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sonic/native/scanning.c
liu 1443eb3bcf
fix: move large-size local array to _Stack (#162) 
* fix: move large-size local array to _Stack

* fix: adjust jsonstate and add alwaysinline

* fix: initialize types.JsonState's dbuf at prologue

* fix: replace `always_inline` with `inline`

* fix: remove unused types

* feat: update asm2asm

* fix: check stack size befor call JIT function

Co-authored-by: liuqiang <liuqiang.06@bytedance.com>
Co-authored-by: duanyi.aster <duanyi.aster@bytedance.com>
2021-12-30 14:51:23 +08:00

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/*
* Copyright 2021 ByteDance Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "native.h"
static const char *CS_ARRAY = "[]{},\"[]{},\"[]{}";
static const char *CS_OBJECT = "[]{},:\"[]{}:,\"[]";
static const uint64_t ODD_MASK = 0xaaaaaaaaaaaaaaaa;
static const uint64_t EVEN_MASK = 0x5555555555555555;
static const double P10_TAB[23] = {
/* <= the connvertion to double is not exact when less than 1 => */ 1e-000,
1e+001, 1e+002, 1e+003, 1e+004, 1e+005, 1e+006, 1e+007, 1e+008, 1e+009, 1e+010,
1e+011, 1e+012, 1e+013, 1e+014, 1e+015, 1e+016, 1e+017, 1e+018, 1e+019, 1e+020,
1e+021, 1e+022 /* <= the connvertion to double is not exact when larger, => */
};
static inline uint64_t add32(uint64_t v1, uint64_t v2, uint64_t *vo) {
uint32_t v;
uint32_t c = __builtin_uadd_overflow((uint32_t)v1, (uint32_t)v2, &v);
/* set the carry */
*vo = c;
return v;
}
static inline uint64_t add64(uint64_t v1, uint64_t v2, uint64_t *vo) {
uint64_t v;
uint64_t c = __builtin_uaddll_overflow(v1, v2, &v);
/* set the carry */
*vo = c;
return v;
}
static inline char isspace(char ch) {
return ch == ' ' || ch == '\r' || ch == '\n' | ch == '\t';
}
static inline void vdigits(const GoString *src, long *p, JsonState *ret) {
--*p;
vnumber(src, p, ret);
}
static inline char advance_ns(const GoString *src, long *p) {
size_t vi = *p;
size_t nb = src->len;
const char * sp = src->buf;
/* it's likely to run into non-spaces within a few
* characters, so test up to 4 characters manually */
if (vi < nb && !isspace(sp[vi])) goto nospace; else vi++;
if (vi < nb && !isspace(sp[vi])) goto nospace; else vi++;
if (vi < nb && !isspace(sp[vi])) goto nospace; else vi++;
if (vi < nb && !isspace(sp[vi])) goto nospace; else vi++;
/* check EOF */
if (vi >= nb) {
*p = vi;
return 0;
}
/* too many spaces, use SIMD to search for characters */
if ((vi = lspace(sp, nb, vi)) >= nb) {
return 0;
}
nospace:
*p = vi + 1;
return src->buf[vi];
}
static inline int64_t advance_dword(const GoString *src, long *p, long dec, int64_t ret, uint32_t val) {
if (*p > src->len + dec - 4) {
*p = src->len;
return -ERR_EOF;
} else if (*(uint32_t *)(src->buf + *p - dec) == val) {
*p += 4 - dec;
return ret;
} else {
*p -= dec;
for (int i = 0; src->buf[*p] == (val & 0xff); i++, ++*p) { val >>= 8; }
return -ERR_INVAL;
}
}
static inline ssize_t advance_string(const GoString *src, long p, int64_t *ep) {
char ch;
uint64_t es;
uint64_t fe;
uint64_t os;
uint64_t m0;
