Home | History | Annotate | Download | only in mtp 
      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "MtpStringBuffer"
     18 
     19 #include <codecvt>
     20 #include <locale>
     21 #include <string>
     22 #include <vector>
     23 
     24 #include "MtpDataPacket.h"
     25 #include "MtpStringBuffer.h"
     26 
     27 namespace {
     28 
     29 std::wstring_convert<std::codecvt_utf8_utf16<char16_t>,char16_t> gConvert;
     30 
     31 static std::string utf16ToUtf8(std::u16string input_str) {
     32     return gConvert.to_bytes(input_str);
     33 }
     34 
     35 static std::u16string utf8ToUtf16(std::string input_str) {
     36     return gConvert.from_bytes(input_str);
     37 }
     38 
     39 } // namespace
     40 
     41 namespace android {
     42 
     43 MtpStringBuffer::MtpStringBuffer(const char* src)
     44 {
     45     set(src);
     46 }
     47 
     48 MtpStringBuffer::MtpStringBuffer(const uint16_t* src)
     49 {
     50     set(src);
     51 }
     52 
     53 MtpStringBuffer::MtpStringBuffer(const MtpStringBuffer& src)
     54 {
     55     mString = src.mString;
     56 }
     57 
     58 void MtpStringBuffer::set(const char* src) {
     59     mString = std::string(src);
     60 }
     61 
     62 void MtpStringBuffer::set(const uint16_t* src) {
     63     mString = utf16ToUtf8(std::u16string((const char16_t*)src));
     64 }
     65 
     66 bool MtpStringBuffer::readFromPacket(MtpDataPacket* packet) {
     67     uint8_t count;
     68     if (!packet->getUInt8(count))
     69         return false;
     70     if (count == 0)
     71         return true;
     72 
     73     std::vector<char16_t> buffer(count);
     74     for (int i = 0; i < count; i++) {
     75         uint16_t ch;
     76         if (!packet->getUInt16(ch))
     77             return false;
     78         buffer[i] = ch;
     79     }
     80     if (buffer[count-1] != '\0') {
     81         ALOGE("Mtp string not null terminated\n");
     82         return false;
     83     }
     84     mString = utf16ToUtf8(std::u16string(buffer.data()));
     85     return true;
     86 }
     87 
     88 void MtpStringBuffer::writeToPacket(MtpDataPacket* packet) const {
     89     std::u16string src16 = utf8ToUtf16(mString);
     90     int count = src16.length();
     91 
     92     if (count == 0) {
     93         packet->putUInt8(0);
     94         return;
     95     }
     96     packet->putUInt8(std::min(count + 1, MTP_STRING_MAX_CHARACTER_NUMBER));
     97 
     98     int i = 0;
     99     for (char16_t &c : src16) {
    100         if (i == MTP_STRING_MAX_CHARACTER_NUMBER - 1) {
    101             // Leave a slot for null termination.
    102             ALOGI("Mtp truncating long string\n");
    103             break;
    104         }
    105         packet->putUInt16(c);
    106         i++;
    107     }
    108     // only terminate with zero if string is not empty
    109     packet->putUInt16(0);
    110 }
    111 
    112 }  // namespace android
    113