diff options
Diffstat (limited to 'klibc/klibc/vsnprintf.c')
| -rw-r--r-- | klibc/klibc/vsnprintf.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/klibc/klibc/vsnprintf.c b/klibc/klibc/vsnprintf.c new file mode 100644 index 0000000000..5cb9331954 --- /dev/null +++ b/klibc/klibc/vsnprintf.c @@ -0,0 +1,433 @@ +/* + * vsnprintf.c + * + * vsnprintf(), from which the rest of the printf() + * family is built + */ + +#include <stdarg.h> +#include <stddef.h> +#include <inttypes.h> +#include <string.h> +#include <limits.h> +#include <stdio.h> + +enum flags { + FL_ZERO = 0x01, /* Zero modifier */ + FL_MINUS = 0x02, /* Minus modifier */ + FL_PLUS = 0x04, /* Plus modifier */ + FL_TICK = 0x08, /* ' modifier */ + FL_SPACE = 0x10, /* Space modifier */ + FL_HASH = 0x20, /* # modifier */ + FL_SIGNED = 0x40, /* Number is signed */ + FL_UPPER = 0x80 /* Upper case digits */ +}; + +/* These may have to be adjusted on certain implementations */ +enum ranks { + rank_char = -2, + rank_short = -1, + rank_int = 0, + rank_long = 1, + rank_longlong = 2 +}; + +#define MIN_RANK rank_char +#define MAX_RANK rank_longlong + +#define INTMAX_RANK rank_longlong +#define SIZE_T_RANK rank_long +#define PTRDIFF_T_RANK rank_long + +#define EMIT(x) ({ if (o<n){*q++ = (x);} o++; }) + +static size_t +format_int(char *q, size_t n, uintmax_t val, enum flags flags, + int base, int width, int prec) +{ + char *qq; + size_t o = 0, oo; + static const char lcdigits[] = "0123456789abcdef"; + static const char ucdigits[] = "0123456789ABCDEF"; + const char *digits; + uintmax_t tmpval; + int minus = 0; + int ndigits = 0, nchars; + int tickskip, b4tick; + + /* Select type of digits */ + digits = (flags & FL_UPPER) ? ucdigits : lcdigits; + + /* If signed, separate out the minus */ + if ( flags & FL_SIGNED && (intmax_t)val < 0 ) { + minus = 1; + val = (uintmax_t)(-(intmax_t)val); + } + + /* Count the number of digits needed. This returns zero for 0. */ + tmpval = val; + while ( tmpval ) { + tmpval /= base; + ndigits++; + } + + /* Adjust ndigits for size of output */ + + if ( flags & FL_HASH && base == 8 ) { + if ( prec < ndigits+1 ) + prec = ndigits+1; + } + + if ( ndigits < prec ) { + ndigits = prec; /* Mandatory number padding */ + } else if ( val == 0 ) { + ndigits = 1; /* Zero still requires space */ + } + + /* For ', figure out what the skip should be */ + if ( flags & FL_TICK ) { + tickskip = (base == 16) ? 4 : 3; + } else { + tickskip = ndigits; /* No tick marks */ + } + + /* Tick marks aren't digits, but generated by the number converter */ + ndigits += (ndigits-1)/tickskip; + + /* Now compute the number of nondigits */ + nchars = ndigits; + + if ( minus || (flags & (FL_PLUS|FL_SPACE)) ) + nchars++; /* Need space for sign */ + if ( (flags & FL_HASH) && base == 16 ) { + nchars += 2; /* Add 0x for hex */ + } + + /* Emit early space padding */ + if ( !(flags & (FL_MINUS|FL_ZERO)) && width > nchars ) { + while ( width > nchars ) { + EMIT(' '); + width--; + } + } + + /* Emit nondigits */ + if ( minus ) + EMIT('-'); + else if ( flags & FL_PLUS ) + EMIT('+'); + else if ( flags & FL_SPACE ) + EMIT(' '); + + if ( (flags & FL_HASH) && base == 16 ) { + EMIT('0'); + EMIT((flags & FL_UPPER) ? 