[chore] Update gin to v1.9.0 (#1553)

vendor/github.com/bytedance/sonic/internal/caching/fcache.go

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2021 ByteDance Inc.
+ *
+ * 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.
+ */
+
+package caching
+
+import (
+    `strings`
+    `unsafe`
+
+    `github.com/bytedance/sonic/internal/rt`
+)
+
+type FieldMap struct {
+    N uint64
+    b unsafe.Pointer
+    m map[string]int
+}
+
+type FieldEntry struct {
+    ID   int
+    Name string
+    Hash uint64
+}
+
+const (
+    FieldMap_N     = int64(unsafe.Offsetof(FieldMap{}.N))
+    FieldMap_b     = int64(unsafe.Offsetof(FieldMap{}.b))
+	FieldEntrySize = int64(unsafe.Sizeof(FieldEntry{}))
+)
+
+func newBucket(n int) unsafe.Pointer {
+    v := make([]FieldEntry, n)
+    return (*rt.GoSlice)(unsafe.Pointer(&v)).Ptr
+}
+
+func CreateFieldMap(n int) *FieldMap {
+    return &FieldMap {
+        N: uint64(n * 2),
+        b: newBucket(n * 2),    // LoadFactor = 0.5
+        m: make(map[string]int, n * 2),
+    }
+}
+
+func (self *FieldMap) At(p uint64) *FieldEntry {
+    off := uintptr(p) * uintptr(FieldEntrySize)
+    return (*FieldEntry)(unsafe.Pointer(uintptr(self.b) + off))
+}
+
+// Get searches FieldMap by name. JIT generated assembly does NOT call this
+// function, rather it implements its own version directly in assembly. So
+// we must ensure this function stays in sync with the JIT generated one.
+func (self *FieldMap) Get(name string) int {
+    h := StrHash(name)
+    p := h % self.N
+    s := self.At(p)
+
+    /* find the element;
+     * the hash map is never full, so the loop will always terminate */
+    for s.Hash != 0 {
+        if s.Hash == h && s.Name == name {
+            return s.ID
+        } else {
+            p = (p + 1) % self.N
+            s = self.At(p)
+        }
+    }
+
+    /* not found */
+    return -1
+}
+
+func (self *FieldMap) Set(name string, i int) {
+    h := StrHash(name)
+    p := h % self.N
+    s := self.At(p)
+
+    /* searching for an empty slot;
+     * the hash map is never full, so the loop will always terminate */
+    for s.Hash != 0 {
+        p = (p + 1) % self.N
+        s = self.At(p)
+    }
+
+    /* set the value */
+    s.ID   = i
+    s.Hash = h
+    s.Name = name
+
+    /* add the case-insensitive version, prefer the one with smaller field ID */
+    key := strings.ToLower(name)
+    if v, ok := self.m[key]; !ok || i < v {
+        self.m[key] = i
+    }
+}
+
+func (self *FieldMap) GetCaseInsensitive(name string) int {
+    if i, ok := self.m[strings.ToLower(name)]; ok {
+        return i
+    } else {
+        return -1
+    }
+}