第2章　写真のデータを読み込もう

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <Windows.h>
#define true 1
#define false 0
#define HEADER_SIZE 54 //heder size 54 = 14 + 40
#define MAX_WIDTH 3000 //upper limit of width(pixel)
#define MAX_HEIGHT 3000 //upper limit of height(pixel)
#define COLOR_CATEGORY_NUM 1000
#define PLUS_MINUS(a, b, c) ((a) + (c) >= b && (a) - (c) <= b)
#define SIZE 10

// r,g,b values of one pixel
typedef struct {
  unsigned char r;
  unsigned char g;
  unsigned char b;
  int color_type;// どの色か
  int color_num;// color_categoryの場合、どれだけのピクセルがその色に入っているのか
  int sum;// r + g + b;
} color;

typedef struct {
  long height;
  long width;
  color data[MAX_HEIGHT][MAX_WIDTH];
  int color_num;// 色の数
  color color_category[COLOR_CATEGORY_NUM];
} img;

int ReadBmp(char *file_name, img *imgp) {
  unsigned char bmp_header_buf[HEADER_SIZE]; // this store header data of bmp
  char bmp_type[2];
  long bmp_height;
  long bmp_width;
  unsigned short bmp_color;
  long real_width;

  unsigned char *bmp_data;
  FILE *bmp_file;

  bmp_file = fopen(file_name, "rb");

  if(bmp_file == NULL) {
    printf("\n\n\n\nFailed to open bmp file\n");
    return 0;
  }

  // ヘッダー(両方)を取得
  fread(bmp_header_buf, sizeof(unsigned char), HEADER_SIZE, bmp_file);

  // ファイルの最初がBMかどうか
  memcpy(&bmp_type, bmp_header_buf, sizeof(bmp_type));
  if(strncmp(bmp_type, "BM", 2) != 0) {
    printf("Error: %s is not a bmp file.\n", file_name);
    return 0;
  }

  memcpy(&imgp->width, bmp_header_buf + 18, sizeof(bmp_width));
  memcpy(&imgp->height, bmp_header_buf + 22, sizeof(bmp_height));
  memcpy(&bmp_color, bmp_header_buf + 28, sizeof(bmp_color));
  if(bmp_color != 24) {
    printf("Error: bmp_color = %d is not implemented in this program.\n", bmp_color);
    return 0;
  }
  if(imgp->width > MAX_WIDTH) {
    printf("Error: bmp_width = %ld > %d = MAX_WIDTH\n", imgp->width, MAX_WIDTH);
    return 0;
  }
  if(imgp->height > MAX_HEIGHT) {
    printf("Error: bmp_height = %ld > %d = MAX_HEIGHT\n", imgp->height, MAX_HEIGHT);
    return 0;
  }
  if(imgp->height < 0) {
    printf("Error hight is under 0\n");
    return 0;
  }

  printf("Finished checking file format\n");

  real_width = imgp->width * 3 + imgp->width % 4;//calculate real width to fit 4 byte border


  if((bmp_data = (unsigned char *)calloc(real_width, sizeof(unsigned char))) == NULL) {
    printf("Eroor: memory allocation failed for bmp_data\n");
    return 0;
  }

  printf("Reading data...\n");
  for(int i = 0; i < imgp->height; i++) {
    fread(bmp_data, 1, real_width, bmp_file);
    for(int j = 0; j < imgp->width; j++) {
      imgp->data[imgp->height-i-1][j].b = bmp_data[j*3];
      imgp->data[imgp->height-i-1][j].g = bmp_data[j*3+1];
      imgp->data[imgp->height-i-1][j].r = bmp_data[j*3+2];
      imgp->data[imgp->height-i-1][j].sum = bmp_data[j*3] + bmp_data[j*3+1] + bmp_data[j*3+2];
    }
  }
  printf("Finished Reading data\n");

  printf("Please wait a few seconds...\n");

  free(bmp_data);
  fclose(bmp_file);
  return 1;
}



int main() {
  FILE *color_data_file;
  FILE *out_put_data_file;
  img *receiver_data;
  receiver_data = (img *)malloc(sizeof(img));

  char file_name[100];
  // Get file name
  printf("Drag and drop a bmp picture which you want to convert\n");
  printf("And push enter key if I don't say start opening\n");
  // If the name of picture have \n or ", it will be failed.
  scanf("%s", file_name);

  if(!ReadBmp(file_name, receiver_data)) {
    //unsuccess
    return -1;
  }
  return 0;
}
// ご苦労さま