[json] Optimize primitive numbers to string (50%-250% faster) (#7819)

# Which issue does this PR close?

We generally require a GitHub issue to be filed for all bug fixes and
enhancements and this helps us generate change logs for our releases.
You can link an issue to this PR using the GitHub syntax.

- Closes #7273 .

# Rationale for this change

Why are you proposing this change? If this is already explained clearly
in the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand
your changes and offer better suggestions for fixes.

# What changes are included in this PR?

There is no need to duplicate the description in the issue here but it
is sometimes worth providing a summary of the individual changes in this
PR.

Added ryu and itoa to convert primitive numbers to strings

# Are these changes tested?

We typically require tests for all PRs in order to:
1. Prevent the code from being accidentally broken by subsequent changes
2. Serve as another way to document the expected behavior of the code

If tests are not included in your PR, please explain why (for example,
are they covered by existing tests)?

I assume since I am not adding any functionality there are already tests
covering this

# Are there any user-facing changes?

If there are user-facing changes then we may require documentation to be
updated before approving the PR.

If there are any breaking changes to public APIs, please call them out.

There should not be

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

Author: abacef

arrow-json/Cargo.toml

@@ -50,6 +50,8 @@ chrono = { workspace = true }
 lexical-core = { version = "1.0", default-features = false}
 memchr = "2.7.4"
 simdutf8 = { workspace = true }
+ryu = "1.0"
+itoa = "1.0"
 
 [dev-dependencies]
 flate2 = { version = "1", default-features = false, features = ["rust_backend"] }

arrow-json/src/reader/string_array.rs

@@ -24,6 +24,9 @@ use std::marker::PhantomData;
 use crate::reader::ArrayDecoder;
 use crate::reader::tape::{Tape, TapeElement};
 
+use itoa;
+use ryu;
+
 const TRUE: &str = "true";
 const FALSE: &str = "false";
 
@@ -85,6 +88,9 @@ impl<O: OffsetSizeTrait> ArrayDecoder for StringArrayDecoder<O> {
 
         let mut builder = GenericStringBuilder::<O>::with_capacity(pos.len(), data_capacity);
 
+        let mut float_formatter = ryu::Buffer::new();
+        let mut int_formatter = itoa::Buffer::new();
+
         for p in pos {
             match tape.get(*p) {
                 TapeElement::String(idx) => {
@@ -103,20 +109,20 @@ impl<O: OffsetSizeTrait> ArrayDecoder for StringArrayDecoder<O> {
                 TapeElement::I64(high) if coerce_primitive => match tape.get(p + 1) {
                     TapeElement::I32(low) => {
                         let val = ((high as i64) << 32) | (low as u32) as i64;
-                        builder.append_value(val.to_string());
+                        builder.append_value(int_formatter.format(val));
                     }
                     _ => unreachable!(),
                 },
                 TapeElement::I32(n) if coerce_primitive => {
-                    builder.append_value(n.to_string());
+                    builder.append_value(int_formatter.format(n));
                 }
                 TapeElement::F32(n) if coerce_primitive => {
-                    builder.append_value(n.to_string());
+                    builder.append_value(int_formatter.format(n));
                 }
                 TapeElement::F64(high) if coerce_primitive => match tape.get(p + 1) {
                     TapeElement::F32(low) => {
                         let val = f64::from_bits(((high as u64) << 32) | low as u64);
-                        builder.append_value(val.to_string());
+                        builder.append_value(float_formatter.format_finite(val));
                     }
                     _ => unreachable!(),
                 },