Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 300 insertions, 0 deletions

diff --git a/vendor/ryu/src/d2s.rs b/vendor/ryu/src/d2s.rs
new file mode 100644
index 0000000..392577a
--- /dev/null
+++ b/vendor/ryu/src/d2s.rs
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+// Translated from C to Rust. The original C code can be found at
+// https://github.com/ulfjack/ryu and carries the following license:
+//
+// Copyright 2018 Ulf Adams
+//
+// The contents of this file may be used under the terms of the Apache License,
+// Version 2.0.
+//
+//    (See accompanying file LICENSE-Apache or copy at
+//     http://www.apache.org/licenses/LICENSE-2.0)
+//
+// Alternatively, the contents of this file may be used under the terms of
+// the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE-Boost or copy at
+//     https://www.boost.org/LICENSE_1_0.txt)
+//
+// Unless required by applicable law or agreed to in writing, this software
+// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.
+
+use crate::common::*;
+#[cfg(not(feature = "small"))]
+pub use crate::d2s_full_table::*;
+use crate::d2s_intrinsics::*;
+#[cfg(feature = "small")]
+pub use crate::d2s_small_table::*;
+use core::mem::MaybeUninit;
+
+pub const DOUBLE_MANTISSA_BITS: u32 = 52;
+pub const DOUBLE_EXPONENT_BITS: u32 = 11;
+pub const DOUBLE_BIAS: i32 = 1023;
+pub const DOUBLE_POW5_INV_BITCOUNT: i32 = 125;
+pub const DOUBLE_POW5_BITCOUNT: i32 = 125;
+
+#[cfg_attr(feature = "no-panic", inline)]
+pub fn decimal_length17(v: u64) -> u32 {
+    // This is slightly faster than a loop.
+    // The average output length is 16.38 digits, so we check high-to-low.
+    // Function precondition: v is not an 18, 19, or 20-digit number.
+    // (17 digits are sufficient for round-tripping.)
+    debug_assert!(v < 100000000000000000);
+
+    if v >= 10000000000000000 {
+        17
+    } else if v >= 1000000000000000 {
+        16
+    } else if v >= 100000000000000 {
+        15
+    } else if v >= 10000000000000 {
+        14
+    } else if v >= 1000000000000 {
+        13
+    } else if v >= 100000000000 {
+        12
+    } else if v >= 10000000000 {
+        11
+    } else if v >= 1000000000 {
+        10
+    } else if v >= 100000000 {
+        9
+    } else if v >= 10000000 {
+        8
+    } else if v >= 1000000 {
+        7
+    } else if v >= 100000 {
+        6
+    } else if v >= 10000 {
+        5
+    } else if v >= 1000 {
+        4
+    } else if v >= 100 {
+        3
+    } else if v >= 10 {
+        2
+    } else {
+        1
+    }
+}
+
+// A floating decimal representing m * 10^e.
+pub struct FloatingDecimal64 {
+    pub mantissa: u64,
+    // Decimal exponent's range is -324 to 308
+    // inclusive, and can fit in i16 if needed.
+    pub exponent: i32,
+}
+
+#[cfg_attr(feature = "no-panic", inline)]
+pub fn d2d(ieee_mantissa: u64, ieee_exponent: u32) -> FloatingDecimal64 {
+    let (e2, m2) = if ieee_exponent == 0 {
+        (
+            // We subtract 2 so that the bounds computation has 2 additional bits.
+            1 - DOUBLE_BIAS - DOUBLE_MANTISSA_BITS as i32 - 2,
+            ieee_mantissa,
+        )
+    } else {
+        (
+            ieee_exponent as i32 - DOUBLE_BIAS - DOUBLE_MANTISSA_BITS as i32 - 2,
+            (1u64 << DOUBLE_MANTISSA_BITS) | ieee_mantissa,
+        )
+    };
+    let even = (m2 & 1) == 0;
+    let accept_bounds = even;
+
+    // Step 2: Determine the interval of valid decimal representations.
+    let mv = 4 * m2;
+    // Implicit bool -> int conversion. True is 1, false is 0.
+    let mm_shift = (ieee_mantissa != 0 || ieee_exponent <= 1) as u32;
+    // We would compute mp and mm like this:
+    // uint64_t mp = 4 * m2 + 2;
+    // uint64_t mm = mv - 1 - mm_shift;
+
+    // Step 3: Convert to a decimal power base using 128-bit arithmetic.
