scrollview.cpp

一个google的OCR源码

///////////////////////////////////////////////////////////////////////
// File:        scrollview.cc
// Description: ScrollView
// Author:      Joern Wanke
// Created:     Thu Nov 29 2007
//
// (C) Copyright 2007, Google Inc.
// 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.
//
///////////////////////////////////////////////////////////////////////
//
// This class contains the main ScrollView-logic,
// e.g. parsing & sending messages, images etc.
#ifdef WIN32
#pragma warning(disable:4786)  // Don't give stupid warnings for stl
#endif

const int kSvPort = 8461;
const int kMaxMsgSize = 4096;
const int kMaxIntPairSize = 45;  // Holds %d,%d, for upto 64 bit.

#include "scrollview.h"

#include <stdarg.h>
#include <map>
#include <utility>
#include <algorithm>
#include <vector>
#include <string>

#include "svutil.h"

#ifdef HAVE_LIBLEPT
#include "allheaders.h"
#endif

struct SVPolyLineBuffer {
  bool empty;  // Independent indicator to allow SendMsg to call SendPolygon.
  std::vector<int> xcoords;
  std::vector<int> ycoords;
};

// A map between the window IDs and their corresponding pointers.
static std::map<int, ScrollView*> svmap;
// A map of all semaphores waiting for a specific event on a specific window.
static std::map<std::pair<ScrollView*, SVEventType>,
                std::pair<SVSemaphore*, SVEvent*> > waiting_for_events;
SVMutex* mutex_waiting;

SVEvent* SVEvent::copy() {
  SVEvent* any = new SVEvent;
  any->command_id = command_id;
  any->counter = counter;
  any->parameter = new char[strlen(parameter) + 1];
  strncpy(any->parameter, parameter, strlen(parameter));
  any->parameter[strlen(parameter)] = '\0';
  any->type = type;
  any->x = x;
  any->y = y;
  any->x_size = x_size;
  any->y_size = y_size;
  any->window = window;
  return any;
}

// This is the main loop which handles the ScrollView-logic from the server
// to the client. It basically loops through messages, parses them to events
// and distributes it to the waiting handlers.
// It is run from a different thread and synchronizes via SVSync.
void* ScrollView::MessageReceiver(void* a) {
  int counter_event_id = 0;  // ongoing counter
  char* message = NULL;
  // Wait until a new message appears in the input stream_.
  do {
    message = ScrollView::GetStream()->Receive();
  } while (message == NULL);

// This is the main loop which iterates until the server is dead (strlen = -1).
// It basically parses for 3 different messagetypes and then distributes the
// events accordingly.
  while (strlen(message) != -1) {
      // The new event we create.
      SVEvent* cur = new SVEvent;
      // The ID of the corresponding window.
      int window_id;

      int ev_type;

      int n;
      // Fill the new SVEvent properly.
      sscanf(message, "%d,%d,%d,%d,%d,%d,%d,%n", &window_id, &ev_type, &cur->x,
             &cur->y, &cur->x_size, &cur->y_size, &cur->command_id, &n);
      char* p = (message + n);

      cur->window = svmap[window_id];

      if (cur->window != NULL) {
        cur->parameter = new char[strlen(p) + 1];
        strncpy(cur->parameter, p, strlen(p) + 1);
        if (strlen(p) > 0) {  // remove the last \n
          cur->parameter[strlen(p)] = '\0';
        }
        cur->type = static_cast<SVEventType>(ev_type);
        cur->y = cur->window->TranslateYCoordinate(cur->y);
        cur->counter = counter_event_id;
        // Increase by 2 since we will also create an SVET_ANY event from cur,
        // which will have a counter_id of cur + 1 (and thus gets processed
        // after cur).
        counter_event_id += 2;

        // In case of an SVET_EXIT event, quit the whole application.
        if (ev_type == SVET_EXIT) { ScrollView::Exit(); }

        // Place two copies of it in the table for the window.
        cur->window->SetEvent(cur);

        // Check if any of the threads currently waiting want it.
        std::pair<ScrollView*, SVEventType> awaiting_list(cur->window,
                                                          cur->type);
        std::pair<ScrollView*, SVEventType> awaiting_list_any(cur->window,
                                                              SVET_ANY);
        std::pair<ScrollView*, SVEventType> awaiting_list_any_window(NULL,
                                                              SVET_ANY);
        mutex_waiting->Lock();
        if (waiting_for_events.count(awaiting_list) > 0) {
          waiting_for_events[awaiting_list].second = cur;
          waiting_for_events[awaiting_list].first->Signal();
        } else if (waiting_for_events.count(awaiting_list_any) > 0) {
          waiting_for_events[awaiting_list_any].second = cur;
          waiting_for_events[awaiting_list_any].first->Signal();
        } else if (waiting_for_events.count(awaiting_list_any_window) > 0) {
          waiting_for_events[awaiting_list_any_window].second = cur;
          waiting_for_events[awaiting_list_any_window].first->Signal();
        } else {
          // No one wanted it, so delete it.
          delete cur;
        }
        mutex_waiting->Unlock();
        // Signal the corresponding semaphore twice (for both copies).
        ScrollView* sv = svmap[window_id];
        if (sv != NULL) {
          sv->Signal();
          sv->Signal();
        }
      }

