From bf289563f6849feb4900c265584c1f5b3434c129 Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Mon, 3 Apr 2017 15:36:16 -0700
Subject: [PATCH] Start gen script for new settings handling

---
 tools/codegen/core/gen_settings_ids.py | 81 ++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100755 tools/codegen/core/gen_settings_ids.py

diff --git a/tools/codegen/core/gen_settings_ids.py b/tools/codegen/core/gen_settings_ids.py
new file mode 100755
index 00000000000..fa3aad1f1f2
--- /dev/null
+++ b/tools/codegen/core/gen_settings_ids.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python2.7
+
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import perfection
+
+_SETTINGS = {
+  'HEADER_TABLE_SIZE': 1,
+  'ENABLE_PUSH': 2,
+  'MAX_CONCURRENT_STREAMS': 3,
+  'INITIAL_WINDOW_SIZE': 4,
+  'MAX_FRAME_SIZE': 5,
+  'MAX_HEADER_LIST_SIZE': 6,
+  'GRPC_ALLOW_TRUE_BINARY_METADATA': 0xfe03,
+}
+
+p = perfection.hash_parameters(sorted(_SETTINGS.values()))
+print p
+
+def hash(i):
+  i += p.offset
+  x = i % p.t
+  y = i / p.t
+  return x + p.r[y]
+
+print 'typedef enum {'
+for name in sorted(_SETTINGS.keys()):
+  index = _SETTINGS[name]
+  print '  GRPC_CHTTP2_SETTING_%s = %d, /* wire id %d */' % (
+      name, hash(index), index)
+print '} grpc_chttp2_setting_id;'
+
+print 'const uint16_t grpc_setting_id_to_wire_id[] = {%s};' % ','.join(
+    '%d' % s for s in p.slots)
+
+print """
+bool grpc_wire_id_to_setting_id(uint32_t wire_id, grpc_chttp2_setting_id *out) {
+  static const uint32_t r[] = {%(r)s};
+  uint32_t i = wire_id %(offset_sign)s %(offset)d;
+  uint32_t x = i %% %(t)d;
+  uint32_t y = i / %(t)d;
+  uint32_t h = x;
+  if (y < GPR_ARRAY_SIZE(r)) {
+    uint32_t delta = (uint32_t)r[y];
+    h += delta;
+  }
+  *out = (grpc_chttp2_setting_id)i;
+  return i < GPR_ARRAY_SIZE(grpc_setting_id_to_wire_id) && grpc_setting_id_to_wire_id[i] == wire_id;
+}""" % {
+      'r': ','.join('%d' % (r if r is not None else 0) for r in p.r),
+      't': p.t,
+      'offset': abs(p.offset),
+      'offset_sign': '+' if p.offset > 0 else '-'
+  }