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refactor(parser): extract u8 not &u8 when iterating over bytes (#…
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…4568)

Iterating over `str.as_bytes()` produces `&u8`s. Dereference to `u8` in `for` statement. Should make no difference to generated assembly, purely making this change for neater code style.
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@overlookmotel
overlookmotel committed Jul 31, 2024
1 parent 59f00c0 commit 649913e
Showing 1 changed file with 35 additions and 35 deletions.
70 changes: 35 additions & 35 deletions crates/oxc_parser/src/lexer/number.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -71,15 +71,15 @@ fn parse_decimal(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
for &b in s.as_bytes() {
// The latency of the multiplication can be hidden by issuing it
// before the result is needed to improve performance on
// modern out-of-order CPU as multiplication here is slower
// than the other instructions, we can get the end result faster
// doing multiplication first and let the CPU spends other cycles
// doing other computation and get multiplication result later.
result *= 10;
let n = decimal_byte_to_value(*b);
let n = decimal_byte_to_value(b);
result += n as u64;
}
result as f64
Expand All @@ -97,10 +97,10 @@ fn parse_decimal_with_underscores(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
if *b != b'_' {
for &b in s.as_bytes() {
if b != b'_' {
result *= 10;
let n = decimal_byte_to_value(*b);
let n = decimal_byte_to_value(b);
result += n as u64;
}
}
Expand Down Expand Up @@ -159,9 +159,9 @@ fn parse_binary(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
for &b in s.as_bytes() {
result <<= 1;
result |= binary_byte_to_value(*b) as u64;
result |= binary_byte_to_value(b) as u64;
}
result as f64
}
Expand All @@ -170,8 +170,8 @@ fn parse_binary(s: &str) -> f64 {
#[inline(never)]
fn parse_binary_slow(s: &str) -> f64 {
let mut result = 0_f64;
for b in s.as_bytes() {
let value = f64::from(binary_byte_to_value(*b));
for &b in s.as_bytes() {
let value = f64::from(binary_byte_to_value(b));
result = result.mul_add(2.0, value);
}
result
Expand All @@ -191,10 +191,10 @@ fn parse_binary_with_underscores(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
if *b != b'_' {
for &b in s.as_bytes() {
if b != b'_' {
result <<= 1;
result |= binary_byte_to_value(*b) as u64;
result |= binary_byte_to_value(b) as u64;
}
}
result as f64
Expand All @@ -204,9 +204,9 @@ fn parse_binary_with_underscores(s: &str) -> f64 {
#[inline(never)]
fn parse_binary_with_underscores_slow(s: &str) -> f64 {
let mut result = 0_f64;
for b in s.as_bytes() {
if *b != b'_' {
let value = f64::from(binary_byte_to_value(*b));
for &b in s.as_bytes() {
if b != b'_' {
let value = f64::from(binary_byte_to_value(b));
result = result.mul_add(2.0, value);
}
}
Expand Down Expand Up @@ -239,8 +239,8 @@ fn parse_octal(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
let n = octal_byte_to_value(*b);
for &b in s.as_bytes() {
let n = octal_byte_to_value(b);
result <<= 3;
result |= n as u64;
}
Expand All @@ -252,8 +252,8 @@ fn parse_octal(s: &str) -> f64 {
#[allow(clippy::cast_precision_loss, clippy::cast_lossless)]
fn parse_octal_slow(s: &str) -> f64 {
let mut result = 0_f64;
for b in s.as_bytes() {
let value = f64::from(octal_byte_to_value(*b));
for &b in s.as_bytes() {
let value = f64::from(octal_byte_to_value(b));
result = result.mul_add(8.0, value);
}
result
Expand All @@ -271,9 +271,9 @@ fn parse_octal_with_underscores(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
if *b != b'_' {
let n = octal_byte_to_value(*b);
for &b in s.as_bytes() {
if b != b'_' {
let n = octal_byte_to_value(b);
result <<= 3;
result |= n as u64;
}
Expand All @@ -286,9 +286,9 @@ fn parse_octal_with_underscores(s: &str) -> f64 {
#[allow(clippy::cast_precision_loss, clippy::cast_lossless)]
fn parse_octal_with_underscores_slow(s: &str) -> f64 {
let mut result = 0_f64;
for b in s.as_bytes() {
if *b != b'_' {
let value = f64::from(octal_byte_to_value(*b));
for &b in s.as_bytes() {
if b != b'_' {
let value = f64::from(octal_byte_to_value(b));
result = result.mul_add(8.0, value);
}
}
Expand Down Expand Up @@ -333,8 +333,8 @@ fn parse_hex(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
let n = hex_byte_to_value(*b);
for &b in s.as_bytes() {
let n = hex_byte_to_value(b);
result <<= 4;
result |= n as u64;
}
Expand All @@ -345,8 +345,8 @@ fn parse_hex(s: &str) -> f64 {
#[inline(never)]
fn parse_hex_slow(s: &str) -> f64 {
let mut result = 0_f64;
for b in s.as_bytes() {
let value = f64::from(hex_byte_to_value(*b));
for &b in s.as_bytes() {
let value = f64::from(hex_byte_to_value(b));
result = result.mul_add(16.0, value);
}
result
Expand All @@ -365,9 +365,9 @@ fn parse_hex_with_underscores(s: &str) -> f64 {
}

let mut result = 0_u64;
for b in s.as_bytes() {
if *b != b'_' {
let n = hex_byte_to_value(*b);
for &b in s.as_bytes() {
if b != b'_' {
let n = hex_byte_to_value(b);
result <<= 4;
result |= n as u64;
}
Expand All @@ -379,9 +379,9 @@ fn parse_hex_with_underscores(s: &str) -> f64 {
#[inline(never)]
fn parse_hex_with_underscores_slow(s: &str) -> f64 {
let mut result = 0_f64;
for b in s.as_bytes() {
if *b != b'_' {
let value = f64::from(hex_byte_to_value(*b));
for &b in s.as_bytes() {
if b != b'_' {
let value = f64::from(hex_byte_to_value(b));
result = result.mul_add(16.0, value);
}
}
Expand Down

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