8List* result = new Int8List;
     for (uint32_t i = 0; i < count; i++) {
         int8_t value;
         if (!getInt8(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 UInt8List* MtpDataPacket::getAUInt8() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     UInt8List* result = new UInt8List;
     for (uint32_t i = 0; i < count; i++) {
         uint8_t value;
         if (!getUInt8(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 Int16List* MtpDataPacket::getAInt16() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     Int16List* result = new Int16List;
     for (uint32_t i = 0; i < count; i++) {
         int16_t value;
         if (!getInt16(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 UInt16List* MtpDataPacket::getAUInt16() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     UInt16List* result = new UInt16List;
     for (uint32_t i = 0; i < count; i++) {
         uint16_t value;
         if (!getUInt16(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 Int32List* MtpDataPacket::getAInt32() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     Int32List* result = new Int32List;
     for (uint32_t i = 0; i < count; i++) {
         int32_t value;
         if (!getInt32(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 UInt32List* MtpDataPacket::getAUInt32() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     UInt32List* result = new UInt32List;
     for (uint32_t i = 0; i < count; i++) {
         uint32_t value;
         if (!getUInt32(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 Int64List* MtpDataPacket::getAInt64() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     Int64List* result = new Int64List;
     for (uint32_t i = 0; i < count; i++) {
         int64_t value;
         if (!getInt64(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 UInt64List* MtpDataPacket::getAUInt64() {
     uint32_t count;
     if (!getUInt32(count))
         return NULL;
     UInt64List* result = new UInt64List;
     for (uint32_t i = 0; i < count; i++) {
         uint64_t value;
         if (!getUInt64(value)) {
             delete result;
             return NULL;
         }
         result->push_back(value);
     }
     return result;
 }

 void MtpDataPacket::putInt8(int8_t value) {
     allocate(mOffset + 1);
     mBuffer[mOffset++] = (uint8_t)value;
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putUInt8(uint8_t value) {
     allocate(mOffset + 1);
     mBuffer[mOffset++] = (uint8_t)value;
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putInt16(int16_t value) {
     allocate(mOffset + 2);
     mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putUInt16(uint16_t value) {
     allocate(mOffset + 2);
     mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putInt32(int32_t value) {
     allocate(mOffset + 4);
     mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putUInt32(uint32_t value) {
     allocate(mOffset + 4);
     mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putInt64(int64_t value) {
     allocate(mOffset + 8);
     mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 32) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 40) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 48) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 56) & 0xFF);
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putUInt64(uint64_t value) {
     allocate(mOffset + 8);
     mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 32) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 40) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 48) & 0xFF);
     mBuffer[mOffset++] = (uint8_t)((value >> 56) & 0xFF);
     if (mPacketSize < mOffset)
         mPacketSize = mOffset;
 }

 void MtpDataPacket::putInt128(const int128_t& value) {
     putInt32(value[0]);
     putInt32(value[1]);
     putInt32(value[2]);
     putInt32(value[3]);
 }

 void MtpDataPacket::putUInt128(const uint128_t& value) {
     putUInt32(value[0]);
     putUInt32(value[1]);
     putUInt32(value[2]);
     putUInt32(value[3]);
 }

 void MtpDataPacket::putInt128(int64_t value) {
     putInt64(value);
     putInt64(value < 0 ? -1 : 0);
 }

 void MtpDataPacket::putUInt128(uint64_t value) {
     putUInt64(value);
     putUInt64(0);
 }

 void MtpDataPacket::putAInt8(const int8_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putInt8(*values++);
 }

 void MtpDataPacket::putAUInt8(const uint8_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putUInt8(*values++);
 }

 void MtpDataPacket::putAInt16(const int16_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putInt16(*values++);
 }

 void MtpDataPacket::putAUInt16(const uint16_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putUInt16(*values++);
 }

 void MtpDataPacket::putAUInt16(const UInt16List* values) {
     size_t count = (values ? values->size() : 0);
     putUInt32(count);
     for (size_t i = 0; i < count; i++)
         putUInt16((*values)[i]);
 }

 void MtpDataPacket::putAInt32(const int32_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putInt32(*values++);
 }

 void MtpDataPacket::putAUInt32(const uint32_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putUInt32(*values++);
 }

