Add BMP image decoder

kernel/core/main.c

@@ -251,6 +251,12 @@ static void init_subsystems(void *dtb) {
   ramfs_create_file_bytes("Pictures/test.png", 0644, bootstrap_test_png,
                           bootstrap_test_png_len);
 
+  /* Add BMP test image to Pictures */
+  extern const unsigned char bootstrap_test_bmp[];
+  extern const unsigned int bootstrap_test_bmp_len;
+  ramfs_create_file_bytes("Pictures/test.bmp", 0644, bootstrap_test_bmp,
+                          bootstrap_test_bmp_len);
+
   /* Mount proc, sys, dev (placeholders) */
   printk(KERN_INFO "  Mounting procfs...\n");
 

kernel/gui/terminal.c

@@ -667,8 +667,9 @@ void term_execute_command(struct terminal *term, const char *cmd) {
       return;
     }
 
-    if (!str_ends_with_ci(path, ".jpg") && !str_ends_with_ci(path, ".jpeg")) {
-      term_puts(term, "view: only .jpg/.jpeg supported\n");
+    if (!str_ends_with_ci(path, ".jpg") && !str_ends_with_ci(path, ".jpeg") &&
+        !str_ends_with_ci(path, ".png") && !str_ends_with_ci(path, ".bmp")) {
+      term_puts(term, "view: only .jpg/.jpeg/.png/.bmp supported\n");
       return;
     }
 

kernel/gui/window.c

@@ -1047,7 +1047,8 @@ static int fm_render_callback(void *ctx, const char *name, int len,
       bmp = icon_notepad;
       color = 0xFFFFFF;
     } else if (str_ends_with_ci(name, ".jpg") ||
-               str_ends_with_ci(name, ".jpeg")) {
+               str_ends_with_ci(name, ".jpeg") ||
+               str_ends_with_ci(name, ".bmp")) {
       color = 0xF9E2AF;
     } else if (str_ends_with_ci(name, ".mp3")) {
       color = 0xA6E3A1;
@@ -1280,7 +1281,8 @@ static void fm_on_mouse(struct window *win, int x, int y, int buttons) {
       gui_open_notepad(full_path);
     } else if (str_ends_with_ci(st->selected, ".jpg") ||
                str_ends_with_ci(st->selected, ".jpeg") ||
-               str_ends_with_ci(st->selected, ".png")) {
+               str_ends_with_ci(st->selected, ".png") ||
+               str_ends_with_ci(st->selected, ".bmp")) {
       gui_open_image_viewer(full_path);
     } else if (str_ends_with_ci(st->selected, ".mp3")) {
       gui_play_mp3_file(full_path);
@@ -1423,6 +1425,11 @@ void gui_open_image_viewer(const char *path) {
     if (decode_ret != 0) {
       printk("Image Viewer: PNG decode failed\n");
     }
+  } else if (size >= 2 && data[0] == 'B' && data[1] == 'M') {
+    decode_ret = media_decode_bmp(data, size, &g_imgview.image);
+    if (decode_ret != 0) {
+      printk("Image Viewer: BMP decode failed\n");
+    }
   } else {
     /* Assume JPEG */
     decode_ret = media_decode_jpeg(data, size, &g_imgview.image);
@@ -4413,6 +4420,8 @@ static void image_viewer_load_bootstrap(int index) {
   if (len >= 4 && data[0] == 0x89 && data[1] == 'P' && data[2] == 'N' &&
       data[3] == 'G') {
     ret = media_decode_png(data, len, &g_imgview.image);
+  } else if (len >= 2 && data[0] == 'B' && data[1] == 'M') {
+    ret = media_decode_bmp(data, len, &g_imgview.image);
   } else {
     ret = media_decode_jpeg(data, len, &g_imgview.image);
   }
@@ -4475,6 +4484,8 @@ static void image_viewer_load_from_folder(int index) {
   if (size >= 4 && data[0] == 0x89 && data[1] == 'P' && data[2] == 'N' &&
       data[3] == 'G') {
     ret = media_decode_png(data, size, &g_imgview.image);
+  } else if (size >= 2 && data[0] == 'B' && data[1] == 'M') {
+    ret = media_decode_bmp(data, size, &g_imgview.image);
   } else {
     ret = media_decode_jpeg(data, size, &g_imgview.image);
   }

kernel/include/media/media.h

@@ -30,4 +30,7 @@ void media_free_audio(media_audio_t *audio);
 
 int media_decode_png(const uint8_t *data, size_t size, media_image_t *out);
 
+/* Uncompressed 24/32bpp BMP (BITMAPINFOHEADER and V4/V5 variants) */
+int media_decode_bmp(const uint8_t *data, size_t size, media_image_t *out);
+
 #endif /* _KERNEL_MEDIA_H */

