269 lines
7.1 KiB
V
269 lines
7.1 KiB
V
// Copyright (c) 2019-2020 Alexander Medvednikov. All rights reserved.
|
|
// Use of this source code is governed by an MIT license
|
|
// that can be found in the LICENSE file.
|
|
// TODO: use optionals, or some way to return default with error.
|
|
module strconv
|
|
|
|
const (
|
|
// int_size is the size in bits of an int or uint value.
|
|
// int_size = 32 << (~u32(0) >> 63)
|
|
// max_u64 = u64(u64(1 << 63) - 1)
|
|
int_size = 32
|
|
max_u64 = u64(C.UINT64_MAX) // use this until we add support
|
|
)
|
|
|
|
fn byte_to_lower(c byte) byte {
|
|
return c | (`x` - `X`)
|
|
}
|
|
|
|
// common_parse_uint is called by parse_uint and allows the parsing
|
|
// to stop on non or invalid digit characters and return the result so far
|
|
pub fn common_parse_uint(s string, _base int, _bit_size int, error_on_non_digit bool, error_on_high_digit bool) u64 {
|
|
mut bit_size := _bit_size
|
|
mut base := _base
|
|
if s.len < 1 || !underscore_ok(s) {
|
|
// return error('parse_uint: syntax error $s')
|
|
return u64(0)
|
|
}
|
|
base0 := base == 0
|
|
mut start_index := 0
|
|
if 2 <= base && base <= 36 {
|
|
// valid base; nothing to do
|
|
}
|
|
else if base == 0 {
|
|
// Look for octal, hex prefix.
|
|
base = 10
|
|
if s[0] == `0` {
|
|
if s.len >= 3 && byte_to_lower(s[1]) == `b` {
|
|
base = 2
|
|
start_index += 2
|
|
}
|
|
else if s.len >= 3 && byte_to_lower(s[1]) == `o` {
|
|
base = 8
|
|
start_index += 2
|
|
}
|
|
else if s.len >= 3 && byte_to_lower(s[1]) == `x` {
|
|
base = 16
|
|
start_index += 2
|
|
}
|
|
// manage leading zeros in decimal base's numbers
|
|
else if s.len >= 2 && (s[1] >= `0` && s[1] <= `9`) {
|
|
base = 10
|
|
start_index++
|
|
}
|
|
else {
|
|
base = 8
|
|
start_index++
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
// return error('parse_uint: base error $s - $base')
|
|
return u64(0)
|
|
}
|
|
if bit_size == 0 {
|
|
bit_size = int_size
|
|
}
|
|
else if bit_size < 0 || bit_size > 64 {
|
|
// return error('parse_uint: bitsize error $s - $bit_size')
|
|
return u64(0)
|
|
}
|
|
// Cutoff is the smallest number such that cutoff*base > maxUint64.
|
|
// Use compile-time constants for common cases.
|
|
cutoff := max_u64 / u64(base) + u64(1)
|
|
max_val := if bit_size == 64 { max_u64 } else { (u64(1)<<u64(bit_size)) - u64(1) }
|
|
mut underscores := false
|
|
mut n := u64(0)
|
|
for i in start_index .. s.len {
|
|
c := s[i]
|
|
cl := byte_to_lower(c)
|
|
mut d := byte(0)
|
|
if c == `_` && base0 {
|
|
// underscore_ok already called
|
|
underscores = true
|
|
continue
|
|
}
|
|
else if `0` <= c && c <= `9` {
|
|
d = c - `0`
|
|
}
|
|
else if `a` <= cl && cl <= `z` {
|
|
d = cl - `a` + 10
|
|
}
|
|
else {
|
|
if error_on_non_digit {
|
|
// return error('parse_uint: syntax error $s')
|
|
return u64(0)
|
|
}
|
|
else {
|
|
break
|
|
}
|
|
}
|
|
if d >= byte(base) {
|
|
if error_on_high_digit {
|
|
// return error('parse_uint: syntax error $s')
|
|
return u64(0)
|
|
}
|
|
else {
|
|
break
|
|
}
|
|
}
|
|
if n >= cutoff {
|
|
// n*base overflows
|
|
// return error('parse_uint: range error $s')
|
|
return max_val
|
|
}
|
|
n *= u64(base)
|
|
n1 := n + u64(d)
|
|
if n1 < n || n1 > max_val {
|
|
// n+v overflows
|
|
// return error('parse_uint: range error $s')
|
|
return max_val
|
|
}
|
|
n = n1
|
|
}
|
|
if underscores && !underscore_ok(s) {
|
|
// return error('parse_uint: syntax error $s')
|
|
return u64(0)
|
|
}
|
|
return n
|
|
}
|
|
|
|
// parse_uint is like parse_int but for unsigned numbers.
|
|
pub fn parse_uint(s string, _base int, _bit_size int) u64 {
|
|
return common_parse_uint(s, _base, _bit_size, true, true)
|
|
}
|
|
|
|
// common_parse_int is called by parse int and allows the parsing
|
|
// to stop on non or invalid digit characters and return the result so far
|
|
pub fn common_parse_int(_s string, base int, _bit_size int, error_on_non_digit bool, error_on_high_digit bool) i64 {
|
|
mut s := _s
|
|
mut bit_size := _bit_size
|
|
if s.len < 1 {
|
|
// return error('parse_int: syntax error $s')
|
|
return i64(0)
|
|
}
|
|
// Pick off leading sign.
