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WIP: MVP

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This commit is contained in:
Andrey Gumirov
2024-01-11 02:44:53 +07:00
parent 8780822f95
commit b6a619303d
6 changed files with 201 additions and 57 deletions
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60
bitstream.cpp
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@ -6,11 +6,16 @@
// i.e when stream is 0b12345678 0bABCDEFGH and command is
// to read 12 bits:
// out = 00000000 00000000 0000EFGH 12345678
// out = 00000000 00000000 0000EFGH 12345678 -- wrong
// to read 2 bits:
// out = 00000000 00000000 00000000 00000078
// TODO:
// to read 12 bits:
// out = 00000000 00000000 00008765 4321HGFE
// to read 2 bits:
// out = 00000000 00000000 00000000 00000087
int ibitstream::getbits(size_t n) {
std::cerr << "To read " << n << " count: " << this->count << " " << this->cache << std::endl;
// std::cerr << "To read " << n << " count: " << this->count << " " << this->cache << std::endl;
int out = 0, read = 0, to_read;
if (n > 32 || n < 0) {
@ -25,16 +30,29 @@ int ibitstream::getbits(size_t n) {
while (n > 0) {
to_read = min(n, 8 - this->count);
std::cerr << "Iter n: " << n << " count: " << this->count << " "
<< this->cache << " to_read: " << to_read << " already read: " << read << std::endl;
// std::cerr << "Iter n: " << n << " count: " << this->count << " "
// << this->cache << " to_read: " << to_read << " already read: " << read << std::endl;
// cache & 0b11111000 if count = 3;
// cache & 0b10000000 if count = 7;
// cache & 0b11111111 if count = 0, etc;
uint8_t mask = (((1 << to_read) - 1) << this->count);
out |= ((cache & mask) >> this->count) << read;
uint8_t chunk = ((cache & mask) >> this->count);
std::cerr << "Read result: " << std::bitset<8>((cache & mask) >> this->count) << " " << std::bitset<32>(((cache & mask) >> this->count) << read) << std::endl;
// todo inverse chunk
uint8_t inv = 0;
for (size_t i = 0; i < to_read; i++)
{
inv |= ((chunk >> i) & 1) << (to_read - i - 1);
}
out <<= to_read; // shift by length of chunk
out |= inv; // concat with chunk
// out |= inv << read;
// std::cerr << "Mask " << std::bitset<8>(mask) << " chunk " << std::bitset<8>(chunk) <<
// " inv " << std::bitset<8>(inv) << " out " << std::bitset<32>(out) << std::endl;
this->count += to_read;
read += to_read;
@ -51,13 +69,33 @@ int ibitstream::getbits(size_t n) {
}
void obitstream::writebits(short bits, size_t n) {
std::cerr << "Write: " << std::bitset<16>(bits) << " n: " << n << " count: " << this->count << " cache: " << std::bitset<8>(this->cache) << std::endl;
// std::cerr << "Write: " << std::bitset<16>(bits) << " n: " << n << " count: " << this->count << " cache: " << std::bitset<8>(this->cache) << std::endl;
int written = 0, to_write;
while (n > 0) {
to_write = min(n, 8 - this->count);
// mask:
// ------- n -----------------------------
// 00000..00000 1...1111111111 000000..000 == bits
// - written - | - to_write - | - offset -
// so offset = n - to_write
// because n = n - to_write at every step, so written is already present
uint8_t chunk = (bits & (((1 << to_write) - 1) << written)) >> written;
this->cache |= (chunk << this->count);
uint16_t mask = (((1 << to_write) - 1) << (n - to_write));
uint8_t chunk = (bits & mask) >> (n - to_write);
// todo inverse bits in chunk
uint8_t inv = 0;
for (size_t i = 0; i < to_write; i++)
{
inv |= ((chunk >> i) & 1) << (to_write - i - 1);
}
// std::cerr << "Chunk " << std::bitset<8>(chunk) << " inv " << std::bitset<8>(inv) << " to_write "
// << to_write << " written " << written << " n " << n << " mask " << std::bitset<16>(mask)
// << " offset " << (n - to_write) << std::endl;
this->cache |= (inv << this->count);
this->count += to_write;
written += to_write;
@ -65,7 +103,7 @@ void obitstream::writebits(short bits, size_t n) {
if (this->count == 8){
// flush chunk
std::cerr << "Flush: " << std::bitset<8>(this->cache) << std::endl;
// std::cerr << "Flush: " << std::bitset<8>(this->cache) << std::endl;
os << this->cache;
os.flush();
@ -78,7 +116,7 @@ void obitstream::writebits(short bits, size_t n) {
}
void obitstream::flush() {
std::cerr << "Flush: " << std::bitset<8>(this->cache) << std::endl;
// std::cerr << "Flush: " << std::bitset<8>(this->cache) << std::endl;
os << this->cache;
os.flush();