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#include "internal.h"
#include <stdatomic.h>
#define atomic _Atomic
#define MaxFmt 128
#define atomic·load atomic_load
#define atomic·store atomic_store
static struct
{
atomic int len;
Verb verb[MaxFmt];
} formatter =
{
ATOMIC_VAR_INIT(27),
{
{' ', ·fmtflag},
{'#', ·fmtflag},
{'%', ·fmtpercent},
{'\'',·fmtflag},
{'+', ·fmtflag},
{',', ·fmtflag},
{'-', ·fmtflag},
{'C', ·fmtrune},
{'E', ·fmtfloat},
{'G', ·fmtfloat},
{'S', ·fmtutf8},
{'X', ·fmtint},
{'b', ·fmtint},
{'c', ·fmtchar},
{'d', ·fmtint},
{'e', ·fmtfloat},
{'f', ·fmtfloat},
{'g', ·fmtfloat},
{'h', ·fmtflag},
{'l', ·fmtflag},
{'n', ·fmtcount},
{'o', ·fmtint},
{'p', ·fmtint},
{'r', ·fmterr},
{'s', ·fmtstr},
{'u', ·fmtflag},
{'u', ·fmtint},
{'x', ·fmtint},
}
};
static Formatter
format(int c)
{
Verb *v, *e;
e = &formatter.verb[atomic·load(&formatter.len)];
for(v=e; v > formatter.verb; --v){
if(v->c == c)
return v->fmt;
}
return ·fmterr;
}
static char *
dispatch(fmt·State *io, char *fmt)
{
rune r;
int i, n;
io->flag = 0;
io->width = io->prec = 0;
/*
* the form of each print verb:
* % [flags] verb
* + the verb is a single character
* + each flag is either
* - a single character
* - a decimal numeric string
* - up to 2 decimal strings can be used
* - [width|*].[prec|*]
* - if missing, set to 0
* - if *, grab from varargs
*/
for(;;){
fmt += utf8·decode(fmt, &r);
io->verb = r;
switch(r){
case 0:
return nil;
case '.':
io->flag |= fmt·Width|fmt·Prec;
continue;
case '0':
if(!(io->flag & fmt·Width)){
io->flag |= fmt·Zero;
continue;
}
/* fallthrough */
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
i = 0;
while('0' <= r && r <= '9'){
i = 10*i + (r-'0');
r = *fmt++;
}
fmt--;
number:
if(io->flag & fmt·Width){
io->flag |= fmt·Prec;
io->prec = i;
}else{
io->flag |= fmt·Width;
io->width = i;
}
continue;
case '*':
i = va_arg(io->args, int);
if(i < 0){
if(io->flag&fmt·Prec){
io->flag ^= fmt·Prec;
io->prec = 0;
}
i = -i;
io->flag |= fmt·Left;
}
goto number;
}
n = format(r)(io);
if(n < 0)
return nil;
if(!n)
return fmt;
}
}
static char *
flush(fmt·State *io, char *b, int len)
{
io->n += b - io->buffer.cur;
io->buffer.cur = b;
if(!io->flush || !(*io->flush)(io) || io->buffer.cur + len >= io->buffer.end) {
io->buffer.end = io->buffer.cur;
return nil;
}
return io->buffer.cur;
}
int
fmt·do(fmt·State *io, char *fmt)
{
rune r;
int c, n;
char *b, *e;
for(;;){
b = io->buffer.cur;
e = io->buffer.end;
while((c = *(uchar *)fmt) && c != '%'){
if(utf8·onebyte(c)){
if(b + 1 > e){
if(!(b=flush(io, b, sizeof(*b))))
return -1;
e = io->buffer.end;
}
*b++ = *fmt++;
}else{
n = utf8·decode(fmt, &r);
if(b + n > e){
if(!(b=flush(io, b, sizeof(*b))))
return -1;
e = io->buffer.end;
}
while(n--)
*b++ = *fmt++;
}
fmt++;
io->n += b - io->buffer.cur;
io->buffer.cur = b;
if(c=='\0') /* we hit our nul terminator */
return io->n = n;
io->buffer.end = e;
}
if(!(fmt=dispatch(io, fmt)))
return -1;
}
}
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