1 files changed, 90 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jpegli/source_manager.cc b/third_party/jpeg-xl/lib/jpegli/source_manager.cc
new file mode 100644
index 0000000000..0b8e0a5c8c
--- /dev/null
+++ b/third_party/jpeg-xl/lib/jpegli/source_manager.cc
@@ -0,0 +1,90 @@
+// 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/jpegli/decode.h"
+#include "lib/jpegli/error.h"
+#include "lib/jpegli/memory_manager.h"
+
+namespace jpegli {
+
+void init_mem_source(j_decompress_ptr cinfo) {}
+void init_stdio_source(j_decompress_ptr cinfo) {}
+
+void skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
+  if (num_bytes <= 0) return;
+  while (num_bytes > static_cast<long>(cinfo->src->bytes_in_buffer)) {
+    num_bytes -= cinfo->src->bytes_in_buffer;
+    (*cinfo->src->fill_input_buffer)(cinfo);
+  }
+  cinfo->src->next_input_byte += num_bytes;
+  cinfo->src->bytes_in_buffer -= num_bytes;
+}
+
+void term_source(j_decompress_ptr cinfo) {}
+
+boolean EmitFakeEoiMarker(j_decompress_ptr cinfo) {
+  static constexpr uint8_t kFakeEoiMarker[2] = {0xff, 0xd9};
+  cinfo->src->next_input_byte = kFakeEoiMarker;
+  cinfo->src->bytes_in_buffer = 2;
+  return TRUE;
+}
+
+constexpr size_t kStdioBufferSize = 64 << 10;
+
+struct StdioSourceManager {
+  jpeg_source_mgr pub;
+  FILE* f;
+  uint8_t* buffer;
+
+  static boolean fill_input_buffer(j_decompress_ptr cinfo) {
+    auto src = reinterpret_cast<StdioSourceManager*>(cinfo->src);
+    size_t num_bytes_read = fread(src->buffer, 1, kStdioBufferSize, src->f);
+    if (num_bytes_read == 0) {
+      return EmitFakeEoiMarker(cinfo);
+    }
+    src->pub.next_input_byte = src->buffer;
+    src->pub.bytes_in_buffer = num_bytes_read;
+    return TRUE;
+  }
+};
+
+}  // namespace jpegli
+
+void jpegli_mem_src(j_decompress_ptr cinfo, const unsigned char* inbuffer,
+                    unsigned long insize) {
+  if (cinfo->src && cinfo->src->init_source != jpegli::init_mem_source) {
+    JPEGLI_ERROR("jpegli_mem_src: a different source manager was already set");
+  }
+  if (!cinfo->src) {
+    cinfo->src = jpegli::Allocate<jpeg_source_mgr>(cinfo, 1);
+  }
+  cinfo->src->next_input_byte = inbuffer;
+  cinfo->src->bytes_in_buffer = insize;
+  cinfo->src->init_source = jpegli::init_mem_source;
+  cinfo->src->fill_input_buffer = jpegli::EmitFakeEoiMarker;
+  cinfo->src->skip_input_data = jpegli::skip_input_data;
+  cinfo->src->resync_to_restart = jpegli_resync_to_restart;
+  cinfo->src->term_source = jpegli::term_source;
+}
+
+void jpegli_stdio_src(j_decompress_ptr cinfo, FILE* infile) {
+  if (cinfo->src && cinfo->src->init_source != jpegli::init_stdio_source) {
+    JPEGLI_ERROR("jpeg_stdio_src: a different source manager was already set");
+  }
+  if (!cinfo->src) {
+    cinfo->src = reinterpret_cast<jpeg_source_mgr*>(
+        jpegli::Allocate<jpegli::StdioSourceManager>(cinfo, 1));
+  }
+  auto src = reinterpret_cast<jpegli::StdioSourceManager*>(cinfo->src);
+  src->f = infile;
+  src->buffer = jpegli::Allocate<uint8_t>(cinfo, jpegli::kStdioBufferSize);
+  src->pub.next_input_byte = src->buffer;
+  src->pub.bytes_in_buffer = 0;
+  src->pub.init_source = jpegli::init_stdio_source;
+  src->pub.fill_input_buffer = jpegli::StdioSourceManager::fill_input_buffer;
+  src->pub.skip_input_data = jpegli::skip_input_data;
+  src->pub.resync_to_restart = jpegli_resync_to_restart;
+  src->pub.term_source = jpegli::term_source;
+}