Fix Unicode string handling
Linux uses UTF8 but java and MTP both
use UTF16. In a few places, this results
in the top byte of a UTF16 string being
truncated on conversion to UTF8.
Also, the hardcoded UTF to byte serialization
in MtpStringBuffer is incorrect.
Replace it with conversions from std, and
replace usages of MtpString with MtpStringBuffer.
Remove any remaining usages of libutils
and replace them with corresponding std
libraries.
Bug: 70546563
Test: Mtp works, tests pass
Test: file/folder names containing emoji can be transferred to/from
windows
Change-Id: Idbcb73f1beac17ce8a90843fa254e759dd1a6369
diff --git a/media/mtp/MtpStringBuffer.cpp b/media/mtp/MtpStringBuffer.cpp
index df04694..cd379bf 100644
--- a/media/mtp/MtpStringBuffer.cpp
+++ b/media/mtp/MtpStringBuffer.cpp
@@ -16,168 +16,97 @@
#define LOG_TAG "MtpStringBuffer"
-#include <string.h>
+#include <codecvt>
+#include <locale>
+#include <string>
+#include <vector>
#include "MtpDataPacket.h"
#include "MtpStringBuffer.h"
-namespace android {
+namespace {
-MtpStringBuffer::MtpStringBuffer()
- : mCharCount(0),
- mByteCount(1)
-{
- mBuffer[0] = 0;
+std::wstring_convert<std::codecvt_utf8_utf16<char16_t>,char16_t> gConvert;
+
+static std::string utf16ToUtf8(std::u16string input_str) {
+ return gConvert.to_bytes(input_str);
}
+static std::u16string utf8ToUtf16(std::string input_str) {
+ return gConvert.from_bytes(input_str);
+}
+
+} // namespace
+
+namespace android {
+
MtpStringBuffer::MtpStringBuffer(const char* src)
- : mCharCount(0),
- mByteCount(1)
{
set(src);
}
MtpStringBuffer::MtpStringBuffer(const uint16_t* src)
- : mCharCount(0),
- mByteCount(1)
{
set(src);
}
MtpStringBuffer::MtpStringBuffer(const MtpStringBuffer& src)
- : mCharCount(src.mCharCount),
- mByteCount(src.mByteCount)
{
- memcpy(mBuffer, src.mBuffer, mByteCount);
-}
-
-
-MtpStringBuffer::~MtpStringBuffer() {
+ mString = src.mString;
}
void MtpStringBuffer::set(const char* src) {
- // count the characters
- int count = 0;
- char ch;
- char* dest = (char*)mBuffer;
-
- while ((ch = *src++) != 0 && count < MTP_STRING_MAX_CHARACTER_NUMBER) {
- if ((ch & 0x80) == 0) {
- // single byte character
- *dest++ = ch;
- } else if ((ch & 0xE0) == 0xC0) {
- // two byte character
- char ch1 = *src++;
- if (! ch1) {
- // last character was truncated, so ignore last byte
- break;
- }
-
- *dest++ = ch;
- *dest++ = ch1;
- } else if ((ch & 0xF0) == 0xE0) {
- // 3 byte char
- char ch1 = *src++;
- if (! ch1) {
- // last character was truncated, so ignore last byte
- break;
- }
- char ch2 = *src++;
- if (! ch2) {
- // last character was truncated, so ignore last byte
- break;
- }
-
- *dest++ = ch;
- *dest++ = ch1;
- *dest++ = ch2;
- }
- count++;
- }
-
- *dest++ = 0;
- mByteCount = dest - (char*)mBuffer;
- mCharCount = count;
+ mString = std::string(src);
}
void MtpStringBuffer::set(const uint16_t* src) {
- int count = 0;
- uint16_t ch;
- uint8_t* dest = mBuffer;
-
- while ((ch = *src++) != 0 && count < MTP_STRING_MAX_CHARACTER_NUMBER) {
- if (ch >= 0x0800) {
- *dest++ = (uint8_t)(0xE0 | (ch >> 12));
- *dest++ = (uint8_t)(0x80 | ((ch >> 6) & 0x3F));
- *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
- } else if (ch >= 0x80) {
- *dest++ = (uint8_t)(0xC0 | (ch >> 6));
- *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
- } else {
- *dest++ = ch;
- }
- count++;
- }
- *dest++ = 0;
- mCharCount = count;
- mByteCount = dest - mBuffer;
+ mString = utf16ToUtf8(std::u16string((const char16_t*)src));
}
bool MtpStringBuffer::readFromPacket(MtpDataPacket* packet) {
uint8_t count;
if (!packet->getUInt8(count))
return false;
+ if (count == 0)
+ return true;
- uint8_t* dest = mBuffer;
+ std::vector<char16_t> buffer(count);
for (int i = 0; i < count; i++) {
uint16_t ch;
-
if (!packet->getUInt16(ch))
return false;
- if (ch >= 0x0800) {
- *dest++ = (uint8_t)(0xE0 | (ch >> 12));
- *dest++ = (uint8_t)(0x80 | ((ch >> 6) & 0x3F));
- *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
- } else if (ch >= 0x80) {
- *dest++ = (uint8_t)(0xC0 | (ch >> 6));
- *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
- } else {
- *dest++ = ch;
- }
+ buffer[i] = ch;
}
- *dest++ = 0;
- mCharCount = count;
- mByteCount = dest - mBuffer;
+ if (buffer[count-1] != '\0') {
+ ALOGE("Mtp string not null terminated\n");
+ return false;
+ }
+ mString = utf16ToUtf8(std::u16string(buffer.data()));
return true;
}
void MtpStringBuffer::writeToPacket(MtpDataPacket* packet) const {
- int count = mCharCount;
- const uint8_t* src = mBuffer;
- packet->putUInt8(count > 0 ? count + 1 : 0);
+ std::u16string src16 = utf8ToUtf16(mString);
+ int count = src16.length();
- // expand utf8 to 16 bit chars
- for (int i = 0; i < count; i++) {
- uint16_t ch;
- uint16_t ch1 = *src++;
- if ((ch1 & 0x80) == 0) {
- // single byte character
- ch = ch1;
- } else if ((ch1 & 0xE0) == 0xC0) {
- // two byte character
- uint16_t ch2 = *src++;
- ch = ((ch1 & 0x1F) << 6) | (ch2 & 0x3F);
- } else {
- // three byte character
- uint16_t ch2 = *src++;
- uint16_t ch3 = *src++;
- ch = ((ch1 & 0x0F) << 12) | ((ch2 & 0x3F) << 6) | (ch3 & 0x3F);
+ if (count == 0) {
+ packet->putUInt8(0);
+ return;
+ }
+ packet->putUInt8(std::min(count + 1, MTP_STRING_MAX_CHARACTER_NUMBER));
+
+ int i = 0;
+ for (char16_t &c : src16) {
+ if (i == MTP_STRING_MAX_CHARACTER_NUMBER - 1) {
+ // Leave a slot for null termination.
+ ALOGI("Mtp truncating long string\n");
+ break;
}
- packet->putUInt16(ch);
+ packet->putUInt16(c);
+ i++;
}
// only terminate with zero if string is not empty
- if (count > 0)
- packet->putUInt16(0);
+ packet->putUInt16(0);
}
} // namespace android