Files
simdjson-simdjson/src/jsonminifier.cpp
T
2019-02-23 17:31:38 +01:00

252 lines
13 KiB
C++

#include "simdjson/portability.h"
#include <cstdint>
#ifndef __AVX2__
static uint8_t jump_table[256 * 3] = {
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0,
1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0,
1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1,
1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1,
};
size_t jsonminify(const unsigned char *bytes, size_t howmany,
unsigned char *out) {
size_t i = 0, pos = 0;
uint8_t quote = 0;
uint8_t nonescape = 1;
while (i < howmany) {
unsigned char c = bytes[i];
uint8_t *meta = jump_table + 3 * c;
quote = quote ^ (meta[0] & nonescape);
out[pos] = c;
pos += meta[2] | quote;
i += 1;
nonescape = (~nonescape) | (meta[1]);
}
return pos;
}
#else
#include "simdjson/simdprune_tables.h"
#include <cstring>
// a straightforward comparison of a mask against input.
static uint64_t cmp_mask_against_input_mini(__m256i input_lo, __m256i input_hi,
__m256i mask) {
__m256i cmp_res_0 = _mm256_cmpeq_epi8(input_lo, mask);
uint64_t res_0 = static_cast<uint32_t>(_mm256_movemask_epi8(cmp_res_0));
__m256i cmp_res_1 = _mm256_cmpeq_epi8(input_hi, mask);
uint64_t res_1 = _mm256_movemask_epi8(cmp_res_1);
return res_0 | (res_1 << 32);
}
// take input from buf and remove useless whitespace, input and output can be
// the same, result is null terminated, return the string length (minus the null termination)
size_t jsonminify(const uint8_t *buf, size_t len, uint8_t *out) {
// Useful constant masks
const uint64_t even_bits = 0x5555555555555555ULL;
const uint64_t odd_bits = ~even_bits;
uint8_t *initout(out);
uint64_t prev_iter_ends_odd_backslash =
0ULL; // either 0 or 1, but a 64-bit value
uint64_t prev_iter_inside_quote = 0ULL; // either all zeros or all ones
size_t idx = 0;
if (len >= 64) {
size_t avxlen = len - 63;
for (; idx < avxlen; idx += 64) {
__m256i input_lo = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(buf + idx + 0));
__m256i input_hi = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(buf + idx + 32));
uint64_t bs_bits = cmp_mask_against_input_mini(input_lo, input_hi,
_mm256_set1_epi8('\\'));
uint64_t start_edges = bs_bits & ~(bs_bits << 1);
uint64_t even_start_mask = even_bits ^ prev_iter_ends_odd_backslash;
uint64_t even_starts = start_edges & even_start_mask;
uint64_t odd_starts = start_edges & ~even_start_mask;
uint64_t even_carries = bs_bits + even_starts;
uint64_t odd_carries;
bool iter_ends_odd_backslash = add_overflow(
bs_bits, odd_starts, &odd_carries);
odd_carries |= prev_iter_ends_odd_backslash;
prev_iter_ends_odd_backslash = iter_ends_odd_backslash ? 0x1ULL : 0x0ULL;
uint64_t even_carry_ends = even_carries & ~bs_bits;
uint64_t odd_carry_ends = odd_carries & ~bs_bits;
uint64_t even_start_odd_end = even_carry_ends & odd_bits;
uint64_t odd_start_even_end = odd_carry_ends & even_bits;