 void MtpDataPacket::putAUInt32(const UInt32List* list) {
     if (!list) {
         putEmptyArray();
     } else {
         size_t size = list->size();
         putUInt32(size);
         for (size_t i = 0; i < size; i++)
             putUInt32((*list)[i]);
     }
 }

 void MtpDataPacket::putAInt64(const int64_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putInt64(*values++);
 }

 void MtpDataPacket::putAUInt64(const uint64_t* values, int count) {
     putUInt32(count);
     for (int i = 0; i < count; i++)
         putUInt64(*values++);
 }

 void MtpDataPacket::putString(const MtpStringBuffer& string) {
     string.writeToPacket(this);
 }

 void MtpDataPacket::putString(const char* s) {
     MtpStringBuffer string(s);
     string.writeToPacket(this);
 }

 void MtpDataPacket::putString(const uint16_t* string) {
     int count = 0;
     for (int i = 0; i <= MTP_STRING_MAX_CHARACTER_NUMBER; i++) {
         if (string[i])
             count++;
         else
             break;
     }
     putUInt8(count > 0 ? count + 1 : 0);
     for (int i = 0; i < count; i++)
         putUInt16(string[i]);
     // only terminate with zero if string is not empty
     if (count > 0)
         putUInt16(0);
 }

 #ifdef MTP_DEVICE
 int MtpDataPacket::read(IMtpHandle *h) {
     int ret = h->read(mBuffer, MTP_BUFFER_SIZE);
     if (ret < MTP_CONTAINER_HEADER_SIZE)
         return -1;
     mPacketSize = ret;
     mOffset = MTP_CONTAINER_HEADER_SIZE;
     return ret;
 }

 int MtpDataPacket::write(IMtpHandle *h) {
     MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
     MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
     int ret = h->write(mBuffer, mPacketSize);
     return (ret < 0 ? ret : 0);
 }

 int MtpDataPacket::writeData(IMtpHandle *h, void* data, uint32_t length) {
     allocate(length + MTP_CONTAINER_HEADER_SIZE);
     memcpy(mBuffer + MTP_CONTAINER_HEADER_SIZE, data, length);
     length += MTP_CONTAINER_HEADER_SIZE;
     MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, length);
     MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
     int ret = h->write(mBuffer, length);
     return (ret < 0 ? ret : 0);
 }

 #endif // MTP_DEVICE

 #ifdef MTP_HOST
 int MtpDataPacket::read(struct usb_request *request) {
     // first read the header
     request->buffer = mBuffer;
     request->buffer_length = mBufferSize;
     int length = transfer(request);
     if (length >= MTP_CONTAINER_HEADER_SIZE) {
         // look at the length field to see if the data spans multiple packets
         uint32_t totalLength = MtpPacket::getUInt32(MTP_CONTAINER_LENGTH_OFFSET);
         allocate(totalLength);
         while (totalLength > static_cast<uint32_t>(length)) {
             request->buffer = mBuffer + length;
             request->buffer_length = totalLength - length;
             int ret = transfer(request);
             if (ret >= 0)
                 length += ret;
             else {
                 length = ret;
                 break;
             }
         }
     }
     if (length >= 0)
         mPacketSize = length;
     return length;
 }

 int MtpDataPacket::readData(struct usb_request *request, void* buffer, int length) {
     int read = 0;
     while (read < length) {
         request->buffer = (char *)buffer + read;
         request->buffer_length = length - read;
         int ret = transfer(request);
         if (ret < 0) {
             return ret;
         }
         read += ret;
     }
     return read;
 }

 // Queue a read request.  Call readDataWait to wait for result
 int MtpDataPacket::readDataAsync(struct usb_request *req) {
     if (usb_request_queue(req)) {
         ALOGE("usb_endpoint_queue failed, errno: %d", errno);
         return -1;
     }
     return 0;
 }

