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Cr4sh/sprintf.c

Last active April 26, 2018 05:03
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Position independent sprintf without dependencies
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sprintf.c
/**
* Declaration
*/
/*
'tfp_format' really is the central function for all tinyprintf. For each output character
after formatting, the 'putf' callback is called with 2 args:
- an arbitrary void* 'putp' param defined by the user and passed unmodified from 'tfp_format';
- the character;
The 'tfp_printf' and 'tfp_sprintf' functions simply define their own callback and pass to
it the right 'putp' it is expecting.
*/
void tfp_format(void *putp, const char *format, __builtin_va_list va);
int tfp_vsnprintf(char *str, unsigned long size, const char *format, __builtin_va_list ap);
int tfp_snprintf(char *str, unsigned long size, const char *format, ...) __attribute__((format(printf, 3, 4)));
int tfp_vsprintf(char *str, const char *format, __builtin_va_list ap);
int tfp_sprintf(char *str, const char *format, ...) __attribute__((format(printf, 2, 3)));
/**
* Configuration
*/
/* Enable long int support */
#define PRINTF_LONG_SUPPORT
/* Enable long long int support (implies long int support) */
#define PRINTF_LONG_LONG_SUPPORT
/**
* Configuration adjustments
*/
#ifdef PRINTF_SIZE_T_SUPPORT
#include <sys/types.h>
#endif
#ifdef PRINTF_LONG_LONG_SUPPORT
#define PRINTF_LONG_SUPPORT
#endif
/* __SIZEOF_<type>__ defined at least by gcc */
#ifdef __SIZEOF_POINTER__
#define SIZEOF_POINTER __SIZEOF_POINTER__
#endif
#ifdef __SIZEOF_LONG_LONG__
#define SIZEOF_LONG_LONG __SIZEOF_LONG_LONG__
#endif
#ifdef __SIZEOF_LONG__
#define SIZEOF_LONG __SIZEOF_LONG__
#endif
#ifdef __SIZEOF_INT__
#define SIZEOF_INT __SIZEOF_INT__
#endif
#ifdef __GNUC__
#define _TFP_GCC_NO_INLINE_ __attribute__ ((noinline))
#else
#define _TFP_GCC_NO_INLINE_
#endif
/**
* Implementation
*/
struct param
{
char leading_zeros : 1; // Leading zeros
char alt_form : 1; // Alternate form
char upper_case : 1; // Upper case (for base16 only)
char align_left : 1; // 0 == align right (default), 1 == align left
unsigned int width; // Field width
unsigned int base; // Number base (e.g.: 8, 10, 16)
char sign; // The sign to display (if any)
char *buff; // Buffer to output
};
#ifdef PRINTF_LONG_LONG_SUPPORT
static void _TFP_GCC_NO_INLINE_ ulli2a(unsigned long long int num, struct param *p)
{
int n = 0;
unsigned long long int d = 1;
char *buff = p->buff;
while (num / d >= p->base)
{
d *= p->base;
}
while (d != 0)
{
int digit = (int)(num / d);
num %= d;
d /= p->base;
if (n || digit > 0 || d == 0)
{
*buff++ = digit + (digit < 10 ? '0' : (p->upper_case ? 'A' : 'a') - 10);
++n;
}
}
*buff = 0;
}
static void lli2a(long long int num, struct param *p)
{
if (num < 0)
{
num = -num;
p->sign = '-';
}
ulli2a(num, p);
}
#endif // PRINTF_LONG_LONG_SUPPORT
#ifdef PRINTF_LONG_SUPPORT
static void uli2a(unsigned long int num, struct param *p)
{
int n = 0;
unsigned long int d = 1;
char *buff = p->buff;
while (num / d >= p->base)
{
d *= p->base;
}
while (d != 0)
{
int digit = num / d;
num %= d;
d /= p->base;
if (n || digit > 0 || d == 0)
{
*buff++ = digit + (digit < 10 ? '0' : (p->upper_case ? 'A' : 'a') - 10);
++n;
}
}
*buff = 0;
}
static void li2a(long num, struct param *p)
{
if (num < 0)
