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Fix bit packing #447

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Merged
AlexanderSaydakov merged 3 commits into from
Jan 9, 2025
Merged

Fix bit packing #447

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5c19333
fixed bit packing
AlexanderSaydakov Jan 9, 2025
666df8b
unused import
AlexanderSaydakov Jan 9, 2025
6e944cf
fixed name clash
AlexanderSaydakov Jan 9, 2025
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6 changes: 3 additions & 3 deletions theta/include/bit_packing.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -329,7 +329,7 @@ static inline void pack_bits_13(const uint64_t* values, uint8_t* ptr) {

*ptr++ = static_cast<uint8_t>(values[3] >> 4);

*ptr = static_cast<uint8_t>(values[3] >> 4);
*ptr = static_cast<uint8_t>(values[3] << 4);
*ptr++ |= static_cast<uint8_t>(values[4] >> 9);

*ptr++ = static_cast<uint8_t>(values[4] >> 1);
Expand Down Expand Up @@ -4227,7 +4227,7 @@ static inline void unpack_bits_33(uint64_t* values, const uint8_t* ptr) {
values[6] |= *ptr >> 1;

values[7] = static_cast<uint64_t>(*ptr++ & 1) << 32;
values[7] |= *ptr++ << 24;
values[7] |= static_cast<uint64_t>(*ptr++) << 24;
values[7] |= *ptr++ << 16;
values[7] |= *ptr++ << 8;
values[7] |= *ptr;
Expand Down Expand Up @@ -4296,7 +4296,7 @@ static inline void unpack_bits_35(uint64_t* values, const uint8_t* ptr) {
values[1] |= *ptr++ << 6;
values[1] |= *ptr >> 2;

values[2] = static_cast<uint64_t>(*ptr++ & 2) << 33;
values[2] = static_cast<uint64_t>(*ptr++ & 3) << 33;
values[2] |= static_cast<uint64_t>(*ptr++) << 25;
values[2] |= *ptr++ << 17;
values[2] |= *ptr++ << 9;
Expand Down
80 changes: 41 additions & 39 deletions theta/test/bit_packing_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,51 +29,53 @@ namespace datasketches {
static const uint64_t IGOLDEN64 = 0x9e3779b97f4a7c13ULL;

TEST_CASE("pack unpack bits") {
for (uint8_t bits = 1; bits <= 63; ++bits) {
int n = 8;
const uint64_t mask = (1ULL << bits) - 1;
std::vector<uint64_t> input(n, 0);
const uint64_t igolden64 = IGOLDEN64;
uint64_t value = 0xaa55aa55aa55aa55ULL; // arbitrary starting value
for (int i = 0; i < n; ++i) {
input[i] = value & mask;
value += igolden64;
}
std::vector<uint8_t> bytes(n * sizeof(uint64_t), 0);
uint8_t offset = 0;
uint8_t* ptr = bytes.data();
for (int i = 0; i < n; ++i) {
offset = pack_bits(input[i], bits, ptr, offset);
}
uint64_t value = 0xaa55aa55aa55aa55ULL; // arbitrary starting value
for (int m = 0; m < 100; ++m) {
for (uint8_t bits = 1; bits <= 63; ++bits) {
int n = 8;
const uint64_t mask = (1ULL << bits) - 1;
std::vector<uint64_t> input(n, 0);
for (int i = 0; i < n; ++i) {
input[i] = value & mask;
value += IGOLDEN64;
}
std::vector<uint8_t> bytes(n * sizeof(uint64_t), 0);
uint8_t offset = 0;
uint8_t* ptr = bytes.data();
for (int i = 0; i < n; ++i) {
offset = pack_bits(input[i], bits, ptr, offset);
}

std::vector<uint64_t> output(n, 0);
offset = 0;
const uint8_t* cptr = bytes.data();
for (int i = 0; i < n; ++i) {
offset = unpack_bits(output[i], bits, cptr, offset);
}
for (int i = 0; i < n; ++i) {
REQUIRE(input[i] == output[i]);
std::vector<uint64_t> output(n, 0);
offset = 0;
const uint8_t* cptr = bytes.data();
for (int i = 0; i < n; ++i) {
offset = unpack_bits(output[i], bits, cptr, offset);
}
for (int i = 0; i < n; ++i) {
REQUIRE(input[i] == output[i]);
}
}
}
}

TEST_CASE("pack unpack blocks") {
for (uint8_t bits = 1; bits <= 63; ++bits) {
const uint64_t mask = (1ULL << bits) - 1;
std::vector<uint64_t> input(8, 0);
const uint64_t igolden64 = IGOLDEN64;
uint64_t value = 0xaa55aa55aa55aa55ULL; // arbitrary starting value
for (int i = 0; i < 8; ++i) {
input[i] = value & mask;
value += igolden64;
}
std::vector<uint8_t> bytes(8 * sizeof(uint64_t), 0);
pack_bits_block8(input.data(), bytes.data(), bits);
std::vector<uint64_t> output(8, 0);
unpack_bits_block8(output.data(), bytes.data(), bits);
for (int i = 0; i < 8; ++i) {
REQUIRE((input[i] & mask) == output[i]);
uint64_t value = 0xaa55aa55aa55aa55ULL; // arbitrary starting value
for (int n = 0; n < 100; ++n) {
for (uint8_t bits = 1; bits <= 63; ++bits) {
const uint64_t mask = (1ULL << bits) - 1;
std::vector<uint64_t> input(8, 0);
for (int i = 0; i < 8; ++i) {
input[i] = value & mask;
value += IGOLDEN64;
}
std::vector<uint8_t> bytes(bits, 0);
pack_bits_block8(input.data(), bytes.data(), bits);
std::vector<uint64_t> output(8, 0);
unpack_bits_block8(output.data(), bytes.data(), bits);
for (int i = 0; i < 8; ++i) {
REQUIRE(input[i] == output[i]);
}
}
}
}
Expand Down
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