 // Wait for result of readDataAsync
 int MtpDataPacket::readDataWait(struct usb_device *device) {
     struct usb_request *req = usb_request_wait(device, -1);
     return (req ? req->actual_length : -1);
 }

 int MtpDataPacket::readDataHeader(struct usb_request *request) {
     request->buffer = mBuffer;
     request->buffer_length = request->max_packet_size;
     int length = transfer(request);
     if (length >= 0)
         mPacketSize = length;
     return length;
 }

 int MtpDataPacket::write(struct usb_request *request, UrbPacketDivisionMode divisionMode) {
     if (mPacketSize < MTP_CONTAINER_HEADER_SIZE || mPacketSize > MTP_BUFFER_SIZE) {
         ALOGE("Illegal packet size.");
         return -1;
     }

     MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
     MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);

     size_t processedBytes = 0;
     while (processedBytes < mPacketSize) {
         const size_t write_size =
                 processedBytes == 0 && divisionMode == FIRST_PACKET_ONLY_HEADER ?
                         MTP_CONTAINER_HEADER_SIZE : mPacketSize - processedBytes;
         request->buffer = mBuffer + processedBytes;
         request->buffer_length = write_size;
         const int result = transfer(request);
         if (result < 0) {
             ALOGE("Failed to write bytes to the device.");
             return -1;
         }
         processedBytes += result;
     }

     return processedBytes == mPacketSize ? processedBytes : -1;
 }

 int64_t MtpDataPacket::write(struct usb_request *request,
                          UrbPacketDivisionMode divisionMode,
                          int fd,
                          size_t payloadSize) {
     // Obtain the greatest multiple of minimum packet size that is not greater than
     // MTP_BUFFER_SIZE.
     if (request->max_packet_size <= 0) {
         ALOGE("Cannot determine bulk transfer size due to illegal max packet size %d.",
               request->max_packet_size);
         return -1;
     }
     const size_t maxBulkTransferSize =
             MTP_BUFFER_SIZE - (MTP_BUFFER_SIZE % request->max_packet_size);
     const size_t containerLength = payloadSize + MTP_CONTAINER_HEADER_SIZE;
     size_t processedBytes = 0;
     bool readError = false;

     // Bind the packet with given request.
     request->buffer = mBuffer;
     allocate(maxBulkTransferSize);

     while (processedBytes < containerLength) {
         size_t bulkTransferSize = 0;

         // prepare header.
         const bool headerSent = processedBytes != 0;
         if (!headerSent) {
             MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, containerLength);
             MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
             bulkTransferSize += MTP_CONTAINER_HEADER_SIZE;
         }

         // Prepare payload.
         if (headerSent || divisionMode == FIRST_PACKET_HAS_PAYLOAD) {
             const size_t processedPayloadBytes =
                     headerSent ? processedBytes - MTP_CONTAINER_HEADER_SIZE : 0;
             const size_t maxRead = payloadSize - processedPayloadBytes;
             const size_t maxWrite = maxBulkTransferSize - bulkTransferSize;
             const size_t bulkTransferPayloadSize = std::min(maxRead, maxWrite);
             // prepare payload.
             if (!readError) {
                 const ssize_t result = readExactBytes(
                         fd,
                         mBuffer + bulkTransferSize,
                         bulkTransferPayloadSize);
                 if (result < 0) {
                     ALOGE("Found an error while reading data from FD. Send 0 data instead.");
                     readError = true;
                 }
             }
             if (readError) {
                 memset(mBuffer + bulkTransferSize, 0, bulkTransferPayloadSize);
             }
             bulkTransferSize += bulkTransferPayloadSize;
         }

         // Bulk transfer.
         mPacketSize = bulkTransferSize;
         request->buffer_length = bulkTransferSize;
         const int result = transfer(request);
         if (result != static_cast<ssize_t>(bulkTransferSize)) {
             // Cannot recover writing error.
             ALOGE("Found an error while write data to MtpDevice.");
             return -1;
         }

         // Update variables.
         processedBytes += bulkTransferSize;
     }

     return readError ? -1 : processedBytes;
 }

 #endif // MTP_HOST

 void* MtpDataPacket::getData(int* outLength) const {
     int length = mPacketSize - MTP_CONTAINER_HEADER_SIZE;
     if (length > 0) {
         void* result = malloc(length);
         if (result) {
             memcpy(result, mBuffer + MTP_CONTAINER_HEADER_SIZE, length);
             *outLength = length;
             return result;
         }
     }
     *outLength = 0;
     return NULL;
 }