uint64_t m1;
uint64_t cr = 0;
/* prevent out-of-bounds accessing */
if (unlikely(src->len == p)) {
return -ERR_EOF;
}
/* buffer pointers */
size_t nb = src->len;
const char * sp = src->buf;
const char * ss = src->buf;
#define ep_init() *ep = -1;
#define ep_setc() ep_setx(sp - ss - 1)
#define ep_setx(x) if (*ep == -1) { *ep = (x); }
/* seek to `p` */
nb -= p;
sp += p;
ep_init()
#if USE_AVX2
/* initialize vectors */
__m256i v0;
__m256i v1;
__m256i q0;
__m256i q1;
__m256i x0;
__m256i x1;
__m256i cq = _mm256_set1_epi8('"');
__m256i cx = _mm256_set1_epi8('\\');
/* partial masks */
uint32_t s0;
uint32_t s1;
uint32_t t0;
uint32_t t1;
#else
/* initialize vectors */
__m128i v0;
__m128i v1;
__m128i v2;
__m128i v3;
__m128i q0;
__m128i q1;
__m128i q2;
__m128i q3;
__m128i x0;
__m128i x1;
__m128i x2;
__m128i x3;
__m128i cq = _mm_set1_epi8('"');
__m128i cx = _mm_set1_epi8('\\');
/* partial masks */
uint32_t s0;
uint32_t s1;
uint32_t s2;
uint32_t s3;
uint32_t t0;
uint32_t t1;
uint32_t t2;
uint32_t t3;
#endif
#define m0_mask(add) \
m1 &= ~cr; \
fe = (m1 << 1) | cr; \
os = (m1 & ~fe) & ODD_MASK; \
es = add(os, m1, &cr) << 1; \
m0 &= ~(fe & (es ^ EVEN_MASK));
/* 64-byte SIMD loop */
while (likely(nb >= 64)) {
#if USE_AVX2
v0 = _mm256_loadu_si256 ((const void *)(sp + 0));
v1 = _mm256_loadu_si256 ((const void *)(sp + 32));
q0 = _mm256_cmpeq_epi8 (v0, cq);
q1 = _mm256_cmpeq_epi8 (v1, cq);
x0 = _mm256_cmpeq_epi8 (v0, cx);
x1 = _mm256_cmpeq_epi8 (v1, cx);
s0 = _mm256_movemask_epi8 (q0);
s1 = _mm256_movemask_epi8 (q1);
t0 = _mm256_movemask_epi8 (x0);
t1 = _mm256_movemask_epi8 (x1);
m0 = ((uint64_t)s1 << 32) | (uint64_t)s0;
m1 = ((uint64_t)t1 << 32) | (uint64_t)t0;
#else
v0 = _mm_loadu_si128 ((const void *)(sp + 0));
v1 = _mm_loadu_si128 ((const void *)(sp + 16));
v2 = _mm_loadu_si128 ((const void *)(sp + 32));
v3 = _mm_loadu_si128 ((const void *)(sp + 48));
q0 = _mm_cmpeq_epi8 (v0, cq);
q1 = _mm_cmpeq_epi8 (v1, cq);
q2 = _mm_cmpeq_epi8 (v2, cq);
q3 = _mm_cmpeq_epi8 (v3, cq);
x0 = _mm_cmpeq_epi8 (v0, cx);
x1 = _mm_cmpeq_epi8 (v1, cx);
x2 = _mm_cmpeq_epi8 (v2, cx);
x3 = _mm_cmpeq_epi8 (v3, cx);
s0 = _mm_movemask_epi8 (q0);
s1 = _mm_movemask_epi8 (q1);
s2 = _mm_movemask_epi8 (q2);
s3 = _mm_movemask_epi8 (q3);
t0 = _mm_movemask_epi8 (x0);
t1 = _mm_movemask_epi8 (x1);
t2 = _mm_movemask_epi8 (x2);
t3 = _mm_movemask_epi8 (x3);
m0 = ((uint64_t)s3 << 48) | ((uint64_t)s2 << 32) | ((uint64_t)s1 << 16) | (uint64_t)s0;
m1 = ((uint64_t)t3 << 48) | ((uint64_t)t2 << 32) | ((uint64_t)t1 << 16) | (uint64_t)t0;
#endif
/** update first quote position */
if (unlikely(m1 != 0)) {
ep_setx(sp - ss + __builtin_ctzll(m1))
}
/** mask all the escaped quotes */
if (unlikely(m1 != 0 || cr != 0)) {
m0_mask(add64)
}
/* check for end quote */
if (m0 != 0) {
return sp - ss + __builtin_ctzll(m0) + 1;
}
/* move to the next block */
sp += 64;
nb -= 64;
}
/* 32-byte SIMD round */
if (likely(nb >= 32)) {
#if USE_AVX2
v0 = _mm256_loadu_si256 ((const void *)sp);
q0 = _mm256_cmpeq_epi8 (v0, cq);
x0 = _mm256_cmpeq_epi8 (v0, cx);
s0 = _mm256_movemask_epi8 (q0);
