{

/** @brief The number of bits. */

uint8_t bits:6;

/** @brief The number of trits. */

uint8_t trits:1;

/** @brief The number of quints. */

uint8_t quints:1;

{

/** @brief The scaling parameter. */

uint8_t scale:6;

/** @brief The divisor parameter. */

uint8_t divisor:2;

unsigned int character_count,

quant_method quant_level

) {

// Cope with out-of bounds values - input might be invalid

if (static_cast<size_t>(quant_level) >= ise_sizes.size())

{

// Arbitrary large number that's more than an ASTC block can hold

return 1024;

}

auto& entry = ise_sizes[quant_level];

unsigned int divisor = (entry.divisor << 1) + 1;

return (entry.scale * character_count + divisor - 1) / divisor;

unsigned int value,

unsigned int bitcount,

unsigned int bitoffset,

uint8_t ptr[2]

) {

unsigned int mask = (1 << bitcount) - 1;

value &= mask;

ptr += bitoffset >> 3;

bitoffset &= 7;

value <<= bitoffset;

mask <<= bitoffset;

mask = ~mask;

ptr[0] &= mask;

ptr[0] |= value;

ptr[1] &= mask >> 8;

ptr[1] |= value >> 8;

unsigned int bitcount,

unsigned int bitoffset,

const uint8_t* ptr

) {

unsigned int mask = (1 << bitcount) - 1;

ptr += bitoffset >> 3;

bitoffset &= 7;

unsigned int value = ptr[0] | (ptr[1] << 8);

value >>= bitoffset;

value &= mask;

return value;

quant_method quant_level,

unsigned int character_count,

const uint8_t* input_data,

uint8_t* output_data,

unsigned int bit_offset

) {

promise(character_count > 0);

unsigned int bits = btq_counts[quant_level].bits;

unsigned int trits = btq_counts[quant_level].trits;

unsigned int quints = btq_counts[quant_level].quints;

unsigned int mask = (1 << bits) - 1;

// Write out trits and bits

if (trits)

{

unsigned int i = 0;

unsigned int full_trit_blocks = character_count / 5;

for (unsigned int j = 0; j < full_trit_blocks; j++)

{

unsigned int i4 = input_data[i + 4] >> bits;

unsigned int i3 = input_data[i + 3] >> bits;

unsigned int i2 = input_data[i + 2] >> bits;

unsigned int i1 = input_data[i + 1] >> bits;

unsigned int i0 = input_data[i + 0] >> bits;

uint8_t T = integer_of_trits[i4][i3][i2][i1][i0];

// The max size of a trit bit count is 6, so we can always safely

// pack a single MX value with the following 1 or 2 T bits.

uint8_t pack;

// Element 0 + T0 + T1

pack = (input_data[i++] & mask) | (((T >> 0) & 0x3) << bits);

write_bits(pack, bits + 2, bit_offset, output_data);

bit_offset += bits + 2;

// Element 1 + T2 + T3

pack = (input_data[i++] & mask) | (((T >> 2) & 0x3) << bits);

write_bits(pack, bits + 2, bit_offset, output_data);

bit_offset += bits + 2;

// Element 2 + T4

pack = (input_data[i++] & mask) | (((T >> 4) & 0x1) << bits);

write_bits(pack, bits + 1, bit_offset, output_data);

bit_offset += bits + 1;

// Element 3 + T5 + T6

pack = (input_data[i++] & mask) | (((T >> 5) & 0x3) << bits);

write_bits(pack, bits + 2, bit_offset, output_data);

bit_offset += bits + 2;

// Element 4 + T7

pack = (input_data[i++] & mask) | (((T >> 7) & 0x1) << bits);

write_bits(pack, bits + 1, bit_offset, output_data);

bit_offset += bits + 1;

}

// Loop tail for a partial block

if (i != character_count)

{

// i4 cannot be present - we know the block is partial

// i0 must be present - we know the block isn't empty

unsigned int i4 = 0;

unsigned int i3 = i + 3 >= character_count ? 0 : input_data[i + 3] >> bits;

unsigned int i2 = i + 2 >= character_count ? 0 : input_data[i + 2] >> bits;

unsigned int i1 = i + 1 >= character_count ? 0 : input_data[i + 1] >> bits;

unsigned int i0 = input_data[i + 0] >> bits;

uint8_t T = integer_of_trits[i4][i3][i2][i1][i0];

for (unsigned int j = 0; i < character_count; i++, j++)

{

// Truncated table as this iteration is always partial

static const uint8_t tbits[4] { 2, 2, 1, 2 };

static const uint8_t tshift[4] { 0, 2, 4, 5 };

uint8_t pack = (input_data[i] & mask) |

(((T >> tshift[j]) & ((1 << tbits[j]) - 1)) << bits);

write_bits(pack, bits + tbits[j], bit_offset, output_data);

bit_offset += bits + tbits[j];

}

}

}

// Write out quints and bits

else if (quints)

{

unsigned int i = 0;

unsigned int full_quint_blocks = character_count / 3;

for (unsigned int j = 0; j < full_quint_blocks; j++)

{

unsigned int i2 = input_data[i + 2] >> bits;

unsigned int i1 = input_data[i + 1] >> bits;

unsigned int i0 = input_data[i + 0] >> bits;

uint8_t T = integer_of_quints[i2][i1][i0];

