/
util.go
151 lines (134 loc) · 2.84 KB
/
util.go
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package _zdecode
import (
"bufio"
)
const (
kEnd = iota
kHeader = iota
kArchiveProperties = iota
kAdditionalStreamsInfo = iota
kMainStreamsInfo = iota
kFilesInfo = iota
kPackInfo = iota
kUnpackInfo = iota
kSubStreamsInfo = iota
kSize = iota
kCRC = iota
kFolder = iota
kCodersUnpackSize = iota
kNumUnpackStream = iota
kEmptyStream = iota
kEmptyFile = iota
kAnti = iota
kName = iota
kCTime = iota
kATime = iota
kMTime = iota
kWinAttrib = iota
kComment = iota
kEncodedHeader = iota
kStartPos = iota
kDummy = iota
// kNtSecure,
// kParent,
// kIsAux
)
type functionWithError func() error
func readEncodedUInt64(reader *bufio.Reader) (uint64, error) {
first, err := reader.ReadByte()
if err != nil {
return 0, err
}
if (first & 0x80) == 0 {
return uint64(first), nil
}
b, err := reader.ReadByte()
if err != nil {
return 0, err
}
next := uint64(b)
for i := uint64(1) ; i < 8 ; i++ {
mask := byte(0x80) >> i
if (first & mask) == 0 {
return next | uint64(first & (mask - 1)) << (i *8), nil
}
b, err = reader.ReadByte()
if err != nil {
return 0, err
}
next |= uint64(b) << (i *8)
}
return next, nil
}
func readUntil(reader *bufio.Reader, id int) error {
for {
next, err := reader.ReadByte()
if err != nil {
return err
}
if int(next) == id {
return nil
}
if int(next) == kEnd {
return errInvalidFile
}
_, err = reader.ReadByte()
if err != nil {
return err
}
}
}
func readEndOrCrc(reader *bufio.Reader, crcFunction functionWithError) error {
for {
if packType, err := reader.ReadByte() ; err != nil {
return err
} else {
if packType == kEnd {
return nil
}
if packType == kCRC {
err := crcFunction()
if err != nil {
return err
}
continue
}
}
}
return nil
}
func readBooleans(reader * bufio.Reader, numItems int) ([]bool, int, error) {
bools := make([]bool, numItems)
mask := byte(0)
var b byte
var count int
var err error
for i := 0; i < numItems; i++ {
if mask == 0 {
b, err = reader.ReadByte()
if err != nil {
return nil, 0, err
}
mask = 0x80
}
bools[i] = (b & mask) != 0
if bools[i] {
count++
}
mask >>= 1
}
return bools, count, nil
}
func readDefinedBooleans(reader *bufio.Reader, numItems int) ([]bool, int, error) {
allAreDefined, err := reader.ReadByte()
if err != nil {
return nil, 0, err
}
if allAreDefined == 0 {
return readBooleans(reader, numItems)
} else {
bools := make([]bool, numItems)
for index, _ := range bools { bools[index] = true}
return bools, numItems, nil
}
}