t0 = _mm256_movemask_epi8 (x0);
m0 = (uint64_t)s0;
m1 = (uint64_t)t0;
#else
v0 = _mm_loadu_si128 ((const void *)(sp + 0));
v1 = _mm_loadu_si128 ((const void *)(sp + 16));
q0 = _mm_cmpeq_epi8 (v0, cq);
q1 = _mm_cmpeq_epi8 (v1, cq);
x0 = _mm_cmpeq_epi8 (v0, cx);
x1 = _mm_cmpeq_epi8 (v1, cx);
s0 = _mm_movemask_epi8 (q0);
s1 = _mm_movemask_epi8 (q1);
t0 = _mm_movemask_epi8 (x0);
t1 = _mm_movemask_epi8 (x1);
m0 = ((uint64_t)s1 << 16) | (uint64_t)s0;
m1 = ((uint64_t)t1 << 16) | (uint64_t)t0;
#endif
/** update first quote position */
if (unlikely(m1 != 0)) {
ep_setx(sp - ss + __builtin_ctzll(m1))
}
/** mask all the escaped quotes */
if (unlikely(m1 != 0 || cr != 0)) {
m0_mask(add32)
}
/* check for end quote */
if (m0 != 0) {
return sp - ss + __builtin_ctzll(m0) + 1;
}
/* move to the next block */
sp += 32;
nb -= 32;
}
/* check for carry */
if (unlikely(cr != 0)) {
if (nb == 0) {
return -ERR_EOF;
} else {
ep_setc()
sp++, nb--;
}
}
/* handle the remaining bytes with scalar code */
while (nb-- > 0 && (ch = *sp++) != '"') {
if (unlikely(ch == '\\')) {
if (nb == 0) {
return -ERR_EOF;
} else {
ep_setc()
sp++, nb--;
}
}
}
#undef ep_init
#undef ep_setc
#undef ep_setx
#undef m0_mask
/* check for quotes */
if (ch == '"') {
return sp - ss;
} else {
return -ERR_EOF;
}
}
/** Value Scanning Routines **/
long value(const char *s, size_t n, long p, JsonState *ret, int allow_control) {
long q = p;
GoString m = {.buf = s, .len = n};
/* parse the next identifier, q is UNSAFE, may cause out-of-bounds accessing */
switch (advance_ns(&m, &q)) {
case '-' : /* fallthrough */
case '0' : /* fallthrough */
case '1' : /* fallthrough */
case '2' : /* fallthrough */
case '3' : /* fallthrough */
case '4' : /* fallthrough */
case '5' : /* fallthrough */
case '6' : /* fallthrough */
case '7' : /* fallthrough */
case '8' : /* fallthrough */
case '9' : vdigits(&m, &q, ret) ; return q;
case '"' : vstring(&m, &q, ret) ; return q;
case 'n' : ret->vt = advance_dword(&m, &q, 1, V_NULL, VS_NULL) ; return q;
case 't' : ret->vt = advance_dword(&m, &q, 1, V_TRUE, VS_TRUE) ; return q;
case 'f' : ret->vt = advance_dword(&m, &q, 0, V_FALSE, VS_ALSE) ; return q;
case '[' : ret->vt = V_ARRAY ; return q;
case '{' : ret->vt = V_OBJECT ; return q;
case ':' : ret->vt = allow_control ? V_KEY_SEP : -ERR_INVAL ; return allow_control ? q : q - 1;
case ',' : ret->vt = allow_control ? V_ELEM_SEP : -ERR_INVAL ; return allow_control ? q : q - 1;
case ']' : ret->vt = allow_control ? V_ARRAY_END : -ERR_INVAL ; return allow_control ? q : q - 1;
case '}' : ret->vt = allow_control ? V_OBJECT_END : -ERR_INVAL ; return allow_control ? q : q - 1;
case 0 : ret->vt = V_EOF ; return q;
default : ret->vt = -ERR_INVAL ; return q - 1;
}
}
void vstring(const GoString *src, long *p, JsonState *ret) {
int64_t v = -1;
int64_t i = *p;
ssize_t e = advance_string(src, i, &v);
/* check for errors */
if (e < 0) {
*p = src->len;
ret->vt = e;
return;
}
/* update the result, and fix the escape position (escaping past the end of string) */
*p = e;
ret->iv = i;
ret->vt = V_STRING;
