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author | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
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committer | Matthew Heon <matthew.heon@gmail.com> | 2017-11-01 11:24:59 -0400 |
commit | a031b83a09a8628435317a03f199cdc18b78262f (patch) | |
tree | bc017a96769ce6de33745b8b0b1304ccf38e9df0 /vendor/github.com/pquerna/ffjson/fflib/v1/internal | |
parent | 2b74391cd5281f6fdf391ff8ad50fd1490f6bf89 (diff) | |
download | podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.gz podman-a031b83a09a8628435317a03f199cdc18b78262f.tar.bz2 podman-a031b83a09a8628435317a03f199cdc18b78262f.zip |
Initial checkin from CRI-O repo
Signed-off-by: Matthew Heon <matthew.heon@gmail.com>
Diffstat (limited to 'vendor/github.com/pquerna/ffjson/fflib/v1/internal')
4 files changed, 2292 insertions, 0 deletions
diff --git a/vendor/github.com/pquerna/ffjson/fflib/v1/internal/atof.go b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/atof.go new file mode 100644 index 000000000..46c1289ec --- /dev/null +++ b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/atof.go @@ -0,0 +1,936 @@ +/** + * Copyright 2014 Paul Querna + * + * 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. + * + */ + +/* Portions of this file are on Go stdlib's strconv/atof.go */ + +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package internal + +// decimal to binary floating point conversion. +// Algorithm: +// 1) Store input in multiprecision decimal. +// 2) Multiply/divide decimal by powers of two until in range [0.5, 1) +// 3) Multiply by 2^precision and round to get mantissa. + +import "math" + +var optimize = true // can change for testing + +func equalIgnoreCase(s1 []byte, s2 []byte) bool { + if len(s1) != len(s2) { + return false + } + for i := 0; i < len(s1); i++ { + c1 := s1[i] + if 'A' <= c1 && c1 <= 'Z' { + c1 += 'a' - 'A' + } + c2 := s2[i] + if 'A' <= c2 && c2 <= 'Z' { + c2 += 'a' - 'A' + } + if c1 != c2 { + return false + } + } + return true +} + +func special(s []byte) (f float64, ok bool) { + if len(s) == 0 { + return + } + switch s[0] { + default: + return + case '+': + if equalIgnoreCase(s, []byte("+inf")) || equalIgnoreCase(s, []byte("+infinity")) { + return math.Inf(1), true + } + case '-': + if equalIgnoreCase(s, []byte("-inf")) || equalIgnoreCase(s, []byte("-infinity")) { + return math.Inf(-1), true + } + case 'n', 'N': + if equalIgnoreCase(s, []byte("nan")) { + return math.NaN(), true + } + case 'i', 'I': + if equalIgnoreCase(s, []byte("inf")) || equalIgnoreCase(s, []byte("infinity")) { + return math.Inf(1), true + } + } + return +} + +func (b *decimal) set(s []byte) (ok bool) { + i := 0 + b.neg = false + b.trunc = false + + // optional sign + if i >= len(s) { + return + } + switch { + case s[i] == '+': + i++ + case s[i] == '-': + b.neg = true + i++ + } + + // digits + sawdot := false + sawdigits := false + for ; i < len(s); i++ { + switch { + case s[i] == '.': + if sawdot { + return + } + sawdot = true + b.dp = b.nd + continue + + case '0' <= s[i] && s[i] <= '9': + sawdigits = true + if s[i] == '0' && b.nd == 0 { // ignore leading zeros + b.dp-- + continue + } + if b.nd < len(b.d) { + b.d[b.nd] = s[i] + b.nd++ + } else if s[i] != '0' { + b.trunc = true + } + continue + } + break + } + if !sawdigits { + return + } + if !sawdot { + b.dp = b.nd + } + + // optional exponent moves decimal point. + // if we read a very large, very long number, + // just be sure to move the decimal point by + // a lot (say, 100000). it doesn't matter if it's + // not the exact number. + if i < len(s) && (s[i] == 'e' || s[i] == 'E') { + i++ + if i >= len(s) { + return + } + esign := 1 + if s[i] == '+' { + i++ + } else if s[i] == '-' { + i++ + esign = -1 + } + if i >= len(s) || s[i] < '0' || s[i] > '9' { + return + } + e := 0 + for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ { + if e < 10000 { + e = e*10 + int(s[i]) - '0' + } + } + b.dp += e * esign + } + + if i != len(s) { + return + } + + ok = true + return +} + +// readFloat reads a decimal mantissa and exponent from a float +// string representation. It sets ok to false if the number could +// not fit return types or is invalid. +func readFloat(s []byte) (mantissa uint64, exp int, neg, trunc, ok bool) { + const uint64digits = 19 + i := 0 + + // optional sign + if i >= len(s) { + return + } + switch { + case s[i] == '+': + i++ + case s[i] == '-': + neg = true + i++ + } + + // digits + sawdot := false + sawdigits := false + nd := 0 + ndMant := 0 + dp := 0 + for ; i < len(s); i++ { + switch c := s[i]; true { + case c == '.': + if sawdot { + return + } + sawdot = true + dp = nd + continue + + case '0' <= c && c <= '9': + sawdigits = true + if c == '0' && nd == 0 { // ignore leading zeros + dp-- + continue + } + nd++ + if ndMant < uint64digits { + mantissa *= 10 + mantissa += uint64(c - '0') + ndMant++ + } else if s[i] != '0' { + trunc = true + } + continue + } + break + } + if !sawdigits { + return + } + if !sawdot { + dp = nd + } + + // optional exponent moves decimal point. + // if we read a very large, very long number, + // just be sure to move the decimal point by + // a lot (say, 100000). it doesn't matter if it's + // not the exact number. + if i < len(s) && (s[i] == 'e' || s[i] == 'E') { + i++ + if i >= len(s) { + return + } + esign := 1 + if s[i] == '+' { + i++ + } else if s[i] == '-' { + i++ + esign = -1 + } + if i >= len(s) || s[i] < '0' || s[i] > '9' { + return + } + e := 0 + for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ { + if e < 10000 { + e = e*10 + int(s[i]) - '0' + } + } + dp += e * esign + } + + if i != len(s) { + return + } + + exp = dp - ndMant + ok = true + return + +} + +// decimal power of ten to binary power of two. +var powtab = []int{1, 3, 6, 9, 13, 16, 19, 23, 26} + +func (d *decimal) floatBits(flt *floatInfo) (b uint64, overflow bool) { + var exp int + var mant uint64 + + // Zero is always a special case. + if d.nd == 0 { + mant = 0 + exp = flt.bias + goto out + } + + // Obvious overflow/underflow. + // These bounds are for 64-bit floats. + // Will have to change if we want to support 80-bit floats in the future. + if d.dp > 310 { + goto overflow + } + if d.dp < -330 { + // zero + mant = 0 + exp = flt.bias + goto out + } + + // Scale by powers of two until in range [0.5, 1.0) + exp = 0 + for d.dp > 0 { + var n int + if d.dp >= len(powtab) { + n = 27 + } else { + n = powtab[d.dp] + } + d.Shift(-n) + exp += n + } + for d.dp < 0 || d.dp == 0 && d.d[0] < '5' { + var n int + if -d.dp >= len(powtab) { + n = 27 + } else { + n = powtab[-d.dp] + } + d.Shift(n) + exp -= n + } + + // Our range is [0.5,1) but floating point range is [1,2). + exp-- + + // Minimum representable exponent is flt.bias+1. + // If the exponent is smaller, move it up and + // adjust d accordingly. + if exp < flt.bias+1 { + n := flt.bias + 1 - exp + d.Shift(-n) + exp += n + } + + if exp-flt.bias >= 1<<flt.expbits-1 { + goto overflow + } + + // Extract 1+flt.mantbits bits. + d.Shift(int(1 + flt.mantbits)) + mant = d.RoundedInteger() + + // Rounding might have added a bit; shift down. + if mant == 2<<flt.mantbits { + mant >>= 1 + exp++ + if exp-flt.bias >= 1<<flt.expbits-1 { + goto overflow + } + } + + // Denormalized? + if