Add pnmfile.h

felz/src/pnmfile.h

@@ -0,0 +1,211 @@
+/*
+Copyright (C) 2006 Pedro Felzenszwalb
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+*/
+
+/* basic image I/O */
+
+#ifndef PNM_FILE_H
+#define PNM_FILE_H
+
+#include <cstdlib>
+#include <climits>
+#include <cstring>
+#include <fstream>
+#include "image.h"
+#include "misc.h"
+
+#define BUF_SIZE 256
+
+class pnm_error { };
+
+static void read_packed(unsigned char *data, int size, std::ifstream &f) {
+  unsigned char c = 0;
+
+  int bitshift = -1;
+  for (int pos = 0; pos < size; pos++) {
+    if (bitshift == -1) {
+      c = f.get();
+      bitshift = 7;
+    }
+    data[pos] = (c >> bitshift) & 1;
+    bitshift--;
+    }
+}
+
+static void write_packed(unsigned char *data, int size, std::ofstream &f) {
+  unsigned char c = 0;
+
+  int bitshift = 7;
+  for (int pos = 0; pos < size; pos++) {
+      c = c | (data[pos] << bitshift);
+      bitshift--;
+      if ((bitshift == -1) || (pos == size-1)) {
+	f.put(c);
+	bitshift = 7;
+	c = 0;
+      }
+  }
+}
+
+/* read PNM field, skipping comments */ 
+static void pnm_read(std::ifstream &file, char *buf) {
+  char doc[BUF_SIZE];
+  char c;
+
+  file >> c;
+  while (c == '#') {
+    file.getline(doc, BUF_SIZE);
+    file >> c;
+  }
+  file.putback(c);
+
+  file.width(BUF_SIZE);
+  file >> buf;
+  file.ignore();
+}
+
+static image<uchar> *loadPBM(const char *name) {
+  char buf[BUF_SIZE];
+
+  /* read header */
+  std::ifstream file(name, std::ios::in | std::ios::binary);
+  pnm_read(file, buf);
+  if (strncmp(buf, "P4", 2))
+    throw pnm_error();
+
+  pnm_read(file, buf);
+  int width = atoi(buf);
+  pnm_read(file, buf);
+  int height = atoi(buf);
+
+  /* read data */
+  image<uchar> *im = new image<uchar>(width, height);
+  for (int i = 0; i < height; i++)
+    read_packed(imPtr(im, 0, i), width, file);
+
+  return im;
+}
+
+static void savePBM(image<uchar> *im, const char *name) {
+  int width = im->width();
+  int height = im->height();
+  std::ofstream file(name, std::ios::out | std::ios::binary);
+
+  file << "P4\n" << width << " " << height << "\n";
+  for (int i = 0; i < height; i++)
+    write_packed(imPtr(im, 0, i), width, file);
+}
+
+static image<uchar> *loadPGM(const char *name) {
+  char buf[BUF_SIZE];
+
+  /* read header */
+  std::ifstream file(name, std::ios::in | std::ios::binary);
+  pnm_read(file, buf);
+  if (strncmp(buf, "P5", 2))
+    throw pnm_error();
+
+  pnm_read(file, buf);
+  int width = atoi(buf);
+  pnm_read(file, buf);
+  int height = atoi(buf);
+
+  pnm_read(file, buf);
+  if (atoi(buf) > UCHAR_MAX)
+    throw pnm_error();
+
+  /* read data */
+  image<uchar> *im = new image<uchar>(width, height);
+  file.read((char *)imPtr(im, 0, 0), width * height * sizeof(uchar));
+
+  return im;
+}
+
+static void savePGM(image<uchar> *im, const char *name) {
+  int width = im->width();
+  int height = im->height();
+  std::ofstream file(name, std::ios::out | std::ios::binary);
+
+  file << "P5\n" << width << " " << height << "\n" << UCHAR_MAX << "\n";
+  file.write((char *)imPtr(im, 0, 0), width * height * sizeof(uchar));
+}
+
+static image<rgb> *loadPPM(const char *name) {
+  char buf[BUF_SIZE], doc[BUF_SIZE];
+
+  /* read header */
+  std::ifstream file(name, std::ios::in | std::ios::binary);
+  pnm_read(file, buf);
+  if (strncmp(buf, "P6", 2))
+    throw pnm_error();
+
+  pnm_read(file, buf);
+  int width = atoi(buf);
+  pnm_read(file, buf);
+  int height = atoi(buf);
+
+  pnm_read(file, buf);
+  if (atoi(buf) > UCHAR_MAX)
+    throw pnm_error();
+
+  /* read data */
+  image<rgb> *im = new image<rgb>(width, height);
+  file.read((char *)imPtr(im, 0, 0), width * height * sizeof(rgb));
+
+  return im;
+}
+
+static void savePPM(image<rgb> *im, const char *name) {
+  int width = im->width();
+  int height = im->height();
+  std::ofstream file(name, std::ios::out | std::ios::binary);
+
+  file << "P6\n" << width << " " << height << "\n" << UCHAR_MAX << "\n";
+  file.write((char *)imPtr(im, 0, 0), width * height * sizeof(rgb));
+}
+
+template <class T>
+void load_image(image<T> **im, const char *name) {
+  char buf[BUF_SIZE];
+
+  /* read header */
+  std::ifstream file(name, std::ios::in | std::ios::binary);
+  pnm_read(file, buf);
+  if (strncmp(buf, "VLIB", 9))
+    throw pnm_error();
+
+  pnm_read(file, buf);
+  int width = atoi(buf);
+  pnm_read(file, buf);
+  int height = atoi(buf);
+
+  /* read data */
+  *im = new image<T>(width, height);
+  file.read((char *)imPtr((*im), 0, 0), width * height * sizeof(T));
+}
+
+template <class T>
+void save_image(image<T> *im, const char *name) {
+  int width = im->width();
+  int height = im->height();
+  std::ofstream file(name, std::ios::out | std::ios::binary);
+
+  file << "VLIB\n" << width << " " << height << "\n";
+  file.write((char *)imPtr(im, 0, 0), width * height * sizeof(T));
+}
+
+#endif