ret->ep = v >= e ? -1 : v;
}
#define set_vt(t) \
ret->vt = t;
#define init_ret(t) \
ret->vt = t; \
ret->dv = 0.0; \
ret->iv = 0; \
ret->ep = *p;
#define check_eof() \
if (i >= n) { \
*p = n; \
ret->vt = -ERR_EOF; \
return; \
}
#define check_sign(on_neg) \
if (s[i] == '-') { \
i++; \
on_neg; \
check_eof() \
}
#define check_digit() \
if (s[i] < '0' || s[i] > '9') { \
*p = i; \
ret->vt = -ERR_INVAL; \
return; \
}
#define check_leading_zero() \
if (s[i] == '0' && (i >= n || (s[i + 1] != '.' && s[i + 1] != 'e' && s[i + 1] != 'E'))) { \
*p = ++i; \
return; \
}
#define parse_sign(sgn) \
if (s[i] == '+' || s[i] == '-') { \
sgn = s[i++] == '+' ? 1 : -1; \
check_eof() \
}
#define is_digit(val) \
'0' <= val && val <= '9'
#define add_integer_to_mantissa(man, man_nd, exp10, dig) \
if (man_nd < 19) { \
man = man * 10 + dig; \
man_nd++; \
} else { \
exp10++; \
}
#define add_float_to_mantissa(man, man_nd, exp10, dig) \
man = man * 10 + dig; \
man_nd++; \
exp10--;
#define parse_float_digits(val, sgn, ...) \
while (i < n && s[i] >= '0' && s[i] <= '9' __VA_ARGS__) { \
val *= 10; \
val += sgn * (s[i++] - '0'); \
}
#define parse_integer_digits(val, sgn, ovf) \
while (i < n && s[i] >= '0' && s[i] <= '9') { \
if (add_digit_overflow(val, sgn * (s[i++] - '0'))) { \
ovf = 1; \
break; \
} \
}
#define add_digit_overflow(val, chr) ( \
__builtin_mul_overflow(val, 10, &val) || \
__builtin_add_overflow(val, chr, &val) \
)
#define vinteger(type, sgn, on_neg) \
int ovf = 0; \
type val = 0; \
\
/* initial buffer pointers */ \
long i = *p; \
size_t n = src->len; \
const char * s = src->buf; \
\
/* initialize the result, and check for '-' */ \
init_ret(V_INTEGER) \
check_eof() \
check_sign(on_neg) \
\
/* check for leading zero or any digits */ \
check_digit() \
check_leading_zero() \
parse_integer_digits(val, sgn, ovf) \
\
/* check for overflow */ \
if (ovf) { \
*p = i - 1; \
ret->vt = -ERR_OVERFLOW; \
return; \
} \
\
/* check for the decimal part */ \
if (i < n && s[i] == '.') { \
*p = i; \
ret->vt = -ERR_NUMBER_FMT; \
return; \
} \
\
/* check for the exponent part */ \
if (i < n && (s[i] == 'e' || s[i] == 'E')) { \
*p = i; \
ret->vt = -ERR_NUMBER_FMT; \
return; \
} \
\
/* update the result */ \
*p = i; \
ret->iv = val;
/** check whether float can represent the val exactly **/
static inline bool is_atof_exact(uint64_t man, int exp, int sgn, double *val) {
*val = (double)man;
if (man >> 52 != 0) {
return false;
}
/* equal to if (sgn == -1) { *val *= -1; } */
*(uint64_t *)val |= ((uint64_t)(sgn) >> 63 << 63);
if (exp == 0 || man == 0) {
return true;
} else if (exp > 0 && exp <= 15+22) {
/* uint64 integers: accurate range <= 10^15 *
* Powers of 10: accurate range <= 10^22, as P10_TAB *
* Example: man 1, exp 36, is ok */
if (exp > 22) {
*val *= P10_TAB[exp-22];
exp = 22;
}
/* f is not accurate when too larger */
if (*val > 1e15 || *val < -1e15) {
return false;
}
*val *= P10_TAB[exp];
return true;
} else if (exp < 0 && exp >= -22) {
*val /= P10_TAB[-exp];
return true;
}
return false;
}
