1 files changed, 77 insertions, 0 deletions
diff --git a/image/ICOFileHeaders.h b/image/ICOFileHeaders.h
new file mode 100644
index 0000000000..a47919b91a
--- /dev/null
+++ b/image/ICOFileHeaders.h
@@ -0,0 +1,77 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_image_ICOFileHeaders_h
+#define mozilla_image_ICOFileHeaders_h
+
+namespace mozilla {
+namespace image {
+
+#define ICONFILEHEADERSIZE 6
+#define ICODIRENTRYSIZE 16
+#define PNGSIGNATURESIZE 8
+#define BMPFILEHEADERSIZE 14
+
+/**
+ * The header that comes right at the start of an icon file. (This
+ * corresponds to the Windows ICONDIR structure.)
+ */
+struct IconFileHeader {
+  /**
+   * Must be set to 0;
+   */
+  uint16_t mReserved;
+  /**
+   * 1 for icon (.ICO) image (or 2 for cursor (.CUR) image (icon with the
+   * addition of a hotspot), but we don't support cursor).
+   */
+  uint16_t mType;
+  /**
+   * The number of BMP/PNG images contained in the icon file.
+   */
+  uint16_t mCount;
+};
+
+/**
+ * For each BMP/PNG image that the icon file contains there must be a
+ * corresponding icon dir entry. (This corresponds to the Windows
+ * ICONDIRENTRY structure.) These entries are encoded directly after the
+ * IconFileHeader.
+ */
+struct IconDirEntry {
+  uint8_t mWidth;
+  uint8_t mHeight;
+  /**
+   * The number of colors in the color palette of the BMP/PNG that this dir
+   * entry corresponds to, or 0 if the image does not use a color palette.
+   */
+  uint8_t mColorCount;
+  /**
+   * Should be set to 0.
+   */
+  uint8_t mReserved;
+  union {
+    uint16_t mPlanes;    // ICO
+    uint16_t mXHotspot;  // CUR
+  };
+  union {
+    uint16_t mBitCount;  // ICO (bits per pixel)
+    uint16_t mYHotspot;  // CUR
+  };
+  /**
+   * "bytes in resource" is the length of the encoded BMP/PNG that this dir
+   * entry corresponds to.
+   */
+  uint32_t mBytesInRes;
+  /**
+   * The offset of the start of the encoded BMP/PNG that this dir entry
+   * corresponds to (from the start of the icon file).
+   */
+  uint32_t mImageOffset;
+};
+
+}  // namespace image
+}  // namespace mozilla
+
+#endif  // mozilla_image_ICOFileHeaders_h