+    let mut vr: u64;
+    let mut vp: u64;
+    let mut vm: u64;
+    let mut vp_uninit: MaybeUninit<u64> = MaybeUninit::uninit();
+    let mut vm_uninit: MaybeUninit<u64> = MaybeUninit::uninit();
+    let e10: i32;
+    let mut vm_is_trailing_zeros = false;
+    let mut vr_is_trailing_zeros = false;
+    if e2 >= 0 {
+        // I tried special-casing q == 0, but there was no effect on performance.
+        // This expression is slightly faster than max(0, log10_pow2(e2) - 1).
+        let q = log10_pow2(e2) - (e2 > 3) as u32;
+        e10 = q as i32;
+        let k = DOUBLE_POW5_INV_BITCOUNT + pow5bits(q as i32) - 1;
+        let i = -e2 + q as i32 + k;
+        vr = unsafe {
+            mul_shift_all_64(
+                m2,
+                #[cfg(feature = "small")]
+                &compute_inv_pow5(q),
+                #[cfg(not(feature = "small"))]
+                {
+                    debug_assert!(q < DOUBLE_POW5_INV_SPLIT.len() as u32);
+                    DOUBLE_POW5_INV_SPLIT.get_unchecked(q as usize)
+                },
+                i as u32,
+                vp_uninit.as_mut_ptr(),
+                vm_uninit.as_mut_ptr(),
+                mm_shift,
+            )
+        };
+        vp = unsafe { vp_uninit.assume_init() };
+        vm = unsafe { vm_uninit.assume_init() };
+        if q <= 21 {
+            // This should use q <= 22, but I think 21 is also safe. Smaller values
+            // may still be safe, but it's more difficult to reason about them.
+            // Only one of mp, mv, and mm can be a multiple of 5, if any.
+            let mv_mod5 = (mv as u32).wrapping_sub(5u32.wrapping_mul(div5(mv) as u32));
+            if mv_mod5 == 0 {
+                vr_is_trailing_zeros = multiple_of_power_of_5(mv, q);
+            } else if accept_bounds {
+                // Same as min(e2 + (~mm & 1), pow5_factor(mm)) >= q
+                // <=> e2 + (~mm & 1) >= q && pow5_factor(mm) >= q
+                // <=> true && pow5_factor(mm) >= q, since e2 >= q.
+                vm_is_trailing_zeros = multiple_of_power_of_5(mv - 1 - mm_shift as u64, q);
+            } else {
+                // Same as min(e2 + 1, pow5_factor(mp)) >= q.
+                vp -= multiple_of_power_of_5(mv + 2, q) as u64;
+            }
+        }
+    } else {
+        // This expression is slightly faster than max(0, log10_pow5(-e2) - 1).
+        let q = log10_pow5(-e2) - (-e2 > 1) as u32;
+        e10 = q as i32 + e2;
+        let i = -e2 - q as i32;
+        let k = pow5bits(i) - DOUBLE_POW5_BITCOUNT;
+        let j = q as i32 - k;
+        vr = unsafe {
+            mul_shift_all_64(
+                m2,
+                #[cfg(feature = "small")]
+                &compute_pow5(i as u32),
+                #[cfg(not(feature = "small"))]
+                {
+                    debug_assert!(i < DOUBLE_POW5_SPLIT.len() as i32);
+                    DOUBLE_POW5_SPLIT.get_unchecked(i as usize)
+                },
+                j as u32,
+                vp_uninit.as_mut_ptr(),
+                vm_uninit.as_mut_ptr(),
+                mm_shift,
+            )
+        };
+        vp = unsafe { vp_uninit.assume_init() };
+        vm = unsafe { vm_uninit.assume_init() };
+        if q <= 1 {
+            // {vr,vp,vm} is trailing zeros if {mv,mp,mm} has at least q trailing 0 bits.
+            // mv = 4 * m2, so it always has at least two trailing 0 bits.
+            vr_is_trailing_zeros = true;
+            if accept_bounds {
+                // mm = mv - 1 - mm_shift, so it has 1 trailing 0 bit iff mm_shift == 1.
+                vm_is_trailing_zeros = mm_shift == 1;
+            } else {
+                // mp = mv + 2, so it always has at least one trailing 0 bit.
+                vp -= 1;
+            }
+        } else if q < 63 {
+            // TODO(ulfjack): Use a tighter bound here.
+            // We want to know if the full product has at least q trailing zeros.