'X' : 'x'); + } + + /* Emit zero padding */ + if ( (flags & (FL_MINUS|FL_ZERO)) == FL_ZERO && width > ndigits ) { + while ( width > nchars ) { + EMIT('0'); + width--; + } + } + + /* Generate the number. This is done from right to left. */ + q += ndigits; /* Advance the pointer to end of number */ + o += ndigits; + qq = q; oo = o; /* Temporary values */ + + b4tick = tickskip; + while ( ndigits > 0 ) { + if ( !b4tick-- ) { + qq--; oo--; ndigits--; + if ( oo < n ) *qq = '_'; + b4tick = tickskip-1; + } + qq--; oo--; ndigits--; + if ( oo < n ) *qq = digits[val%base]; + val /= base; + } + + /* Emit late space padding */ + while ( (flags & FL_MINUS) && width > nchars ) { + EMIT(' '); + width--; + } + + return o; +} + + +int vsnprintf(char *buffer, size_t n, const char *format, va_list ap) +{ + const char *p = format; + char ch; + char *q = buffer; + size_t o = 0; /* Number of characters output */ + uintmax_t val = 0; + int rank = rank_int; /* Default rank */ + int width = 0; + int prec = -1; + int base; + size_t sz; + enum flags flags = 0; + enum { + st_normal, /* Ground state */ + st_flags, /* Special flags */ + st_width, /* Field width */ + st_prec, /* Field precision */ + st_modifiers /* Length or conversion modifiers */ + } state = st_normal; + const char *sarg; /* %s string argument */ + char carg; /* %c char argument */ + int slen; /* String length */ + + while ( (ch = *p++) ) { + switch ( state ) { + case st_normal: + if ( ch == '%' ) { + state = st_flags; + flags = 0; rank = rank_int; width = 0; prec = -1; + } else { + EMIT(ch); + } + break; + + case st_flags: + switch ( ch ) { + case '-': + flags |= FL_MINUS; + break; + case '+': + flags |= FL_PLUS; + break; + case '\'': + flags |= FL_TICK; + break; + case ' ': + flags |= FL_SPACE; + break; + case '#': + flags |= FL_HASH; + break; + case '0': + flags |= FL_ZERO; + break; + default: + state = st_width; + p--; /* Process this character again */ + break; + } + break; + + case st_width: + if ( ch >= '0' && ch <= '9' ) { + width = width*10+(ch-'0'); + } else if ( ch == '*' ) { + width = va_arg(ap, int); + if ( width < 0 ) { + width = -width; + flags |= FL_MINUS; + } + } else if ( ch == '.' ) { + prec = 0; /* Precision given */ + state = st_prec; + } else { + state = st_modifiers; + p--; /* Process this character again */ + } + break; + + case st_prec: + if ( ch >= '0' && ch <= '9' ) { + prec = prec*10+(ch-'0'); + } else if ( ch == '*' ) { + prec = va_arg(ap, int); + if ( prec < 0 ) + prec = -1; + } else { + state = st_modifiers; + p--; /* Process this character again */ + } + break; + + case st_modifiers: + switch ( ch ) { + /* Length modifiers - nonterminal sequences */ + case 'h': + rank--; /* Shorter rank */ + break; + case 'l': + rank++; /* Longer rank */ + break; + case 'j': + rank = INTMAX_RANK; + break; + case 'z': + rank = SIZE_T_RANK; + break; + case 't': + rank = PTRDIFF_T_RANK; + break; + case 'L': + case 'q': + rank += 2; + break; + default: + /* Output modifiers - terminal sequences */ + state = st_normal; /* Next state will be normal */ + if ( rank < MIN_RANK ) /* Canonicalize rank */ + rank = MIN_RANK; + else if ( rank > MAX_RANK ) + rank = MAX_RANK; + + switch ( ch ) { + case 'P': /* Upper case pointer */ + flags |= FL_UPPER; + /* fall through */ + case 'p': /* Pointer */ + base = 16; + prec = (CHAR_BIT*sizeof(void *)+3)/4; + flags |= FL_HASH; + val = (uintmax_t)(uintptr_t)va_arg(ap, void *); + goto is_integer; + + case 'd': /* Signed decimal output */ + case 'i': + base = 10; + flags |= FL_SIGNED; + switch (rank) { + case rank_char: + /* Yes, all these casts are needed... */ + val = (uintmax_t)(intmax_t)(signed char)va_arg(ap, signed int); + break; + case rank_short: + val = (uintmax_t)(intmax_t)(signed short)va_arg(ap, signed int); + break; + case rank_int: + val = (uintmax_t)(intmax_t)va_arg(ap, signed int); + break; + case rank_long: + val = (uintmax_t)(intmax_t)va_arg(ap, signed long); + break; + case rank_longlong: + val = (uintmax_t)(intmax_t)va_arg(ap, signed long long); + break; + } + goto is_integer; + case 'o': /* Octal */ + base = 8; + goto is_unsigned; + case 'u': /* Unsigned decimal */ + base = 10; + goto is_unsigned; + case 'X': /* Upper case hexadecimal */ + flags |= FL_UPPER; + /* fall through */ + case 'x': /* Hexadecimal */ + base = 16; + goto is_unsigned; + + is_unsigned: + switch (rank) { + case rank_char: + val = (uintmax_t)(unsigned char)va_arg(ap, unsigned int); + break; + case rank_short: + val = (uintmax_t)(unsigned short)va_arg(ap, unsigned int); + break; + case rank_int: + val = (uintmax_t)va_arg(ap, unsigned int); + break; + case rank_long: + val = (uintmax_t)va_arg(ap, unsigned long); + break; + case rank_longlong: + val = (uintmax_t)va_arg(ap, unsigned long long); + break; + } + /* fall through */ + + is_integer: + sz = format_int(q, (o<n) ? n-o : 0, val, flags, base, width, prec); + q += sz; o += sz; + break; + + case 'c': /* Character */ + carg = (char)va_arg(ap, int); + sarg = &carg; + slen = 1; + goto is_string; + case 's': /* String */ + sarg = va_arg(ap, const char *); + sarg = sarg ? sarg : "(null)"; + slen = strlen(sarg); + goto is_string; + + is_string: + { + char sch; + int i; + + if ( prec != -1 && slen > prec ) + slen = prec; + + if ( width > slen && !(flags & FL_MINUS) ) { + char pad = (flags & FL_ZERO) ? '0' : ' '; + while ( width > slen ) { + EMIT(pad); + width--; + } + } + for ( i = slen ; i ; i-- ) { + sch = *sarg++; + EMIT(sch); + } + if ( width > slen && (flags & FL_MINUS) ) { + while ( width > slen ) { + EMIT(' '); + width--; + } + } + } + break; + + case 'n': /* Output the number of characters written */ + { + switch (rank) { + case rank_char: + *va_arg(ap, signed char *) = o; + break; + case rank_short: + *va_arg(ap, signed short *) = o; + break; + case rank_int: + *va_arg(ap, signed int *) = o; + break; + case rank_long: + *va_arg(ap, signed long *) = o; + break; + case rank_longlong: + *va_arg(ap, signed long long *) = o; + break; + } + } + break; + + default: /* Anything else, including % */ + EMIT(ch); + break; + } + } + } + } + + /* Null-terminate the string */ + if ( o<n ) + *q = '\0'; /* No overflow */ + else if ( n>0 ) + buffer[n-1] = '\0'; /* Overflow - terminate at end of buffer */ + + return o; +} |