      // Wait until a new message appears in the input stream_.
      do {
        message = ScrollView::GetStream()->Receive();
      } while (message == NULL);
    }
  return 0;
}

// Table to implement the color index values in the old system.
int table_colors[ScrollView::GREEN_YELLOW+1][4]= {
  {0, 0, 0, 0},        // NONE (transparent)
  {0, 0, 0, 255},        // BLACK.
  {255, 255, 255, 255},  // WHITE.
  {255, 0, 0, 255},      // RED.
  {255, 255, 0, 255},    // YELLOW.
  {0, 255, 0, 255},      // GREEN.
  {0, 255, 255, 255},    // CYAN.
  {0, 0, 255, 255},      // BLUE.
  {255, 0, 255, 255},    // MAGENTA.
  {0, 128, 255, 255},    // AQUAMARINE.
  {0, 0, 64, 255},       // DARK_SLATE_BLUE.
  {128, 128, 255, 255},  // LIGHT_BLUE.
  {64, 64, 255, 255},    // MEDIUM_BLUE.
  {0, 0, 32, 255},       // MIDNIGHT_BLUE.
  {0, 0, 128, 255},      // NAVY_BLUE.
  {192, 192, 255, 255},  // SKY_BLUE.
  {64, 64, 128, 255},    // SLATE_BLUE.
  {32, 32, 64, 255},     // STEEL_BLUE.
  {255, 128, 128, 255},  // CORAL.
  {128, 64, 0, 255},     // BROWN.
  {128, 128, 0, 255},    // SANDY_BROWN.
  {192, 192, 0, 255},    // GOLD.
  {192, 192, 128, 255},  // GOLDENROD.
  {0, 64, 0, 255},       // DARK_GREEN.
  {32, 64, 0, 255},      // DARK_OLIVE_GREEN.
  {64, 128, 0, 255},     // FOREST_GREEN.
  {128, 255, 0, 255},    // LIME_GREEN.
  {192, 255, 192, 255},  // PALE_GREEN.
  {192, 255, 0, 255},    // YELLOW_GREEN.
  {192, 192, 192, 255},  // LIGHT_GREY.
  {64, 64, 128, 255},    // DARK_SLATE_GREY.
  {64, 64, 64, 255},     // DIM_GREY.
  {128, 128, 128, 255},  // GREY.
  {64, 192, 0, 255},     // KHAKI.
  {255, 0, 192, 255},    // MAROON.
  {255, 128, 0, 255},    // ORANGE.
  {255, 128, 64, 255},   // ORCHID.
  {255, 192, 192, 255},  // PINK.
  {128, 0, 128, 255},    // PLUM.
  {255, 0, 64, 255},     // INDIAN_RED.
  {255, 64, 0, 255},     // ORANGE_RED.
  {255, 0, 192, 255},    // VIOLET_RED.
  {255, 192, 128, 255},  // SALMON.
  {128, 128, 0, 255},    // TAN.
  {0, 255, 255, 255},    // TURQUOISE.
  {0, 128, 128, 255},    // DARK_TURQUOISE.
  {192, 0, 255, 255},    // VIOLET.
  {128, 128, 0, 255},    // WHEAT.
  {128, 255, 0, 255}     // GREEN_YELLOW
};


/*******************************************************************************
* Scrollview implementation.
*******************************************************************************/

SVNetwork* ScrollView::stream_ = NULL;
int ScrollView::nr_created_windows_ = 0;

// Calls Initialize with all arguments given.
ScrollView::ScrollView(const char* name, int x_pos, int y_pos, int x_size,
                       int y_size, int x_canvas_size, int y_canvas_size,
                       bool y_axis_reversed, const char* server_name) {
  Initialize(name, x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size,
             y_axis_reversed, server_name);}

// Calls Initialize with default argument for server_name_.
ScrollView::ScrollView(const char* name, int x_pos, int y_pos, int x_size,
                       int y_size, int x_canvas_size, int y_canvas_size,
                       bool y_axis_reversed) {
  Initialize(name, x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size,
             y_axis_reversed, "localhost");
}

// Calls Initialize with default argument for server_name_ & y_axis_reversed.
ScrollView::ScrollView(const char* name, int x_pos, int y_pos, int x_size,
                       int y_size, int x_canvas_size, int y_canvas_size) {
  Initialize(name, x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size,
             false, "localhost");
}

// Sets up a ScrollView window, depending on the constructor variables.
void ScrollView::Initialize(const char* name, int x_pos, int y_pos, int x_size,
                            int y_size, int x_canvas_size, int y_canvas_size,
                            bool y_axis_reversed, const char* server_name) {
  // If this is the first ScrollView Window which gets created, there is no
  // network connection yet and we have to set it up in a different thread.
  if (stream_ == NULL) {
    nr_created_windows_ = 0;
    stream_ = new SVNetwork(server_name, kSvPort);
    mutex_waiting = new SVMutex();
    SendRawMessage(
        "svmain = luajava.bindClass('com.google.scrollview.ScrollView')\n");
    SVSync::StartThread(MessageReceiver, NULL);
  }

