From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 21:33:14 +0200
Subject: Adding upstream version 115.7.0esr.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 third_party/jpeg-xl/lib/jxl/exif.h | 87 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 third_party/jpeg-xl/lib/jxl/exif.h

(limited to 'third_party/jpeg-xl/lib/jxl/exif.h')

diff --git a/third_party/jpeg-xl/lib/jxl/exif.h b/third_party/jpeg-xl/lib/jxl/exif.h
new file mode 100644
index 0000000000..0cf493fc71
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/exif.h
@@ -0,0 +1,87 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#ifndef LIB_JXL_EXIF_H_
+#define LIB_JXL_EXIF_H_
+
+// Basic parsing of Exif (just enough for the render-impacting things
+// like orientation)
+
+#include <jxl/codestream_header.h>
+
+#include "lib/jxl/base/padded_bytes.h"
+#include "lib/jxl/image_metadata.h"
+
+namespace jxl {
+
+constexpr uint16_t kExifOrientationTag = 274;
+
+// Checks if a blob looks like Exif, and if so, sets bigendian
+// according to the tiff endianness
+inline bool IsExif(const std::vector<uint8_t>& exif, bool* bigendian) {
+  if (exif.size() < 12) return false;  // not enough bytes for a valid exif blob
+  const uint8_t* t = exif.data();
+  if (LoadLE32(t) == 0x2A004D4D) {
+    *bigendian = true;
+    return true;
+  } else if (LoadLE32(t) == 0x002A4949) {
+    *bigendian = false;
+    return true;
+  }
+  return false;  // not a valid tiff header
+}
+
+// Finds the position of an Exif tag, or 0 if it is not found
+inline size_t FindExifTagPosition(const std::vector<uint8_t>& exif,
+                                  uint16_t tagname) {
+  bool bigendian;
+  if (!IsExif(exif, &bigendian)) return 0;
+  const uint8_t* t = exif.data() + 4;
+  uint64_t offset = (bigendian ? LoadBE32(t) : LoadLE32(t));
+  if (exif.size() < 12 + offset + 2 || offset < 8) return 0;
+  t += offset - 4;
+  if (offset + 2 >= exif.size()) return 0;
+  uint16_t nb_tags = (bigendian ? LoadBE16(t) : LoadLE16(t));
+  t += 2;
+  while (nb_tags > 0) {
+    if (t + 12 >= exif.data() + exif.size()) return 0;
+    uint16_t tag = (bigendian ? LoadBE16(t) : LoadLE16(t));
+    t += 2;
+    if (tag == tagname) return static_cast<size_t>(t - exif.data());
+    t += 10;
+    nb_tags--;
+  }
+  return 0;
+}
+
+// TODO (jon): tag 1 can be used to represent Adobe RGB 1998 if it has value
+// "R03"
+// TODO (jon): set intrinsic dimensions according to
+// https://discourse.wicg.io/t/proposal-exif-image-resolution-auto-and-from-image/4326/24
+// Parses the Exif data just enough to extract any render-impacting info.
+// If the Exif data is invalid or could not be parsed, then it is treated
+// as a no-op.
+inline void InterpretExif(const std::vector<uint8_t>& exif,
+                          JxlOrientation* orientation) {
+  bool bigendian;
+  if (!IsExif(exif, &bigendian)) return;
+  size_t o_pos = FindExifTagPosition(exif, kExifOrientationTag);
+  if (o_pos) {
+    const uint8_t* t = exif.data() + o_pos;
+    uint16_t type = (bigendian ? LoadBE16(t) : LoadLE16(t));
+    t += 2;
+    uint32_t count = (bigendian ? LoadBE32(t) : LoadLE32(t));
+    t += 4;
+    uint16_t value = (bigendian ? LoadBE16(t) : LoadLE16(t));
+    t += 4;
+    if (type == 3 && count == 1 && value >= 1 && value <= 8) {
+      *orientation = static_cast<JxlOrientation>(value);
+    }
+  }
+}
+
+}  // namespace jxl
+
+#endif  // LIB_JXL_EXIF_H_
-- 
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