podman

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/*
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 * Copyright 2021 ByteDance Inc.
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *     http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package caching
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import (
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    `strings`
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    `unsafe`
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    `github.com/bytedance/sonic/internal/rt`
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)
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type FieldMap struct {
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    N uint64
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    b unsafe.Pointer
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    m map[string]int
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}
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type FieldEntry struct {
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    ID   int
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    Name string
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    Hash uint64
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}
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const (
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    FieldMap_N     = int64(unsafe.Offsetof(FieldMap{}.N))
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    FieldMap_b     = int64(unsafe.Offsetof(FieldMap{}.b))
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	FieldEntrySize = int64(unsafe.Sizeof(FieldEntry{}))
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)
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func newBucket(n int) unsafe.Pointer {
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    v := make([]FieldEntry, n)
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    return (*rt.GoSlice)(unsafe.Pointer(&v)).Ptr
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}
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func CreateFieldMap(n int) *FieldMap {
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    return &FieldMap {
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        N: uint64(n * 2),
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        b: newBucket(n * 2),    // LoadFactor = 0.5
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        m: make(map[string]int, n * 2),
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    }
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}
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func (self *FieldMap) At(p uint64) *FieldEntry {
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    off := uintptr(p) * uintptr(FieldEntrySize)
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    return (*FieldEntry)(unsafe.Pointer(uintptr(self.b) + off))
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}
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// Get searches FieldMap by name. JIT generated assembly does NOT call this
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// function, rather it implements its own version directly in assembly. So
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// we must ensure this function stays in sync with the JIT generated one.
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func (self *FieldMap) Get(name string) int {
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    h := StrHash(name)
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    p := h % self.N
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    s := self.At(p)
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    /* find the element;
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     * the hash map is never full, so the loop will always terminate */
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    for s.Hash != 0 {
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        if s.Hash == h && s.Name == name {
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            return s.ID
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        } else {
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            p = (p + 1) % self.N
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            s = self.At(p)
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        }
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    }
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    /* not found */
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    return -1
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}
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func (self *FieldMap) Set(name string, i int) {
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    h := StrHash(name)
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    p := h % self.N
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    s := self.At(p)
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    /* searching for an empty slot;
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     * the hash map is never full, so the loop will always terminate */
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    for s.Hash != 0 {
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        p = (p + 1) % self.N
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        s = self.At(p)
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    }
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    /* set the value */
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    s.ID   = i
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    s.Hash = h
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    s.Name = name
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    /* add the case-insensitive version, prefer the one with smaller field ID */
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    key := strings.ToLower(name)
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    if v, ok := self.m[key]; !ok || i < v {
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        self.m[key] = i
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    }
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}
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func (self *FieldMap) GetCaseInsensitive(name string) int {
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    if i, ok := self.m[strings.ToLower(name)]; ok {
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        return i
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    } else {
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        return -1
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    }
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}
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