kernel/media/media.c

@@ -300,3 +300,90 @@ int media_decode_png(const uint8_t *data, size_t size, media_image_t *out) {
   out->pixels = pixels;
   return 0;
 }
+
+/* --------------------------------------------------------------------- */
+/* BMP decoding (uncompressed 24/32bpp)                                   */
+/* --------------------------------------------------------------------- */
+
+static uint32_t bmp_read_le32(const uint8_t *p) {
+  return (uint32_t)p[0] | ((uint32_t)p[1] << 8) | ((uint32_t)p[2] << 16) |
+         ((uint32_t)p[3] << 24);
+}
+
+static uint16_t bmp_read_le16(const uint8_t *p) {
+  return (uint16_t)((uint32_t)p[0] | ((uint32_t)p[1] << 8));
+}
+
+int media_decode_bmp(const uint8_t *data, size_t size, media_image_t *out) {
+  if (!data || !out || size < 54 || data[0] != 'B' || data[1] != 'M')
+    return -EINVAL;
+
+  uint32_t pixel_offset = bmp_read_le32(data + 10);
+  uint32_t dib_size = bmp_read_le32(data + 14);
+
+  /* BITMAPINFOHEADER (40) or the larger V4/V5 headers that extend it */
+  if (dib_size < 40 || (size_t)14 + dib_size > size) {
+    printk(KERN_ERR "BMP: unsupported DIB header (%u bytes)\n", dib_size);
+    return -EINVAL;
+  }
+
+  int32_t width = (int32_t)bmp_read_le32(data + 18);
+  int32_t height = (int32_t)bmp_read_le32(data + 22);
+  uint16_t planes = bmp_read_le16(data + 26);
+  uint16_t bpp = bmp_read_le16(data + 28);
+  uint32_t compression = bmp_read_le32(data + 30);
+
+  int top_down = 0;
+  if (height < 0) {
+    top_down = 1;
+    height = -height;
+  }
+
+  /* BI_RGB only; BI_BITFIELDS (3) is accepted for 32bpp since the
+   * standard BGRA masks match our channel extraction anyway */
+  if (planes != 1 || (bpp != 24 && bpp != 32) ||
+      (compression != 0 && !(compression == 3 && bpp == 32))) {
+    printk(KERN_ERR "BMP: unsupported format (%u bpp, compression %u)\n", bpp,
+           compression);
+    return -EINVAL;
+  }
+
+  if (width <= 0 || height <= 0 ||
+      (size_t)width > SIZE_MAX / (size_t)height) {
+    printk(KERN_ERR "BMP: bad dimensions\n");
+    return -EINVAL;
+  }
+
+  size_t pixel_count = (size_t)width * (size_t)height;
+  if (pixel_count > 16 * 1024 * 1024) {
+    printk(KERN_ERR "BMP: image too large (%zu pixels)\n", pixel_count);
+    return -EINVAL;
+  }
+
+  size_t bytes_per_px = bpp / 8;
+  size_t stride = ((size_t)width * bytes_per_px + 3) & ~(size_t)3;
+  if (pixel_offset > size || stride > (size - pixel_offset) / (size_t)height) {
+    printk(KERN_ERR "BMP: pixel data out of bounds\n");
+    return -EINVAL;
+  }
+
+  uint32_t *pixels =
+      (uint32_t *)kmalloc(pixel_count * sizeof(uint32_t), GFP_KERNEL);
+  if (!pixels)
+    return -ENOMEM;
+
+  for (int32_t y = 0; y < height; y++) {
+    int32_t src_y = top_down ? y : height - 1 - y;
+    const uint8_t *row = data + pixel_offset + (size_t)src_y * stride;
+    for (int32_t x = 0; x < width; x++) {
+      const uint8_t *px = row + (size_t)x * bytes_per_px;
+      pixels[(size_t)y * width + x] =
+          ((uint32_t)px[2] << 16) | ((uint32_t)px[1] << 8) | px[0];
+    }
+  }
+
+  out->width = (uint32_t)width;
+  out->height = (uint32_t)height;
+  out->pixels = pixels;
+  return 0;
+}

kernel/syscall/syscall.c

@@ -762,7 +762,7 @@ void handle_sync_exception(struct pt_regs *regs) {
   case 0x20: /* Instruction abort from lower EL */
   case 0x21: /* Instruction abort from same EL */
     printk(KERN_EMERG "Instruction abort at PC=0x%llx\n",
-           (unsigned long long)arch_context_get_pc(regs));
+           (unsigned long long)regs->pc);
     panic("Instruction abort");
     break;
 
@@ -773,28 +773,28 @@ void handle_sync_exception(struct pt_regs *regs) {
     uint64_t far;
     asm volatile("mrs %0, far_el1" : "=r"(far));
     printk(KERN_EMERG "Data abort at PC=0x%llx, FAR=0x%llx\n",
-           (unsigned long long)arch_context_get_pc(regs),
+           (unsigned long long)regs->pc,
            (unsigned long long)far);
 #elif defined(ARCH_X86_64) || defined(ARCH_X86)
     uint64_t cr2;
     asm volatile("mov %%cr2, %0" : "=r"(cr2));
     printk(KERN_EMERG "Page fault at PC=0x%llx, CR2=0x%llx\n",
-           (unsigned long long)arch_context_get_pc(regs),
+           (unsigned long long)regs->pc,
            (unsigned long long)cr2);
 #endif
     panic("Data abort");
   } break;
 
   case 0x00: /* Unknown reason */
     printk(KERN_EMERG "Unknown exception at PC=0x%llx\n",
-           (unsigned long long)arch_context_get_pc(regs));
+           (unsigned long long)regs->pc);
     panic("Unknown exception");
     break;
 
   default:
     printk(KERN_EMERG "Unhandled exception class 0x%x, ISS=0x%x\n", ec, iss);
     printk(KERN_EMERG "PC=0x%llx\n",
-           (unsigned long long)arch_context_get_pc(regs));
+           (unsigned long long)regs->pc);
     panic("Unhandled exception");
     break;
   }