static inline double atof_fast(uint64_t man, int exp, int sgn, int trunc, double *val) {
double val_up = 0.0;
/* look-up for fast atof if the conversion can be exactly */
if (is_atof_exact(man, exp, sgn, val)) {
return true;
}
/* A fast atof algorithm for high percison */
if (atof_eisel_lemire64(man, exp, sgn, val)) {
if (!trunc || (atof_eisel_lemire64(man+1, exp, sgn, &val_up) && val_up == *val)) {
return true;
}
}
return false;
}
static bool inline is_overflow(uint64_t man, int sgn, int exp10) {
/* the former exp10 != 0 means man has overflowed
* the later euqals to man*sgn < INT64_MIN or > INT64_MAX */
return exp10 != 0 ||
((man >> 63) == 1 && ((uint64_t)sgn & man) != (1ull << 63));
}
void vnumber(const GoString *src, long *p, JsonState *ret) {
int sgn = 1;
uint64_t man = 0; // mantissa for double (float64)
int man_nd = 0; // # digits of mantissa, 10 ^ 19 fits uint64_t
int exp10 = 0; // val = sgn * man * 10 ^ exp10
int trunc = 0;
double val = 0;
/* initial buffer pointers */
long i = *p;
size_t n = src->len;
const char * s = src->buf;
char *dbuf = ret->dbuf;
ssize_t dcap = ret->dcap;
/* initialize the result, and check for EOF */
init_ret(V_INTEGER)
check_eof()
check_sign(sgn = -1)
/* check for leading zero */
check_digit()
check_leading_zero()
/* parse the integer part */
while (i < n && is_digit(s[i])) {
add_integer_to_mantissa(man, man_nd, exp10, (s[i] - '0'))
i++;
}
if (exp10 > 0) {
trunc = 1;
}
/* check for decimal points */
if (i < n && s[i] == '.') {
i++;
set_vt(V_DOUBLE)
check_eof()
check_digit()
}
/* skip the leading zeros of 0.000xxxx */
if (man == 0 && exp10 == 0) {
while (i < n && s[i] == '0') {
i++;
exp10--;
}
man = 0;
man_nd = 0;
}
/* the fractional part (uint64_t mantissa can represent at most 19 digits) */
while (i < n && man_nd < 19 && is_digit(s[i])) {
add_float_to_mantissa(man, man_nd, exp10, (s[i] - '0'))
i++;
}
/* skip the remaining digits */
while (i < n && is_digit(s[i])) {
trunc = 1;
i++;
}
/* check for exponent */
if (i < n && (s[i] == 'e' || s[i] == 'E')) {
int esm = 1;
int exp = 0;
/* check for the '+' or '-' sign, and parse the power */
i++;
set_vt(V_DOUBLE)
check_eof()
parse_sign(esm)
check_digit()
while (i < n && is_digit(s[i])) {
if (exp < 10000) {
exp = exp * 10 + (s[i] - '0');
}
i++;
}
exp10 += exp * esm;
goto parse_float;
}
if (ret->vt == V_INTEGER) {
if (!is_overflow(man, sgn, exp10)) {
ret->iv = (int64_t)man * sgn;
/* following lines equal to ret->dv = (double)(man) * sgn */
ret->dv = (double)(man);
*(uint64_t *)&ret->dv |= ((uint64_t)(sgn) >> 63 << 63);
*p = i;
return;
}
set_vt(V_DOUBLE)
}
parse_float:
/* when fast algorithms failed, use slow fallback.*/
if(!atof_fast(man, exp10, sgn, trunc, &val)) {
val = atof_native(s + *p, i - *p, dbuf, dcap);
}
/* check parsed double val */
if (is_infinity(val)) {
ret->vt = -ERR_FLOAT_INF;
}
/* update the result */
ret->dv = val;
*p = i;
}
void vsigned(const GoString *src, long *p, JsonState *ret) {
int64_t sgn = 1;
vinteger(int64_t, sgn, sgn = -1)
}
void vunsigned(const GoString *src, long *p, JsonState *ret) {
vinteger(uint64_t, 1, {
*p = i - 1;
