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86 lines
2.9 KiB
C++
86 lines
2.9 KiB
C++
///////////////////////////////////////////////////////////////////////
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// File: unichar.h
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// Description: Unicode character/ligature class.
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// Author: Ray Smith
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// Created: Wed Jun 28 17:05:01 PDT 2006
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//
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// (C) Copyright 2006, Google Inc.
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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///////////////////////////////////////////////////////////////////////
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#ifndef TESSERACT_CCUTIL_UNICHAR_H__
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#define TESSERACT_CCUTIL_UNICHAR_H__
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#include <memory.h>
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#include <string.h>
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// Maximum number of characters that can be stored in a UNICHAR. Must be
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// at least 4. Must not exceed 31 without changing the coding of length.
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#define UNICHAR_LEN 24
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// A UNICHAR_ID is the unique id of a unichar.
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typedef int UNICHAR_ID;
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// A variable to indicate an invalid or uninitialized unichar id.
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static const int INVALID_UNICHAR_ID = -1;
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// A special unichar that corresponds to INVALID_UNICHAR_ID.
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static const char INVALID_UNICHAR[] = "__INVALID_UNICHAR__";
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// The UNICHAR class holds a single classification result. This may be
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// a single Unicode character (stored as between 1 and 4 utf8 bytes) or
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// multple Unicode characters representing the NFKC expansion of a ligature
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// such as fi, ffl etc. These are also stored as utf8.
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class UNICHAR {
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public:
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UNICHAR() {
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memset(chars, 0, UNICHAR_LEN);
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}
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// Construct from a utf8 string. If len<0 then the string is null terminated.
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// If the string is too long to fit in the UNICHAR then it takes only what
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// will fit.
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UNICHAR(const char* utf8_str, int len);
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// Construct from a single UCS4 character.
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explicit UNICHAR(int unicode);
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// Default copy constructor and operator= are OK.
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// Get the first character as UCS-4.
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int first_uni() const;
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// Get the length of the UTF8 string.
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int utf8_len() const {
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int len = chars[UNICHAR_LEN - 1];
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return len >=0 && len < UNICHAR_LEN ? len : UNICHAR_LEN;
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}
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// Get a UTF8 string, but NOT NULL terminated.
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const char* utf8() const {
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return chars;
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}
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// Get a terminated UTF8 string: Must delete[] it after use.
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char* utf8_str() const;
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// Get the number of bytes in the first character of the given utf8 string.
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static int utf8_step(const char* utf8_str);
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private:
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// A UTF-8 representation of 1 or more Unicode characters.
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// The last element (chars[UNICHAR_LEN - 1]) is a length if
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// its value < UNICHAR_LEN, otherwise it is a genuine character.
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char chars[UNICHAR_LEN];
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};
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#endif // TESSERACT_CCUTIL_UNICHAR_H__
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