From c12f913eba338678ed30382aa2e5235025b6d90b Mon Sep 17 00:00:00 2001
From: lihuiba <huiba.lhb@alibaba-inc.com>
Date: Wed, 25 Sep 2024 16:41:23 +0800
Subject: [PATCH] case-insensitive map_string_key

---
 common/hash_combine.h                | 30 ++++++++++++
 common/string-keyed.h                | 72 +++++++++++++++++++++++++++-
 common/test/test.cpp                 | 17 +++++++
 include/photon/common/hash_combine.h |  1 +
 4 files changed, 118 insertions(+), 2 deletions(-)
 create mode 100644 common/hash_combine.h
 create mode 120000 include/photon/common/hash_combine.h

diff --git a/common/hash_combine.h b/common/hash_combine.h
new file mode 100644
index 00000000..dafedafc
--- /dev/null
+++ b/common/hash_combine.h
@@ -0,0 +1,30 @@
+/*
+Copyright 2022 The Photon Authors
+
+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.
+*/
+
+#pragma once
+#include <unordered_set>
+
+namespace photon {
+
+inline size_t hash_combine(size_t a) { return a; }
+
+template<typename...Ts> inline
+size_t hash_combine(size_t a, size_t b, Ts...xs) {
+    auto x = (a<<6) + (a>>2) + 0x9e3779b9 + b;
+    return hash_combine(x, xs...);
+}
+
+} // namespace photon
diff --git a/common/string-keyed.h b/common/string-keyed.h
index 9aea4c9e..0f90ddd4 100644
--- a/common/string-keyed.h
+++ b/common/string-keyed.h
@@ -17,6 +17,7 @@ limitations under the License.
 #pragma once
 
 #include <photon/common/string_view.h>
+#include <photon/common/hash_combine.h>
 #include <cstring>
 #include <unordered_map>
 #include <map>
@@ -156,6 +157,43 @@ template<class T,
 using unordered_map_string_key = basic_map_string_key<
     std::unordered_map<string_key, T, Hasher, KeyEqual, Alloc>>;
 
+class Hasher_CaseInsensitive {
+    const size_t BUF_CAP = 64;
+    size_t partial_hash(std::string_view sv, size_t i, size_t n) const {
+        char buf[BUF_CAP];
+        sv = sv.substr(i, n);
+        assert(sv.size() <= BUF_CAP);
+        for (size_t j = 0; j < sv.size(); ++j)
+            buf[j] = (char)tolower(sv[j]);
+        return std::hash<std::string_view>()({buf, n});
+    }
+public:
+    size_t operator()(std::string_view sv) const {
+        size_t h = 0;
+        for (size_t i = 0; i < sv.size(); i += BUF_CAP) {
+            auto len = std::min(BUF_CAP, sv.size() - i);
+            auto ph = partial_hash(sv, i, len);
+            h = photon::hash_combine(h, ph);
+        }
+        return h;
+    }
+};
+
+class Equal_CaseInsensitive {
+public:
+    bool operator()(std::string_view a, std::string_view b) const {
+        return a.size() == b.size() && strncasecmp(
+               a.begin(), b.begin(), a.size()) == 0;
+    }
+};
+
+template<class T,
+    class Hasher = Hasher_CaseInsensitive,
+    class KeyEqual = Equal_CaseInsensitive,
+    class Alloc = std::allocator<std::pair<const string_key, T>>>
+using unordered_map_string_key_case_insensitive = basic_map_string_key<
+    std::unordered_map<string_key, T, Hasher, KeyEqual, Alloc>>;
+
 template<class T,
     class Pred = std::less<string_key>,
     class Alloc = std::allocator<std::pair<const string_key,T>>>
@@ -189,6 +227,23 @@ class map_string_key : public basic_map_string_key<
     }
 };
 
+class Less_CaseInsensitive {
+public:
+    bool operator()(std::string_view a, std::string_view b) const {
+        auto len = std::min(a.size(), b.size());
+        auto cmp = strncasecmp(a.begin(), b.begin(), len);
+        if (cmp < 0) return true;
+        if (cmp > 0) return false;
+        return a.size() < b.size();
+    }
+};
+
+template<class T,
+    class Pred = Less_CaseInsensitive,
+    class Alloc = std::allocator<std::pair<const string_key,T>>>
+using map_string_key_case_insensitive = basic_map_string_key<
+    std::map<string_key, T, Pred, Alloc>>;
+
 // the String Key-Value (Mutable), stored together
 // in a consecutive area, so as to save one allocation
 class skvm : public string_key {
@@ -418,9 +473,16 @@ class basic_map_string_kv : public M
 using unordered_map_string_kv = basic_map_string_kv<std::unordered_map<
     skvm, size_t, std::hash<std::string_view>>>;
 
-class map_string_kv : public basic_map_string_kv<std::map<skvm, size_t>> {
+using unordered_map_string_kv_case_insensitive = basic_map_string_kv<
+    std::unordered_map<skvm, size_t, Hasher_CaseInsensitive,
+            Equal_CaseInsensitive>>;
+
+template<class Compare = std::less<skvm>, class Allocator =
+                std::allocator<std::pair<const skvm, size_t>>>
+class __basic_map_string_kv : public basic_map_string_kv<
+         std::map<skvm, size_t, Compare, Allocator>> {
 public:
-    using base = basic_map_string_kv<std::map<skvm, size_t>>;
+    using base = basic_map_string_kv<std::map<skvm, size_t, Compare, Allocator>>;
     using typename base::key_type;
     using typename base::const_iterator;
     using typename base::iterator;
@@ -445,3 +507,9 @@ class map_string_kv : public basic_map_string_kv<std::map<skvm, size_t>> {
         return {base::upper_bound((const skvm&)k)};
     }
 };
+
+using map_string_kv = __basic_map_string_kv<>;
+
+using map_string_kv_case_insensitive =
+    __basic_map_string_kv<Less_CaseInsensitive>;
+
diff --git a/common/test/test.cpp b/common/test/test.cpp
index 59c33b61..ea5f6779 100644
--- a/common/test/test.cpp
+++ b/common/test/test.cpp
@@ -1204,6 +1204,23 @@ TEST(string_key, unordered_map_string_kv_perf) {
     basic_map_test(test_map);
 }
 
+template<typename M> static
+void test_map_case_insensitive() {
+    M m;
+    m.emplace("asdf", "jkl;");
+    auto it = m.find("ASDF");
+    EXPECT_NE(it, m.end());
+    EXPECT_EQ(it->second, "jkl;");
+    EXPECT_EQ(m.count("kuherqf"), 0);
+}
+
+TEST(string_key, case_insensitive) {
+    test_map_case_insensitive<unordered_map_string_key_case_insensitive<estring>>();
+    test_map_case_insensitive<unordered_map_string_kv_case_insensitive>();
+    test_map_case_insensitive<map_string_key_case_insensitive<estring>>();
+    test_map_case_insensitive<map_string_kv_case_insensitive>();
+}
+
 TEST(RangeLock, Basic) {
   RangeLock m;
 
diff --git a/include/photon/common/hash_combine.h b/include/photon/common/hash_combine.h
new file mode 120000
index 00000000..afb24037
--- /dev/null
+++ b/include/photon/common/hash_combine.h
@@ -0,0 +1 @@
+../../../common/hash_combine.h
\ No newline at end of file