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xNBA/src/core/vsprintf.c
2006-07-25 14:33:20 +00:00

380 lines
9.0 KiB
C

/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stddef.h>
#include <stdarg.h>
#include <console.h>
#include <errno.h>
#include <vsprintf.h>
/** @file */
#define CHAR_LEN 0 /**< "hh" length modifier */
#define SHORT_LEN 1 /**< "h" length modifier */
#define INT_LEN 2 /**< no length modifier */
#define LONG_LEN 3 /**< "l" length modifier */
#define LONGLONG_LEN 4 /**< "ll" length modifier */
#define SIZE_T_LEN 5 /**< "z" length modifier */
static uint8_t type_sizes[] = {
[CHAR_LEN] = sizeof ( char ),
[SHORT_LEN] = sizeof ( short ),
[INT_LEN] = sizeof ( int ),
[LONG_LEN] = sizeof ( long ),
[LONGLONG_LEN] = sizeof ( long long ),
[SIZE_T_LEN] = sizeof ( size_t ),
};
/**
* Use lower-case for hexadecimal digits
*
* Note that this value is set to 0x20 since that makes for very
* efficient calculations. (Bitwise-ORing with @c LCASE converts to a
* lower-case character, for example.)
*/
#define LCASE 0x20
/**
* Use "alternate form"
*
* For hexadecimal numbers, this means to add a "0x" or "0X" prefix to
* the number.
*/
#define ALT_FORM 0x02
/**
* Format a hexadecimal number
*
* @v end End of buffer to contain number
* @v num Number to format
* @v width Minimum field width
* @ret ptr End of buffer
*
* Fills a buffer in reverse order with a formatted hexadecimal
* number. The number will be zero-padded to the specified width.
* Lower-case and "alternate form" (i.e. "0x" prefix) flags may be
* set.
*
* There must be enough space in the buffer to contain the largest
* number that this function can format.
*/
static char * format_hex ( char *end, unsigned long long num, int width,
int flags ) {
char *ptr = end;
int case_mod;
/* Generate the number */
case_mod = flags & LCASE;
do {
*(--ptr) = "0123456789ABCDEF"[ num & 0xf ] | case_mod;
num >>= 4;
} while ( num );
/* Zero-pad to width */
while ( ( end - ptr ) < width )
*(--ptr) = '0';
/* Add "0x" or "0X" if alternate form specified */
if ( flags & ALT_FORM ) {
*(--ptr) = 'X' | case_mod;
*(--ptr) = '0';
}
return ptr;
}
/**
* Format a decimal number
*
* @v end End of buffer to contain number
* @v num Number to format
* @v width Minimum field width
* @ret ptr End of buffer
*
* Fills a buffer in reverse order with a formatted decimal number.
* The number will be space-padded to the specified width.
*
* There must be enough space in the buffer to contain the largest
* number that this function can format.
*/
static char * format_decimal ( char *end, signed long num, int width ) {
char *ptr = end;
int negative = 0;
/* Generate the number */
if ( num < 0 ) {
negative = 1;
num = -num;
}
do {
*(--ptr) = '0' + ( num % 10 );
num /= 10;
} while ( num );
/* Add "-" if necessary */
if ( negative )
*(--ptr) = '-';
/* Space-pad to width */
while ( ( end - ptr ) < width )
*(--ptr) = ' ';
return ptr;
}
/**
* Print character via a printf context
*
* @v ctx Context
* @v c Character
*
* Call's the printf_context::handler() method and increments
* printf_context::len.
*/
static inline void cputchar ( struct printf_context *ctx, unsigned int c ) {
ctx->handler ( ctx, c );
++ctx->len;
}
/**
* Write a formatted string to a printf context
*
* @v ctx Context
* @v fmt Format string
* @v args Arguments corresponding to the format string
* @ret len Length of formatted string
*/
size_t vcprintf ( struct printf_context *ctx, const char *fmt, va_list args ) {
int flags;
int width;
uint8_t *length;
char *ptr;
char tmp_buf[32]; /* 32 is enough for all numerical formats.
