1 files changed, 142 insertions, 0 deletions
diff --git a/third_party/rust/ryu/src/d2s_small_table.rs b/third_party/rust/ryu/src/d2s_small_table.rs
new file mode 100644
index 0000000000..262fc04f94
--- /dev/null
+++ b/third_party/rust/ryu/src/d2s_small_table.rs
@@ -0,0 +1,142 @@
+// 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::*;
+
+pub static DOUBLE_POW5_INV_SPLIT2: [(u64, u64); 15] = [
+    (1, 2305843009213693952),
+    (5955668970331000884, 1784059615882449851),
+    (8982663654677661702, 1380349269358112757),
+    (7286864317269821294, 2135987035920910082),
+    (7005857020398200553, 1652639921975621497),
+    (17965325103354776697, 1278668206209430417),
+    (8928596168509315048, 1978643211784836272),
+    (10075671573058298858, 1530901034580419511),
+    (597001226353042382, 1184477304306571148),
+    (1527430471115325346, 1832889850782397517),
+    (12533209867169019542, 1418129833677084982),
+    (5577825024675947042, 2194449627517475473),
+    (11006974540203867551, 1697873161311732311),
+    (10313493231639821582, 1313665730009899186),
+    (12701016819766672773, 2032799256770390445),
+];
+
+pub static POW5_INV_OFFSETS: [u32; 19] = [
+    0x54544554, 0x04055545, 0x10041000, 0x00400414, 0x40010000, 0x41155555, 0x00000454, 0x00010044,
+    0x40000000, 0x44000041, 0x50454450, 0x55550054, 0x51655554, 0x40004000, 0x01000001, 0x00010500,
+    0x51515411, 0x05555554, 0x00000000,
+];
+
+pub static DOUBLE_POW5_SPLIT2: [(u64, u64); 13] = [
+    (0, 1152921504606846976),
+    (0, 1490116119384765625),
+    (1032610780636961552, 1925929944387235853),
+    (7910200175544436838, 1244603055572228341),
+    (16941905809032713930, 1608611746708759036),
+    (13024893955298202172, 2079081953128979843),
+    (6607496772837067824, 1343575221513417750),
+    (17332926989895652603, 1736530273035216783),
+    (13037379183483547984, 2244412773384604712),
+    (1605989338741628675, 1450417759929778918),
+    (9630225068416591280, 1874621017369538693),
+    (665883850346957067, 1211445438634777304),
+    (14931890668723713708, 1565756531257009982),
+];
+
+pub static POW5_OFFSETS: [u32; 21] = [
+    0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x40000000, 0x59695995, 0x55545555, 0x56555515,
+    0x41150504, 0x40555410, 0x44555145, 0x44504540, 0x45555550, 0x40004000, 0x96440440, 0x55565565,
+    0x54454045, 0x40154151, 0x55559155, 0x51405555, 0x00000105,
+];
+
+pub static DOUBLE_POW5_TABLE: [u64; 26] = [
+    1,
+    5,
+    25,
+    125,
+    625,
+    3125,
+    15625,
+    78125,
+    390625,
+    1953125,
+    9765625,
+    48828125,
+    244140625,
+    1220703125,
+    6103515625,
+    30517578125,
+    152587890625,
+    762939453125,
+    3814697265625,
+    19073486328125,
+    95367431640625,
+    476837158203125,
+    2384185791015625,
+    11920928955078125,
+    59604644775390625,
+    298023223876953125,
+];
+
+// Computes 5^i in the form required by Ryū.
+#[cfg_attr(feature = "no-panic", inline)]
+pub unsafe fn compute_pow5(i: u32) -> (u64, u64) {
+    let base = i / DOUBLE_POW5_TABLE.len() as u32;
+    let base2 = base * DOUBLE_POW5_TABLE.len() as u32;
+    let offset = i - base2;
+    debug_assert!(base < DOUBLE_POW5_SPLIT2.len() as u32);
+    let mul = *DOUBLE_POW5_SPLIT2.get_unchecked(base as usize);
+    if offset == 0 {
+        return mul;
+    }
+    debug_assert!(offset < DOUBLE_POW5_TABLE.len() as u32);
+    let m = *DOUBLE_POW5_TABLE.get_unchecked(offset as usize);
+    let b0 = m as u128 * mul.0 as u128;
+    let b2 = m as u128 * mul.1 as u128;
+    let delta = pow5bits(i as i32) - pow5bits(base2 as i32);
+    debug_assert!(i / 16 < POW5_OFFSETS.len() as u32);
+    let shifted_sum = (b0 >> delta)
+        + (b2 << (64 - delta))
+        + ((*POW5_OFFSETS.get_unchecked((i / 16) as usize) >> ((i % 16) << 1)) & 3) as u128;
+    (shifted_sum as u64, (shifted_sum >> 64) as u64)
+}
+
+// Computes 5^-i in the form required by Ryū.
+#[cfg_attr(feature = "no-panic", inline)]
+pub unsafe fn compute_inv_pow5(i: u32) -> (u64, u64) {
+    let base = (i + DOUBLE_POW5_TABLE.len() as u32 - 1) / DOUBLE_POW5_TABLE.len() as u32;
+    let base2 = base * DOUBLE_POW5_TABLE.len() as u32;
+    let offset = base2 - i;
+    debug_assert!(base < DOUBLE_POW5_INV_SPLIT2.len() as u32);
+    let mul = *DOUBLE_POW5_INV_SPLIT2.get_unchecked(base as usize); // 1/5^base2
+    if offset == 0 {
+        return mul;
+    }
+    debug_assert!(offset < DOUBLE_POW5_TABLE.len() as u32);
+    let m = *DOUBLE_POW5_TABLE.get_unchecked(offset as usize); // 5^offset
+    let b0 = m as u128 * (mul.0 - 1) as u128;
+    let b2 = m as u128 * mul.1 as u128; // 1/5^base2 * 5^offset = 1/5^(base2-offset) = 1/5^i
+    let delta = pow5bits(base2 as i32) - pow5bits(i as i32);
+    debug_assert!(base < POW5_INV_OFFSETS.len() as u32);
+    let shifted_sum = ((b0 >> delta) + (b2 << (64 - delta)))
+        + 1
+        + ((*POW5_INV_OFFSETS.get_unchecked((i / 16) as usize) >> ((i % 16) << 1)) & 3) as u128;
+    (shifted_sum as u64, (shifted_sum >> 64) as u64)
+}