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 <string.h>
20
21 #include "MtpDataPacket.h"
22 #include "MtpStringBuffer.h"
23
24 namespace android {
25
MtpStringBuffer()26 MtpStringBuffer::MtpStringBuffer()
27 : mCharCount(0),
28 mByteCount(1)
29 {
30 mBuffer[0] = 0;
31 }
32
MtpStringBuffer(const char * src)33 MtpStringBuffer::MtpStringBuffer(const char* src)
34 : mCharCount(0),
35 mByteCount(1)
36 {
37 set(src);
38 }
39
MtpStringBuffer(const uint16_t * src)40 MtpStringBuffer::MtpStringBuffer(const uint16_t* src)
41 : mCharCount(0),
42 mByteCount(1)
43 {
44 set(src);
45 }
46
MtpStringBuffer(const MtpStringBuffer & src)47 MtpStringBuffer::MtpStringBuffer(const MtpStringBuffer& src)
48 : mCharCount(src.mCharCount),
49 mByteCount(src.mByteCount)
50 {
51 memcpy(mBuffer, src.mBuffer, mByteCount);
52 }
53
54
~MtpStringBuffer()55 MtpStringBuffer::~MtpStringBuffer() {
56 }
57
set(const char * src)58 void MtpStringBuffer::set(const char* src) {
59 // count the characters
60 int count = 0;
61 char ch;
62 char* dest = (char*)mBuffer;
63
64 while ((ch = *src++) != 0 && count < MTP_STRING_MAX_CHARACTER_NUMBER) {
65 if ((ch & 0x80) == 0) {
66 // single byte character
67 *dest++ = ch;
68 } else if ((ch & 0xE0) == 0xC0) {
69 // two byte character
70 char ch1 = *src++;
71 if (! ch1) {
72 // last character was truncated, so ignore last byte
73 break;
74 }
75
76 *dest++ = ch;
77 *dest++ = ch1;
78 } else if ((ch & 0xF0) == 0xE0) {
79 // 3 byte char
80 char ch1 = *src++;
81 if (! ch1) {
82 // last character was truncated, so ignore last byte
83 break;
84 }
85 char ch2 = *src++;
86 if (! ch2) {
87 // last character was truncated, so ignore last byte
88 break;
89 }
90
91 *dest++ = ch;
92 *dest++ = ch1;
93 *dest++ = ch2;
94 }
95 count++;
96 }
97
98 *dest++ = 0;
99 mByteCount = dest - (char*)mBuffer;
100 mCharCount = count;
101 }
102
set(const uint16_t * src)103 void MtpStringBuffer::set(const uint16_t* src) {
104 int count = 0;
105 uint16_t ch;
106 uint8_t* dest = mBuffer;
107
108 while ((ch = *src++) != 0 && count < MTP_STRING_MAX_CHARACTER_NUMBER) {
109 if (ch >= 0x0800) {
110 *dest++ = (uint8_t)(0xE0 | (ch >> 12));
111 *dest++ = (uint8_t)(0x80 | ((ch >> 6) & 0x3F));
112 *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
113 } else if (ch >= 0x80) {
114 *dest++ = (uint8_t)(0xC0 | (ch >> 6));
115 *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
116 } else {
117 *dest++ = ch;
118 }
119 count++;
120 }
121 *dest++ = 0;
122 mCharCount = count;
123 mByteCount = dest - mBuffer;
124 }
125
readFromPacket(MtpDataPacket * packet)126 void MtpStringBuffer::readFromPacket(MtpDataPacket* packet) {
127 int count = packet->getUInt8();
128 uint8_t* dest = mBuffer;
129 for (int i = 0; i < count; i++) {
130 uint16_t ch = packet->getUInt16();
131 if (ch >= 0x0800) {
132 *dest++ = (uint8_t)(0xE0 | (ch >> 12));
133 *dest++ = (uint8_t)(0x80 | ((ch >> 6) & 0x3F));
134 *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
135 } else if (ch >= 0x80) {
136 *dest++ = (uint8_t)(0xC0 | (ch >> 6));
137 *dest++ = (uint8_t)(0x80 | (ch & 0x3F));
138 } else {
139 *dest++ = ch;
140 }
141 }
142 *dest++ = 0;
143 mCharCount = count;
144 mByteCount = dest - mBuffer;
145 }
146
writeToPacket(MtpDataPacket * packet) const147 void MtpStringBuffer::writeToPacket(MtpDataPacket* packet) const {
148 int count = mCharCount;
149 const uint8_t* src = mBuffer;
150 packet->putUInt8(count > 0 ? count + 1 : 0);
151
152 // expand utf8 to 16 bit chars
153 for (int i = 0; i < count; i++) {
154 uint16_t ch;
155 uint16_t ch1 = *src++;
156 if ((ch1 & 0x80) == 0) {
157 // single byte character
158 ch = ch1;
159 } else if ((ch1 & 0xE0) == 0xC0) {
160 // two byte character
161 uint16_t ch2 = *src++;
162 ch = ((ch1 & 0x1F) << 6) | (ch2 & 0x3F);
163 } else {
164 // three byte character
165 uint16_t ch2 = *src++;
166 uint16_t ch3 = *src++;
167 ch = ((ch1 & 0x0F) << 12) | ((ch2 & 0x3F) << 6) | (ch3 & 0x3F);
168 }
169 packet->putUInt16(ch);
170 }
171 // only terminate with zero if string is not empty
172 if (count > 0)
173 packet->putUInt16(0);
174 }
175
176 } // namespace android
177