chundoong-lab-ta/APWS23/image-rotation-skeleton/util.cpp

#include "util.h"

#include <cmath>
#include <cstdbool>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

double get_current_time() {
  struct timespec tv;
  clock_gettime(CLOCK_MONOTONIC, &tv);
  return tv.tv_sec + tv.tv_nsec * 1e-9;
}

void storeImage(float *imageOut, const char *filename, int rows, int cols,
                const char *refFilename) {
  FILE *ifp, *ofp;
  unsigned char tmp;
  int offset;
  unsigned char *buffer;
  int i, j;

  int bytes;

  int height, width;

  ifp = fopen(refFilename, "rb");
  if (ifp == NULL) {
    perror(filename);
    exit(-1);
  }

  fseek(ifp, 10, SEEK_SET);
  fread(&offset, 4, 1, ifp);

  fseek(ifp, 18, SEEK_SET);
  fread(&width, 4, 1, ifp);
  fread(&height, 4, 1, ifp);

  fseek(ifp, 0, SEEK_SET);

  buffer = (unsigned char *) malloc(offset);
  if (buffer == NULL) {
    perror("malloc");
    exit(-1);
  }

  fread(buffer, 1, offset, ifp);

  printf("Writing output image to %s\n", filename);
  ofp = fopen(filename, "wb");
  if (ofp == NULL) {
    perror("opening output file");
    exit(-1);
  }
  bytes = fwrite(buffer, 1, offset, ofp);
  if (bytes != offset) {
    printf("error writing header!\n");
    exit(-1);
  }

  // NOTE bmp formats store data in reverse raster order (see comment in
  // readImage function), so we need to flip it upside down here.
  int mod = width % 4;
  if (mod != 0) { mod = 4 - mod; }
  for (i = height - 1; i >= 0; i--) {
    for (j = 0; j < width; j++) {
      tmp = (unsigned char) imageOut[i * cols + j];
      fwrite(&tmp, sizeof(char), 1, ofp);
    }
    // In bmp format, rows must be a multiple of 4-bytes.
    // So if we're not at a multiple of 4, add junk padding.
    for (j = 0; j < mod; j++) { fwrite(&tmp, sizeof(char), 1, ofp); }
  }

  fclose(ofp);
  fclose(ifp);

  free(buffer);
}

/*
 * Read bmp image and convert to byte array. Also output the width and height
 */
float *readImage(const char *filename, int *widthOut, int *heightOut) {
  uchar *imageData;

  int height, width;
  uchar tmp;
  int offset;
  int i, j;

  printf("Reading input image from %s\n", filename);
  FILE *fp = fopen(filename, "rb");
  if (fp == NULL) {
    perror(filename);
    exit(-1);
  }

  fseek(fp, 10, SEEK_SET);
  fread(&offset, 4, 1, fp);

  fseek(fp, 18, SEEK_SET);
  fread(&width, 4, 1, fp);
  fread(&height, 4, 1, fp);

  *widthOut = width;
  *heightOut = height;

  imageData = (uchar *) malloc(width * height);
  if (imageData == NULL) {
    perror("malloc");
    exit(-1);
  }

  fseek(fp, offset, SEEK_SET);
  fflush(NULL);

  int mod = width % 4;
  if (mod != 0) { mod = 4 - mod; }

  // NOTE bitmaps are stored in upside-down raster order.  So we begin
  // reading from the bottom left pixel, then going from left-to-right,
  // read from the bottom to the top of the image.  For image analysis,
  // we want the image to be right-side up, so we'll modify it here.

  // First we read the image in upside-down

  // Read in the actual image
  for (i = 0; i < height; i++) {
    // add actual data to the image
    for (j = 0; j < width; j++) {
      fread(&tmp, sizeof(char), 1, fp);
      imageData[i * width + j] = tmp;
    }
    // For the bmp format, each row has to be a multiple of 4,
    // so I need to read in the junk data and throw it away
    for (j = 0; j < mod; j++) { fread(&tmp, sizeof(char), 1, fp); }
  }

  // Then we flip it over
  int flipRow;
  for (i = 0; i < height / 2; i++) {
    flipRow = height - (i + 1);
    for (j = 0; j < width; j++) {
      tmp = imageData[i * width + j];
      imageData[i * width + j] = imageData[flipRow * width + j];
      imageData[flipRow * width + j] = tmp;
    }
  }

  fclose(fp);

  // Input image on the host
  float *floatImage = NULL;
  floatImage = (float *) malloc(sizeof(float) * width * height);
  if (floatImage == NULL) {
    perror("malloc");
    exit(-1);
  }

  // Convert the BMP image to float (not required)
  for (i = 0; i < height; i++) {
    for (j = 0; j < width; j++) {
      floatImage[i * width + j] = (float) imageData[i * width + j];
    }
  }

  free(imageData);
  return floatImage;
}