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Add support for hex integer literals

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This commit is contained in:
Nick Fitzgerald
2021-11-02 15:15:07 -07:00
committed by Chris Fallin
parent 8f5dffab72
commit bd8c7faf12
1 changed files with 37 additions and 10 deletions
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47
cranelift/isle/isle/src/lexer.rs
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@@ -248,21 +248,48 @@ impl<'a> Lexer<'a> {
} else {
false
};
let mut num = 0_i64;
while self.pos.offset < self.buf.len()
&& (self.buf[self.pos.offset] >= b'0' && self.buf[self.pos.offset] <= b'9')
let mut radix = 10;
// Check for hex literals.
if self.buf.get(self.pos.offset).copied() == Some(b'0')
&& self.buf.get(self.pos.offset + 1).copied() == Some(b'x')
{
let base = num
.checked_mul(10)
.ok_or_else(|| self.error(start_pos, "integer literal too large"))?;
num = base
.checked_add((self.buf[self.pos.offset] - b'0') as i64)
.ok_or_else(|| self.error(start_pos, "integer literal too large"))?;
self.advance_pos();
self.advance_pos();
radix = 16;
}
// Find the range in the buffer for this integer literal. We'll
// pass this range to `i64::from_str_radix` to do the actual
// string-to-integer conversion.
let start_offset = self.pos.offset;
while self.pos.offset < self.buf.len()
&& ((radix == 10
&& self.buf[self.pos.offset] >= b'0'
&& self.buf[self.pos.offset] <= b'9')
|| (radix == 16
&& ((self.buf[self.pos.offset] >= b'0'
&& self.buf[self.pos.offset] <= b'9')
|| (self.buf[self.pos.offset] >= b'a'
&& self.buf[self.pos.offset] <= b'f')
|| (self.buf[self.pos.offset] >= b'A'
&& self.buf[self.pos.offset] <= b'F'))))
{
self.advance_pos();
}
let end_offset = self.pos.offset;
let num = i64::from_str_radix(
std::str::from_utf8(&self.buf[start_offset..end_offset]).unwrap(),
radix,
)
.map_err(|e| self.error(start_pos, e.to_string()))?;
let tok = if neg {
Token::Int(-num)
Token::Int(num.checked_neg().ok_or_else(|| {
self.error(start_pos, "integer literal cannot fit in i64")
})?)
} else {
Token::Int(num)
};