 }  // namespace android
	/*
	* Copyright (C) 2010 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 "MtpDataPacket"

	#include "MtpDataPacket.h"

	#include <algorithm>
	#include <errno.h>
	#include <fcntl.h>
	#include <stdio.h>
	#include <sys/types.h>
	#include <usbhost/usbhost.h>
	#include "MtpStringBuffer.h"
	#include "IMtpHandle.h"

	namespace android {

	namespace {
	// Reads the exact \|count\| bytes from \|fd\| to \|buf\|.
	// Returns \|count\| if it succeed to read the bytes. Otherwise returns -1. If it reaches EOF, the
	// function regards it as an error.
	ssize_t readExactBytes(int fd, void* buf, size_t count) {
	if (count > SSIZE_MAX) {
	return -1;
	}
	size_t read_count = 0;
	while (read_count < count) {
	int result = read(fd, static_cast<int8_t*>(buf) + read_count, count - read_count);
	// Assume that EOF is error.
	if (result <= 0) {
	return -1;
	}
	read_count += result;
	}
	return read_count == count ? count : -1;
	}
	} // namespace

	MtpDataPacket::MtpDataPacket()
	: MtpPacket(MTP_BUFFER_SIZE), // MAX_USBFS_BUFFER_SIZE
	mOffset(MTP_CONTAINER_HEADER_SIZE)
	{
	}

	MtpDataPacket::~MtpDataPacket() {
	}

	void MtpDataPacket::reset() {
	MtpPacket::reset();
	mOffset = MTP_CONTAINER_HEADER_SIZE;
	}

	void MtpDataPacket::setOperationCode(MtpOperationCode code) {
	MtpPacket::putUInt16(MTP_CONTAINER_CODE_OFFSET, code);
	}

	void MtpDataPacket::setTransactionID(MtpTransactionID id) {
	MtpPacket::putUInt32(MTP_CONTAINER_TRANSACTION_ID_OFFSET, id);
	}

	bool MtpDataPacket::getUInt8(uint8_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
	return false;
	value = mBuffer[mOffset++];
	return true;
	}

	bool MtpDataPacket::getUInt16(uint16_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
	return false;
	int offset = mOffset;
	value = (uint16_t)mBuffer[offset] \| ((uint16_t)mBuffer[offset + 1] << 8);
	mOffset += sizeof(value);
	return true;
	}

	bool MtpDataPacket::getUInt32(uint32_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
	return false;
	int offset = mOffset;
	value = (uint32_t)mBuffer[offset] \| ((uint32_t)mBuffer[offset + 1] << 8) \|
	((uint32_t)mBuffer[offset + 2] << 16) \| ((uint32_t)mBuffer[offset + 3] << 24);
	mOffset += sizeof(value);
	return true;
	}

	bool MtpDataPacket::getUInt64(uint64_t& value) {
	if (mPacketSize - mOffset < sizeof(value))
	return false;
	int offset = mOffset;
	value = (uint64_t)mBuffer[offset] \| ((uint64_t)mBuffer[offset + 1] << 8) \|
	((uint64_t)mBuffer[offset + 2] << 16) \| ((uint64_t)mBuffer[offset + 3] << 24) \|
	((uint64_t)mBuffer[offset + 4] << 32) \| ((uint64_t)mBuffer[offset + 5] << 40) \|
	((uint64_t)mBuffer[offset + 6] << 48) \| ((uint64_t)mBuffer[offset + 7] << 56);
	mOffset += sizeof(value);
	return true;
	}

	bool MtpDataPacket::getUInt128(uint128_t& value) {
	return getUInt32(value[0]) && getUInt32(value[1]) && getUInt32(value[2]) && getUInt32(value[3]);
	}

	bool MtpDataPacket::getString(MtpStringBuffer& string)
	{
	return string.readFromPacket(this);
	}