mant&(1<<flt.mantbits) == 0 { + exp = flt.bias + } + goto out + +overflow: + // ±Inf + mant = 0 + exp = 1<<flt.expbits - 1 + flt.bias + overflow = true + +out: + // Assemble bits. + bits := mant & (uint64(1)<<flt.mantbits - 1) + bits |= uint64((exp-flt.bias)&(1<<flt.expbits-1)) << flt.mantbits + if d.neg { + bits |= 1 << flt.mantbits << flt.expbits + } + return bits, overflow +} + +// Exact powers of 10. +var float64pow10 = []float64{ + 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, + 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, + 1e20, 1e21, 1e22, +} +var float32pow10 = []float32{1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10} + +// If possible to convert decimal representation to 64-bit float f exactly, +// entirely in floating-point math, do so, avoiding the expense of decimalToFloatBits. +// Three common cases: +// value is exact integer +// value is exact integer * exact power of ten +// value is exact integer / exact power of ten +// These all produce potentially inexact but correctly rounded answers. +func atof64exact(mantissa uint64, exp int, neg bool) (f float64, ok bool) { + if mantissa>>float64info.mantbits != 0 { + return + } + f = float64(mantissa) + if neg { + f = -f + } + switch { + case exp == 0: + // an integer. + return f, true + // Exact integers are <= 10^15. + // Exact powers of ten are <= 10^22. + case exp > 0 && exp <= 15+22: // int * 10^k + // If exponent is big but number of digits is not, + // can move a few zeros into the integer part. + if exp > 22 { + f *= float64pow10[exp-22] + exp = 22 + } + if f > 1e15 || f < -1e15 { + // the exponent was really too large. + return + } + return f * float64pow10[exp], true + case exp < 0 && exp >= -22: // int / 10^k + return f / float64pow10[-exp], true + } + return +} + +// If possible to compute mantissa*10^exp to 32-bit float f exactly, +// entirely in floating-point math, do so, avoiding the machinery above. +func atof32exact(mantissa uint64, exp int, neg bool) (f float32, ok bool) { + if mantissa>>float32info.mantbits != 0 { + return + } + f = float32(mantissa) + if neg { + f = -f + } + switch { + case exp == 0: + return f, true + // Exact integers are <= 10^7. + // Exact powers of ten are <= 10^10. + case exp > 0 && exp <= 7+10: // int * 10^k + // If exponent is big but number of digits is not, + // can move a few zeros into the integer part. + if exp > 10 { + f *= float32pow10[exp-10] + exp = 10 + } + if f > 1e7 || f < -1e7 { + // the exponent was really too large. + return + } + return f * float32pow10[exp], true + case exp < 0 && exp >= -10: // int / 10^k + return f / float32pow10[-exp], true + } + return +} + +const fnParseFloat = "ParseFloat" + +func atof32(s []byte) (f float32, err error) { + if val, ok := special(s); ok { + return float32(val), nil + } + + if optimize { + // Parse mantissa and exponent. + mantissa, exp, neg, trunc, ok := readFloat(s) + if ok { + // Try pure floating-point arithmetic conversion. + if !trunc { + if f, ok := atof32exact(mantissa, exp, neg); ok { + return f, nil + } + } + // Try another fast path. + ext := new(extFloat) + if ok := ext.AssignDecimal(mantissa, exp, neg, trunc, &float32info); ok { + b, ovf := ext.floatBits(&float32info) + f = math.Float32frombits(uint32(b)) + if ovf { + err = rangeError(fnParseFloat, string(s)) + } + return f, err + } + } + } + var d decimal + if !d.set(s) { + return 0, syntaxError(fnParseFloat, string(s)) + } + b, ovf := d.floatBits(&float32info) + f = math.Float32frombits(uint32(b)) + if ovf { + err = rangeError(fnParseFloat, string(s)) + } + return f, err +} + +func atof64(s []byte) (f float64, err error) { + if val, ok := special(s); ok { + return val, nil + } + + if optimize { + // Parse mantissa and exponent. + mantissa, exp, neg, trunc, ok := readFloat(s) + if ok { + // Try pure floating-point arithmetic conversion. + if !trunc { + if f, ok := atof64exact(mantissa, exp, neg); ok { + return f, nil + } + } + // Try another fast path. + ext := new(extFloat) + if ok := ext.AssignDecimal(mantissa, exp, neg, trunc, &float64info); ok { + b, ovf := ext.floatBits(&float64info) + f = math.Float64frombits(b) + if ovf { + err = rangeError(fnParseFloat, string(s)) + } + return f, err + } + } + } + var d decimal + if !d.set(s) { + return 0, syntaxError(fnParseFloat, string(s)) + } + b, ovf := d.floatBits(&float64info) + f = math.Float64frombits(b) + if ovf { + err = rangeError(fnParseFloat, string(s)) + } + return f, err +} + +// ParseFloat converts the string s to a floating-point number +// with the precision specified by bitSize: 32 for float32, or 64 for float64. +// When bitSize=32, the result still has type float64, but it will be +// convertible to float32 without changing its value. +// +// If s is well-formed and near a valid floating point number, +// ParseFloat returns the nearest floating point number rounded +// using IEEE754 unbiased rounding. +// +// The errors that ParseFloat returns have concrete type *NumError +// and include err.Num = s. +// +// If s is not syntactically well-formed, ParseFloat returns err.Err = ErrSyntax. +// +// If s is syntactically well-formed but is more than 1/2 ULP +// away from the largest floating point number of the given size, +// ParseFloat returns f = ±Inf, err.Err = ErrRange. +func ParseFloat(s []byte, bitSize int) (f float64, err error) { + if bitSize == 32 { + f1, err1 := atof32(s) + return float64(f1), err1 + } + f1, err1 := atof64(s) + return f1, err1 +} + +// oroginal: strconv/decimal.go, but not exported, and needed for PareFloat. + +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Multiprecision decimal numbers. +// For floating-point formatting only; not general purpose. +// Only operations are assign and (binary) left/right shift. +// Can do binary floating point in multiprecision decimal precisely +// because 2 divides 10; cannot do decimal floating point +// in multiprecision binary precisely. + +type decimal struct { + d [800]byte // digits + nd int // number of digits used + dp int // decimal point + neg bool + trunc bool // discarded nonzero digits beyond d[:nd] +} + +func (a *decimal) String() string { + n := 10 + a.nd + if a.dp > 0 { + n += a.dp + } + if a.dp < 0 { + n += -a.dp + } + + buf := make([]byte, n) + w := 0 + switch { + case a.nd == 0: + return "0" + + case a.dp <= 0: + // zeros fill space between decimal point and digits + buf[w] = '0' + w++ + buf[w] = '.' + w++ + w += digitZero(buf[w : w+-a.dp]) + w += copy(buf[w:], a.d[0:a.nd]) + + case a.dp < a.nd: + // decimal point in middle of digits + w += copy(buf[w:], a.d[0:a.dp]) + buf[w] = '.' + w++ + w += copy(buf[w:], a.d[a.dp:a.nd]) + + default: + // zeros fill space between digits and decimal point + w += copy(buf[w:], a.d[0:a.nd]) + w += digitZero(buf[w : w+a.dp-a.nd]) + } + return string(buf[0:w]) +} + +func digitZero(dst []byte) int { + for i := range dst { + dst[i] = '0' + } + return len(dst) +} + +// trim trailing zeros from number. +// (They are meaningless; the decimal point is tracked +// independent of the number of digits.) +func trim(a *decimal) { + for a.nd > 0 && a.d[a.nd-1] == '0' { + a.nd-- + } + if a.nd == 0 { + a.dp = 0 + } +} + +// Assign v to a. +func (a *decimal) Assign(v uint64) { + var buf [24]byte + + // Write reversed decimal in buf. + n := 0 + for v > 0 { + v1 := v / 10 + v -= 10 * v1 + buf[n] = byte(v + '0') + n++ + v = v1 + } + + // Reverse again to produce forward decimal in a.d. + a.nd = 0 + for n--; n >= 0; n-- { + a.d[a.nd] = buf[n] + a.nd++ + } + a.dp = a.nd + trim(a) +} + +// Maximum shift that we can do in one pass without overflow. +// Signed int has 31 bits, and we have to be able to accommodate 9<<k. +const maxShift = 27 + +// Binary shift right (* 2) by k bits. k <= maxShift to avoid overflow. +func rightShift(a *decimal, k uint) { + r := 0 // read pointer + w := 0 // write pointer + + // Pick up enough leading digits to cover first shift. + n := 0 + for ; n>>k == 0; r++ { + if r >= a.nd { + if n == 0 { + // a == 0; shouldn't get here, but handle anyway. + a.nd = 0 + return + } + for n>>k == 0 { + n = n * 10 + r++ + } + break + } + c := int(a.d[r]) + n = n*10 + c - '0' + } + a.dp -= r - 1 + + // Pick up a digit, put down a digit. + for ; r < a.nd; r++ { + c := int(a.d[r]) + dig := n >> k + n -= dig << k + a.d[w] = byte(dig + '0') + w++ + n = n*10 + c - '0' + } + + // Put down extra digits. + for n > 0 { + dig := n >> k + n -= dig << k + if w < len(a.d) { + a.d[w] = byte(dig + '0') + w++ + } else if dig > 0 { + a.trunc = true + } + n = n * 10 + } + + a.nd = w + trim(a) +} + +// Cheat sheet for left shift: table indexed by shift count giving +// number of new digits that will be introduced by that shift. +// +// For example, leftcheats[4] = {2, "625"}. That means that +// if we are shifting by 4 (multiplying by 16), it will add 2 digits +// when the string prefix is "625" through "999", and one fewer digit +// if the string prefix is "000" through "624". +// +// Credit for this trick goes to Ken. + +type leftCheat struct { + delta int // number of new digits + cutoff string // minus one digit if original < a. +} + +var leftcheats = []leftCheat{ + // Leading digits of 1/2^i = 5^i. + // 5^23 is not an exact 64-bit floating point number, + // so have to use bc for the math. + /* + seq 27 | sed 's/^/5^/' | bc | + awk 'BEGIN{ print "\tleftCheat{ 0, \"\" }," } + { + log2 = log(2)/log(10) + printf("\tleftCheat{ %d, \"%s\" },\t// * %d\n", + int(log2*NR+1), $0, 2**NR) + }' + */ + {0, ""}, + {1, "5"}, // * 2 + {1, "25"}, // * 4 + {1, "125"}, // * 8 + {2, "625"}, // * 16 + {2, "3125"}, // * 32 + {2, "15625"}, // * 64 + {3, "78125"}, // * 128 + {3, "390625"}, // * 256 + {3, "1953125"}, // * 512 + {4, "9765625"}, // * 1024 + {4, "48828125"}, // * 2048 + {4, "244140625"}, // * 4096 + {4, "1220703125"}, // * 8192 + {5, "6103515625"}, // * 16384 + {5, "30517578125"}, // * 32768 + {5, "152587890625"}, // * 65536 + {6, "762939453125"}, // * 131072 + {6, "3814697265625"}, // * 262144 + {6, "19073486328125"}, // * 524288 + {7, "95367431640625"}, // * 1048576 + {7, "476837158203125"}, // * 2097152 + {7, "2384185791015625"}, // * 4194304 + {7, "11920928955078125"}, // * 8388608 + {8, "59604644775390625"}, // * 16777216 + {8, "298023223876953125"}, // * 33554432 + {8, "1490116119384765625"}, // * 67108864 + {9, "7450580596923828125"}, // * 134217728 +} + +// Is the leading prefix of b lexicographically less than s? +func prefixIsLessThan(b []byte, s string) bool { + for i := 0; i < len(s); i++ { + if i >= len(b) { + return true + } + if b[i] != s[i] { + return b[i] < s[i] + } + } + return false +} + +// Binary shift left (/ 2) by k bits. k <= maxShift to avoid overflow. +func leftShift(a *decimal, k uint) { + delta := leftcheats[k].delta + if prefixIsLessThan(a.d[0:a.nd], leftcheats[k].cutoff) { + delta-- + } + + r := a.nd // read index + w := a.nd + delta // write index + n := 0 + + // Pick up a digit, put down a digit. + for r--; r >= 0; r-- { + n += (int(a.d[r]) - '0') << k + quo := n / 10 + rem := n - 10*quo + w-- + if w < len(a.d) { + a.d[w] = byte(rem + '0') + } else if rem != 0 { + a.trunc = true + } + n = quo + } + + // Put down extra digits. + for n > 0 { + quo := n / 10 + rem := n - 10*quo + w-- + if w < len(a.d) { + a.d[w] = byte(rem + '0') + } else if rem != 0 { + a.trunc = true + } + n = quo + } + + a.nd += delta + if a.nd >= len(a.d) { + a.nd = len(a.d) + } + a.dp += delta + trim(a) +} + +// Binary shift left (k > 0) or right (k < 0). +func (a *decimal) Shift(k int) { + switch { + case a.nd == 0: + // nothing to do: a == 0 + case k > 0: + for k > maxShift { + leftShift(a, maxShift) + k -= maxShift + } + leftShift(a, uint(k)) + case k < 0: + for k < -maxShift { + rightShift(a, maxShift) + k += maxShift + } + rightShift(a, uint(-k)) + } +} + +// If we chop a at nd digits, should we round up? +func shouldRoundUp(a *decimal, nd int) bool { + if nd < 0 || nd >= a.nd { + return false + } + if a.d[nd] == '5' && nd+1 == a.nd { // exactly halfway - round to even + // if we truncated, a little higher than what's recorded - always round up + if a.trunc { + return true + } + return nd > 0 && (a.d[nd-1]-'0')%2 != 0 + } + // not halfway - digit tells all + return a.d[nd] >= '5' +} + +// Round a to nd digits (or fewer). +// If nd is zero, it means we're rounding +// just to the left of the digits, as in +// 0.09 -> 0.1. +func (a *decimal) Round(nd int) { + if nd < 0 || nd >= a.nd { + return + } + if shouldRoundUp(a, nd) { + a.RoundUp(nd) + } else { + a.RoundDown(nd) + } +} + +// Round a down to nd digits (or fewer). +func (a *decimal) RoundDown(nd int) { + if nd < 0 || nd >= a.nd { + return + } + a.nd = nd + trim(a) +} + +// Round a up to nd digits (or fewer). +func (a *decimal) RoundUp(nd int) { + if nd < 0 || nd >= a.nd { + return + } + + // round up + for i := nd - 1; i >= 0; i-- { + c := a.d[i] + if c < '9' { // can stop after this digit + a.d[i]++ + a.nd = i + 1 + return + } + } + + // Number is all 9s. + // Change to single 1 with adjusted decimal point. + a.d[0] = '1' + a.nd = 1 + a.dp++ +} + +// Extract integer part, rounded appropriately. +// No guarantees about overflow. +func (a *decimal) RoundedInteger() uint64 { + if a.dp > 20 { + return 0xFFFFFFFFFFFFFFFF + } + var i int + n := uint64(0) + for i = 0; i < a.dp && i < a.nd; i++ { + n = n*10 + uint64(a.d[i]-'0') + } + for ; i < a.dp; i++ { + n *= 10 + } + if shouldRoundUp(a, a.dp) { + n++ + } + return n +} diff --git a/vendor/github.com/pquerna/ffjson/fflib/v1/internal/atoi.go b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/atoi.go new file mode 100644 index 000000000..06eb2ec29 --- /dev/null +++ b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/atoi.go @@ -0,0 +1,213 @@ +/** + * Copyright 2014 Paul Querna + * + * 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. + * + */ + +/* Portions of this file are on Go stdlib's strconv/atoi.go */ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package internal + +import ( + "errors" + "strconv" +) + +// ErrRange indicates that a value is out of range for the target type. +var ErrRange = errors.New("value out of range") + +// ErrSyntax indicates that a value does not have the right syntax for the target type. +var ErrSyntax = errors.New("invalid syntax") + +// A NumError records a failed conversion. +type NumError struct { + Func string // the failing function (ParseBool, ParseInt, ParseUint, ParseFloat) + Num string // the input + Err error // the reason the conversion failed (ErrRange, ErrSyntax) +} + +func (e *NumError) Error() string { + return "strconv." + e.Func + ": " + "parsing " + strconv.Quote(e.Num) + ": " + e.Err.Error() +} + +func syntaxError(fn, str string) *NumError { + return &NumError{fn, str, ErrSyntax} +} + +func rangeError(fn, str string) *NumError { + return &NumError{fn, str, ErrRange} +} + +const intSize = 32 << uint(^uint(0)>>63) + +// IntSize is the size in bits of an int or uint value. +const IntSize = intSize + +// Return the first number n such that n*base >= 1<<64. +func cutoff64(base int) uint64 { + if base < 2 { + return 0 + } + return (1<<64-1)/uint64(base) + 1 +} + +// ParseUint is like ParseInt but for unsigned numbers, and oeprating on []byte +func ParseUint(s []byte, base int, bitSize int) (n uint64, err error) { + var cutoff, maxVal uint64 + + if bitSize == 0 { + bitSize = int(IntSize) + } + + s0 := s + switch { + case len(s) < 1: + err = ErrSyntax + goto Error + + case 2 <= base && base <= 36: + // valid base; nothing to do + + case base == 0: + // Look for octal, hex prefix. + switch { + case s[0] == '0' && len(s) > 1 && (s[1] == 'x' || s[1] == 'X'): + base = 16 + s = s[2:] + if len(s) < 1 { + err = ErrSyntax + goto Error + } + case s[0] == '0': + base = 8 + default: + base = 10 + } + + default: + err = errors.New("invalid base " + strconv.Itoa(base)) + goto Error + } + + n = 0 + cutoff = cutoff64(base) + maxVal = 1<<uint(bitSize) - 1 + + for i := 0; i < len(s); i++ { + var v byte + d := s[i] + switch { + case '0' <= d && d <= '9': + v = d - '0' + case 'a' <= d && d <= 'z': + v = d - 'a' + 10 + case 'A' <= d && d <= 'Z': + v = d - 'A' + 10 + default: + n = 0 + err = ErrSyntax + goto Error + } + if int(v) >= base { + n = 0 + err = ErrSyntax + goto Error + } + + if n >= cutoff { + // n*base overflows + n = 1<<64 - 1 + err = ErrRange + goto Error + } + n *= uint64(base) + + n1 := n + uint64(v) + if n1 < n || n1 > maxVal { + // n+v overflows + n = 1<<64 - 1 + err = ErrRange + goto Error + } + n = n1 + } + + return n, nil + +Error: + return n, &NumError{"ParseUint", string(s0), err} +} + +// ParseInt interprets a string s in the given base (2 to 36) and +// returns the corresponding value i. If base == 0, the base is +// implied by the string's prefix: base 16 for "0x", base 8 for +// "0", and base 10 otherwise. +// +// The bitSize argument specifies the integer type +// that the result must fit into. Bit sizes 0, 8, 16, 32, and 64 +// correspond to int, int8, int16, int32, and int64. +// +// The errors that ParseInt returns have concrete type *NumError +// and include err.Num = s. If s is empty or contains invalid +// digits, err.Err = ErrSyntax and the returned value is 0; +// if the value corresponding to s cannot be represented by a +// signed integer of the given size, err.Err = ErrRange and the +// returned value is the maximum magnitude integer of the +// appropriate bitSize and sign. +func ParseInt(s []byte, base int, bitSize int) (i int64, err error) { + const fnParseInt = "ParseInt" + + if bitSize == 0 { + bitSize = int(IntSize) + } + + // Empty string bad. + if len(s) == 0 { + return 0, syntaxError(fnParseInt, string(s)) + } + + // Pick off leading sign. + s0 := s + neg := false + if s[0] == '+' { + s = s[1:] + } else if s[0] == '-' { + neg = true + s = s[1:] + } + + // Convert unsigned and check range. + var un uint64 + un, err = ParseUint(s, base, bitSize) + if err != nil && err.(*NumError).Err != ErrRange { + err.(*NumError).Func = fnParseInt + err.(*NumError).Num = string(s0) + return 0, err + } + cutoff := uint64(1 << uint(bitSize-1)) + if !neg && un >= cutoff { + return int64(cutoff - 1), rangeError(fnParseInt, string(s0)) + } + if neg && un > cutoff { + return -int64(cutoff), rangeError(fnParseInt, string(s0)) + } + n := int64(un) + if neg { + n = -n + } + return n, nil +} diff --git a/vendor/github.com/pquerna/ffjson/fflib/v1/internal/extfloat.go b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/extfloat.go new file mode 100644 index 000000000..ab791085a --- /dev/null +++ b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/extfloat.go @@ -0,0 +1,668 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package internal + +// An extFloat represents an extended floating-point number, with more +// precision than a float64. It does not try to save bits: the +// number represented by the structure is mant*(2^exp), with a negative +// sign if neg is true. +type extFloat struct { + mant uint64 + exp int + neg bool +} + +// Powers of ten taken from double-conversion library. +// http://code.google.com/p/double-conversion/ +const ( + firstPowerOfTen = -348 + stepPowerOfTen = 8 +) + +var smallPowersOfTen = [...]extFloat{ + {1 << 63, -63, false}, // 1 + {0xa << 60, -60, false}, // 1e1 + {0x64 << 57, -57, false}, // 1e2 + {0x3e8 << 54, -54, false}, // 1e3 + {0x2710 << 50, -50, false}, // 1e4 + {0x186a0 << 47, -47, false}, // 1e5 + {0xf4240 << 44, -44, false}, // 1e6 + {0x989680 << 40, -40, false}, // 1e7 +} + +var powersOfTen = [...]extFloat{ + {0xfa8fd5a0081c0288, -1220, false}, // 10^-348 + {0xbaaee17fa23ebf76, -1193, false}, // 10^-340 + {0x8b16fb203055ac76, -1166, false}, // 10^-332 + {0xcf42894a5dce35ea, -1140, false}, // 10^-324 + {0x9a6bb0aa55653b2d, -1113, false}, // 10^-316 + {0xe61acf033d1a45df, -1087, false}, // 10^-308 + {0xab70fe17c79ac6ca, -1060, false}, // 10^-300 + {0xff77b1fcbebcdc4f, -1034, false}, // 10^-292 + {0xbe5691ef416bd60c, -1007, false}, // 10^-284 + {0x8dd01fad907ffc3c, -980, false}, // 10^-276 + {0xd3515c2831559a83, -954, false}, // 10^-268 + {0x9d71ac8fada6c9b5, -927, false}, // 10^-260 + {0xea9c227723ee8bcb, -901, false}, // 10^-252 + {0xaecc49914078536d, -874, false}, // 10^-244 + {0x823c12795db6ce57, -847, false}, // 10^-236 + {0xc21094364dfb5637, -821, false}, // 10^-228 + {0x9096ea6f3848984f, -794, false}, // 10^-220 + {0xd77485cb25823ac7, -768, false}, // 10^-212 + {0xa086cfcd97bf97f4, -741, false}, // 10^-204 + {0xef340a98172aace5, -715, false}, // 10^-196 + {0xb23867fb2a35b28e, -688, false}, // 10^-188 + {0x84c8d4dfd2c63f3b, -661, false}, // 10^-180 + {0xc5dd44271ad3cdba, -635, false}, // 10^-172 + {0x936b9fcebb25c996, -608, false}, // 10^-164 + {0xdbac6c247d62a584, -582, false}, // 10^-156 + {0xa3ab66580d5fdaf6, -555, false}, // 10^-148 + {0xf3e2f893dec3f126, -529, false}, // 10^-140 + {0xb5b5ada8aaff80b8, -502, false}, // 10^-132 + {0x87625f056c7c4a8b, -475, false}, // 10^-124 + {0xc9bcff6034c13053, -449, false}, // 10^-116 + {0x964e858c91ba2655, -422, false}, // 10^-108 + {0xdff9772470297ebd, -396, false}, // 10^-100 + {0xa6dfbd9fb8e5b88f, -369, false}, // 10^-92 + {0xf8a95fcf88747d94, -343, false}, // 10^-84 + {0xb94470938fa89bcf, -316, false}, // 10^-76 + {0x8a08f0f8bf0f156b, -289, false}, // 10^-68 + {0xcdb02555653131b6, -263, false}, // 10^-60 + {0x993fe2c6d07b7fac, -236, false}, // 10^-52 + {0xe45c10c42a2b3b06, -210, false}, // 10^-44 + {0xaa242499697392d3, -183, false}, // 10^-36 + {0xfd87b5f28300ca0e, -157, false}, // 10^-28 + {0xbce5086492111aeb, -130, false}, // 10^-20 + {0x8cbccc096f5088cc, -103, false}, // 10^-12 + {0xd1b71758e219652c, -77, false}, // 10^-4 + {0x9c40000000000000, -50, false}, // 10^4 + {0xe8d4a51000000000, -24, false}, // 10^12 + {0xad78ebc5ac620000, 3, false}, // 