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// Copyright 2016 the V8 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 "src/wasm/switch-logic.h"
namespace v8 {
namespace internal {
namespace wasm {
namespace {
CaseNode* CreateBst(ZoneVector<CaseNode*>* nodes, size_t begin, size_t end) {
if (end < begin) {
return nullptr;
} else if (end == begin) {
return nodes->at(begin);
} else {
size_t root_index = (begin + end) / 2;
CaseNode* root = nodes->at(root_index);
if (root_index != 0) {
root->left = CreateBst(nodes, begin, root_index - 1);
}
root->right = CreateBst(nodes, root_index + 1, end);
return root;
}
}
} // namespace
CaseNode* OrderCases(ZoneVector<int>* cases, Zone* zone) {
const int max_distance = 2;
const int min_size = 4;
if (cases->empty()) {
return nullptr;
}
std::sort(cases->begin(), cases->end());
ZoneVector<size_t> table_breaks(zone);
for (size_t i = 1; i < cases->size(); ++i) {
if (cases->at(i) - cases->at(i - 1) > max_distance) {
table_breaks.push_back(i);
}
}
table_breaks.push_back(cases->size());
ZoneVector<CaseNode*> nodes(zone);
size_t curr_pos = 0;
for (size_t i = 0; i < table_breaks.size(); ++i) {
size_t break_pos = table_breaks[i];
if (break_pos - curr_pos >= min_size) {
int begin = cases->at(curr_pos);
int end = cases->at(break_pos - 1);
nodes.push_back(new (zone) CaseNode(begin, end));
curr_pos = break_pos;
} else {
for (; curr_pos < break_pos; curr_pos++) {
nodes.push_back(new (zone)
CaseNode(cases->at(curr_pos), cases->at(curr_pos)));
}
}
}
return CreateBst(&nodes, 0, nodes.size() - 1);
}
} // namespace wasm
} // namespace internal
} // namespace v8
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