	Int8List* MtpDataPacket::getAInt8() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	Int8List* result = new Int8List;
	for (uint32_t i = 0; i < count; i++) {
	int8_t value;
	if (!getInt8(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	UInt8List* MtpDataPacket::getAUInt8() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	UInt8List* result = new UInt8List;
	for (uint32_t i = 0; i < count; i++) {
	uint8_t value;
	if (!getUInt8(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	Int16List* MtpDataPacket::getAInt16() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	Int16List* result = new Int16List;
	for (uint32_t i = 0; i < count; i++) {
	int16_t value;
	if (!getInt16(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	UInt16List* MtpDataPacket::getAUInt16() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	UInt16List* result = new UInt16List;
	for (uint32_t i = 0; i < count; i++) {
	uint16_t value;
	if (!getUInt16(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	Int32List* MtpDataPacket::getAInt32() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	Int32List* result = new Int32List;
	for (uint32_t i = 0; i < count; i++) {
	int32_t value;
	if (!getInt32(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	UInt32List* MtpDataPacket::getAUInt32() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	UInt32List* result = new UInt32List;
	for (uint32_t i = 0; i < count; i++) {
	uint32_t value;
	if (!getUInt32(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	Int64List* MtpDataPacket::getAInt64() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	Int64List* result = new Int64List;
	for (uint32_t i = 0; i < count; i++) {
	int64_t value;
	if (!getInt64(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	UInt64List* MtpDataPacket::getAUInt64() {
	uint32_t count;
	if (!getUInt32(count))
	return NULL;
	UInt64List* result = new UInt64List;
	for (uint32_t i = 0; i < count; i++) {
	uint64_t value;
	if (!getUInt64(value)) {
	delete result;
	return NULL;
	}
	result->push_back(value);
	}
	return result;
	}

	void MtpDataPacket::putInt8(int8_t value) {
	allocate(mOffset + 1);
	mBuffer[mOffset++] = (uint8_t)value;
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putUInt8(uint8_t value) {
	allocate(mOffset + 1);
	mBuffer[mOffset++] = (uint8_t)value;
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putInt16(int16_t value) {
	allocate(mOffset + 2);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putUInt16(uint16_t value) {
	allocate(mOffset + 2);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putInt32(int32_t value) {
	allocate(mOffset + 4);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putUInt32(uint32_t value) {
	allocate(mOffset + 4);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putInt64(int64_t value) {
	allocate(mOffset + 8);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 32) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 40) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 48) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 56) & 0xFF);
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putUInt64(uint64_t value) {
	allocate(mOffset + 8);
	mBuffer[mOffset++] = (uint8_t)(value & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 8) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 16) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 24) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 32) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 40) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 48) & 0xFF);
	mBuffer[mOffset++] = (uint8_t)((value >> 56) & 0xFF);
	if (mPacketSize < mOffset)
	mPacketSize = mOffset;
	}

	void MtpDataPacket::putInt128(const int128_t& value) {
	putInt32(value[0]);
	putInt32(value[1]);
	putInt32(value[2]);
	putInt32(value[3]);
	}

	void MtpDataPacket::putUInt128(const uint128_t& value) {
	putUInt32(value[0]);
	putUInt32(value[1]);
	putUInt32(value[2]);
	putUInt32(value[3]);
	}

	void MtpDataPacket::putInt128(int64_t value) {
	putInt64(value);
	putInt64(value < 0 ? -1 : 0);
	}

	void MtpDataPacket::putUInt128(uint64_t value) {
	putUInt64(value);
	putUInt64(0);
	}

	void MtpDataPacket::putAInt8(const int8_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putInt8(*values++);
	}

	void MtpDataPacket::putAUInt8(const uint8_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putUInt8(*values++);
	}

	void MtpDataPacket::putAInt16(const int16_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putInt16(*values++);
	}

	void MtpDataPacket::putAUInt16(const uint16_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putUInt16(*values++);
	}

	void MtpDataPacket::putAUInt16(const UInt16List* values) {
	size_t count = (values ? values->size() : 0);
	putUInt32(count);
	for (size_t i = 0; i < count; i++)
	putUInt16((*values)[i]);
	}

	void MtpDataPacket::putAInt32(const int32_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putInt32(*values++);
	}

	void MtpDataPacket::putAUInt32(const uint32_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putUInt32(*values++);
	}

	void MtpDataPacket::putAUInt32(const UInt32List* list) {
	if (!list) {
	putEmptyArray();
	} else {
	size_t size = list->size();
	putUInt32(size);
	for (size_t i = 0; i < size; i++)
	putUInt32((*list)[i]);
	}
	}