+            // We need to compute min(p2(mv), p5(mv) - e2) >= q
+            // <=> p2(mv) >= q && p5(mv) - e2 >= q
+            // <=> p2(mv) >= q (because -e2 >= q)
+            vr_is_trailing_zeros = multiple_of_power_of_2(mv, q);
+        }
+    }
+
+    // Step 4: Find the shortest decimal representation in the interval of valid representations.
+    let mut removed = 0i32;
+    let mut last_removed_digit = 0u8;
+    // On average, we remove ~2 digits.
+    let output = if vm_is_trailing_zeros || vr_is_trailing_zeros {
+        // General case, which happens rarely (~0.7%).
+        loop {
+            let vp_div10 = div10(vp);
+            let vm_div10 = div10(vm);
+            if vp_div10 <= vm_div10 {
+                break;
+            }
+            let vm_mod10 = (vm as u32).wrapping_sub(10u32.wrapping_mul(vm_div10 as u32));
+            let vr_div10 = div10(vr);
+            let vr_mod10 = (vr as u32).wrapping_sub(10u32.wrapping_mul(vr_div10 as u32));
+            vm_is_trailing_zeros &= vm_mod10 == 0;
+            vr_is_trailing_zeros &= last_removed_digit == 0;
+            last_removed_digit = vr_mod10 as u8;
+            vr = vr_div10;
+            vp = vp_div10;
+            vm = vm_div10;
+            removed += 1;
+        }
+        if vm_is_trailing_zeros {
+            loop {
+                let vm_div10 = div10(vm);
+                let vm_mod10 = (vm as u32).wrapping_sub(10u32.wrapping_mul(vm_div10 as u32));
+                if vm_mod10 != 0 {
+                    break;
+                }
+                let vp_div10 = div10(vp);
+                let vr_div10 = div10(vr);
+                let vr_mod10 = (vr as u32).wrapping_sub(10u32.wrapping_mul(vr_div10 as u32));
+                vr_is_trailing_zeros &= last_removed_digit == 0;
+                last_removed_digit = vr_mod10 as u8;
+                vr = vr_div10;
+                vp = vp_div10;
+                vm = vm_div10;
+                removed += 1;
+            }
+        }
+        if vr_is_trailing_zeros && last_removed_digit == 5 && vr % 2 == 0 {
+            // Round even if the exact number is .....50..0.
+            last_removed_digit = 4;
+        }
+        // We need to take vr + 1 if vr is outside bounds or we need to round up.
+        vr + ((vr == vm && (!accept_bounds || !vm_is_trailing_zeros)) || last_removed_digit >= 5)
+            as u64
+    } else {
+        // Specialized for the common case (~99.3%). Percentages below are relative to this.
+        let mut round_up = false;
+        let vp_div100 = div100(vp);
+        let vm_div100 = div100(vm);
+        // Optimization: remove two digits at a time (~86.2%).
+        if vp_div100 > vm_div100 {
+            let vr_div100 = div100(vr);
+            let vr_mod100 = (vr as u32).wrapping_sub(100u32.wrapping_mul(vr_div100 as u32));
+            round_up = vr_mod100 >= 50;
+            vr = vr_div100;
+            vp = vp_div100;
+            vm = vm_div100;
+            removed += 2;
+        }
+        // Loop iterations below (approximately), without optimization above:
+        // 0: 0.03%, 1: 13.8%, 2: 70.6%, 3: 14.0%, 4: 1.40%, 5: 0.14%, 6+: 0.02%
+        // Loop iterations below (approximately), with optimization above:
+        // 0: 70.6%, 1: 27.8%, 2: 1.40%, 3: 0.14%, 4+: 0.02%
+        loop {
+            let vp_div10 = div10(vp);
+            let vm_div10 = div10(vm);
+            if vp_div10 <= vm_div10 {
+                break;
+            }
+            let vr_div10 = div10(vr);
+            let vr_mod10 = (vr as u32).wrapping_sub(10u32.wrapping_mul(vr_div10 as u32));
+            round_up = vr_mod10 >= 5;
+            vr = vr_div10;
+            vp = vp_div10;
+            vm = vm_div10;
+            removed += 1;
+        }
+        // We need to take vr + 1 if vr is outside bounds or we need to round up.
+        vr + (vr == vm || round_up) as u64
+    };
+    let exp = e10 + removed;
+
+    FloatingDecimal64 {
+        exponent: exp,
+        mantissa: output,
+    }
+}