Refactor parse_* procedures: arbitrary bases, and return (value, rest_of_string)

This commit is contained in:
Tetralux
2020-02-20 02:42:27 +00:00
parent a10d180d81
commit 190932935c
+177 -35
View File
@@ -23,7 +23,53 @@ _digit_value :: proc(r: rune) -> int {
return v;
}
parse_i64 :: proc(str: string) -> i64 {
// Parses an integer value from a string, in the given base, without a prefix.
// ```
// n, rest := strconv.parse_i64_of_base("-1234eeee", 10);
// assert(n == -1234 && rest == "eeee");
// ```
parse_i64_of_base :: proc(str: string, base: int) -> (value: i64, rest: string) {
assert(base <= 16, "base must be 1-16");
s := str;
neg := false;
if len(s) > 1 {
switch s[0] {
case '-':
neg = true;
s = s[1:];
case '+':
s = s[1:];
}
}
i := 0;
reached_end := true;
for r in s {
i += 1;
if r == '_' do continue;
v := i64(_digit_value(r));
if v >= i64(base) {
reached_end = false;
break;
}
value *= i64(base);
value += v;
}
if neg do value = -value;
rest = reached_end ? "" : s[i-1:];
return;
}
// Parses a integer value from a string, in base 10, unless there's a prefix.
// ```
// n, rest := strconv.parse_i64_maybe_prefixed("1234");
// assert(n == 1234 && rest == "");
//
// n, rest = strconv.parse_i64_maybe_prefixed("0xeeee");
// assert(n == 0xeeee && rest == "");
// ```
parse_i64_maybe_prefixed :: proc(str: string) -> (value: i64, rest: string) {
s := str;
neg := false;
if len(s) > 1 {
@@ -48,28 +94,71 @@ parse_i64 :: proc(str: string) -> i64 {
}
}
value: i64;
i := 0;
reached_end := true;
for r in s {
if r == '_' {
continue;
}
i += 1;
if r == '_' do continue;
v := i64(_digit_value(r));
if v >= base {
reached_end = false;
break;
}
value *= base;
value += v;
}
if neg do return -value;
return value;
if neg do value = -value;
rest = reached_end ? "" : s[i-1:];
return;
}
parse_u64 :: proc(str: string) -> u64 {
parse_i64 :: proc{parse_i64_maybe_prefixed, parse_i64_of_base};
// Parses an unsigned integer value from a string, in the given base, and
// without a prefix.
// ```
// n, rest := strconv.parse_u64_of_base("1234eeee", 10);
// assert(n == 1234 && rest == "eeee");
//
// n, rest = strconv.parse_u64_of_base("1234eeee", 16);
// assert(n == 0x1234eeee && rest == "");
// ```
parse_u64_of_base :: proc(str: string, base: int) -> (value: u64, rest: string) {
assert(base <= 16, "base must be 1-16");
s := str;
if len(s) > 1 && s[0] == '+' {
s = s[1:];
}
i := 0;
reached_end := true;
for r in s {
i += 1;
if r == '_' do continue;
v := u64(_digit_value(r));
if v >= u64(base) {
reached_end = false;
break;
}
value *= u64(base);
value += v;
}
rest = reached_end ? "" : s[i-1:];
return;
}
// Parses an unsigned integer value from a string in base 10, unless there's a prefix.
// ```
// n, rest := strconv.parse_u64_maybe_prefixed("1234");
// assert(n == 1234 && rest == "");
//
// n, rest = strconv.parse_u64_maybe_prefixed("0xeeee");
// assert(n == 0xeeee && rest == "");
// ```
parse_u64_maybe_prefixed :: proc(str: string) -> (value: u64, rest: string) {
s := str;
neg := false;
if len(s) > 1 && s[0] == '+' {
s = s[1:];
}
@@ -86,36 +175,75 @@ parse_u64 :: proc(str: string) -> u64 {
}
}
value: u64;
i := 0;
reached_end := true;
for r in s {
i += 1;
if r == '_' do continue;
v := u64(_digit_value(r));
if v >= base do break;
if v >= base {
reached_end = false;
break;
}
value *= base;
value += u64(v);
}
if neg do return -value;
return value;
rest = reached_end ? "" : s[i-1:];
return;
}
parse_u64 :: proc{parse_u64_maybe_prefixed, parse_u64_of_base};
// Parses an integer value of the given base, or the base implied by a prefix.
