1 files changed, 101 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/box_content_decoder.cc b/third_party/jpeg-xl/lib/jxl/box_content_decoder.cc
new file mode 100644
index 0000000000..c4cba3a31a
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/box_content_decoder.cc
@@ -0,0 +1,101 @@
+// 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/jxl/box_content_decoder.h"
+
+#include "lib/jxl/sanitizers.h"
+
+namespace jxl {
+
+JxlBoxContentDecoder::JxlBoxContentDecoder() {}
+
+JxlBoxContentDecoder::~JxlBoxContentDecoder() {
+  if (brotli_dec) {
+    BrotliDecoderDestroyInstance(brotli_dec);
+  }
+}
+
+void JxlBoxContentDecoder::StartBox(bool brob_decode, bool box_until_eof,
+                                    size_t contents_size) {
+  if (brotli_dec) {
+    BrotliDecoderDestroyInstance(brotli_dec);
+    brotli_dec = nullptr;
+  }
+  header_done_ = false;
+  brob_decode_ = brob_decode;
+  box_until_eof_ = box_until_eof;
+  remaining_ = box_until_eof ? 0 : contents_size;
+  pos_ = 0;
+}
+
+JxlDecoderStatus JxlBoxContentDecoder::Process(const uint8_t* next_in,
+                                               size_t avail_in, size_t box_pos,
+                                               uint8_t** next_out,
+                                               size_t* avail_out) {
+  next_in += pos_ - box_pos;
+  avail_in -= pos_ - box_pos;
+
+  if (brob_decode_) {
+    if (!header_done_) {
+      if (avail_in < 4) return JXL_DEC_NEED_MORE_INPUT;
+      if (!box_until_eof_) {
+        if (remaining_ < 4) return JXL_DEC_ERROR;
+        remaining_ -= 4;
+      }
+      next_in += 4;
+      avail_in -= 4;
+      pos_ += 4;
+      header_done_ = true;
+    }
+
+    if (!brotli_dec) {
+      brotli_dec = BrotliDecoderCreateInstance(nullptr, nullptr, nullptr);
+    }
+
+    const uint8_t* next_in_before = next_in;
+    uint8_t* next_out_before = *next_out;
+    msan::MemoryIsInitialized(next_in, avail_in);
+    BrotliDecoderResult res = BrotliDecoderDecompressStream(
+        brotli_dec, &avail_in, &next_in, avail_out, next_out, nullptr);
+    size_t consumed = next_in - next_in_before;
+    size_t produced = *next_out - next_out_before;
+    if (res == BROTLI_DECODER_RESULT_ERROR) {
+      return JXL_DEC_ERROR;
+    }
+    msan::UnpoisonMemory(next_out_before, produced);
+    pos_ += consumed;
+    if (!box_until_eof_) remaining_ -= consumed;
+    if (res == BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT) {
+      return JXL_DEC_NEED_MORE_INPUT;
+    }
+    if (res == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT) {
+      return JXL_DEC_BOX_NEED_MORE_OUTPUT;
+    }
+    if (res == BROTLI_DECODER_RESULT_SUCCESS) {
+      return JXL_DEC_SUCCESS;
+    }
+    // unknown Brotli result
+    return JXL_DEC_ERROR;
+  } else {
+    // remaining box bytes as seen from dec->file_pos
+    size_t can_read = avail_in;
+    if (!box_until_eof_) can_read = std::min<size_t>(can_read, remaining_);
+    size_t to_write = std::min<size_t>(can_read, *avail_out);
+    memcpy(*next_out, next_in, to_write);
+
+    *next_out += to_write;
+    *avail_out -= to_write;
+    if (!box_until_eof_) remaining_ -= to_write;
+    pos_ += to_write;
+
+    if (to_write < can_read) return JXL_DEC_BOX_NEED_MORE_OUTPUT;
+
+    if (!box_until_eof_ && remaining_ > 0) return JXL_DEC_NEED_MORE_INPUT;
+
+    return JXL_DEC_SUCCESS;
+  }
+}
+
+}  // namespace jxl