1 /* 2 * Copyright (C) 2018 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 #include "utils/strings/utf8.h" 18 19 namespace libtextclassifier3 { 20 bool IsValidUTF8(const char *src, int size) { 21 for (int i = 0; i < size;) { 22 const int char_length = ValidUTF8CharLength(src + i, size - i); 23 if (char_length <= 0) { 24 return false; 25 } 26 i += char_length; 27 } 28 return true; 29 } 30 31 int ValidUTF8CharLength(const char *src, int size) { 32 // Unexpected trail byte. 33 if (IsTrailByte(src[0])) { 34 return -1; 35 } 36 37 const int num_codepoint_bytes = GetNumBytesForUTF8Char(&src[0]); 38 if (num_codepoint_bytes <= 0 || num_codepoint_bytes > size) { 39 return -1; 40 } 41 42 // Check that remaining bytes in the codepoint are trailing bytes. 43 for (int k = 1; k < num_codepoint_bytes; k++) { 44 if (!IsTrailByte(src[k])) { 45 return -1; 46 } 47 } 48 49 return num_codepoint_bytes; 50 } 51 52 } // namespace libtextclassifier3 53