10^20 + {0x813f3978f8940984, 30, false}, // 10^28 + {0xc097ce7bc90715b3, 56, false}, // 10^36 + {0x8f7e32ce7bea5c70, 83, false}, // 10^44 + {0xd5d238a4abe98068, 109, false}, // 10^52 + {0x9f4f2726179a2245, 136, false}, // 10^60 + {0xed63a231d4c4fb27, 162, false}, // 10^68 + {0xb0de65388cc8ada8, 189, false}, // 10^76 + {0x83c7088e1aab65db, 216, false}, // 10^84 + {0xc45d1df942711d9a, 242, false}, // 10^92 + {0x924d692ca61be758, 269, false}, // 10^100 + {0xda01ee641a708dea, 295, false}, // 10^108 + {0xa26da3999aef774a, 322, false}, // 10^116 + {0xf209787bb47d6b85, 348, false}, // 10^124 + {0xb454e4a179dd1877, 375, false}, // 10^132 + {0x865b86925b9bc5c2, 402, false}, // 10^140 + {0xc83553c5c8965d3d, 428, false}, // 10^148 + {0x952ab45cfa97a0b3, 455, false}, // 10^156 + {0xde469fbd99a05fe3, 481, false}, // 10^164 + {0xa59bc234db398c25, 508, false}, // 10^172 + {0xf6c69a72a3989f5c, 534, false}, // 10^180 + {0xb7dcbf5354e9bece, 561, false}, // 10^188 + {0x88fcf317f22241e2, 588, false}, // 10^196 + {0xcc20ce9bd35c78a5, 614, false}, // 10^204 + {0x98165af37b2153df, 641, false}, // 10^212 + {0xe2a0b5dc971f303a, 667, false}, // 10^220 + {0xa8d9d1535ce3b396, 694, false}, // 10^228 + {0xfb9b7cd9a4a7443c, 720, false}, // 10^236 + {0xbb764c4ca7a44410, 747, false}, // 10^244 + {0x8bab8eefb6409c1a, 774, false}, // 10^252 + {0xd01fef10a657842c, 800, false}, // 10^260 + {0x9b10a4e5e9913129, 827, false}, // 10^268 + {0xe7109bfba19c0c9d, 853, false}, // 10^276 + {0xac2820d9623bf429, 880, false}, // 10^284 + {0x80444b5e7aa7cf85, 907, false}, // 10^292 + {0xbf21e44003acdd2d, 933, false}, // 10^300 + {0x8e679c2f5e44ff8f, 960, false}, // 10^308 + {0xd433179d9c8cb841, 986, false}, // 10^316 + {0x9e19db92b4e31ba9, 1013, false}, // 10^324 + {0xeb96bf6ebadf77d9, 1039, false}, // 10^332 + {0xaf87023b9bf0ee6b, 1066, false}, // 10^340 +} + +// floatBits returns the bits of the float64 that best approximates +// the extFloat passed as receiver. Overflow is set to true if +// the resulting float64 is ±Inf. +func (f *extFloat) floatBits(flt *floatInfo) (bits uint64, overflow bool) { + f.Normalize() + + exp := f.exp + 63 + + // Exponent too small. + if exp < flt.bias+1 { + n := flt.bias + 1 - exp + f.mant >>= uint(n) + exp += n + } + + // Extract 1+flt.mantbits bits from the 64-bit mantissa. + mant := f.mant >> (63 - flt.mantbits) + if f.mant&(1<<(62-flt.mantbits)) != 0 { + // Round up. + mant += 1 + } + + // Rounding might have added a bit; shift down. + if mant == 2<<flt.mantbits { + mant >>= 1 + exp++ + } + + // Infinities. + if exp-flt.bias >= 1<<flt.expbits-1 { + // ±Inf + mant = 0 + exp = 1<<flt.expbits - 1 + flt.bias + overflow = true + } else if mant&(1<<flt.mantbits) == 0 { + // Denormalized? + exp = flt.bias + } + // Assemble bits. + bits = mant & (uint64(1)<<flt.mantbits - 1) + bits |= uint64((exp-flt.bias)&(1<<flt.expbits-1)) << flt.mantbits + if f.neg { + bits |= 1 << (flt.mantbits + flt.expbits) + } + return +} + +// AssignComputeBounds sets f to the floating point value +// defined by mant, exp and precision given by flt. It returns +// lower, upper such that any number in the closed interval +// [lower, upper] is converted back to the same floating point number. +func (f *extFloat) AssignComputeBounds(mant uint64, exp int, neg bool, flt *floatInfo) (lower, upper extFloat) { + f.mant = mant + f.exp = exp - int(flt.mantbits) + f.neg = neg + if f.exp <= 0 && mant == (mant>>uint(-f.exp))<<uint(-f.exp) { + // An exact integer + f.mant >>= uint(-f.exp) + f.exp = 0 + return *f, *f + } + expBiased := exp - flt.bias + + upper = extFloat{mant: 2*f.mant + 1, exp: f.exp - 1, neg: f.neg} + if mant != 1<<flt.mantbits || expBiased == 1 { + lower = extFloat{mant: 2*f.mant - 1, exp: f.exp - 1, neg: f.neg} + } else { + lower = extFloat{mant: 4*f.mant - 1, exp: f.exp - 2, neg: f.neg} + } + return +} + +// Normalize normalizes f so that the highest bit of the mantissa is +// set, and returns the number by which the mantissa was left-shifted. +func (f *extFloat) Normalize() (shift uint) { + mant, exp := f.mant, f.exp + if mant == 0 { + return 0 + } + if mant>>(64-32) == 0 { + mant <<= 32 + exp -= 32 + } + if mant>>(64-16) == 0 { + mant <<= 16 + exp -= 16 + } + if mant>>(64-8) == 0 { + mant <<= 8 + exp -= 8 + } + if mant>>(64-4) == 0 { + mant <<= 4 + exp -= 4 + } + if mant>>(64-2) == 0 { + mant <<= 2 + exp -= 2 + } + if mant>>(64-1) == 0 { + mant <<= 1 + exp -= 1 + } + shift = uint(f.exp - exp) + f.mant, f.exp = mant, exp + return +} + +// Multiply sets f to the product f*g: the result is correctly rounded, +// but not normalized. +func (f *extFloat) Multiply(g extFloat) { + fhi, flo := f.mant>>32, uint64(uint32(f.mant)) + ghi, glo := g.mant>>32, uint64(uint32(g.mant)) + + // Cross products. + cross1 := fhi * glo + cross2 := flo * ghi + + // f.mant*g.mant is fhi*ghi << 64 + (cross1+cross2) << 32 + flo*glo + f.mant = fhi*ghi + (cross1 >> 32) + (cross2 >> 32) + rem := uint64(uint32(cross1)) + uint64(uint32(cross2)) + ((flo * glo) >> 32) + // Round up. + rem += (1 << 31) + + f.mant += (rem >> 32) + f.exp = f.exp + g.exp + 64 +} + +var uint64pow10 = [...]uint64{ + 1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, + 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, +} + +// AssignDecimal sets f to an approximate value mantissa*10^exp. It +// returns true if the value represented by f is guaranteed to be the +// best approximation of d after being rounded to a float64 or +// float32 depending on flt. +func (f *extFloat) AssignDecimal(mantissa uint64, exp10 int, neg bool, trunc bool, flt *floatInfo) (ok bool) { + const uint64digits = 19 + const errorscale = 8 + errors := 0 // An upper bound for error, computed in errorscale*ulp. + if trunc { + // the decimal number was truncated. + errors += errorscale / 2 + } + + f.mant = mantissa + f.exp = 0 + f.neg = neg + + // Multiply by powers of ten. + i := (exp10 - firstPowerOfTen) / stepPowerOfTen + if exp10 < firstPowerOfTen || i >= len(powersOfTen) { + return false + } + adjExp := (exp10 - firstPowerOfTen) % stepPowerOfTen + + // We multiply by exp%step + if adjExp < uint64digits && mantissa < uint64pow10[uint64digits-adjExp] { + // We can multiply the mantissa exactly. + f.mant *= uint64pow10[adjExp] + f.Normalize() + } else { + f.Normalize() + f.Multiply(smallPowersOfTen[adjExp]) + errors += errorscale / 2 + } + + // We multiply by 10 to the exp - exp%step. + f.Multiply(powersOfTen[i]) + if errors > 0 { + errors += 1 + } + errors += errorscale / 2 + + // Normalize + shift := f.Normalize() + errors <<= shift + + // Now f is a good approximation of the decimal. + // Check whether the error is too large: that is, if the mantissa + // is perturbated by the error, the resulting float64 will change. + // The 64 bits mantissa is 1 + 52 bits for float64 + 11 extra bits. + // + // In many cases the approximation will be good enough. + denormalExp := flt.bias - 63 + var extrabits uint + if f.exp <= denormalExp { + // f.mant * 2^f.exp is smaller than 2^(flt.bias+1). + extrabits = uint(63 - flt.mantbits + 1 + uint(denormalExp-f.exp)) + } else { + extrabits = uint(63 - flt.mantbits) + } + + halfway := uint64(1) << (extrabits - 1) + mant_extra := f.mant & (1<<extrabits - 1) + + // Do a signed comparison