Add C++ stream for log messages and use it in two debug messages

src/ccmain/control.cpp

@@ -41,6 +41,7 @@
 #endif
 #include "sorthelper.h"
 #include "tesseractclass.h"
+#include "tesserrstream.h"  // for tesserr
 #include "tessvars.h"
 #include "werdit.h"
 
@@ -1313,9 +1314,10 @@ void Tesseract::classify_word_and_language(int pass_n, PAGE_RES_IT *pr_it, WordD
   PointerVector<WERD_RES> best_words;
   // Points to the best result. May be word or in lang_words.
   const WERD_RES *word = word_data->word;
-  clock_t start_t = 0;
-  if (tessedit_timing_debug) {
-    start_t = clock();
+  clock_t total_time = 0;
+  const bool timing_debug = tessedit_timing_debug;
+  if (timing_debug) {
+    total_time = clock();
   }
   const bool debug = classify_debug_level > 0 || multilang_debug_level > 0;
   if (debug) {
@@ -1368,10 +1370,10 @@ void Tesseract::classify_word_and_language(int pass_n, PAGE_RES_IT *pr_it, WordD
   } else {
     tprintf("no best words!!\n");
   }
-  if (tessedit_timing_debug) {
-    clock_t ocr_t = clock();
-    tprintf("%s (ocr took %.2f sec)\n", word_data->word->best_choice->unichar_string().c_str(),
-            static_cast<double>(ocr_t - start_t) / CLOCKS_PER_SEC);
+  if (timing_debug) {
+    total_time = clock() - total_time;
+    tesserr << word_data->word->best_choice->unichar_string()
+            << " (ocr took " << 1000 * total_time / CLOCKS_PER_SEC << " ms)\n";
   }
 }
 

src/ccutil/tesserrstream.h

@@ -0,0 +1,68 @@
+// File:        tesserrstream.h
+// Description: C++ stream which enhances tprintf
+// Author:      Stefan Weil
+//
+// (C) Copyright 2024
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef TESSERACT_CCUTIL_TESSERRSTREAM_H
+#define TESSERACT_CCUTIL_TESSERRSTREAM_H
+
+#include "tprintf.h"
+#include <tesseract/export.h> // for TESS_API
+
+#include <ostream> // for std::ostream
+
+namespace tesseract {
+
+class TessStreamBuf : public std::streambuf {
+public:
+  TessStreamBuf() = default;
+
+protected:
+  virtual int_type overflow(int_type c) override {
+    if (c != EOF) {
+      if (debugfp == nullptr) {
+        debugfp = get_debugfp();
+      }
+      if (fputc(c, debugfp) == EOF) {
+        return EOF;
+      }
+    }
+    return c;
+  }
+
+  virtual std::streamsize xsputn(const char* s, std::streamsize n) override {
+    if (debugfp == nullptr) {
+      debugfp = get_debugfp();
+    }
+    return fwrite(s, 1, n, debugfp);
+  }
+
+private:
+  FILE *debugfp = nullptr;
+};
+
+class TessErrStream : public std::ostream {
+private:
+  TessStreamBuf buf;
+
+public:
+  TessErrStream() : std::ostream(nullptr), buf() {
+    rdbuf(&buf);
+  }
+};
+
+extern TESS_API TessErrStream tesserr;
+
+} // namespace tesseract
+
+#endif // TESSERACT_CCUTIL_TESSERRSTREAM_H

src/ccutil/tprintf.cpp

@@ -21,6 +21,7 @@
 #  include "config_auto.h"
 #endif
 
+#include "tesserrstream.h"
 #include "tprintf.h"
 
 #include "params.h"
@@ -36,7 +37,7 @@ INT_VAR(log_level, INT_MAX, "Logging level");
 static STRING_VAR(debug_file, "", "File to send tprintf output to");
 
 // File for debug output.
-static FILE *debugfp;
+FILE *debugfp;
 
 // Set output for log messages.
 // The output is written to stderr if debug_file is empty.
@@ -49,7 +50,7 @@ static FILE *debugfp;
 // tprintf("write to /tmp/log\n");
 // debug_file = "";
 // tprintf("write to stderr\n");
-static void set_debugfp() {
+FILE *get_debugfp() {
   if (debug_file.empty()) {
     // Write to stderr.
     if (debugfp != stderr && debugfp != nullptr) {
@@ -66,15 +67,18 @@ static void set_debugfp() {
 #endif
     debugfp = fopen(debug_file.c_str(), "wb");
   }
+  return debugfp;
 }
 
 // Trace printf.
 void tprintf(const char *format, ...) {
-  set_debugfp();
+  FILE *f = get_debugfp();
   va_list args;           // variable args
   va_start(args, format); // variable list
-  vfprintf(debugfp, format, args);
+  vfprintf(f, format, args);
   va_end(args);
 }
 
+TessErrStream tesserr;
+
 } // namespace tesseract

src/ccutil/tprintf.h

@@ -36,6 +36,9 @@ extern TESS_API void tprintf( // Trace printf
     const char *format, ...)  // Message
     __attribute__((format(printf, 1, 2)));
 
+// Get file for debug output.
+FILE *get_debugfp();
+
 } // namespace tesseract
 
 #undef __attribute__

src/training/common/errorcounter.cpp

@@ -23,6 +23,7 @@
 #include "sampleiterator.h"
 #include "shapeclassifier.h"
 #include "shapetable.h"
+#include "tesserrstream.h"
 #include "trainingsample.h"
 #include "trainingsampleset.h"
 #include "unicity_table.h"
@@ -50,7 +51,10 @@ double ErrorCounter::ComputeErrorRate(ShapeClassifier *classifier, int report_le
   ErrorCounter counter(classifier->GetUnicharset(), fontsize);
   std::vector<UnicharRating> results;
 
-  clock_t start = clock();
+  clock_t total_time = 0;
+  if (report_level > 1) {
+    total_time = clock();
+  }
   unsigned total_samples = 0;
   double unscaled_error = 0.0;
   // Set a number of samples on which to run the classify debug mode.
@@ -85,7 +89,6 @@ double ErrorCounter::ComputeErrorRate(ShapeClassifier *classifier, int report_le
     }
     ++total_samples;
   }
-  const double total_time = 1.0 * (clock() - start) / CLOCKS_PER_SEC;
   // Create the appropriate error report.
   unscaled_error = counter.ReportErrors(report_level, boosting_mode, fontinfo_table, *it,
                                         unichar_error, fonts_report);
@@ -94,8 +97,9 @@ double ErrorCounter::ComputeErrorRate(ShapeClassifier *classifier, int report_le
   }
   if (report_level > 1 && total_samples > 0) {
     // It is useful to know the time in microseconds/char.
-    tprintf("Errors computed in %.2fs at %.1f μs/char\n", total_time,
-            1000000.0 * total_time / total_samples);
+    total_time = 1000 * (clock() - total_time) / CLOCKS_PER_SEC;
+    tesserr << "Errors computed in " << total_time << "  ms at "
+            << 1000 * total_time / total_samples << " μs/char\n";
   }
   return unscaled_error;
 }