uint64_t odd_ends = even_start_odd_end | odd_start_even_end;
uint64_t quote_bits = cmp_mask_against_input_mini(input_lo, input_hi,
_mm256_set1_epi8('"'));
quote_bits = quote_bits & ~odd_ends;
uint64_t quote_mask = _mm_cvtsi128_si64(_mm_clmulepi64_si128(
_mm_set_epi64x(0ULL, quote_bits), _mm_set1_epi8(0xFF), 0));
quote_mask ^= prev_iter_inside_quote;
prev_iter_inside_quote = static_cast<uint64_t>(static_cast<int64_t>(quote_mask) >> 63);// might be undefined behavior, should be fully defined in C++20, ok according to John Regher from Utah University
const __m256i low_nibble_mask = _mm256_setr_epi8(
// 0 9 a b c d
16, 0, 0, 0, 0, 0, 0, 0, 0, 8, 12, 1, 2, 9, 0, 0, 16, 0, 0, 0, 0, 0,
0, 0, 0, 8, 12, 1, 2, 9, 0, 0);
const __m256i high_nibble_mask = _mm256_setr_epi8(
// 0 2 3 5 7
8, 0, 18, 4, 0, 1, 0, 1, 0, 0, 0, 3, 2, 1, 0, 0, 8, 0, 18, 4, 0, 1, 0,
1, 0, 0, 0, 3, 2, 1, 0, 0);
__m256i whitespace_shufti_mask = _mm256_set1_epi8(0x18);
__m256i v_lo = _mm256_and_si256(
_mm256_shuffle_epi8(low_nibble_mask, input_lo),
_mm256_shuffle_epi8(high_nibble_mask,
_mm256_and_si256(_mm256_srli_epi32(input_lo, 4),
_mm256_set1_epi8(0x7f))));
__m256i v_hi = _mm256_and_si256(
_mm256_shuffle_epi8(low_nibble_mask, input_hi),
_mm256_shuffle_epi8(high_nibble_mask,
_mm256_and_si256(_mm256_srli_epi32(input_hi, 4),
_mm256_set1_epi8(0x7f))));
__m256i tmp_ws_lo = _mm256_cmpeq_epi8(
_mm256_and_si256(v_lo, whitespace_shufti_mask), _mm256_set1_epi8(0));
__m256i tmp_ws_hi = _mm256_cmpeq_epi8(
_mm256_and_si256(v_hi, whitespace_shufti_mask), _mm256_set1_epi8(0));
uint64_t ws_res_0 = static_cast<uint32_t>(_mm256_movemask_epi8(tmp_ws_lo));
uint64_t ws_res_1 = _mm256_movemask_epi8(tmp_ws_hi);
uint64_t whitespace = ~(ws_res_0 | (ws_res_1 << 32));
whitespace &= ~quote_mask;
int mask1 = whitespace & 0xFFFF;
int mask2 = (whitespace >> 16) & 0xFFFF;
int mask3 = (whitespace >> 32) & 0xFFFF;
int mask4 = (whitespace >> 48) & 0xFFFF;
int pop1 = hamming((~whitespace) & 0xFFFF);
int pop2 = hamming((~whitespace) & UINT64_C(0xFFFFFFFF));
int pop3 = hamming((~whitespace) & UINT64_C(0xFFFFFFFFFFFF));
int pop4 = hamming((~whitespace));
__m256i vmask1 =
_mm256_loadu2_m128i(reinterpret_cast<const __m128i *>(mask128_epi8) + (mask2 & 0x7FFF),
reinterpret_cast<const __m128i *>(mask128_epi8) + (mask1 & 0x7FFF));
__m256i vmask2 =
_mm256_loadu2_m128i(reinterpret_cast<const __m128i *>(mask128_epi8) + (mask4 & 0x7FFF),
reinterpret_cast<const __m128i *>(mask128_epi8) + (mask3 & 0x7FFF));
__m256i result1 = _mm256_shuffle_epi8(input_lo, vmask1);
__m256i result2 = _mm256_shuffle_epi8(input_hi, vmask2);
_mm256_storeu2_m128i(reinterpret_cast<__m128i *>(out + pop1), reinterpret_cast<__m128i *>(out), result1);
_mm256_storeu2_m128i(reinterpret_cast<__m128i *>(out + pop3), reinterpret_cast<__m128i *>(out + pop2),
result2);
out += pop4;
}
}
// we finish off the job... copying and pasting the code is not ideal here,
// but it gets the job done.