// If base is zero, assumes base 10, unless there's a prefix. e.g. '0x' for hexadecimal.
//
// ```
// n, rest := strconv.parse_int("1234"); // without prefix, inferred base 10
// assert(n == 1234 && rest == "");
//
// n, rest = strconv.parse_int("ffff", 16); // without prefix, explicit base
// assert(n == 0xffff && rest == "");
//
// n, rest = strconv.parse_int("0xffff"); // with prefix and inferred base
// assert(n == 0xffff && rest == "");
// ```
parse_int :: proc(s: string, base := 0) -> (value: int, rest: string) {
v: i64 = ---;
switch base {
case 0: v, rest = parse_i64_maybe_prefixed(s);
case: v, rest = parse_i64_of_base(s, base);
}
value = int(v);
return;
}
parse_uint :: proc(s: string, base := 0) -> (value: uint, rest: string) {
v: u64 = ---;
switch base {
case 0: v, rest = parse_u64_maybe_prefixed(s);
case: v, rest = parse_u64_of_base(s, base);
}
value = uint(v);
return;
}
parse_int :: proc(s: string) -> int {
return int(parse_i64(s));
}
parse_uint :: proc(s: string) -> uint {
return uint(parse_u64(s));
parse_f32 :: proc(s: string) -> (value: f32, rest: string) {
v, r := parse_f64(s);
return f32(v), r;
}
parse_f32 :: proc(s: string) -> f32 {
return f32(parse_f64(s));
}
parse_f64 :: proc(s: string) -> f64 {
// Parses a floating point number from a string.
// ```
// n, rest := strconv.parse_f64("12.34eee");
// assert(n == 12.34 && rest == "eee");
//
// n, rest = strconv.parse_f64("12.34");
// assert(n == 12.34 && rest == "");
// ```
parse_f64 :: proc(s: string) -> (value: f64, rest: string) {
if s == "" {
return 0;
return;
}
i := 0;
@@ -125,7 +253,6 @@ parse_f64 :: proc(s: string) -> f64 {
case '+': i += 1;
}
value: f64 = 0;
for ; i < len(s); i += 1 {
r := rune(s[i]);
if r == '_' do continue;
@@ -136,6 +263,7 @@ parse_f64 :: proc(s: string) -> f64 {
value += f64(v);
}
reached_end := true;
if i < len(s) && s[i] == '.' {
pow10: f64 = 10;
i += 1;
@@ -145,7 +273,10 @@ parse_f64 :: proc(s: string) -> f64 {
if r == '_' do continue;
v := _digit_value(r);
if v >= 10 do break;
if v >= 10 {
reached_end = false;
break;
}
value += f64(v)/pow10;
pow10 *= 10;
}
@@ -169,7 +300,10 @@ parse_f64 :: proc(s: string) -> f64 {
if r == '_' do continue;
d := u32(_digit_value(r));
if d >= 10 do break;
if d >= 10 {
reached_end = false;
break;
}
exp = exp * 10 + d;
}
if exp > 308 { exp = 308; }
@@ -180,8 +314,14 @@ parse_f64 :: proc(s: string) -> f64 {
}
}
if frac do return sign * (value/scale);
return sign * (value*scale);
if frac {
value = sign * (value/scale);
} else {
value = sign * (value*scale);
}
rest = reached_end ? "" : s[i-1:];
return;
}
@@ -203,10 +343,12 @@ itoa :: proc(buf: []byte, i: int) -> string {
return append_int(buf, i64(i), 10);
}
atoi :: proc(s: string) -> int {
return parse_int(s);
v, _ := parse_int(s);
return v;
}
atof :: proc(s: string) -> f64 {
return parse_f64(s);
v, _ := parse_f64(s);
return v;
}
ftoa :: append_float;