mirror of
https://github.com/tesseract-ocr/tesseract.git
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251 lines
9.1 KiB
C++
251 lines
9.1 KiB
C++
// (C) Copyright 2017, 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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#include "unicharcompress.h"
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#include "gunit.h"
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#include "serialis.h"
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#include "printf.h"
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namespace tesseract {
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namespace {
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class UnicharcompressTest : public ::testing::Test {
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protected:
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// Loads and compresses the given unicharset.
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void LoadUnicharset(const string& unicharset_name) {
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string radical_stroke_file =
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file::JoinPath(FLAGS_test_srcdir,
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"langdata/radical-stroke.txt");
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string unicharset_file = file::JoinPath(
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FLAGS_test_srcdir, "testdata",
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unicharset_name);
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string uni_data;
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CHECK_OK(file::GetContents(unicharset_file, &uni_data, file::Defaults()));
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string radical_data;
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CHECK_OK(file::GetContents(radical_stroke_file, &radical_data,
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file::Defaults()));
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CHECK(
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unicharset_.load_from_inmemory_file(uni_data.data(), uni_data.size()));
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STRING radical_str(radical_data.c_str());
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null_char_ =
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unicharset_.has_special_codes() ? UNICHAR_BROKEN : unicharset_.size();
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compressed_.ComputeEncoding(unicharset_, null_char_, &radical_str);
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// Get the encoding of the null char.
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RecodedCharID code;
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compressed_.EncodeUnichar(null_char_, &code);
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encoded_null_char_ = code(0);
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string output_name = file::JoinPath(
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FLAGS_test_tmpdir, absl::StrCat(unicharset_name, ".encoding.txt"));
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STRING encoding = compressed_.GetEncodingAsString(unicharset_);
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string encoding_str(&encoding[0], encoding.size());
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CHECK_OK(file::SetContents(output_name, encoding_str, file::Defaults()));
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LOG(INFO) << "Wrote encoding to:" << output_name;
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}
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// Serializes and de-serializes compressed_ over itself.
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void SerializeAndUndo() {
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GenericVector<char> data;
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TFile wfp;
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wfp.OpenWrite(&data);
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EXPECT_TRUE(compressed_.Serialize(&wfp));
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TFile rfp;
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rfp.Open(&data[0], data.size());
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EXPECT_TRUE(compressed_.DeSerialize(&rfp));
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}
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// Returns true if the lang is in CJK.
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bool IsCJKLang(const string& lang) {
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return lang == "chi_sim" || lang == "chi_tra" || lang == "kor" ||
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lang == "jpn";
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}
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// Returns true if the lang is Indic.
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bool IsIndicLang(const string& lang) {
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return lang == "asm" || lang == "ben" || lang == "bih" || lang == "hin" ||
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lang == "mar" || lang == "nep" || lang == "san" || lang == "bod" ||
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lang == "dzo" || lang == "guj" || lang == "kan" || lang == "mal" ||
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lang == "ori" || lang == "pan" || lang == "sin" || lang == "tam" ||
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lang == "tel";
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}
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// Expects the appropriate results from the compressed_ unicharset_.
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void ExpectCorrect(const string& lang) {
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// Count the number of times each code is used in each element of
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// RecodedCharID.
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RecodedCharID zeros;
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for (int i = 0; i < RecodedCharID::kMaxCodeLen; ++i) zeros.Set(i, 0);
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int code_range = compressed_.code_range();
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std::vector<RecodedCharID> times_seen(code_range, zeros);
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for (int u = 0; u <= unicharset_.size(); ++u) {
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if (u != UNICHAR_SPACE && u != null_char_ &&
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(u == unicharset_.size() || (unicharset_.has_special_codes() &&
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u < SPECIAL_UNICHAR_CODES_COUNT))) {
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continue; // Not used so not encoded.
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}
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RecodedCharID code;
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int len = compressed_.EncodeUnichar(u, &code);
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// Check round-trip encoding.
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int unichar_id;
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GenericVector<UNICHAR_ID> normed_ids;
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if (u == null_char_ || u == unicharset_.size()) {
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unichar_id = null_char_;
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} else {
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unichar_id = u;
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}
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EXPECT_EQ(unichar_id, compressed_.DecodeUnichar(code));
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// Check that the codes are valid.
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for (int i = 0; i < len; ++i) {
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int code_val = code(i);
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EXPECT_GE(code_val, 0);
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EXPECT_LT(code_val, code_range);
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times_seen[code_val].Set(i, times_seen[code_val](i) + 1);
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}
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}
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// Check that each code is used in at least one position.
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for (int c = 0; c < code_range; ++c) {
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int num_used = 0;
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for (int i = 0; i < RecodedCharID::kMaxCodeLen; ++i) {
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if (times_seen[c](i) != 0) ++num_used;
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}
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EXPECT_GE(num_used, 1) << "c=" << c << "/" << code_range;
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}
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// Check that GetNextCodes/GetFinalCodes lists match the times_seen,
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// and create valid codes.
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RecodedCharID code;
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CheckCodeExtensions(code, times_seen);
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// Finally, we achieved all that using a codebook < 10% of the size of
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// the original unicharset, for CK or Indic, and 20% with J, but just
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// no bigger for all others.
