1 files changed, 148 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/extras/dec/decode.cc b/third_party/jpeg-xl/lib/extras/dec/decode.cc
new file mode 100644
index 0000000000..b3ca711bb2
--- /dev/null
+++ b/third_party/jpeg-xl/lib/extras/dec/decode.cc
@@ -0,0 +1,148 @@
+// 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.
+
+#include "lib/extras/dec/decode.h"
+
+#include <locale>
+
+#include "lib/extras/dec/apng.h"
+#include "lib/extras/dec/exr.h"
+#include "lib/extras/dec/gif.h"
+#include "lib/extras/dec/jpg.h"
+#include "lib/extras/dec/jxl.h"
+#include "lib/extras/dec/pgx.h"
+#include "lib/extras/dec/pnm.h"
+
+namespace jxl {
+namespace extras {
+namespace {
+
+// Any valid encoding is larger (ensures codecs can read the first few bytes)
+constexpr size_t kMinBytes = 9;
+
+std::string GetExtension(const std::string& path) {
+  // Pattern: "name.png"
+  size_t pos = path.find_last_of('.');
+  if (pos != std::string::npos) {
+    return path.substr(pos);
+  }
+
+  // Extension not found
+  return "";
+}
+
+}  // namespace
+
+Codec CodecFromPath(std::string path, size_t* JXL_RESTRICT bits_per_sample,
+                    std::string* extension) {
+  std::string ext = GetExtension(path);
+  if (extension) {
+    if (extension->empty()) {
+      *extension = ext;
+    } else {
+      ext = *extension;
+    }
+  }
+  std::transform(ext.begin(), ext.end(), ext.begin(), [](char c) {
+    return std::tolower(c, std::locale::classic());
+  });
+  if (ext == ".png") return Codec::kPNG;
+
+  if (ext == ".jpg") return Codec::kJPG;
+  if (ext == ".jpeg") return Codec::kJPG;
+
+  if (ext == ".pgx") return Codec::kPGX;
+
+  if (ext == ".pam") return Codec::kPNM;
+  if (ext == ".pnm") return Codec::kPNM;
+  if (ext == ".pgm") return Codec::kPNM;
+  if (ext == ".ppm") return Codec::kPNM;
+  if (ext == ".pfm") {
+    if (bits_per_sample != nullptr) *bits_per_sample = 32;
+    return Codec::kPNM;
+  }
+
+  if (ext == ".gif") return Codec::kGIF;
+
+  if (ext == ".exr") return Codec::kEXR;
+
+  return Codec::kUnknown;
+}
+
+bool CanDecode(Codec codec) {
+  switch (codec) {
+    case Codec::kEXR:
+      return CanDecodeEXR();
+    case Codec::kGIF:
+      return CanDecodeGIF();
+    case Codec::kJPG:
+      return CanDecodeJPG();
+    case Codec::kPNG:
+      return CanDecodeAPNG();
+    case Codec::kPNM:
+    case Codec::kPGX:
+    case Codec::kJXL:
+      return true;
+    default:
+      return false;
+  }
+}
+
+Status DecodeBytes(const Span<const uint8_t> bytes,
+                   const ColorHints& color_hints, extras::PackedPixelFile* ppf,
+                   const SizeConstraints* constraints, Codec* orig_codec) {
+  if (bytes.size() < kMinBytes) return JXL_FAILURE("Too few bytes");
+
+  *ppf = extras::PackedPixelFile();
+
+  // Default values when not set by decoders.
+  ppf->info.uses_original_profile = true;
+  ppf->info.orientation = JXL_ORIENT_IDENTITY;
+
+  const auto choose_codec = [&]() -> Codec {
+    if (DecodeImageAPNG(bytes, color_hints, ppf, constraints)) {
+      return Codec::kPNG;
+    }
+    if (DecodeImagePGX(bytes, color_hints, ppf, constraints)) {
+      return Codec::kPGX;
+    }
+    if (DecodeImagePNM(bytes, color_hints, ppf, constraints)) {
+      return Codec::kPNM;
+    }
+    JXLDecompressParams dparams = {};
+    for (const uint32_t num_channels : {1, 2, 3, 4}) {
+      dparams.accepted_formats.push_back(
+          {num_channels, JXL_TYPE_FLOAT, JXL_LITTLE_ENDIAN, /*align=*/0});
+    }
+    size_t decoded_bytes;
+    if (DecodeImageJXL(bytes.data(), bytes.size(), dparams, &decoded_bytes,
+                       ppf) &&
+        ApplyColorHints(color_hints, true, ppf->info.num_color_channels == 1,
+                        ppf)) {
+      return Codec::kJXL;
+    }
+    if (DecodeImageGIF(bytes, color_hints, ppf, constraints)) {
+      return Codec::kGIF;
+    }
+    if (DecodeImageJPG(bytes, color_hints, ppf, constraints)) {
+      return Codec::kJPG;
+    }
+    if (DecodeImageEXR(bytes, color_hints, ppf, constraints)) {
+      return Codec::kEXR;
+    }
+    return Codec::kUnknown;
+  };
+
+  Codec codec = choose_codec();
+  if (codec == Codec::kUnknown) {
+    return JXL_FAILURE("Codecs failed to decode");
+  }
+  if (orig_codec) *orig_codec = codec;
+
+  return true;
+}
+
+}  // namespace extras
+}  // namespace jxl