mirror of
https://github.com/rclone/rclone.git
synced 2024-12-22 03:30:11 +08:00
102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
// Package filename provides utilities for encoder.
|
|
package filename
|
|
|
|
import (
|
|
"encoding/base64"
|
|
"sync"
|
|
|
|
"github.com/klauspost/compress/huff0"
|
|
)
|
|
|
|
// encodeURL is base64 url encoding values.
|
|
const encodeURL = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
|
|
|
|
// decodeMap will return x = decodeMap[encodeURL[byte(x)]] - 1 if x >= 0 and x < 64, otherwise -1 is returned.
|
|
var decodeMap [256]byte
|
|
|
|
// maxLength is the maximum length that will be attempted to be compressed.
|
|
const maxLength = 256
|
|
|
|
var (
|
|
initOnce sync.Once // Used to control init of tables.
|
|
|
|
encTables [64]*huff0.Scratch // Encoders.
|
|
encTableLocks [64]sync.Mutex // Temporary locks for encoders since they are stateful.
|
|
decTables [64]*huff0.Decoder // Stateless decoders.
|
|
)
|
|
|
|
const (
|
|
tableUncompressed = 0
|
|
|
|
tableSCSU = 59
|
|
tableSCSUPlain = 60
|
|
tableRLE = 61
|
|
tableCustom = 62
|
|
tableReserved = 63
|
|
)
|
|
|
|
// predefined tables as base64 URL encoded string.
|
|
var tablesData = [64]string{
|
|
// Uncompressed
|
|
tableUncompressed: "",
|
|
// ncw home directory
|
|
1: "MRDIEtAAMAzDMAzDSjX_ybu0w97bb-L3b2mR-rUl5LXW3lZII43kIDMzM1NXu3okgQs=",
|
|
// ncw images
|
|
2: "IhDIAEAA______-Pou_4Sf5z-uS-39MVWjullFLKM7EBECs=",
|
|
// ncw Google Drive:
|
|
3: "JxDQAIIBMDMzMwOzbv7nJJCyd_m_9D2llCarnQX33nvvlFKEhUxAAQ==",
|
|
// Hex
|
|
4: "ExDoSTD___-tfXfhJ0hKSkryTxU=",
|
|
// Base64
|
|
5: "JRDIcQf_______8PgIiIiIgINkggARHlkQwSSCCBxHFYINHdfXI=",
|
|
// Hex plus a bit...
|
|
6: "E5CxwAHm9sYcAlmWZVvMHA4Y5jw=",
|
|
// Hex, upper case letters.
|
|
7: "FICxgAMMAGC3YwMthe3DWM_wDAAQ",
|
|
|
|
// Special tables:
|
|
// SCSU and a fairly generic table:
|
|
tableSCSU: "UxAgZmEB-RYPU8hrnAk6uMgpTNQMB5MGRBx0D3T0JjyUyY-yOi5CoGgktbAktSh7d36HtPTFu7SXJ7FYw_AYmA74ZH2vWgc8O6Z5jLnWnsFqU_4B",
|
|
// SCSU with no table...
|
|
tableSCSUPlain: "",
|
|
// Compressed data has its own table.
|
|
tableCustom: "",
|
|
// Reserved for extension.
|
|
tableReserved: "",
|
|
}
|
|
|
|
func initCoders() {
|
|
initOnce.Do(func() {
|
|
// Init base 64 decoder.
|
|
for i, v := range encodeURL {
|
|
decodeMap[v] = byte(i) + 1
|
|
}
|
|
|
|
// Initialize encoders and decoders.
|
|
for i, dataString := range tablesData {
|
|
if len(dataString) == 0 {
|
|
continue
|
|
}
|
|
data, err := base64.URLEncoding.DecodeString(dataString)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
s, _, err := huff0.ReadTable(data, nil)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
// We want to save at least len(in) >> 5
|
|
s.WantLogLess = 5
|
|
s.Reuse = huff0.ReusePolicyMust
|
|
encTables[i] = s
|
|
decTables[i] = s.Decoder()
|
|
}
|
|
// Add custom table type.
|
|
var s huff0.Scratch
|
|
s.Reuse = huff0.ReusePolicyNone
|
|
encTables[tableCustom] = &s
|
|
decTables[tableCustom] = nil
|
|
})
|
|
}
|