mirror of
https://github.com/tesseract-ocr/tesseract.git
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57 lines
2.0 KiB
C++
57 lines
2.0 KiB
C++
/**
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* Copyright 2010 Google Inc.
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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// Author: sligocki@google.com (Shawn Ligocki)
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#include "util/utf8/unilib.h"
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#include "syntaxnet/base.h"
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#include "third_party/utf/utf.h"
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namespace UniLib {
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// Codepoints not allowed for interchange are:
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// C0 (ASCII) controls: U+0000 to U+001F excluding Space (SP, U+0020),
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// Horizontal Tab (HT, U+0009), Line-Feed (LF, U+000A),
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// Form Feed (FF, U+000C) and Carriage-Return (CR, U+000D)
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// C1 controls: U+007F to U+009F
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// Surrogates: U+D800 to U+DFFF
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// Non-characters: U+FDD0 to U+FDEF and U+xxFFFE to U+xxFFFF for all xx
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bool IsInterchangeValid(char32 c) {
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return !((c >= 0x00 && c <= 0x08) || c == 0x0B || (c >= 0x0E && c <= 0x1F) ||
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(c >= 0x7F && c <= 0x9F) || (c >= 0xD800 && c <= 0xDFFF) ||
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(c >= 0xFDD0 && c <= 0xFDEF) || (c & 0xFFFE) == 0xFFFE);
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}
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int SpanInterchangeValid(const char *begin, int byte_length) {
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char32 rune;
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const char *p = begin;
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const char *end = begin + byte_length;
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while (p < end) {
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int bytes_consumed = charntorune(&rune, p, end - p);
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// We want to accept Runeerror == U+FFFD as a valid char, but it is used
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// by chartorune to indicate error. Luckily, the real codepoint is size 3
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// while errors return bytes_consumed <= 1.
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if ((rune == Runeerror && bytes_consumed <= 1) || !IsInterchangeValid(rune)) {
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break; // Found
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}
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p += bytes_consumed;
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}
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return p - begin;
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}
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} // namespace UniLib
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