	void MtpDataPacket::putAInt64(const int64_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putInt64(*values++);
	}

	void MtpDataPacket::putAUInt64(const uint64_t* values, int count) {
	putUInt32(count);
	for (int i = 0; i < count; i++)
	putUInt64(*values++);
	}

	void MtpDataPacket::putString(const MtpStringBuffer& string) {
	string.writeToPacket(this);
	}

	void MtpDataPacket::putString(const char* s) {
	MtpStringBuffer string(s);
	string.writeToPacket(this);
	}

	void MtpDataPacket::putString(const uint16_t* string) {
	int count = 0;
	for (int i = 0; i <= MTP_STRING_MAX_CHARACTER_NUMBER; i++) {
	if (string[i])
	count++;
	else
	break;
	}
	putUInt8(count > 0 ? count + 1 : 0);
	for (int i = 0; i < count; i++)
	putUInt16(string[i]);
	// only terminate with zero if string is not empty
	if (count > 0)
	putUInt16(0);
	}

	#ifdef MTP_DEVICE
	int MtpDataPacket::read(IMtpHandle *h) {
	int ret = h->read(mBuffer, MTP_BUFFER_SIZE);
	if (ret < MTP_CONTAINER_HEADER_SIZE)
	return -1;
	mPacketSize = ret;
	mOffset = MTP_CONTAINER_HEADER_SIZE;
	return ret;
	}

	int MtpDataPacket::write(IMtpHandle *h) {
	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
	int ret = h->write(mBuffer, mPacketSize);
	return (ret < 0 ? ret : 0);
	}

	int MtpDataPacket::writeData(IMtpHandle h, void data, uint32_t length) {
	allocate(length + MTP_CONTAINER_HEADER_SIZE);
	memcpy(mBuffer + MTP_CONTAINER_HEADER_SIZE, data, length);
	length += MTP_CONTAINER_HEADER_SIZE;
	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, length);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
	int ret = h->write(mBuffer, length);
	return (ret < 0 ? ret : 0);
	}

	#endif // MTP_DEVICE

	#ifdef MTP_HOST
	int MtpDataPacket::read(struct usb_request *request) {
	// first read the header
	request->buffer = mBuffer;
	request->buffer_length = mBufferSize;
	int length = transfer(request);
	if (length >= MTP_CONTAINER_HEADER_SIZE) {
	// look at the length field to see if the data spans multiple packets
	uint32_t totalLength = MtpPacket::getUInt32(MTP_CONTAINER_LENGTH_OFFSET);
	allocate(totalLength);
	while (totalLength > static_cast<uint32_t>(length)) {
	request->buffer = mBuffer + length;
	request->buffer_length = totalLength - length;
	int ret = transfer(request);
	if (ret >= 0)
	length += ret;
	else {
	length = ret;
	break;
	}
	}
	}
	if (length >= 0)
	mPacketSize = length;
	return length;
	}

	int MtpDataPacket::readData(struct usb_request request, void buffer, int length) {
	int read = 0;
	while (read < length) {
	request->buffer = (char *)buffer + read;
	request->buffer_length = length - read;
	int ret = transfer(request);
	if (ret < 0) {
	return ret;
	}
	read += ret;
	}
	return read;
	}

	// Queue a read request. Call readDataWait to wait for result
	int MtpDataPacket::readDataAsync(struct usb_request *req) {
	if (usb_request_queue(req)) {
	ALOGE("usb_endpoint_queue failed, errno: %d", errno);
	return -1;
	}
	return 0;
	}

	// Wait for result of readDataAsync
	int MtpDataPacket::readDataWait(struct usb_device *device) {
	struct usb_request *req = usb_request_wait(device, -1);
	return (req ? req->actual_length : -1);
	}

	int MtpDataPacket::readDataHeader(struct usb_request *request) {
	request->buffer = mBuffer;
	request->buffer_length = request->max_packet_size;
	int length = transfer(request);
	if (length >= 0)
	mPacketSize = length;
	return length;
	}

	int MtpDataPacket::write(struct usb_request *request, UrbPacketDivisionMode divisionMode) {
	if (mPacketSize < MTP_CONTAINER_HEADER_SIZE \|\| mPacketSize > MTP_BUFFER_SIZE) {
	ALOGE("Illegal packet size.");
	return -1;
	}