ret->vt = -ERR_NUMBER_FMT;
return;
})
}
#undef init_ret
#undef check_eof
#undef check_digit
#undef check_leading_zero
#undef parse_sign
#undef is_digit
#undef add_integer_to_mantissa
#undef add_float_to_mantissa
#undef parse_float_digits
#undef parse_integer_digits
#undef add_digit_overflow
#undef vinteger
/** Value Skipping FSM **/
#define FSM_VAL 0
#define FSM_ARR 1
#define FSM_OBJ 2
#define FSM_KEY 3
#define FSM_ELEM 4
#define FSM_ARR_0 5
#define FSM_OBJ_0 6
#define FSM_DROP(v) (v)->sp--
#define FSM_REPL(v, t) (v)->vt[(v)->sp - 1] = (t)
#define FSM_CHAR(c) do { if (ch != (c)) return -ERR_INVAL; } while (0)
#define FSM_XERR(v) do { long r = (v); if (r < 0) return r; } while (0)
static inline void fsm_init(StateMachine *self, int vt) {
self->sp = 1;
self->vt[0] = vt;
}
static inline long fsm_push(StateMachine *self, int vt) {
if (self->sp >= MAX_RECURSE) {
return -ERR_RECURSE_MAX;
} else {
self->vt[self->sp++] = vt;
return 0;
}
}
static inline long fsm_exec(StateMachine *self, const GoString *src, long *p) {
int vt;
char ch;
long vi = -1;
/* run until no more nested values */
while (self->sp) {
ch = advance_ns(src, p);
vt = self->vt[self->sp - 1];
/* set the start address if any */
if (vi == -1) {
vi = *p - 1;
}
/* check for special types */
switch (vt) {
default: {
FSM_DROP(self);
break;
}
/* arrays */
case FSM_ARR: {
switch (ch) {
case ']' : FSM_DROP(self); continue;
case ',' : FSM_XERR(fsm_push(self, FSM_VAL)); continue;
default : return -ERR_INVAL;
}
}
/* objects */
case FSM_OBJ: {
switch (ch) {
case '}' : FSM_DROP(self); continue;
case ',' : FSM_XERR(fsm_push(self, FSM_KEY)); continue;
default : return -ERR_INVAL;
}
}
/* object keys */
case FSM_KEY: {
FSM_CHAR('"');
FSM_REPL(self, FSM_ELEM);
FSM_XERR(skip_string(src, p));
continue;
}
/* object element */
case FSM_ELEM: {
FSM_CHAR(':');
FSM_REPL(self, FSM_VAL);
continue;
}
/* arrays, first element */
case FSM_ARR_0: {
if (ch == ']') {
FSM_DROP(self);
continue;
} else {
FSM_REPL(self, FSM_ARR);
break;
}
}
/* objects, first pair */
case FSM_OBJ_0: {
switch (ch) {
default: {
return -ERR_INVAL;
}
/* empty object */
case '}': {
FSM_DROP(self);
continue;
}
/* the quote of the first key */
case '"': {
FSM_REPL(self, FSM_OBJ);
FSM_XERR(skip_string(src, p));
FSM_XERR(fsm_push(self, FSM_ELEM));
continue;
}
}
}
}
/* simple values */
switch (ch) {
case '0' : /* fallthrough */
case '1' : /* fallthrough */
case '2' : /* fallthrough */
case '3' : /* fallthrough */
case '4' : /* fallthrough */
case '5' : /* fallthrough */
case '6' : /* fallthrough */
case '7' : /* fallthrough */
case '8' : /* fallthrough */
case '9' : FSM_XERR(skip_positive(src, p)); break;
case '-' : FSM_XERR(skip_negative(src, p)); break;
case 'n' : FSM_XERR(advance_dword(src, p, 1, *p - 1, VS_NULL)); break;
case 't' : FSM_XERR(advance_dword(src, p, 1, *p - 1, VS_TRUE)); break;
case 'f' : FSM_XERR(advance_dword(src, p, 0, *p - 1, VS_ALSE)); break;
case '"' : FSM_XERR(skip_string(src, p)); break;
case '[' : FSM_XERR(fsm_push(self, FSM_ARR_0)); break;
case '{' : FSM_XERR(fsm_push(self, FSM_OBJ_0)); break;
