From e3fd938bca0e9bdf80590a775fe1d9ee4dff6bb7 Mon Sep 17 00:00:00 2001
From: Stefan Weil <sw@weilnetz.de>
Date: Thu, 21 Jan 2021 23:17:14 +0100
Subject: [PATCH] lstmtrainer: Modernize code

Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 src/training/unicharset/lstmtrainer.cpp | 53 +++++++++++++------------
 1 file changed, 28 insertions(+), 25 deletions(-)

diff --git a/src/training/unicharset/lstmtrainer.cpp b/src/training/unicharset/lstmtrainer.cpp
index 23801358e..a78093196 100644
--- a/src/training/unicharset/lstmtrainer.cpp
+++ b/src/training/unicharset/lstmtrainer.cpp
@@ -699,11 +699,11 @@ bool LSTMTrainer::EncodeString(const STRING& str, const UNICHARSET& unicharset,
   if (unicharset.encode_string(cleaned.c_str(), true, &internal_labels, nullptr,
                                &err_index)) {
     bool success = true;
-    for (int i = 0; i < internal_labels.size(); ++i) {
+    for (auto internal_label : internal_labels) {
       if (recoder != nullptr) {
         // Re-encode labels via recoder.
         RecodedCharID code;
-        int len = recoder->EncodeUnichar(internal_labels[i], &code);
+        int len = recoder->EncodeUnichar(internal_label, &code);
         if (len > 0) {
           for (int j = 0; j < len; ++j) {
             labels->push_back(code(j));
@@ -715,7 +715,7 @@ bool LSTMTrainer::EncodeString(const STRING& str, const UNICHARSET& unicharset,
           break;
         }
       } else {
-        labels->push_back(internal_labels[i]);
+        labels->push_back(internal_label);
         if (!simple_text) labels->push_back(null_char);
       }
     }
@@ -791,9 +791,10 @@ Trainability LSTMTrainer::PrepareForBackward(const ImageData* trainingdata,
       // Apart from space and null, increment the label. This is changes the
       // script-id to the same script-id but upside-down.
       // The labels need to be reversed in order, as the first is now the last.
-      for (int c = 0; c < truth_labels.size(); ++c) {
-        if (truth_labels[c] != UNICHAR_SPACE && truth_labels[c] != null_char_)
-          ++truth_labels[c];
+      for (auto truth_label : truth_labels) {
+        if (truth_label != UNICHAR_SPACE && truth_label != null_char_) {
+          ++truth_label;
+	}
       }
       std::reverse(truth_labels.begin(), truth_labels.end());
     }
@@ -1088,10 +1089,12 @@ bool LSTMTrainer::ComputeTextTargets(const NetworkIO& outputs,
             DecodeLabels(truth_labels).c_str(), targets->Width());
     return false;
   }
-  for (int i = 0; i < truth_labels.size() && i < targets->Width(); ++i) {
-    targets->SetActivations(i, truth_labels[i], 1.0);
+  size_t i = 0;
+  for (auto truth_label : truth_labels) {
+    targets->SetActivations(i, truth_label, 1.0);
+    ++i;
   }
-  for (int i = truth_labels.size(); i < targets->Width(); ++i) {
+  for (i = truth_labels.size(); i < targets->Width(); ++i) {
     targets->SetActivations(i, null_char_, 1.0);
   }
   return true;
@@ -1173,20 +1176,20 @@ double LSTMTrainer::ComputeCharError(const std::vector<int>& truth_str,
   std::vector<int> label_counts;
   label_counts.resize(NumOutputs(), 0);
   int truth_size = 0;
-  for (int i = 0; i < truth_str.size(); ++i) {
-    if (truth_str[i] != null_char_) {
-      ++label_counts[truth_str[i]];
+  for (auto ch : truth_str) {
+    if (ch != null_char_) {
+      ++label_counts[ch];
       ++truth_size;
     }
   }
-  for (int i = 0; i < ocr_str.size(); ++i) {
-    if (ocr_str[i] != null_char_) {
-      --label_counts[ocr_str[i]];
+  for (auto ch : ocr_str) {
+    if (ch != null_char_) {
+      --label_counts[ch];
     }
   }
   int char_errors = 0;
-  for (int i = 0; i < label_counts.size(); ++i) {
-    char_errors += abs(label_counts[i]);
+  for (auto label_count : label_counts) {
+    char_errors += abs(label_count);
   }
   if (truth_size == 0) {
     return (char_errors == 0) ? 0.0 : 1.0;
@@ -1203,19 +1206,19 @@ double LSTMTrainer::ComputeWordError(STRING* truth_str, STRING* ocr_str) {
   if (truth_words.empty()) return 0.0;
   ocr_str->split(' ', &ocr_words);
   StrMap word_counts;
-  for (int i = 0; i < truth_words.size(); ++i) {
-    std::string truth_word(truth_words[i].c_str());
-    auto it = word_counts.find(truth_word);
+  for (auto truth_word : truth_words) {
+    std::string truth_word_string(truth_word.c_str());
+    auto it = word_counts.find(truth_word_string);
     if (it == word_counts.end())
-      word_counts.insert(std::make_pair(truth_word, 1));
+      word_counts.insert(std::make_pair(truth_word_string, 1));
     else
       ++it->second;
   }
-  for (int i = 0; i < ocr_words.size(); ++i) {
-    std::string ocr_word(ocr_words[i].c_str());
-    auto it = word_counts.find(ocr_word);
+  for (auto ocr_word : ocr_words) {
+    std::string ocr_word_string(ocr_word.c_str());
+    auto it = word_counts.find(ocr_word_string);
     if (it == word_counts.end())
-      word_counts.insert(std::make_pair(ocr_word, -1));
+      word_counts.insert(std::make_pair(ocr_word_string, -1));
     else
       --it->second;
   }