1 files changed, 119 insertions, 0 deletions
diff --git a/rust/vendor/num-bigint/src/biguint/serde.rs b/rust/vendor/num-bigint/src/biguint/serde.rs
new file mode 100644
index 0000000..3240f09
--- /dev/null
+++ b/rust/vendor/num-bigint/src/biguint/serde.rs
@@ -0,0 +1,119 @@
+use super::{biguint_from_vec, BigUint};
+
+use crate::std_alloc::Vec;
+
+use core::{cmp, fmt, mem};
+use serde::de::{SeqAccess, Visitor};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+// `cautious` is based on the function of the same name in `serde`, but specialized to `u32`:
+// https://github.com/dtolnay/serde/blob/399ef081ecc36d2f165ff1f6debdcbf6a1dc7efb/serde/src/private/size_hint.rs#L11-L22
+fn cautious(hint: Option<usize>) -> usize {
+    const MAX_PREALLOC_BYTES: usize = 1024 * 1024;
+
+    cmp::min(
+        hint.unwrap_or(0),
+        MAX_PREALLOC_BYTES / mem::size_of::<u32>(),
+    )
+}
+
+impl Serialize for BigUint {
+    #[cfg(not(u64_digit))]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        // Note: do not change the serialization format, or it may break forward
+        // and backward compatibility of serialized data!  If we ever change the
+        // internal representation, we should still serialize in base-`u32`.
+        let data: &[u32] = &self.data;
+        data.serialize(serializer)
+    }
+
+    #[cfg(u64_digit)]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        use serde::ser::SerializeSeq;
+
+        if let Some((&last, data)) = self.data.split_last() {
+            let last_lo = last as u32;
+            let last_hi = (last >> 32) as u32;
+            let u32_len = data.len() * 2 + 1 + (last_hi != 0) as usize;
+            let mut seq = serializer.serialize_seq(Some(u32_len))?;
+            for &x in data {
+                seq.serialize_element(&(x as u32))?;
+                seq.serialize_element(&((x >> 32) as u32))?;
+            }
+            seq.serialize_element(&last_lo)?;
+            if last_hi != 0 {
+                seq.serialize_element(&last_hi)?;
+            }
+            seq.end()
+        } else {
+            let data: &[u32] = &[];
+            data.serialize(serializer)
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for BigUint {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_seq(U32Visitor)
+    }
+}
+
+struct U32Visitor;
+
+impl<'de> Visitor<'de> for U32Visitor {
+    type Value = BigUint;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+        formatter.write_str("a sequence of unsigned 32-bit numbers")
+    }
+
+    #[cfg(not(u64_digit))]
+    fn visit_seq<S>(self, mut seq: S) -> Result<Self::Value, S::Error>
+    where
+        S: SeqAccess<'de>,
+    {
+        let len = cautious(seq.size_hint());
+        let mut data = Vec::with_capacity(len);
+
+        while let Some(value) = seq.next_element::<u32>()? {
+            data.push(value);
+        }
+
+        Ok(biguint_from_vec(data))
+    }
+
+    #[cfg(u64_digit)]
+    fn visit_seq<S>(self, mut seq: S) -> Result<Self::Value, S::Error>
+    where
+        S: SeqAccess<'de>,
+    {
+        use crate::big_digit::BigDigit;
+        use num_integer::Integer;
+
+        let u32_len = cautious(seq.size_hint());
+        let len = Integer::div_ceil(&u32_len, &2);
+        let mut data = Vec::with_capacity(len);
+
+        while let Some(lo) = seq.next_element::<u32>()? {
+            let mut value = BigDigit::from(lo);
+            if let Some(hi) = seq.next_element::<u32>()? {
+                value |= BigDigit::from(hi) << 32;
+                data.push(value);
+            } else {
+                data.push(value);
+                break;
+            }
+        }
+
+        Ok(biguint_from_vec(data))
+    }
+}