{
num = -num;
p->sign = '-';
}
uli2a(num, p);
}
#endif // PRINTF_LONG_SUPPORT
static void ui2a(unsigned int num, struct param *p)
{
int n = 0;
unsigned int d = 1;
char *buff = p->buff;
while (num / d >= p->base)
{
d *= p->base;
}
while (d != 0)
{
int digit = num / d;
num %= d;
d /= p->base;
if (n || digit > 0 || d == 0)
{
*buff++ = digit + (digit < 10 ? '0' : (p->upper_case ? 'A' : 'a') - 10);
++n;
}
}
*buff = 0;
}
static void i2a(int num, struct param *p)
{
if (num < 0)
{
num = -num;
p->sign = '-';
}
ui2a(num, p);
}
static int a2d(char ch)
{
if (ch >= '0' && ch <= '9')
{
return ch - '0';
}
else if (ch >= 'a' && ch <= 'f')
{
return ch - 'a' + 10;
}
else if (ch >= 'A' && ch <= 'F')
{
return ch - 'A' + 10;
}
return -1;
}
static char a2u(char ch, const char **src, int base, unsigned int *nump)
{
const char *p = *src;
unsigned int num = 0;
int digit = 0;
while ((digit = a2d(ch)) >= 0)
{
if (digit > base)
{
break;
}
num = num * base + digit;
ch = *p++;
}
*src = p;
*nump = num;
return ch;
}
struct putcf_data
{
char *dest;
unsigned long dest_capacity;
unsigned long num_chars;
char is_vsnprintf;
};
static void putcf(void *p, char c)
{
struct putcf_data *data = (struct putcf_data *)p;
if (data->is_vsnprintf == 0 ||
data->num_chars < data->dest_capacity)
{
data->dest[data->num_chars] = c;
}
data->num_chars += 1;
}
static void putchw(void *putp, struct param *p)
{
char ch;
int n = p->width;
char *buff = p->buff;
/* Number of filling characters */
while (*buff++ && n > 0)
{
n--;
}
if (p->sign)
{
n--;
}
if (p->alt_form && p->base == 16)
{
n -= 2;
}
else if (p->alt_form && p->base == 8)
{
n--;
}
/* Fill with space to align to the right, before alternate or sign */
if (!p->leading_zeros && !p->align_left)
{
while (n-- > 0)
{
putcf(putp, ' ');
}
}
/* print sign */
if (p->sign)
{
putcf(putp, p->sign);
}
/* Alternate */
if (p->alt_form && p->base == 16)
{
putcf(putp, '0');
putcf(putp, (p->upper_case ? 'X' : 'x'));
}
else if (p->alt_form && p->base == 8)
{
putcf(putp, '0');
}
/* Fill with zeros, after alternate or sign */
if (p->leading_zeros)
{
while (n-- > 0)
{
putcf(putp, '0');
}
}
/* Put actual buffer */
buff = p->buff;
while ((ch = *buff++))
{
putcf(putp, ch);
}
/* Fill with space to align to the left, after string */
if (!p->leading_zeros && p->align_left)
{
while (n-- > 0)
{
putcf(putp, ' ');
}
}
}
void tfp_format(void *putp, const char *format, __builtin_va_list va)
{
struct param p;
char ch;
#ifdef PRINTF_LONG_SUPPORT
/* long = 64b on some architectures */
char bf[23];
#else
/* int = 32b on some architectures */
char bf[12];
#endif
p.buff = bf;
while ((ch = *(format++)))
{
if (ch != '%')
{
putcf(putp, ch);
}
else
{
#ifdef PRINTF_LONG_SUPPORT
/* 1 for long, 2 for long long */
char lng = 0;
#endif
/* Init parameter struct */
p.leading_zeros = 0;
p.alt_form = 0;
p.width = 0;
p.align_left = 0;
p.sign = 0;
/* Flags */
while ((ch = *(format++)))
{
if (ch == '-')
{
p.align_left = 1;
continue;
}
else if (ch == '0')
{
p.leading_zeros = 1;
continue;
}
else if (ch == '#')
{
p.alt_form = 1;
continue;
}
else
{
break;
}
break;
}
/* Width */
if (ch >= '0' && ch <= '9')
{
ch = a2u(ch, &format, 10, &(p.width));
}
/**
* We accept 'x.y' format but don't support it completely:
* we ignore the 'y' digit => this ignores 0-fill size and makes it == width (ie. 'x')
*/
if (ch == '.')
