12 uint32_t DecodeBits(std::vector<bool>::const_iterator &bitpos,
13 const std::vector<bool>::const_iterator &endpos,
14 uint8_t minval,
const std::vector<uint8_t> &bit_sizes) {
15 uint32_t val = minval;
17 for (std::vector<uint8_t>::const_iterator bit_sizes_it = bit_sizes.begin();
18 bit_sizes_it != bit_sizes.end(); ++bit_sizes_it) {
19 if (bit_sizes_it + 1 != bit_sizes.end()) {
20 if (bitpos == endpos) {
29 val += (1 << *bit_sizes_it);
31 for (
int b = 0; b < *bit_sizes_it; b++) {
32 if (bitpos == endpos) {
37 val += bit << (*bit_sizes_it - 1 - b);
45 const std::vector<uint8_t> TYPE_BIT_SIZES{0, 0, 1};
46 uint32_t DecodeType(std::vector<bool>::const_iterator &bitpos,
47 const std::vector<bool>::const_iterator &endpos) {
48 return DecodeBits(bitpos, endpos, 0, TYPE_BIT_SIZES);
51 const std::vector<uint8_t> ASN_BIT_SIZES{15, 16, 17, 18, 19,
53 uint32_t DecodeASN(std::vector<bool>::const_iterator &bitpos,
54 const std::vector<bool>::const_iterator &endpos) {
55 return DecodeBits(bitpos, endpos, 1, ASN_BIT_SIZES);
58 const std::vector<uint8_t> MATCH_BIT_SIZES{1, 2, 3, 4, 5, 6, 7, 8};
59 uint32_t DecodeMatch(std::vector<bool>::const_iterator &bitpos,
60 const std::vector<bool>::const_iterator &endpos) {
61 return DecodeBits(bitpos, endpos, 2, MATCH_BIT_SIZES);
64 const std::vector<uint8_t> JUMP_BIT_SIZES{5, 6, 7, 8, 9, 10, 11, 12, 13,
65 14, 15, 16, 17, 18, 19, 20, 21, 22,
66 23, 24, 25, 26, 27, 28, 29, 30};
67 uint32_t DecodeJump(std::vector<bool>::const_iterator &bitpos,
68 const std::vector<bool>::const_iterator &endpos) {
69 return DecodeBits(bitpos, endpos, 17, JUMP_BIT_SIZES);
75 const std::vector<bool> &ip) {
76 std::vector<bool>::const_iterator pos = asmap.begin();
77 const std::vector<bool>::const_iterator endpos = asmap.end();
78 uint8_t bits = ip.size();
79 uint32_t default_asn = 0;
80 uint32_t opcode, jump, match, matchlen;
81 while (pos != endpos) {
82 opcode = DecodeType(pos, endpos);
84 return DecodeASN(pos, endpos);
85 }
else if (opcode == 1) {
86 jump = DecodeJump(pos, endpos);
90 if (ip[ip.size() - bits]) {
91 if (jump >= endpos - pos) {
97 }
else if (opcode == 2) {
98 match = DecodeMatch(pos, endpos);
100 for (uint32_t bit = 0; bit < matchlen; bit++) {
104 if ((ip[ip.size() - bits]) !=
105 ((match >> (matchlen - 1 - bit)) & 1)) {
110 }
else if (opcode == 3) {
111 default_asn = DecodeASN(pos, endpos);
uint32_t Interpret(const std::vector< bool > &asmap, const std::vector< bool > &ip)
static uint64_t CountBits(uint64_t x)
Return the smallest number n such that (x >> n) == 0 (or 64 if the highest bit in x is set...