if (idx < len) {
uint8_t buffer[64];
memset(buffer, 0, 64);
memcpy(buffer, buf + idx, len - idx);
__m256i input_lo = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(buffer));
__m256i input_hi = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(buffer + 32));
uint64_t bs_bits =
cmp_mask_against_input_mini(input_lo, input_hi, _mm256_set1_epi8('\\'));
uint64_t start_edges = bs_bits & ~(bs_bits << 1);
uint64_t even_start_mask = even_bits ^ prev_iter_ends_odd_backslash;
uint64_t even_starts = start_edges & even_start_mask;
uint64_t odd_starts = start_edges & ~even_start_mask;
uint64_t even_carries = bs_bits + even_starts;
uint64_t odd_carries;
//bool iter_ends_odd_backslash =
add_overflow( bs_bits, odd_starts, &odd_carries);
odd_carries |= prev_iter_ends_odd_backslash;
//prev_iter_ends_odd_backslash = iter_ends_odd_backslash ? 0x1ULL : 0x0ULL; // we never use it
uint64_t even_carry_ends = even_carries & ~bs_bits;
uint64_t odd_carry_ends = odd_carries & ~bs_bits;
uint64_t even_start_odd_end = even_carry_ends & odd_bits;
uint64_t odd_start_even_end = odd_carry_ends & even_bits;
uint64_t odd_ends = even_start_odd_end | odd_start_even_end;
uint64_t quote_bits =
cmp_mask_against_input_mini(input_lo, input_hi, _mm256_set1_epi8('"'));
quote_bits = quote_bits & ~odd_ends;
uint64_t quote_mask = _mm_cvtsi128_si64(_mm_clmulepi64_si128(
_mm_set_epi64x(0ULL, quote_bits), _mm_set1_epi8(0xFF), 0));
quote_mask ^= prev_iter_inside_quote;
// prev_iter_inside_quote = (uint64_t)((int64_t)quote_mask >> 63);// we don't need this anymore
__m256i mask_20 = _mm256_set1_epi8(0x20); // c==32
__m256i mask_70 =
_mm256_set1_epi8(0x70); // adding 0x70 does not check low 4-bits
// but moves any value >= 16 above 128
__m256i lut_cntrl = _mm256_setr_epi8(
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x00,
0x00, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0xFF, 0xFF, 0x00, 0x00, 0xFF, 0x00, 0x00);
__m256i tmp_ws_lo = _mm256_or_si256(
_mm256_cmpeq_epi8(mask_20, input_lo),
_mm256_shuffle_epi8(lut_cntrl, _mm256_adds_epu8(mask_70, input_lo)));
__m256i tmp_ws_hi = _mm256_or_si256(
_mm256_cmpeq_epi8(mask_20, input_hi),
_mm256_shuffle_epi8(lut_cntrl, _mm256_adds_epu8(mask_70, input_hi)));
uint64_t ws_res_0 = static_cast<uint32_t>(_mm256_movemask_epi8(tmp_ws_lo));
uint64_t ws_res_1 = _mm256_movemask_epi8(tmp_ws_hi);
uint64_t whitespace = (ws_res_0 | (ws_res_1 << 32));
whitespace &= ~quote_mask;
if (len - idx < 64) {
whitespace |= UINT64_C(0xFFFFFFFFFFFFFFFF) << (len - idx);
}
int mask1 = whitespace & 0xFFFF;
int mask2 = (whitespace >> 16) & 0xFFFF;
int mask3 = (whitespace >> 32) & 0xFFFF;
int mask4 = (whitespace >> 48) & 0xFFFF;
int pop1 = hamming((~whitespace) & 0xFFFF);
int pop2 = hamming((~whitespace) & UINT64_C(0xFFFFFFFF));
int pop3 = hamming((~whitespace) & UINT64_C(0xFFFFFFFFFFFF));
int pop4 = hamming((~whitespace));
__m256i vmask1 =
_mm256_loadu2_m128i(reinterpret_cast<const __m128i *>(mask128_epi8) + (mask2 & 0x7FFF),
reinterpret_cast<const __m128i *>(mask128_epi8) + (mask1 & 0x7FFF));
__m256i vmask2 =
_mm256_loadu2_m128i(reinterpret_cast<const __m128i *>(mask128_epi8) + (mask4 & 0x7FFF),
reinterpret_cast<const __m128i *>(mask128_epi8) + (mask3 & 0x7FFF));
__m256i result1 = _mm256_shuffle_epi8(input_lo, vmask1);
__m256i result2 = _mm256_shuffle_epi8(input_hi, vmask2);
_mm256_storeu2_m128i(reinterpret_cast<__m128i *>(buffer + pop1), reinterpret_cast<__m128i *>(buffer),
result1);
_mm256_storeu2_m128i(reinterpret_cast<__m128i *>(buffer + pop3), reinterpret_cast<__m128i *>(buffer + pop2),
result2);
memcpy(out, buffer, pop4);
out += pop4;
}
*out = '\0';// NULL termination
return out - initout;
}
#endif