Update to spice2x-25-04-25 (pre-apply)

> broken commit

external/cpu_features/src/stack_line_reader.c

@@ -0,0 +1,132 @@
+// Copyright 2017 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "internal/stack_line_reader.h"
+
+#include <assert.h>
+#include <errno.h>
+#include <stdio.h>
+
+#include "internal/filesystem.h"
+
+void StackLineReader_Initialize(StackLineReader* reader, int fd) {
+  reader->view.ptr = reader->buffer;
+  reader->view.size = 0;
+  reader->skip_mode = false;
+  reader->fd = fd;
+}
+
+// Replaces the content of buffer with bytes from the file.
+static int LoadFullBuffer(StackLineReader* reader) {
+  const int read = CpuFeatures_ReadFile(reader->fd, reader->buffer,
+                                        STACK_LINE_READER_BUFFER_SIZE);
+  assert(read >= 0);
+  reader->view.ptr = reader->buffer;
+  reader->view.size = read;
+  return read;
+}
+
+// Appends with bytes from the file to buffer, filling the remaining space.
+static int LoadMore(StackLineReader* reader) {
+  char* const ptr = reader->buffer + reader->view.size;
+  const size_t size_to_read = STACK_LINE_READER_BUFFER_SIZE - reader->view.size;
+  const int read = CpuFeatures_ReadFile(reader->fd, ptr, size_to_read);
+  assert(read >= 0);
+  assert(read <= (int)size_to_read);
+  reader->view.size += read;
+  return read;
+}
+
+static int IndexOfEol(StackLineReader* reader) {
+  return CpuFeatures_StringView_IndexOfChar(reader->view, '\n');
+}
+
+// Relocate buffer's pending bytes at the beginning of the array and fills the
+// remaining space with bytes from the file.
+static int BringToFrontAndLoadMore(StackLineReader* reader) {
+  if (reader->view.size && reader->view.ptr != reader->buffer) {
+    memmove(reader->buffer, reader->view.ptr, reader->view.size);
+  }
+  reader->view.ptr = reader->buffer;
+  return LoadMore(reader);
+}
+
+// Loads chunks of buffer size from disks until it contains a newline character
+// or end of file.
+static void SkipToNextLine(StackLineReader* reader) {
+  for (;;) {
+    const int read = LoadFullBuffer(reader);
+    if (read == 0) {
+      break;
+    } else {
+      const int eol_index = IndexOfEol(reader);
+      if (eol_index >= 0) {
+        reader->view =
+            CpuFeatures_StringView_PopFront(reader->view, eol_index + 1);
+        break;
+      }
+    }
+  }
+}
+
+static LineResult CreateLineResult(bool eof, bool full_line, StringView view) {
+  LineResult result;
+  result.eof = eof;
+  result.full_line = full_line;
+  result.line = view;
+  return result;
+}
+
+// Helper methods to provide clearer semantic in StackLineReader_NextLine.
+static LineResult CreateEOFLineResult(StringView view) {
+  return CreateLineResult(true, true, view);
+}
+
+static LineResult CreateTruncatedLineResult(StringView view) {
+  return CreateLineResult(false, false, view);
+}
+
+static LineResult CreateValidLineResult(StringView view) {
+  return CreateLineResult(false, true, view);
+}
+
+LineResult StackLineReader_NextLine(StackLineReader* reader) {
+  if (reader->skip_mode) {
+    SkipToNextLine(reader);
+    reader->skip_mode = false;
+  }
+  {
+    const bool can_load_more =
+        reader->view.size < STACK_LINE_READER_BUFFER_SIZE;
+    int eol_index = IndexOfEol(reader);
+    if (eol_index < 0 && can_load_more) {
+      const int read = BringToFrontAndLoadMore(reader);
+      if (read == 0) {
+        return CreateEOFLineResult(reader->view);
+      }
+      eol_index = IndexOfEol(reader);
+    }
+    if (eol_index < 0) {
+      reader->skip_mode = true;
+      return CreateTruncatedLineResult(reader->view);
+    }
+    {
+      StringView line =
+          CpuFeatures_StringView_KeepFront(reader->view, eol_index);
+      reader->view =
+          CpuFeatures_StringView_PopFront(reader->view, eol_index + 1);
+      return CreateValidLineResult(line);
+    }
+  }
+}