Merge pull request #1 from prismocr/images_load

Load image and stuff

.gitignore

@@ -0,0 +1,3 @@
+*.out
+*.swp
+

Makefile

@@ -0,0 +1,10 @@
+CC := gcc
+CFLAGS := -Wall -Werror -pedantic -Wpointer-arith
+LDFLAGS := -Iinclude/
+
+all:
+	$(CC) src/*.c $(CFLAGS) $(LDFLAGS)
+
+format:
+	clang-format --style=file -i src/*.c
+

include/error.h

@@ -0,0 +1,8 @@
+#ifndef ERROR_H
+#define ERROR_H
+
+const char *get_last_error();
+void set_last_error(const char *error);
+
+#endif // ERROR_H
+

include/image.h

@@ -0,0 +1,13 @@
+#ifndef IMAGE_H
+#define IMAGE_H
+
+#include "ndarray.h"
+
+// Load an image in grayscale colorspace into an ndarray
+int load_bmp_image(const char *path, ndarray **im);
+
+// read an image and save it
+void save_bmp_image(const char *path, ndarray *im);
+
+#endif // IMAGE_H
+

include/ndarray.h

@@ -0,0 +1,17 @@
+#ifndef NDARRAY_H
+#define NDARRAY_H
+
+#include <stddef.h>
+
+typedef struct ndarray ndarray;
+
+struct ndarray {
+    size_t ndim;
+    size_t *dim;
+    float *val;
+};
+
+void ndarray_print(const ndarray *a);
+
+#endif // NDARRAY_H
+

src/error.c

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+#include "error.h"
+#include "stdlib.h"
+#include "string.h"
+
+static const char *last_error = "";
+
+const char *get_last_error() {
+    return last_error;
+}
+
+void set_last_error(const char *error) {
+    last_error = error;
+}
+

src/image.c

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+#include "image.h"
+#include "ndarray.h"
+#include "error.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+// --- File header ---
+
+// signature : 2
+// file size: 4
+// reserved field: 4
+// image offset: 4
+
+// 14 bytes
+
+// --- Image header ---
+
+// size of the header: 4
+// image width: 4
+// image height: 4
+// depth: 2
+// number of bits/pixels: 2
+// compression size: 4
+// image size: 4
+// horizontal resolution: 4
+// vertical resolution: 4
+// number of palette colors: 4
+// number of important colors: 4
+
+// 40 bytes
+
+// start at 54 bytes
+
+unsigned int read_bmp_qword(FILE *f) {
+    unsigned char b[4];
+    fscanf(f, "%c%c%c%c", &b[0], &b[1], &b[2], &b[3]);
+    return b[0] | b[1] << 8 | b[2] << 16 | b[3] << 24;
+}
+
+float color_to_gray(float values[3]) {
+    int val = ((float) (values[0]) * 0.07f + (float) (values[1]) * 0.71f
+               + (float) (values[2]) * 0.21f);
+    if (val > 255) {
+        return 255;
+    } else if (val < 0) {
+        return 0;
+    }
+    return val;
+}
+
+float color_to_gray_simple(float values[3]) {
+    return (values[0] + values[1] + values[2]) / 3;
+}
+
+void save_image(const char *path, const char *path_grey, ndarray *im) {
+    FILE *f;
+    FILE *fgrey;
+    f = fopen(path, "rt");
+    fgrey = fopen(path_grey, "w");
+
+    int j, i = 0;
+    int count = im->dim[0] * im->dim[1];
+
+    for (i = 0; i < 54; i++) {
+        fputc(fgetc(f), fgrey);
+    }
+    for (i = 0; i < count; i++) {
+        for (j = 0; j < 3; j++) {
+            fputc((int) im->val[i], fgrey);
+        }
+    }
+
+    fclose(f);
+    fclose(fgrey);
+}
+
+// TODO handle errors correctly
+
+int load_bmp_image(const char *path, ndarray **im) {
+    FILE *f;
+    *im = (ndarray *) malloc(sizeof(ndarray));
+    if (*im == NULL) {
+        set_last_error("Failed to allocate memory for ndarray");
+        return 1;
+    }
+
+    (*im)->ndim = 2;
+    (*im)->dim = (size_t *) malloc(2 * sizeof(size_t));
+    if ((*im)->dim == NULL) {
+        set_last_error("Failed to allocate memory for dim");
+        return 1;
+    }
+
+    f = fopen(path, "rb");
+    if ((fgetc(f) << 8 | fgetc(f)) != 0x424d) {
+        set_last_error("Invalid file format");
+        return 1;
+    }
+
+    fseek(f, 18, SEEK_SET);
+    (*im)->dim[0] = read_bmp_qword(f);
+    (*im)->dim[1] = read_bmp_qword(f);
+
+    fseek(f, 54, SEEK_SET);
+
+    (*im)->val = (float *) malloc((*im)->dim[0] * (*im)->dim[1] * sizeof(float));
+
+    int gray_index = 0;
+
+    while (!feof(f)) {
+        (*im)->val[gray_index]
+          = color_to_gray((float[]){fgetc(f), fgetc(f), fgetc(f)});
+        gray_index++;
+    }
+    fclose(f);
+
+    return 0;
+}
+

src/main.c

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+#include <stdio.h>
+#include "ndarray.h"
+#include "image.h"
+#include "error.h"
+
+int main(int argc, char *argv[]) {
+    int res;
+    ndarray *im;
+    res = load_bmp_image(argv[1], &im);
+    if (res) {
+        printf("%s\n", get_last_error());
+    }
+    printf("%ld %ld\n", im->dim[0], im->dim[1]);
+
+    return 0;
+}
+

src/ndarray.c

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+#include <stdio.h>
+#include "ndarray.h"
+
+void ndarray_print(const ndarray *a) {
+
+}
+