{
/* zero-padding */
p.leading_zeros = 1;
/* ignore actual 0-fill size: */
do
{
ch = *(format++);
} while ((ch >= '0') && (ch <= '9'));
}
#ifdef PRINTF_SIZE_T_SUPPORT
#ifdef PRINTF_LONG_SUPPORT
if (ch == 'z')
{
ch = *(format++);
if (sizeof(size_t) == sizeof(unsigned long int))
{
lng = 1;
}
#ifdef PRINTF_LONG_LONG_SUPPORT
else if (sizeof(size_t) == sizeof(unsigned long long int))
{
lng = 2;
}
#endif
}
else
#endif // PRINTF_LONG_SUPPORT
#endif // PRINTF_SIZE_T_SUPPORT
#ifdef PRINTF_LONG_SUPPORT
if (ch == 'l')
{
ch = *(format++);
lng = 1;
#ifdef PRINTF_LONG_LONG_SUPPORT
if (ch == 'l')
{
ch = *(format++);
lng = 2;
}
#endif
}
#endif // PRINTF_LONG_SUPPORT
if (ch == 0)
{
goto abort;
}
else if (ch == 'u')
{
p.base = 10;
#ifdef PRINTF_LONG_SUPPORT
#ifdef PRINTF_LONG_LONG_SUPPORT
if (2 == lng)
{
ulli2a(__builtin_va_arg(va, unsigned long long int), &p);
}
else
#endif
if (1 == lng)
{
uli2a(__builtin_va_arg(va, unsigned long int), &p);
}
else
#endif // PRINTF_LONG_SUPPORT
{
ui2a(__builtin_va_arg(va, unsigned int), &p);
}
putchw(putp, &p);
}
else if (ch == 'd' || ch == 'i')
{
p.base = 10;
#ifdef PRINTF_LONG_SUPPORT
#ifdef PRINTF_LONG_LONG_SUPPORT
if (2 == lng)
{
lli2a(__builtin_va_arg(va, long long int), &p);
}
else
#endif
if (1 == lng)
{
li2a(__builtin_va_arg(va, long int), &p);
}
else
#endif // PRINTF_LONG_SUPPORT
{
i2a(__builtin_va_arg(va, int), &p);
}
putchw(putp, &p);
#ifdef SIZEOF_POINTER
}
else if (ch == 'p')
{
p.alt_form = 1;
# if defined(SIZEOF_INT) && SIZEOF_POINTER <= SIZEOF_INT
lng = 0;
# elif defined(SIZEOF_LONG) && SIZEOF_POINTER <= SIZEOF_LONG
lng = 1;
# elif defined(SIZEOF_LONG_LONG) && SIZEOF_POINTER <= SIZEOF_LONG_LONG
lng = 2;
#endif
#endif // SIZEOF_POINTER
}
else if (ch == 'x' || ch == 'X')
{
p.base = 16;
p.upper_case = (ch == 'X') ? 1 : 0;
#ifdef PRINTF_LONG_SUPPORT
#ifdef PRINTF_LONG_LONG_SUPPORT
if (2 == lng)
{
ulli2a(__builtin_va_arg(va, unsigned long long int), &p);
}
else
#endif
if (1 == lng)
{
uli2a(__builtin_va_arg(va, unsigned long int), &p);
}
else
#endif // PRINTF_LONG_SUPPORT
{
ui2a(__builtin_va_arg(va, unsigned int), &p);
}
putchw(putp, &p);
}
else if (ch == 'o')
{
p.base = 8;
ui2a(__builtin_va_arg(va, unsigned int), &p);
putchw(putp, &p);
}
else if (ch == 'c')
{
putcf(putp, (char)(__builtin_va_arg(va, int)));
}
else if (ch == 's')
{
p.buff = __builtin_va_arg(va, char *);
putchw(putp, &p);
p.buff = bf;
}
else if (ch == '%')
{
putcf(putp, ch);
}
else
{
break;
}
}
}
abort:;
}
int tfp_vsnprintf(char *str, unsigned long size, const char *format, __builtin_va_list ap)
{
struct putcf_data data;
if (size < 1)
{
return 0;
}
data.dest = str;
data.dest_capacity = size - 1;
data.num_chars = 0;
data.is_vsnprintf = 1;
tfp_format(&data, format, ap);
if (data.num_chars < data.dest_capacity)
{
data.dest[data.num_chars] = '\0';
}
else
{
data.dest[data.dest_capacity] = '\0';
}
return (int)data.num_chars;
}
int tfp_snprintf(char *str, unsigned long size, const char *format, ...)
{
__builtin_va_list ap;
int retval;
__builtin_va_start(ap, format);
retval = tfp_vsnprintf(str, size, format, ap);
__builtin_va_end(ap);
return retval;
}
int tfp_vsprintf(char *str, const char *format, __builtin_va_list ap)
{
struct putcf_data data;
data.dest = str;
data.dest_capacity = 0;
data.num_chars = 0;
data.is_vsnprintf = 0;
tfp_format(&data, format, ap);
data.dest[data.num_chars] = '\0';
return (int)data.num_chars;
}
int tfp_sprintf(char *str, const char *format, ...)
{
__builtin_va_list ap;
int retval;
__builtin_va_start(ap, format);
retval = tfp_vsprintf(str, format, ap);
__builtin_va_end(ap);
return retval;
}
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