%e and %g support in fmt.printf

This commit is contained in:
gingerBill
2019-03-15 23:13:06 +00:00
parent 716373836c
commit 332e598357
3 changed files with 126 additions and 26 deletions
+75 -15
View File
@@ -213,28 +213,28 @@ append_float :: proc(buf: []byte, f: f64, fmt: byte, prec, bit_size: int) -> str
DecimalSlice :: struct {
Decimal_Slice :: struct {
digits: []byte,
count: int,
decimal_point: int,
neg: bool,
}
FloatInfo :: struct {
Float_Info :: struct {
mantbits: uint,
expbits: uint,
bias: int,
}
_f16_info := FloatInfo{10, 5, -15};
_f32_info := FloatInfo{23, 8, -127};
_f64_info := FloatInfo{52, 11, -1023};
_f16_info := Float_Info{10, 5, -15};
_f32_info := Float_Info{23, 8, -127};
_f64_info := Float_Info{52, 11, -1023};
generic_ftoa :: proc(buf: []byte, val: f64, fmt: byte, prec, bit_size: int) -> []byte {
bits: u64;
flt: ^FloatInfo;
flt: ^Float_Info;
switch bit_size {
case 32:
bits = u64(transmute(u32)f32(val));
@@ -276,11 +276,11 @@ generic_ftoa :: proc(buf: []byte, val: f64, fmt: byte, prec, bit_size: int) -> [
d := &d_;
assign(d, mant);
shift(d, exp - int(flt.mantbits));
digs: DecimalSlice;
digs: Decimal_Slice;
shortest := prec < 0;
if shortest {
round_shortest(d, mant, exp, flt);
digs = DecimalSlice{digits = d.digits[:], count = d.count, decimal_point = d.decimal_point};
digs = Decimal_Slice{digits = d.digits[:], count = d.count, decimal_point = d.decimal_point};
switch fmt {
case 'e', 'E': prec = digs.count-1;
case 'f', 'F': prec = max(digs.count-digs.decimal_point, 0);
@@ -297,14 +297,14 @@ generic_ftoa :: proc(buf: []byte, val: f64, fmt: byte, prec, bit_size: int) -> [
round(d, prec);
}
digs = DecimalSlice{digits = d.digits[:], count = d.count, decimal_point = d.decimal_point};
digs = Decimal_Slice{digits = d.digits[:], count = d.count, decimal_point = d.decimal_point};
}
return format_digits(buf, shortest, neg, digs, prec, fmt);
}
format_digits :: proc(buf: []byte, shortest: bool, neg: bool, digs: DecimalSlice, prec: int, fmt: byte) -> []byte {
format_digits :: proc(buf: []byte, shortest: bool, neg: bool, digs: Decimal_Slice, prec: int, fmt: byte) -> []byte {
Buffer :: struct {
b: []byte,
n: int,
@@ -347,12 +347,72 @@ format_digits :: proc(buf: []byte, shortest: bool, neg: bool, digs: DecimalSlice
return to_bytes(b);
case 'e', 'E':
panic("strconv: e/E float printing is not yet supported");
return to_bytes(b); // TODO
add_bytes(&b, neg ? '-' : '+');
ch := byte('0');
if digs.count != 0 {
ch = digs.digits[0];
}
add_bytes(&b, ch);
if prec > 0 {
add_bytes(&b, '.');
i := 1;
m := min(digs.count, prec+1);
if i < m {
add_bytes(&b, ..digs.digits[i:m]);
i = m;
}
for ; i <= prec; i += 1 {
add_bytes(&b, '0');
}
}
add_bytes(&b, fmt);
exp := digs.decimal_point-1;
if digs.count == 0 {
// Zero has exponent of 0
exp = 0;
}
ch = '+';
if exp < 0 {
ch = '-';
exp = -exp;
}
add_bytes(&b, ch);
switch {
case exp < 10: add_bytes(&b, '0', byte(exp)+'0'); // add prefix 0
case exp < 100: add_bytes(&b, byte(exp/10)+'0', byte(exp%10)+'0');
case: add_bytes(&b, byte(exp/100)+'0', byte(exp/10)%10+'0', byte(exp%10)+'0');
}
return to_bytes(b);
case 'g', 'G':
panic("strconv: g/G float printing is not yet supported");
return to_bytes(b); // TODO
eprec := prec;
if eprec > digs.count && digs.count >= digs.decimal_point {
eprec = digs.count;
}
if shortest {
eprec = 6;
}
exp := digs.decimal_point - 1;
if exp < -4 || exp >= eprec {
if prec > digs.count {
prec = digs.count;
}
return format_digits(buf, shortest, neg, digs, prec-1, fmt+'e'-'g'); // keep the same case
}
if prec > digs.decimal_point {
prec = digs.count;
}
return format_digits(buf, shortest, neg, digs, max(prec-digs.decimal_point, 0), 'f');
case:
add_bytes(&b, '%', fmt);
@@ -362,7 +422,7 @@ format_digits :: proc(buf: []byte, shortest: bool, neg: bool, digs: DecimalSlice
}
round_shortest :: proc(d: ^Decimal, mant: u64, exp: int, flt: ^FloatInfo) {
round_shortest :: proc(d: ^Decimal, mant: u64, exp: int, flt: ^Float_Info) {
if mant == 0 { // If mantissa is zero, the number is zero
d.count = 0;
return;