  // Set up the variables on the clientside.
  nr_created_windows_++;
  event_handler_ = NULL;
  y_axis_is_reversed_ = y_axis_reversed;
  y_size_ = y_canvas_size;
  window_name_ = name;
  window_id_ = nr_created_windows_;
  // Set up polygon buffering.
  points_ = new SVPolyLineBuffer;
  points_->empty = true;

  svmap[window_id_] = this;

  for (int i = 0; i < SVET_COUNT; i++) {
    event_table_[i] = NULL;
  }

  mutex_ = new SVMutex();
  semaphore_ = new SVSemaphore();

  // Set up an actual Window on the client side.
  char message[kMaxMsgSize];
  snprintf(message, sizeof(message),
           "w%u = luajava.newInstance('com.google.scrollview.ui"
           ".SVWindow','%s',%u,%u,%u,%u,%u,%u,%u)\n",
           window_id_, window_name_, window_id_,
           x_pos, y_pos, x_size, y_size, x_canvas_size, y_canvas_size);
  SendRawMessage(message);

  SVSync::StartThread(StartEventHandler, this);
}

// Sits and waits for events on this window.
void* ScrollView::StartEventHandler(void* a) {
  ScrollView* sv = reinterpret_cast<ScrollView*>(a);
  SVEvent* new_event;

  do {
    stream_->Flush();
    sv->semaphore_->Wait();
    new_event = NULL;
    int serial = INT_MAX;
    int k = -1;
    sv->mutex_->Lock();
    // Check every table entry if he is is valid and not already processed.

    for (int i = 0; i < SVET_COUNT; i++) {
      if ((sv->event_table_[i] != NULL) &&
          (sv->event_table_[i]->counter < serial)) {
        new_event = sv->event_table_[i];
        serial = sv->event_table_[i]->counter;
        k = i;
      }
    }
    // If we didnt find anything we had an old alarm and just sleep again.
    if (new_event != NULL) {
      sv->event_table_[k] = NULL;
      sv->mutex_->Unlock();
      if (sv->event_handler_ != NULL) { sv->event_handler_->Notify(new_event); }
      if (new_event->type == SVET_DESTROY) { sv = NULL; }
      delete new_event;  // Delete the pointer after it has been processed.
    } else { sv->mutex_->Unlock(); }
  // The thread should run as long as its associated window is alive.
  } while (sv != NULL);
  return 0;
}

ScrollView::~ScrollView() {
  if (svmap[window_id_] != NULL) {
    // So the event handling thread can quit.
    SendMsg("destroy()");

    SVEvent* sve = AwaitEvent(SVET_DESTROY);
    delete sve;
  }
  delete mutex_;
  delete semaphore_;
  delete points_;

  svmap.erase(window_id_);
}

// Send a message to the server, attaching the window id.
void ScrollView::SendMsg(const char* format, ...) {
  if (!points_->empty)
    SendPolygon();
  va_list args;
  char message[kMaxMsgSize];

  va_start(args, format);  // variable list
  vsnprintf(message, kMaxMsgSize, format, args);
  va_end(args);

  char form[kMaxMsgSize];
  snprintf(form, kMaxMsgSize, "w%u:%s\n", window_id_, message);

  stream_->Send(form);
}

// Send a message to the server without a
// window id. Used for global events like exit().
void ScrollView::SendRawMessage(const char* msg) {
  stream_->Send(msg);
}

// Add an Event Listener to this ScrollView Window
void ScrollView::AddEventHandler(SVEventHandler* listener) {
  event_handler_ = listener;
}

void ScrollView::Signal() {
  semaphore_->Signal();
}

void ScrollView::SetEvent(SVEvent* svevent) {
// Copy event
  SVEvent* any = svevent->copy();
  SVEvent* specific = svevent->copy();
  any->counter = specific->counter + 1;

// Place both events into the queue.
  mutex_->Lock();
  // Delete the old objects..
  if (event_table_[specific->type] != NULL) {
    delete event_table_[specific->type]; }
  if (event_table_[SVET_ANY] != NULL) {
    delete event_table_[SVET_ANY]; }
  // ...and put the new ones in the table.
  event_table_[specific->type] = specific;
  event_table_[SVET_ANY] = any;
  mutex_->Unlock();
}


// Block until an event of the given type is received.
// Note: The calling function is responsible for deleting the returned
// SVEvent afterwards!
SVEvent* ScrollView::AwaitEvent(SVEventType type) {
  // Initialize the waiting semaphore.
  SVSemaphore* sem = new SVSemaphore();
  std::pair<ScrollView*, SVEventType> ea(this, type);
  mutex_waiting->Lock();
  waiting_for_events[ea] = std::pair<SVSemaphore*, SVEvent*> (sem, NULL);
  mutex_waiting->Unlock();
  // Wait on it, but first flush.
  stream_->Flush();
  sem->Wait();
  // Process the event we got woken up for (its in waiting_for_events pair).
  mutex_waiting->Lock();