case 0 : return -ERR_EOF;
default : return -ERR_INVAL;
}
}
/* all done */
return vi;
}
#undef FSM_DROP
#undef FSM_REPL
#undef FSM_CHAR
#undef FSM_XERR
#define check_bits(mv) \
if (unlikely((v = mv & (mv - 1)) != 0)) { \
return -(sp - ss + __builtin_ctz(v) + 1); \
}
#define check_sidx(iv) \
if (likely(iv == -1)) { \
iv = sp - ss - 1; \
} else { \
return -(sp - ss); \
}
#define check_vidx(iv, mv) \
if (mv != 0) { \
if (likely(iv == -1)) { \
iv = sp - ss + __builtin_ctz(mv); \
} else { \
return -(sp - ss + __builtin_ctz(mv) + 1); \
} \
}
static inline long skip_number(const char *sp, size_t nb) {
long di = -1;
long ei = -1;
long si = -1;
const char * ss = sp;
/* check for EOF */
if (nb == 0) {
return -1;
}
/* special case of '0' */
if (*sp == '0' && (nb == 1 || (sp[1] != '.' && sp[1] != 'e' && sp[1] != 'E'))) {
return 1;
}
#if USE_AVX2
/* can do with AVX-2 */
if (likely(nb >= 32)) {
__m256i d9 = _mm256_set1_epi8('9');
__m256i ds = _mm256_set1_epi8('/');
__m256i dp = _mm256_set1_epi8('.');
__m256i el = _mm256_set1_epi8('e');
__m256i eu = _mm256_set1_epi8('E');
__m256i xp = _mm256_set1_epi8('+');
__m256i xm = _mm256_set1_epi8('-');
/* 32-byte loop */
do {
__m256i sb = _mm256_loadu_si256 ((const void *)sp);
__m256i i0 = _mm256_cmpgt_epi8 (sb, ds);
__m256i i9 = _mm256_cmpgt_epi8 (sb, d9);
__m256i id = _mm256_cmpeq_epi8 (sb, dp);
__m256i il = _mm256_cmpeq_epi8 (sb, el);
__m256i iu = _mm256_cmpeq_epi8 (sb, eu);
__m256i ip = _mm256_cmpeq_epi8 (sb, xp);
__m256i im = _mm256_cmpeq_epi8 (sb, xm);
__m256i iv = _mm256_andnot_si256 (i9, i0);
__m256i ie = _mm256_or_si256 (il, iu);
__m256i is = _mm256_or_si256 (ip, im);
__m256i rt = _mm256_or_si256 (iv, id);
__m256i ru = _mm256_or_si256 (ie, is);
__m256i rv = _mm256_or_si256 (rt, ru);
/* exponent and sign position */
uint32_t md = _mm256_movemask_epi8(id);
uint32_t me = _mm256_movemask_epi8(ie);
uint32_t ms = _mm256_movemask_epi8(is);
uint32_t mr = _mm256_movemask_epi8(rv);
/* mismatch position */
uint32_t v;
uint32_t i = __builtin_ctzll(~(uint64_t)mr | 0x0100000000);
/* mask out excess characters */
if (i != 32) {
md &= (1 << i) - 1;
me &= (1 << i) - 1;
ms &= (1 << i) - 1;
}
/* check & update decimal point, exponent and sign index */
check_bits(md)
check_bits(me)
check_bits(ms)
check_vidx(di, md)
check_vidx(ei, me)
check_vidx(si, ms)
/* check for valid number */
if (i != 32) {
sp += i;
_mm256_zeroupper();
goto check_index;
}
/* move to next block */
sp += 32;
nb -= 32;
} while (nb >= 32);
/* clear the upper half to prevent AVX-SSE transition penalty */
_mm256_zeroupper();
}
#endif
/* can do with SSE */
if (likely(nb >= 16)) {
__m128i dc = _mm_set1_epi8(':');
__m128i ds = _mm_set1_epi8('/');
__m128i dp = _mm_set1_epi8('.');
__m128i el = _mm_set1_epi8('e');
__m128i eu = _mm_set1_epi8('E');
__m128i xp = _mm_set1_epi8('+');
__m128i xm = _mm_set1_epi8('-');
/* 16-byte loop */
do {
