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// Formatting primitives used directly by interpolation and named converters.
// Keep this module free of interpolation: sys can build itself from source.
// spec's low byte is the format kind; bits 8..12 are flags: - + space # 0.
val begin = { -> new aryu8(); };
val end = { aryu8 b ->
val bytes = new u8[b.len];
ary.copy(bytes,0,b.buf,0,b.len);
u8[~] result = bytes;
result;
};
val _pad = { !aryu8 b, i64 n, u8 c ->
for( i64 i=0; i<n; i++ ) b.add(c);
b;
};
val string = { !aryu8 b, u8[~] s, i64 spec, i64 width, i64 precision ->
i64 len=s#;
if( precision>=0 && precision<len ) len=precision;
i64 pad=width-len;
if( !(spec&256) ) _pad(b,pad,' ');
for( i64 i=0; i<len; i++ ) b.add(s[i]);
if( spec&256 ) _pad(b,pad,' ');
b;
};
val integer = { !aryu8 b, i64 value, i64 spec, i64 width, i64 precision ->
i64 kind=spec&255;
if( kind=='b' ) return string(b,value ? "true" : "false",spec,width,-1);
if( kind=='c' ) {
if( !(spec&256) ) _pad(b,width-1,' ');
u8 c=value;
b.add(c);
if( spec&256 ) _pad(b,width-1,' ');
return b;
}
bool signed=kind==0 || kind=='d' || kind=='i';
i64 base=kind=='o' ? 8 : (kind=='x' || kind=='X' ? 16 : 10);
u8[~] alphabet=kind=='X' ? "0123456789ABCDEF" : "0123456789abcdef";
val digits=new u8[22]; // Maximum: 22 octal digits for a 64-bit integer.
i64 count=0, n=value;
// Signed decimal stays nonpositive, including the minimum i64.
if( signed && n>0 ) n=-n;
if( n==0 && precision!=0 ) digits[count++]='0';
while( n!=0 ) {
i64 q=0, r=0;
if( signed ) { q=n/base; r=q*base-n; }
else {
// Unsigned division without a u64 type. Halving first makes
// the dividend nonnegative; the remainder needs at most one fix.
q=((n>>>1)/base)*2;
r=n-q*base;
if( r>=base ) { q++; r-=base; }
}
digits[count++]=alphabet[r];
n=q;
}
u8[~] !prefix="";
if( signed ) {
if( value<0 ) prefix="-";
else if( spec&512 ) prefix="+";
else if( spec&1024 ) prefix=" ";
} else if( (spec&2048) && value!=0 ) {
if( kind=='x' ) prefix="0x";
if( kind=='X' ) prefix="0X";
}
i64 zeros=precision>count ? precision-count : 0;
// Alternate octal always begins with a zero, including precision-zero 0.
if( kind=='o' && (spec&2048) && zeros==0 && (count==0 || digits[count-1]!='0') ) zeros=1;
i64 pad=width-prefix#-zeros-count;
bool left=(spec&256)!=0;
bool zero=(spec&4096)!=0 && precision<0 && !left;
if( !left && !zero ) _pad(b,pad,' ');
b.addAry(prefix);
if( zero ) _pad(b,pad,'0');
_pad(b,zeros,'0');
while( count>0 ) b.add(digits[--count]);
if( left ) _pad(b,pad,' ');
b;
};
// Only conversion of binary floating-point values is delegated to libc.
// The fixed signature accepts a validated format and returns a byte string.
{ f64 i64 i64 i64 -> u8[~] } simple_text_float = "C";
val floating = { !aryu8 b, f64 value, i64 spec, i64 width, i64 precision ->
b.addAry(simple_text_float(value,spec,width,precision));
};
// Explicitly named, typed conversions share the same formatting routines.
val int = { i64 x -> end(integer (begin(),x, 0 ,0,-1)); };
val flt = { f64 x -> end(floating(begin(),x, 0 ,0,-1)); };
val f32 = { f32 x -> end(floating(begin(),x,'g',0,-1)); };
val f64 = { f64 x -> end(floating(begin(),x, 0 ,0,-1)); };
val char = { i64 x -> end(integer (begin(),x,'c',0,-1)); };
val bool = { bool x -> end(integer (begin(),x,'b',0,-1)); };
val hex = { i64 x -> end(integer (begin(),x,'x',0,-1)); };
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