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if (IsCJKLang(lang) || IsIndicLang(lang)) {
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EXPECT_LT(code_range, unicharset_.size() / (lang == "jpn" ? 5 : 10));
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} else {
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EXPECT_LE(code_range, unicharset_.size() + 1);
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}
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LOG(INFO) << "Compressed unicharset of " << unicharset_.size() << " to "
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<< code_range;
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}
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// Checks for extensions of the current code that either finish a code, or
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// extend it and checks those extensions recursively.
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void CheckCodeExtensions(const RecodedCharID& code,
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const std::vector<RecodedCharID>& times_seen) {
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RecodedCharID extended = code;
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int length = code.length();
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const GenericVector<int>* final_codes = compressed_.GetFinalCodes(code);
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if (final_codes != nullptr) {
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for (int i = 0; i < final_codes->size(); ++i) {
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int ending = (*final_codes)[i];
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EXPECT_GT(times_seen[ending](length), 0);
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extended.Set(length, ending);
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int unichar_id = compressed_.DecodeUnichar(extended);
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EXPECT_NE(INVALID_UNICHAR_ID, unichar_id);
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}
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}
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const GenericVector<int>* next_codes = compressed_.GetNextCodes(code);
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if (next_codes != nullptr) {
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for (int i = 0; i < next_codes->size(); ++i) {
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int extension = (*next_codes)[i];
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EXPECT_GT(times_seen[extension](length), 0);
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extended.Set(length, extension);
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CheckCodeExtensions(extended, times_seen);
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}
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}
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}
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UnicharCompress compressed_;
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UNICHARSET unicharset_;
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int null_char_;
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// The encoding of the null_char_.
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int encoded_null_char_;
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};
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TEST_F(UnicharcompressTest, DoesChinese) {
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LOG(INFO) << "Testing chi_tra";
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LoadUnicharset("chi_tra.unicharset");
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ExpectCorrect("chi_tra");
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LOG(INFO) << "Testing chi_sim";
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LoadUnicharset("chi_sim.unicharset");
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ExpectCorrect("chi_sim");
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}
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TEST_F(UnicharcompressTest, DoesJapanese) {
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LOG(INFO) << "Testing jpn";
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LoadUnicharset("jpn.unicharset");
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ExpectCorrect("jpn");
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}
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TEST_F(UnicharcompressTest, DoesKorean) {
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LOG(INFO) << "Testing kor";
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LoadUnicharset("kor.unicharset");
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ExpectCorrect("kor");
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}
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TEST_F(UnicharcompressTest, DoesKannada) {
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LOG(INFO) << "Testing kan";
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LoadUnicharset("kan.unicharset");
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ExpectCorrect("kan");
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SerializeAndUndo();
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ExpectCorrect("kan");
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}
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TEST_F(UnicharcompressTest, DoesMarathi) {
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LOG(INFO) << "Testing mar";
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LoadUnicharset("mar.unicharset");
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ExpectCorrect("mar");
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}
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TEST_F(UnicharcompressTest, DoesEnglish) {
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LOG(INFO) << "Testing eng";
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LoadUnicharset("eng.unicharset");
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ExpectCorrect("eng");
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}
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// Tests that a unicharset that contains double-letter ligatures (eg ff) has
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// no null char in the encoding at all.
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TEST_F(UnicharcompressTest, DoesLigaturesWithDoubles) {
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LOG(INFO) << "Testing por with ligatures";
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LoadUnicharset("por.unicharset");
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ExpectCorrect("por");
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// Check that any unichar-id that is encoded with multiple codes has the
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// correct encoded_nulll_char_ in between.
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for (int u = 0; u <= unicharset_.size(); ++u) {
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RecodedCharID code;
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int len = compressed_.EncodeUnichar(u, &code);
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if (len > 1) {
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// The should not be any null char in the code.
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for (int i = 0; i < len; ++i) {
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EXPECT_NE(encoded_null_char_, code(i));
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}
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}
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}
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}
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// Tests that GetEncodingAsString returns the right result for a trivial
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// unicharset.
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TEST_F(UnicharcompressTest, GetEncodingAsString) {
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LoadUnicharset("trivial.unicharset");
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ExpectCorrect("trivial");
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STRING encoding = compressed_.GetEncodingAsString(unicharset_);
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string encoding_str(&encoding[0], encoding.length());
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std::vector<string> lines =
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strings::Split(encoding_str, "\n", strings::SkipEmpty());
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EXPECT_EQ(5, lines.size());
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// The first line is always space.
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EXPECT_EQ("0\t ", lines[0]);
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// Next we have i.
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EXPECT_EQ("1\ti", lines[1]);
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// Next we have f.
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EXPECT_EQ("2\tf", lines[2]);
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// Next we have the fi ligature: fi. There are no nulls in it, as there are no
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// repeated letter ligatures in this unicharset, unlike por.unicharset above.
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EXPECT_EQ("2,1\tfi", lines[3]);
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// Finally the null character.
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EXPECT_EQ("3\t<nul>", lines[4]);
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}
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} // namespace
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} // namespace tesseract
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