__m128i sb = _mm_loadu_si128 ((const void *)sp);
__m128i i0 = _mm_cmpgt_epi8 (sb, ds);
__m128i i9 = _mm_cmplt_epi8 (sb, dc);
__m128i id = _mm_cmpeq_epi8 (sb, dp);
__m128i il = _mm_cmpeq_epi8 (sb, el);
__m128i iu = _mm_cmpeq_epi8 (sb, eu);
__m128i ip = _mm_cmpeq_epi8 (sb, xp);
__m128i im = _mm_cmpeq_epi8 (sb, xm);
__m128i iv = _mm_and_si128 (i9, i0);
__m128i ie = _mm_or_si128 (il, iu);
__m128i is = _mm_or_si128 (ip, im);
__m128i rt = _mm_or_si128 (iv, id);
__m128i ru = _mm_or_si128 (ie, is);
__m128i rv = _mm_or_si128 (rt, ru);
/* exponent and sign position */
uint32_t md = _mm_movemask_epi8(id);
uint32_t me = _mm_movemask_epi8(ie);
uint32_t ms = _mm_movemask_epi8(is);
uint32_t mr = _mm_movemask_epi8(rv);
/* mismatch position */
uint32_t v;
uint32_t i = __builtin_ctzll(~mr | 0x00010000);
/* mask out excess characters */
if (i != 16) {
md &= (1 << i) - 1;
me &= (1 << i) - 1;
ms &= (1 << i) - 1;
}
/* check & update exponent and sign index */
check_bits(md)
check_bits(me)
check_bits(ms)
check_vidx(di, md)
check_vidx(ei, me)
check_vidx(si, ms)
/* check for valid number */
if (i != 16) {
sp += i;
goto check_index;
}
/* move to next block */
sp += 16;
nb -= 16;
} while (nb >= 16);
}
/* remaining bytes, do with scalar code */
while (likely(--nb >= 0)) {
switch (*sp++) {
case '0' : /* fallthrough */
case '1' : /* fallthrough */
case '2' : /* fallthrough */
case '3' : /* fallthrough */
case '4' : /* fallthrough */
case '5' : /* fallthrough */
case '6' : /* fallthrough */
case '7' : /* fallthrough */
case '8' : /* fallthrough */
case '9' : break;
case '.' : check_sidx(di); break;
case 'e' : /* fallthrough */
case 'E' : check_sidx(ei); break;
case '+' : /* fallthrough */
case '-' : check_sidx(si); break;
default : sp--; goto check_index;
}
}
check_index:
if (di == 0 || si == 0) {
return -1;
} else if (si > 0 && ei != si - 1) {
return -si - 1;
} else if (di >= 0 && ei >= 0 && di > ei - 1) {
return -di - 1;
} else if (di >= 0 && ei >= 0 && di == ei - 1) {
return -ei - 1;
} else {
return sp - ss;
}
}
#undef check_bits
#undef check_sidx
#undef check_vidx
long skip_one(const GoString *src, long *p, StateMachine *m) {
fsm_init(m, FSM_VAL);
return fsm_exec(m, src, p);
}
long skip_array(const GoString *src, long *p, StateMachine *m) {
fsm_init(m, FSM_ARR_0);
return fsm_exec(m, src, p);
}
long skip_object(const GoString *src, long *p, StateMachine *m) {
fsm_init(m, FSM_OBJ_0);
return fsm_exec(m, src, p);
}
long skip_string(const GoString *src, long *p) {
int64_t v;
ssize_t q = *p - 1;
ssize_t e = advance_string(src, *p, &v);
/* check for errors, and update the position */
if (e >= 0) {
*p = e;
return q;
} else {
*p = src->len;
return e;
}
}
long skip_negative(const GoString *src, long *p) {
long i = *p;
long r = skip_number(src->buf + i, src->len - i);
/* check for errors */
if (r < 0) {
*p -= r + 1;
return -ERR_INVAL;
}
/* update value pointer */
*p += r;
return i - 1;
}
long skip_positive(const GoString *src, long *p) {
long i = *p - 1;
long r = skip_number(src->buf + i, src->len - i);
/* check for errors */
if (r < 0) {
*p -= r + 2;
return -ERR_INVAL;
}
/* update value pointer */
*p += r - 1;
return i;
}
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