|
|
mut neg := false
|
|
if s[0] == `+` {
|
|
s = s[1..]
|
|
}
|
|
else if s[0] == `-` {
|
|
neg = true
|
|
s = s[1..]
|
|
}
|
|
// Convert unsigned and check range.
|
|
// un := parse_uint(s, base, bit_size) or {
|
|
// return i64(0)
|
|
// }
|
|
un := common_parse_uint(s, base, bit_size, error_on_non_digit, error_on_high_digit)
|
|
if un == 0 {
|
|
return i64(0)
|
|
}
|
|
if bit_size == 0 {
|
|
bit_size = int_size
|
|
}
|
|
// TODO: check should u64(bit_size-1) be size of int (32)?
|
|
cutoff := u64(1)<<u64(bit_size - 1)
|
|
if !neg && un >= cutoff {
|
|
// return error('parse_int: range error $s0')
|
|
return i64(cutoff - u64(1))
|
|
}
|
|
if neg && un > cutoff {
|
|
// return error('parse_int: range error $s0')
|
|
return -i64(cutoff)
|
|
}
|
|
return if neg { -i64(un) } else { i64(un) }
|
|
}
|
|
|
|
// parse_int interprets a string s in the given base (0, 2 to 36) and
|
|
// bit size (0 to 64) and returns the corresponding value i.
|
|
//
|
|
// If the base argument is 0, the true base is implied by the string's
|
|
// prefix: 2 for "0b", 8 for "0" or "0o", 16 for "0x", and 10 otherwise.
|
|
// Also, for argument base 0 only, underscore characters are permitted
|
|
// as defined by the Go syntax for integer literals.
|
|
//
|
|
// The bitSize argument specifies the integer type
|
|
// that the result must fit into. Bit sizes 0, 8, 16, 32, and 64
|
|
// correspond to int, int8, int16, int32, and int64.
|
|
// If bitSize is below 0 or above 64, an error is returned.
|
|
pub fn parse_int(_s string, base int, _bit_size int) i64 {
|
|
return common_parse_int(_s, base, _bit_size, true, true)
|
|
}
|
|
|
|
// atoi is equivalent to parse_int(s, 10, 0), converted to type int.
|
|
pub fn atoi(s string) int {
|
|
if (int_size == 32 && (0 < s.len && s.len < 10)) || (int_size == 64 && (0 < s.len && s.len < 19)) {
|
|
// Fast path for small integers that fit int type.
|
|
mut start_idx := 0
|
|
if s[0] == `-` || s[0] == `+` {
|
|
start_idx++
|
|
if s.len - start_idx < 1 {
|
|
// return 0, &NumError{fnAtoi, s0, ErrSyntax}
|
|
return 0
|
|
}
|
|
}
|
|
mut n := 0
|
|
for i in start_idx .. s.len {
|
|
ch := s[i] - `0`
|
|
if ch > 9 {
|
|
// return 0, &NumError{fnAtoi, s0, ErrSyntax}
|
|
return 0
|
|
}
|
|
n = n * 10 + int(ch)
|
|
}
|
|
return if s[0] == `-` { -n } else { n }
|
|
}
|
|
// Slow path for invalid, big, or underscored integers.
|
|
int64 := parse_int(s, 10, 0)
|
|
return int(int64)
|
|
}
|
|
|
|
// underscore_ok reports whether the underscores in s are allowed.
|
|
// Checking them in this one function lets all the parsers skip over them simply.
|
|
// Underscore must appear only between digits or between a base prefix and a digit.
|
|
fn underscore_ok(s string) bool {
|
|
// saw tracks the last character (class) we saw:
|
|
// ^ for beginning of number,
|
|
// 0 for a digit or base prefix,
|
|
// _ for an underscore,
|
|
// ! for none of the above.
|
|
mut saw := `^`
|
|
mut i := 0
|
|
// Optional sign.
|
|
if s.len >= 1 && (s[0] == `-` || s[0] == `+`) {
|
|
i++
|
|
}
|
|
// Optional base prefix.
|
|
mut hex := false
|
|
if s.len - i >= 2 && s[i] == `0` && (byte_to_lower(s[i + 1]) == `b` || byte_to_lower(s[i + 1]) == `o` || byte_to_lower(s[i + 1]) == `x`) {
|
|
saw = `0` // base prefix counts as a digit for "underscore as digit separator"
|
|
hex = byte_to_lower(s[i + 1]) == `x`
|
|
i += 2
|
|
}
|
|
// Number proper.
|
|
for ; i < s.len; i++ {
|
|
// Digits are always okay.
|
|
if (`0` <= s[i] && s[i] <= `9`) || (hex && `a` <= byte_to_lower(s[i]) && byte_to_lower(s[i]) <= `f`) {
|
|
saw = `0`
|
|
continue
|
|
}
|
|
// Underscore must follow digit.
|
|
if s[i] == `_` {
|
|
if saw != `0` {
|
|
return false
|
|
}
|
|
saw = `_`
|
|
continue
|
|
}
|
|
// Underscore must also be followed by digit.
|
|
if saw == `_` {
|
|
return false
|
|
}
|
|
// Saw non-digit, non-underscore.
|
|
saw = `!`
|
|
}
|
|
return saw != `_`
|
|
}
|
|
|