	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, mPacketSize);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);

	size_t processedBytes = 0;
	while (processedBytes < mPacketSize) {
	const size_t write_size =
	processedBytes == 0 && divisionMode == FIRST_PACKET_ONLY_HEADER ?
	MTP_CONTAINER_HEADER_SIZE : mPacketSize - processedBytes;
	request->buffer = mBuffer + processedBytes;
	request->buffer_length = write_size;
	const int result = transfer(request);
	if (result < 0) {
	ALOGE("Failed to write bytes to the device.");
	return -1;
	}
	processedBytes += result;
	}

	return processedBytes == mPacketSize ? processedBytes : -1;
	}

	int64_t MtpDataPacket::write(struct usb_request *request,
	UrbPacketDivisionMode divisionMode,
	int fd,
	size_t payloadSize) {
	// Obtain the greatest multiple of minimum packet size that is not greater than
	// MTP_BUFFER_SIZE.
	if (request->max_packet_size <= 0) {
	ALOGE("Cannot determine bulk transfer size due to illegal max packet size %d.",
	request->max_packet_size);
	return -1;
	}
	const size_t maxBulkTransferSize =
	MTP_BUFFER_SIZE - (MTP_BUFFER_SIZE % request->max_packet_size);
	const size_t containerLength = payloadSize + MTP_CONTAINER_HEADER_SIZE;
	size_t processedBytes = 0;
	bool readError = false;

	// Bind the packet with given request.
	request->buffer = mBuffer;
	allocate(maxBulkTransferSize);

	while (processedBytes < containerLength) {
	size_t bulkTransferSize = 0;

	// prepare header.
	const bool headerSent = processedBytes != 0;
	if (!headerSent) {
	MtpPacket::putUInt32(MTP_CONTAINER_LENGTH_OFFSET, containerLength);
	MtpPacket::putUInt16(MTP_CONTAINER_TYPE_OFFSET, MTP_CONTAINER_TYPE_DATA);
	bulkTransferSize += MTP_CONTAINER_HEADER_SIZE;
	}

	// Prepare payload.
	if (headerSent \|\| divisionMode == FIRST_PACKET_HAS_PAYLOAD) {
	const size_t processedPayloadBytes =
	headerSent ? processedBytes - MTP_CONTAINER_HEADER_SIZE : 0;
	const size_t maxRead = payloadSize - processedPayloadBytes;
	const size_t maxWrite = maxBulkTransferSize - bulkTransferSize;
	const size_t bulkTransferPayloadSize = std::min(maxRead, maxWrite);
	// prepare payload.
	if (!readError) {
	const ssize_t result = readExactBytes(
	fd,
	mBuffer + bulkTransferSize,
	bulkTransferPayloadSize);
	if (result < 0) {
	ALOGE("Found an error while reading data from FD. Send 0 data instead.");
	readError = true;
	}
	}
	if (readError) {
	memset(mBuffer + bulkTransferSize, 0, bulkTransferPayloadSize);
	}
	bulkTransferSize += bulkTransferPayloadSize;
	}

	// Bulk transfer.
	mPacketSize = bulkTransferSize;
	request->buffer_length = bulkTransferSize;
	const int result = transfer(request);
	if (result != static_cast<ssize_t>(bulkTransferSize)) {
	// Cannot recover writing error.
	ALOGE("Found an error while write data to MtpDevice.");
	return -1;
	}

	// Update variables.
	processedBytes += bulkTransferSize;
	}

	return readError ? -1 : processedBytes;
	}

	#endif // MTP_HOST

	void* MtpDataPacket::getData(int* outLength) const {
	int length = mPacketSize - MTP_CONTAINER_HEADER_SIZE;
	if (length > 0) {
	void* result = malloc(length);
	if (result) {
	memcpy(result, mBuffer + MTP_CONTAINER_HEADER_SIZE, length);
	*outLength = length;
	return result;
	}
	}
	*outLength = 0;
	return NULL;
	}

	} // namespace android