here! If the error estimate could make + // the mantissa round differently for the conversion to double, + // then we can't give a definite answer. + if int64(halfway)-int64(errors) < int64(mant_extra) && + int64(mant_extra) < int64(halfway)+int64(errors) { + return false + } + return true +} + +// Frexp10 is an analogue of math.Frexp for decimal powers. It scales +// f by an approximate power of ten 10^-exp, and returns exp10, so +// that f*10^exp10 has the same value as the old f, up to an ulp, +// as well as the index of 10^-exp in the powersOfTen table. +func (f *extFloat) frexp10() (exp10, index int) { + // The constants expMin and expMax constrain the final value of the + // binary exponent of f. We want a small integral part in the result + // because finding digits of an integer requires divisions, whereas + // digits of the fractional part can be found by repeatedly multiplying + // by 10. + const expMin = -60 + const expMax = -32 + // Find power of ten such that x * 10^n has a binary exponent + // between expMin and expMax. + approxExp10 := ((expMin+expMax)/2 - f.exp) * 28 / 93 // log(10)/log(2) is close to 93/28. + i := (approxExp10 - firstPowerOfTen) / stepPowerOfTen +Loop: + for { + exp := f.exp + powersOfTen[i].exp + 64 + switch { + case exp < expMin: + i++ + case exp > expMax: + i-- + default: + break Loop + } + } + // Apply the desired decimal shift on f. It will have exponent + // in the desired range. This is multiplication by 10^-exp10. + f.Multiply(powersOfTen[i]) + + return -(firstPowerOfTen + i*stepPowerOfTen), i +} + +// frexp10Many applies a common shift by a power of ten to a, b, c. +func frexp10Many(a, b, c *extFloat) (exp10 int) { + exp10, i := c.frexp10() + a.Multiply(powersOfTen[i]) + b.Multiply(powersOfTen[i]) + return +} + +// FixedDecimal stores in d the first n significant digits +// of the decimal representation of f. It returns false +// if it cannot be sure of the answer. +func (f *extFloat) FixedDecimal(d *decimalSlice, n int) bool { + if f.mant == 0 { + d.nd = 0 + d.dp = 0 + d.neg = f.neg + return true + } + if n == 0 { + panic("strconv: internal error: extFloat.FixedDecimal called with n == 0") + } + // Multiply by an appropriate power of ten to have a reasonable + // number to process. + f.Normalize() + exp10, _ := f.frexp10() + + shift := uint(-f.exp) + integer := uint32(f.mant >> shift) + fraction := f.mant - (uint64(integer) << shift) + ε := uint64(1) // ε is the uncertainty we have on the mantissa of f. + + // Write exactly n digits to d. + needed := n // how many digits are left to write. + integerDigits := 0 // the number of decimal digits of integer. + pow10 := uint64(1) // the power of ten by which f was scaled. + for i, pow := 0, uint64(1); i < 20; i++ { + if pow > uint64(integer) { + integerDigits = i + break + } + pow *= 10 + } + rest := integer + if integerDigits > needed { + // the integral part is already large, trim the last digits. + pow10 = uint64pow10[integerDigits-needed] + integer /= uint32(pow10) + rest -= integer * uint32(pow10) + } else { + rest = 0 + } + + // Write the digits of integer: the digits of rest are omitted. + var buf [32]byte + pos := len(buf) + for v := integer; v > 0; { + v1 := v / 10 + v -= 10 * v1 + pos-- + buf[pos] = byte(v + '0') + v = v1 + } + for i := pos; i < len(buf); i++ { + d.d[i-pos] = buf[i] + } + nd := len(buf) - pos + d.nd = nd + d.dp = integerDigits + exp10 + needed -= nd + + if needed > 0 { + if rest != 0 || pow10 != 1 { + panic("strconv: internal error, rest != 0 but needed > 0") + } + // Emit digits for the fractional part. Each time, 10*fraction + // fits in a uint64 without overflow. + for needed > 0 { + fraction *= 10 + ε *= 10 // the uncertainty scales as we multiply by ten. + if 2*ε > 1<<shift { + // the error is so large it could modify which digit to write, abort. + return false + } + digit := fraction >> shift + d.d[nd] = byte(digit + '0') + fraction -= digit << shift + nd++ + needed-- + } + d.nd = nd + } + + // We have written a truncation of f (a numerator / 10^d.dp). The remaining part + // can be interpreted as a small number (< 1) to be added to the last digit of the + // numerator. + // + // If rest > 0, the amount is: + // (rest<<shift | fraction) / (pow10 << shift) + // fraction being known with a ±ε uncertainty. + // The fact that n > 0 guarantees that pow10 << shift does not overflow a uint64. + // + // If rest = 0, pow10 == 1 and the amount is + // fraction / (1 << shift) + // fraction being known with a ±ε uncertainty. + // + // We pass this information to the rounding routine for adjustment. + + ok := adjustLastDigitFixed(d, uint64(rest)<<shift|fraction, pow10, shift, ε) + if !ok { + return false + } + // Trim trailing zeros. + for i := d.nd - 1; i >= 0; i-- { + if d.d[i] != '0' { + d.nd = i + 1 + break + } + } + return true +} + +// adjustLastDigitFixed assumes d contains the representation of the integral part +// of some number, whose fractional part is num / (den << shift). The numerator +// num is only known up to an uncertainty of size ε, assumed to be less than +// (den << shift)/2. +// +// It will increase the last digit by one to account for correct rounding, typically +// when the fractional part is greater than 1/2, and will return false if ε is such +// that no correct answer can be given. +func adjustLastDigitFixed(d *decimalSlice, num, den uint64, shift uint, ε uint64) bool { + if num > den<<shift { + panic("strconv: num > den<<shift in adjustLastDigitFixed") + } + if 2*ε > den<<shift { + panic("strconv: ε > (den<<shift)/2") + } + if 2*(num+ε) < den<<shift { + return true + } + if 2*(num-ε) > den<<shift { + // increment d by 1. + i := d.nd - 1 + for ; i >= 0; i-- { + if d.d[i] == '9' { + d.nd-- + } else { + break + } + } + if i < 0 { + d.d[0] = '1' + d.nd = 1 + d.dp++ + } else { + d.d[i]++ + } + return true + } + return false +} + +// ShortestDecimal stores in d the shortest decimal representation of f +// which belongs to the open interval (lower, upper), where f is supposed +// to lie. It returns false whenever the result is unsure. The implementation +// uses the Grisu3 algorithm. +func (f *extFloat) ShortestDecimal(d *decimalSlice, lower, upper *extFloat) bool { + if f.mant == 0 { + d.nd = 0 + d.dp = 0 + d.neg = f.neg + return true + } + if f.exp == 0 && *lower == *f && *lower == *upper { + // an exact integer. + var buf [24]byte + n := len(buf) - 1 + for v := f.mant; v > 0; { + v1 := v / 10 + v -= 10 * v1 + buf[n] = byte(v + '0') + n-- + v = v1 + } + nd := len(buf) - n - 1 + for i := 0; i < nd; i++ { + d.d[i] = buf[n+1+i] + } + d.nd, d.dp = nd, nd + for d.nd > 0 && d.d[d.nd-1] == '0' { + d.nd-- + } + if d.nd == 0 { + d.dp = 0 + } + d.neg = f.neg + return true + } + upper.Normalize() + // Uniformize exponents. + if f.exp > upper.exp { + f.mant <<= uint(f.exp - upper.exp) + f.exp = upper.exp + } + if lower.exp > upper.exp { + lower.mant <<= uint(lower.exp - upper.exp) + lower.exp = upper.exp + } + + exp10 := frexp10Many(lower, f, upper) + // Take a safety margin due to rounding in frexp10Many, but we lose precision. + upper.mant++ + lower.mant-- + + // The shortest representation of f is either rounded up or down, but + // in any case, it is a truncation of upper. + shift := uint(-upper.exp) + integer := uint32(upper.mant >> shift) + fraction := upper.mant - (uint64(integer) << shift) + + // How far we can go down from upper until the result is wrong. + allowance := upper.mant - lower.mant + // How far we should go to get a very precise result. + targetDiff := upper.mant - f.mant + + // Count integral digits: there are at most 10. + var integerDigits int + for i, pow := 0, uint64(1); i < 20; i++ { + if pow > uint64(integer) { + integerDigits = i + break + } + pow *= 10 + } + for i := 0; i < integerDigits; i++ { + pow := uint64pow10[integerDigits-i-1] + digit := integer / uint32(pow) + d.d[i] = byte(digit + '0') + integer -= digit * uint32(pow) + // evaluate whether we should stop. + if currentDiff := uint64(integer)<<shift + fraction; currentDiff < allowance { + d.nd = i + 1 + d.dp = integerDigits + exp10 + d.neg = f.neg + // Sometimes allowance is so large the last digit might need to be + // decremented to get closer to f. + return adjustLastDigit(d, currentDiff, targetDiff, allowance, pow<<shift, 2) + } + } + d.nd = integerDigits + d.dp = d.nd + exp10 + d.neg = f.neg + + // Compute digits of the fractional part. At each step fraction does not + // overflow. The choice of minExp implies that fraction is less than 2^60. + var digit int + multiplier := uint64(1) + for { + fraction *= 10 + multiplier *= 10 + digit = int(fraction >> shift) + d.d[d.nd] = byte(digit + '0') + d.nd++ + fraction -= uint64(digit) << shift + if fraction < allowance*multiplier { + // We are in the admissible range. Note that if allowance is about to + // overflow, that is, allowance > 2^64/10, the condition is automatically + // true due to the limited range of fraction. + return adjustLastDigit(d, + fraction, targetDiff*multiplier, allowance*multiplier, + 1<<shift, multiplier*2) + } + } +} + +// adjustLastDigit modifies d = x-currentDiff*ε, to get closest to +// d = x-targetDiff*ε, without becoming smaller than x-maxDiff*ε. +// It assumes that a decimal digit is worth ulpDecimal*ε, and that +// all data is known with a error estimate of ulpBinary*ε. +func adjustLastDigit(d *decimalSlice, currentDiff, targetDiff, maxDiff, ulpDecimal, ulpBinary uint64) bool { + if ulpDecimal < 2*ulpBinary { + // Approximation is too wide. + return false + } + for currentDiff+ulpDecimal/2+ulpBinary < targetDiff { + d.d[d.nd-1]-- + currentDiff += ulpDecimal + } + if currentDiff+ulpDecimal <= targetDiff+ulpDecimal/2+ulpBinary { + // we have two choices, and don't know what to do. + return false + } + if currentDiff < ulpBinary || currentDiff > maxDiff-ulpBinary { + // we went too far + return false + } + if d.nd == 1 && d.d[0] == '0' { + // the number has actually reached zero. + d.nd = 0 + d.dp = 0 + } + return true +} diff --git a/vendor/github.com/pquerna/ffjson/fflib/v1/internal/ftoa.go b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/ftoa.go new file mode 100644 index 000000000..253f83b45 --- /dev/null +++ b/vendor/github.com/pquerna/ffjson/fflib/v1/internal/ftoa.go @@ -0,0 +1,475 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Binary to decimal floating point conversion. +// Algorithm: +// 1) store mantissa in multiprecision decimal +// 2) shift decimal by exponent +// 3) read digits out & format + +package internal + +import "math" + +// TODO: move elsewhere? +type floatInfo struct { + mantbits uint + expbits uint + bias int +} + +var float32info = floatInfo{23, 8, -127} +var float64info = floatInfo{52, 11, -1023} + +// FormatFloat converts the floating-point number f to a string, +// according to the format fmt and precision prec. It rounds the +// result assuming that the original was obtained from a floating-point +// value of bitSize bits (32 for float32, 64 for float64). +// +// The format fmt is one of +// 'b' (-ddddp±ddd, a binary exponent), +// 'e' (-d.dddde±dd, a decimal exponent), +// 'E' (-d.ddddE±dd, a decimal exponent), +// 'f' (-ddd.dddd, no exponent), +// 'g' ('e' for large exponents, 'f' otherwise), or +// 'G' ('E' for large exponents, 'f' otherwise). +// +// The precision prec controls the number of digits +// (excluding the exponent) printed by the 'e', 'E', 'f', 'g', and 'G' formats. +// For 'e', 'E', and 'f' it is the number of digits after the decimal point. +// For 'g' and 'G' it is the total number of digits. +// The special precision -1 uses the smallest number of digits +// necessary such that ParseFloat will return f exactly. +func formatFloat(f float64, fmt byte, prec, bitSize int) string { + return string(genericFtoa(make([]byte, 0, max(prec+4, 24)), f, fmt, prec, bitSize)) +} + +// AppendFloat appends the string form of the floating-point number f, +// as generated by FormatFloat, to dst and returns the extended buffer. +func appendFloat(dst []byte, f float64, fmt byte, prec int, bitSize int) []byte { + return genericFtoa(dst, f, fmt, prec, bitSize) +} + +func genericFtoa(dst []byte, val float64, fmt byte, prec, bitSize int) []byte { + var bits uint64 + var flt *floatInfo + switch bitSize { + case 32: + bits = uint64(math.Float32bits(float32(val))) + flt = &float32info + case 64: + bits = math.Float64bits(val) + flt = &float64info + default: + panic("strconv: illegal AppendFloat/FormatFloat bitSize") + } + + neg := bits>>(flt.expbits+flt.mantbits) != 0 + exp := int(bits>>flt.mantbits) & (1<<flt.expbits - 1) + mant := bits & (uint64(1)<<flt.mantbits - 1) + + switch exp { + case 1<<flt.expbits - 1: + // Inf, NaN + var s string + switch { + case mant != 0: + s = "NaN" + case neg: + s = "-Inf" + default: + s = "+Inf" + } + return append(dst, s...) + + case 0: + // denormalized + exp++ + + default: + // add implicit top bit + mant |= uint64(1) << flt.mantbits + } + exp += flt.bias + + // Pick off easy binary format. + if fmt == 'b' { + return fmtB(dst, neg, mant, exp, flt) + } + + if !optimize { + return bigFtoa(dst, prec, fmt, neg, mant, exp, flt) + } + + var digs decimalSlice + ok := false + // Negative precision means "only as much as needed to be exact." + shortest := prec < 0 + if shortest { + // Try Grisu3 algorithm. + f := new(extFloat) + lower, upper := f.AssignComputeBounds(mant, exp, neg, flt) + var buf [32]byte + digs.d = buf[:] + ok = f.ShortestDecimal(&digs, &lower, &upper) + if !ok { + return bigFtoa(dst, prec, fmt, neg, mant, exp, flt) + } + // Precision for shortest representation mode. + switch fmt { + case 'e', 'E': + prec = digs.nd - 1 + case 'f': + prec = max(digs.nd-digs.dp, 0) + case 'g', 'G': + prec = digs.nd + } + } else if fmt != 'f' { + // Fixed number of digits. + digits := prec + switch fmt { + case 'e', 'E': + digits++ + case 'g', 'G': + if prec == 0 { + prec = 1 + } + digits = prec + } + if digits <= 15 { + // try fast algorithm when the number of digits is reasonable. + var buf [24]byte + digs.d = buf[:] + f := extFloat{mant, exp - int(flt.mantbits), neg} + ok = f.FixedDecimal(&digs, digits) + } + } + if !ok { + return bigFtoa(dst, prec, fmt, neg, mant, exp, flt) + } + return formatDigits(dst, shortest, neg, digs, prec, fmt) +} + +// bigFtoa uses multiprecision computations to format a float. +func bigFtoa(dst []byte, prec int, fmt byte, neg bool, mant uint64, exp int, flt *floatInfo) []byte { + d := new(decimal) + d.Assign(mant) + d.Shift(exp - int(flt.mantbits)) + var digs decimalSlice + shortest := prec < 0 + if shortest { + roundShortest(d, mant, exp, flt) + digs = decimalSlice{d: d.d[:], nd: d.nd, dp: d.dp} + // Precision for shortest representation mode. + switch fmt { + case 'e', 'E': + prec = digs.nd - 1 + case 'f': + prec = max(digs.nd-digs.dp, 0) + case 'g', 'G': + prec = digs.nd + } + } else { + // Round appropriately. + switch fmt { + case 'e', 'E': + d.Round(prec + 1) + case 'f': + d.Round(d.dp + prec) + case 'g', 'G': + if prec == 0 { + prec = 1 + } + d.Round(prec) + } + digs = decimalSlice{d: d.d[:], nd: d.nd, dp: d.dp} + } + return formatDigits(dst, shortest, neg, digs, prec, fmt) +} + +func formatDigits(dst []byte, shortest bool, neg bool, digs decimalSlice, prec int, fmt byte) []byte { + switch fmt { + case 'e', 'E': + return fmtE(dst, neg, digs, prec, fmt) + case 'f': + return fmtF(dst, neg, digs, prec) + case 'g', 'G': + // trailing fractional zeros in 'e' form will be trimmed. + eprec := prec + if eprec > digs.nd && digs.nd >= digs.dp { + eprec = digs.nd + } + // %e is used if the exponent from the conversion + // is less than -4 or greater than or equal to the precision. + // if precision was the shortest possible, use precision 6 for this decision. + if shortest { + eprec = 6 + } + exp := digs.dp - 1 + if exp < -4 || exp >= eprec { + if prec > digs.nd { + prec = digs.nd + } + return fmtE(dst, neg, digs, prec-1, fmt+'e'-'g') + } + if prec > digs.dp { + prec = digs.nd + } + return fmtF(dst, neg, digs, max(prec-digs.dp, 0)) + } + + // unknown format + return append(dst, '%', fmt) +} + +// Round d (= mant * 2^exp) to the shortest number of digits +// that will let the original floating point value be precisely +// reconstructed. Size is original floating point size (64 or 32). +func roundShortest(d *decimal, mant uint64, exp int, flt *floatInfo) { + // If mantissa is zero, the number is zero; stop now. + if mant == 0 { + d.nd = 0 + return + } + + // Compute upper and lower such that any decimal number + // between upper and lower (possibly inclusive) + // will round to the original floating point number. + + // We may see at once that the number is already shortest. + // + // Suppose d is not denormal, so that 2^exp <= d < 10^dp. + // The closest shorter number is at least 10^(dp-nd) away. + // The lower/upper bounds computed below are at distance + // at most 2^(exp-mantbits). + // + // So the number is already shortest if 10^(dp-nd) > 2^(exp-mantbits), + // or equivalently log2(10)*(dp-nd) > exp-mantbits. + // It is true if 332/100*(dp-nd) >= exp-mantbits (log2(10) > 3.32). + minexp := flt.bias + 1 // minimum possible exponent + if exp > minexp && 332*(d.dp-d.nd) >= 100*(exp-int(flt.mantbits)) { + // The number is already shortest. + return + } + + // d = mant << (exp - mantbits) + // Next highest floating point number is mant+1 << exp-mantbits. + // Our upper bound is halfway between, mant*2+1 << exp-mantbits-1. + upper := new(decimal) + upper.Assign(mant*2 + 1) + upper.Shift(exp - int(flt.mantbits) - 1) + + // d = mant << (exp - mantbits) + // Next lowest floating point number is mant-1 << exp-mantbits, + // unless mant-1 drops the significant bit and exp is not the minimum exp, + // in which case the next lowest is mant*2-1 << exp-mantbits-1. + // Either way, call it mantlo << explo-mantbits. + // Our lower bound is halfway between, mantlo*2+1 << explo-mantbits-1. + var mantlo uint64 + var explo int + if mant > 1<<flt.mantbits || exp == minexp { + mantlo = mant - 1 + explo = exp + } else { + mantlo = mant*2 - 1 + explo = exp - 1 + } + lower := new(decimal) + lower.Assign(mantlo*2 + 1) + lower.Shift(explo - int(flt.mantbits) - 1) + + // The upper and lower bounds are possible outputs only if + // the original mantissa is even, so that IEEE round-to-even + // would round to the original mantissa and not the neighbors. + inclusive := mant%2 == 0 + + // Now we can figure out the minimum number of digits required. + // Walk along until d has distinguished itself from upper and lower. + for i := 0; i < d.nd; i++ { + var l, m, u byte // lower, middle, upper digits + if i < lower.nd { + l = lower.d[i] + } else { + l = '0' + } + m = d.d[i] + if i < upper.nd { + u = upper.d[i] + } else { + u = '0' + } + + // Okay to round down (truncate) if lower has a different digit + // or if lower is inclusive and is exactly the result of rounding down. + okdown := l != m || (inclusive && l == m && i+1 == lower.nd) + + // Okay to round up if upper has a different digit and + // either upper is inclusive or upper is bigger than the result of rounding up. + okup := m != u && (inclusive || m+1 < u || i+1 < upper.nd) + + // If it's okay to do either, then round to the nearest one. + // If it's okay to do only one, do it. + switch { + case okdown && okup: + d.Round(i + 1) + return + case okdown: + d.RoundDown(i + 1) + return + case okup: + d.RoundUp(i + 1) + return + } + } +} + +type decimalSlice struct { + d []byte + nd, dp int + neg bool +} + +// %e: -d.ddddde±dd +func fmtE(dst []byte, neg bool, d decimalSlice, prec int, fmt byte) []byte { + // sign + if neg { + dst = append(dst, '-') + } + + // first digit + ch := byte('0') + if d.nd != 0 { + ch = d.d[0] + } + dst = append(dst, ch) + + // .moredigits + if prec > 0 { + dst = append(dst, '.') + i := 1 + m := d.nd + prec + 1 - max(d.nd, prec+1) + for i < m { + dst = append(dst, d.d[i]) + i++ + } + for i <= prec { + dst = append(dst, '0') + i++ + } + } + + // e± + dst = append(dst, fmt) + exp := d.dp - 1 + if d.nd == 0 { // special case: 0 has exponent 0 + exp = 0 + } + if exp < 0 { + ch = '-' + exp = -exp + } else { + ch = '+' + } + dst = append(dst, ch) + + // dddd + var buf [3]byte + i := len(buf) + for exp >= 10 { + i-- + buf[i] = byte(exp%10 + '0') + exp /= 10 + } + // exp < 10 + i-- + buf[i] = byte(exp + '0') + + switch i { + case 0: + dst = append(dst, buf[0], buf[1], buf[2]) + case 1: + dst = append(dst, buf[1], buf[2]) + case 2: + // leading zeroes + dst = append(dst, '0', buf[2]) + } + return dst +} + +// %f: -ddddddd.ddddd +func fmtF(dst []byte, neg bool, d decimalSlice, prec int) []byte { + // sign + if neg { + dst = append(dst, '-') + } + + // integer, padded with zeros as needed. + if d.dp > 0 { + var i int + for i = 0; i < d.dp && i < d.nd; i++ { + dst = append(dst, d.d[i]) + } + for ; i < d.dp; i++ { + dst = append(dst, '0') + } + } else { + dst = append(dst, '0') + } + + // fraction + if prec > 0 { + dst = append(dst, '.') + for i := 0; i < prec; i++ { + ch := byte('0') + if j := d.dp + i; 0 <= j && j < d.nd { + ch = d.d[j] + } + dst = append(dst, ch) + } + } + + return dst +} + +// %b: -ddddddddp+ddd +func fmtB(dst []byte, neg bool, mant uint64, exp int, flt *floatInfo) []byte { + var buf [50]byte + w := len(buf) + exp -= int(flt.mantbits) + esign := byte('+') + if exp < 0 { + esign = '-' + exp = -exp + } + n := 0 + for exp > 0 || n < 1 { + n++ + w-- + buf[w] = byte(exp%10 + '0') + exp /= 10 + } + w-- + buf[w] = esign + w-- + buf[w] = 'p' + n = 0 + for mant > 0 || n < 1 { + n++ + w-- + buf[w] = byte(mant%10 + '0') + mant /= 10 + } + if neg { + w-- + buf[w] = '-' + } + return append(dst, buf[w:]...) +} + +func max(a, b int) int { + if a > b { + return a + } + return b +} |