New addon "tesseract" for OCR

tesseract/vendor/thiagoalessio/tesseract_ocr/src/Process.php

@@ -0,0 +1,83 @@
+<?php namespace thiagoalessio\TesseractOCR;
+
+class Process {
+
+    private $stdin;
+    private $stdout;
+    private $stderr;
+    private $handle;
+    private $startTime;
+
+    public function __construct($command)
+    {
+        $this->startTime = microtime(true);
+        $streamDescriptors = [
+            array("pipe", "r"),
+            array("pipe", "w"),
+            array("pipe", "w")
+        ];
+        $this->handle = proc_open($command, $streamDescriptors, $pipes, NULL, NULL, ["bypass_shell" => true]);
+        list($this->stdin, $this->stdout, $this->stderr) = $pipes;
+
+        FriendlyErrors::checkProcessCreation($this->handle, $command);
+
+        //This is can avoid deadlock on some cases (when stderr buffer is filled up before writing to stdout and vice-versa)
+        stream_set_blocking($this->stdout, 0);
+        stream_set_blocking($this->stderr, 0);
+    }
+
+    public function write($data, $len)
+    {
+        $total = 0;
+        do
+        {
+            $res = fwrite($this->stdin, substr($data, $total));
+        } while($res && $total += $res < $len);
+        return $total === $len;
+    }
+
+
+    public function wait($timeout = 0)
+    {
+        $running = true;
+        $data = ["out" => "", "err" => ""];
+        while (($running === true) && !$this->hasTimedOut($timeout))
+        {
+            $data["out"] .= fread($this->stdout, 8192);
+            $data["err"] .= fread($this->stderr, 8192);
+            $procInfo = proc_get_status($this->handle);
+            $running = $procInfo["running"];
+            if ($running) {
+                usleep(1000); // Sleep 1ms to yield CPU time
+            }
+        }
+        return $data;
+    }
+
+    public function close()
+    {
+        $this->closeStream($this->stdin);
+        $this->closeStream($this->stdout);
+        $this->closeStream($this->stderr);
+        return proc_close($this->handle);
+    }
+
+    public function closeStdin()
+    {
+        $this->closeStream($this->stdin);
+    }
+
+    private function hasTimedOut($timeout)
+    {
+        return (($timeout > 0) &&  ($this->startTime + $timeout < microtime(true)));    
+    }
+    
+    private function closeStream(&$stream)
+    {
+        if ($stream !== NULL)
+        {
+            fclose($stream);
+            $stream = NULL;
+        }
+    }
+}