From c8f064302c00da0a9b8db664120a5b72eb65f0a8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Mon, 14 Jun 2021 21:38:12 +0200
Subject: [PATCH] feat: add ppm image loading

---
 image-viewer/include/image_loader.h |   9 +++
 image-viewer/src/image_loader.c     | 115 ++++++++++++++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 image-viewer/include/image_loader.h
 create mode 100644 image-viewer/src/image_loader.c

diff --git a/image-viewer/include/image_loader.h b/image-viewer/include/image_loader.h
new file mode 100644
index 0000000000000000000000000000000000000000..7693cf0f2d5fc71b423576c07a145a8b0bc6d491
--- /dev/null
+++ b/image-viewer/include/image_loader.h
@@ -0,0 +1,9 @@
+#include "image.h"
+
+image_error_t image_loader_load(image_t *image);
+
+image_error_t image_loader_load_ppm(image_t *image);
+image_error_t image_loader_load_jpeg(image_t *image);
+image_error_t image_loader_load_png(image_t *image);
+
+image_error_t image_deduce_type(image_t *image);
diff --git a/image-viewer/src/image_loader.c b/image-viewer/src/image_loader.c
new file mode 100644
index 0000000000000000000000000000000000000000..1f888c52be9ec3ff03e635d673a34a942dd25abc
--- /dev/null
+++ b/image-viewer/src/image_loader.c
@@ -0,0 +1,115 @@
+#include "image_loader.h"
+#include "display_utils.h"
+
+#include <asm-generic/errno-base.h>
+#include <errno.h>
+#include <magic.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define BUFFER_LENGTH 4
+
+image_error_t image_loader_load(image_t *image) {
+  image_error_t error = image_deduce_type(image);
+  if (error != IMERR_SUCCESS) {
+    return error;
+  }
+
+  switch (image->type) {
+  case IMG_PPM:
+    return image_loader_load_ppm(image);
+  case IMG_JPG:
+    return image_loader_load_jpeg(image);
+  case IMG_PNG:
+    return image_loader_load_png(image);
+  case IMG_UNKNOWN:
+    return IMERR_UNKNOWN_FORMAT;
+  }
+
+  return IMERR_UNKNOWN;
+}
+
+image_error_t image_error_from_errno() {
+  switch (errno) {
+  case ENOENT:
+    return IMERR_FILE_NOT_FOUND;
+  case EACCES:
+    return IMERR_FILE_NO_PERMISSIONS;
+  default:
+    return IMERR_FILE_CANT_OPEN;
+  }
+}
+
+image_error_t image_loader_load_ppm(image_t *image) {
+  FILE *file = fopen(image->path, "r");
+  if (file == NULL) {
+    return image_error_from_errno();
+  }
+
+  char null[10];
+  short height, width, maxBrightness;
+
+  if (fscanf(file, "%2s %hd %hd %hd", null, &width, &height, &maxBrightness) != 4) {
+    return IMERR_WRONG_FORMAT;
+  }
+
+  fseek(file, 1, SEEK_CUR);
+
+  raw_pixel_onebit_t max = {.red = maxBrightness, .green = maxBrightness, .blue = maxBrightness};
+
+  image->pixels = malloc(image->width * image->height * sizeof(display_pixel_t));
+  if (image->pixels == NULL) {
+    return IMERR_UNKNOWN;
+  }
+
+  for (int i = 0; i < image->height * image->width; i++) {
+    raw_pixel_onebit_t pixel;
+    if (fread(&pixel, sizeof(raw_pixel_onebit_t), 1, file) < 1) {
+      free(image->pixels);
+      fclose(file);
+      return IMERR_UNKNOWN;
+    }
+
+    image->pixels[i] = raw_pixel_onebit_convert_to_display(pixel, max);
+  }
+
+  fclose(file);
+  return IMERR_SUCCESS;
+}
+
+
+image_error_t image_loader_load_jpeg(image_t *image) {
+  return IMERR_WRONG_FORMAT;
+}
+
+image_error_t image_loader_load_png(image_t *image) {
+  return IMERR_WRONG_FORMAT;
+}
+
+image_error_t image_deduce_type(image_t *image) {
+  FILE *file = fopen(image->path, "r");
+  if (file == NULL) {
+    return image_error_from_errno();
+  }
+
+  uint8_t data[BUFFER_LENGTH];
+  if (fread(data, 1, BUFFER_LENGTH, file) != BUFFER_LENGTH) {
+    fclose(file);
+    return IMERR_UNKNOWN;
+  }
+
+  fclose(file);
+
+  if (data[0] == 0xFF && data[1] == 0xD8 && data[2] == 0xFF) {
+    image->type = IMG_JPG;
+  } else if (data[0] == 0x89 && data[1] == 0x50 && data[2] == 0x4E &&
+             data[3] == 0x47) {
+    image->type = IMG_PNG;
+  } else if (data[0] == 'P' && data[1] == '6') {
+    image->type = IMG_PPM;
+  } else {
+    return IMERR_UNKNOWN_FORMAT;
+  }
+
+  return IMERR_SUCCESS;
+}