func testReadPostClose(ibs kanzi.InputBitStream) {
defer func() {
if r := recover(); r != nil {
fmt.Printf("Error: %v\n", r.(error).Error())
}
}()
fmt.Printf("\nTrying to read from closed stream\n")
ibs.ReadBit()
}
func DecodeAlphabet(ibs kanzi.InputBitStream, alphabet []byte) (int, error) {
// Read encoding mode from bitstream
aphabetType := ibs.ReadBit()
if aphabetType == FULL_ALPHABET {
mode := ibs.ReadBit()
var alphabetSize int
if mode == EIGHT_BIT_ALPHABET {
alphabetSize = 256
} else {
alphabetSize = 128
}
// Full alphabet
for i := 0; i < alphabetSize; i++ {
alphabet[i] = byte(i)
}
return alphabetSize, nil
}
alphabetSize := 0
mode := ibs.ReadBit()
if mode == BIT_ENCODED_ALPHABET {
// Decode presence flags
for i := 0; i < 256; i += 64 {
val := ibs.ReadBits(64)
for j := 0; j < 64; j++ {
if val&(uint64(1)<<uint(j)) != 0 {
alphabet[alphabetSize] = byte(i + j)
alphabetSize++
}
}
}
} else { // DELTA_ENCODED_ALPHABET
val := int(ibs.ReadBits(6))
log := uint(1 + ibs.ReadBits(3)) // log(max(diff))
alphabetSize = val >> 1
n := 0
symbol := uint8(0)
if val&1 == ABSENT_SYMBOLS_MASK {
for i := 0; i < alphabetSize; i++ {
next := symbol + byte(ibs.ReadBits(log))
for symbol < next {
alphabet[n] = symbol
symbol++
n++
}
symbol++
}
alphabetSize = 256 - alphabetSize
for n < alphabetSize {
alphabet[n] = symbol
n++
symbol++
}
} else {
for i := 0; i < alphabetSize; i++ {
symbol += uint8(ibs.ReadBits(log))
alphabet[i] = symbol
symbol++
}
}
}
return alphabetSize, nil
}