// The max size of a quint bit count is 5, so we can always safely

// pack a single M value with the following 2 or 3 T bits.

uint8_t pack;

// Element 0

pack = (input_data[i++] & mask) | (((T >> 0) & 0x7) << bits);

write_bits(pack, bits + 3, bit_offset, output_data);

bit_offset += bits + 3;

// Element 1

pack = (input_data[i++] & mask) | (((T >> 3) & 0x3) << bits);

write_bits(pack, bits + 2, bit_offset, output_data);

bit_offset += bits + 2;

// Element 2

pack = (input_data[i++] & mask) | (((T >> 5) & 0x3) << bits);

write_bits(pack, bits + 2, bit_offset, output_data);

bit_offset += bits + 2;

}

// Loop tail for a partial block

if (i != character_count)

{

// i2 cannot be present - we know the block is partial

// i0 must be present - we know the block isn't empty

unsigned int i2 = 0;

unsigned int i1 = i + 1 >= character_count ? 0 : input_data[i + 1] >> bits;

unsigned int i0 = input_data[i + 0] >> bits;

uint8_t T = integer_of_quints[i2][i1][i0];

for (unsigned int j = 0; i < character_count; i++, j++)

{

// Truncated table as this iteration is always partial

static const uint8_t tbits[2] { 3, 2 };

static const uint8_t tshift[2] { 0, 3 };

uint8_t pack = (input_data[i] & mask) |

(((T >> tshift[j]) & ((1 << tbits[j]) - 1)) << bits);

write_bits(pack, bits + tbits[j], bit_offset, output_data);

bit_offset += bits + tbits[j];

}

}

}

// Write out just bits

else

{

for (unsigned int i = 0; i < character_count; i++)

{

write_bits(input_data[i], bits, bit_offset, output_data);

bit_offset += bits;

}

}

quant_method quant_level,

unsigned int character_count,

const uint8_t* input_data,

uint8_t* output_data,

unsigned int bit_offset

) {

promise(character_count > 0);

// Note: due to how the trit/quint-block unpacking is done in this function, we may write more

// temporary results than the number of outputs. The maximum actual number of results is 64 bit,

// but we keep 4 additional character_count of padding.

uint8_t results[68];

uint8_t tq_blocks[22] { 0 }; // Trit-blocks or quint-blocks, must be zeroed

unsigned int bits = btq_counts[quant_level].bits;

unsigned int trits = btq_counts[quant_level].trits;

unsigned int quints = btq_counts[quant_level].quints;

unsigned int lcounter = 0;

unsigned int hcounter = 0;

// Collect bits for each element, as well as bits for any trit-blocks and quint-blocks.

for (unsigned int i = 0; i < character_count; i++)

{

results[i] = static_cast<uint8_t>(read_bits(bits, bit_offset, input_data));

bit_offset += bits;

if (trits)

{

static const uint8_t bits_to_read[5] { 2, 2, 1, 2, 1 };

static const uint8_t block_shift[5] { 0, 2, 4, 5, 7 };

static const uint8_t next_lcounter[5] { 1, 2, 3, 4, 0 };

static const uint8_t hcounter_incr[5] { 0, 0, 0, 0, 1 };

unsigned int tdata = read_bits(bits_to_read[lcounter], bit_offset, input_data);

bit_offset += bits_to_read[lcounter];

tq_blocks[hcounter] |= tdata << block_shift[lcounter];

hcounter += hcounter_incr[lcounter];

lcounter = next_lcounter[lcounter];

}

if (quints)

{

static const uint8_t bits_to_read[3] { 3, 2, 2 };

static const uint8_t block_shift[3] { 0, 3, 5 };

static const uint8_t next_lcounter[3] { 1, 2, 0 };

static const uint8_t hcounter_incr[3] { 0, 0, 1 };

unsigned int tdata = read_bits(bits_to_read[lcounter], bit_offset, input_data);

bit_offset += bits_to_read[lcounter];

tq_blocks[hcounter] |= tdata << block_shift[lcounter];

hcounter += hcounter_incr[lcounter];

lcounter = next_lcounter[lcounter];

}

}

// Unpack trit-blocks or quint-blocks as needed

if (trits)

{

unsigned int trit_blocks = (character_count + 4) / 5;

promise(trit_blocks > 0);

for (unsigned int i = 0; i < trit_blocks; i++)

{

const uint8_t *tritptr = trits_of_integer[tq_blocks[i]];

results[5 * i ] |= tritptr[0] << bits;

results[5 * i + 1] |= tritptr[1] << bits;

results[5 * i + 2] |= tritptr[2] << bits;

results[5 * i + 3] |= tritptr[3] << bits;

results[5 * i + 4] |= tritptr[4] << bits;

}

}

if (quints)

{

unsigned int quint_blocks = (character_count + 2) / 3;

promise(quint_blocks > 0);

for (unsigned int i = 0; i < quint_blocks; i++)

{

const uint8_t *quintptr = quints_of_integer[tq_blocks[i]];

results[3 * i ] |= quintptr[0] << bits;

results[3 * i + 1] |= quintptr[1] << bits;

results[3 * i + 2] |= quintptr[2] << bits;

}

}

for (unsigned int i = 0; i < character_count; i++)

{

output_data[i] = results[i];

}