* Insane width fields could overflow this buffer. */
/* Initialise context */
ctx->len = 0;
for ( ; *fmt ; fmt++ ) {
/* Pass through ordinary characters */
if ( *fmt != '%' ) {
cputchar ( ctx, *fmt );
continue;
}
fmt++;
/* Process flag characters */
flags = 0;
for ( ; ; fmt++ ) {
if ( *fmt == '#' ) {
flags |= ALT_FORM;
} else if ( *fmt == '0' ) {
/* We always 0-pad hex and space-pad decimal */
} else {
/* End of flag characters */
break;
}
}
/* Process field width */
width = 0;
for ( ; ; fmt++ ) {
if ( ( ( unsigned ) ( *fmt - '0' ) ) < 10 ) {
width = ( width * 10 ) + ( *fmt - '0' );
} else {
break;
}
}
/* We don't do floating point */
/* Process length modifier */
length = &type_sizes[INT_LEN];
for ( ; ; fmt++ ) {
if ( *fmt == 'h' ) {
length--;
} else if ( *fmt == 'l' ) {
length++;
} else if ( *fmt == 'z' ) {
length = &type_sizes[SIZE_T_LEN];
} else {
break;
}
}
/* Process conversion specifier */
ptr = tmp_buf + sizeof ( tmp_buf ) - 1;
*ptr = '\0';
if ( *fmt == 'c' ) {
cputchar ( ctx, va_arg ( args, unsigned int ) );
} else if ( *fmt == 's' ) {
ptr = va_arg ( args, char * );
} else if ( *fmt == 'p' ) {
intptr_t ptrval;
ptrval = ( intptr_t ) va_arg ( args, void * );
ptr = format_hex ( ptr, ptrval, width,
( ALT_FORM | LCASE ) );
} else if ( ( *fmt & ~0x20 ) == 'X' ) {
unsigned long long hex;
flags |= ( *fmt & 0x20 ); /* LCASE */
if ( *length >= sizeof ( unsigned long long ) ) {
hex = va_arg ( args, unsigned long long );
} else if ( *length >= sizeof ( unsigned long ) ) {
hex = va_arg ( args, unsigned long );
} else {
hex = va_arg ( args, unsigned int );
}
ptr = format_hex ( ptr, hex, width, flags );
} else if ( ( *fmt == 'd' ) || ( *fmt == 'i' ) ){
signed long decimal;
if ( *length >= sizeof ( signed long ) ) {
decimal = va_arg ( args, signed long );
} else {
decimal = va_arg ( args, signed int );
}
ptr = format_decimal ( ptr, decimal, width );
} else {
*(--ptr) = *fmt;
}
/* Write out conversion result */
for ( ; *ptr ; ptr++ ) {
cputchar ( ctx, *ptr );
}
}
return ctx->len;
}
/** Context used by vsnprintf() and friends */
struct sputc_context {
struct printf_context ctx;
/** Buffer for formatted string (used by printf_sputc()) */
char *buf;
/** Buffer length (used by printf_sputc()) */
size_t max_len;
};
/**
* Write character to buffer
*
* @v ctx Context
* @v c Character
*/
static void printf_sputc ( struct printf_context *ctx, unsigned int c ) {
struct sputc_context * sctx =
container_of ( ctx, struct sputc_context, ctx );
if ( ctx->len <= sctx->max_len )
sctx->buf[ctx->len] = c;
}
/**
* Write a formatted string to a buffer
*
* @v buf Buffer into which to write the string
* @v size Size of buffer
* @v fmt Format string
* @v args Arguments corresponding to the format string
* @ret len Length of formatted string
*
* If the buffer is too small to contain the string, the returned
* length is the length that would have been written had enough space
* been available.
*/
int vsnprintf ( char *buf, size_t size, const char *fmt, va_list args ) {
struct sputc_context sctx;
size_t len;
size_t end;
/* Hand off to vcprintf */
sctx.ctx.handler = printf_sputc;
sctx.buf = buf;
sctx.max_len = size;
len = vcprintf ( &sctx.ctx, fmt, args );
/* Add trailing NUL */
if ( size ) {
end = size - 1;
if ( len < end )
end = len;
buf[end] = '\0';
}
return len;
}
/**
* Write a formatted string to a buffer
*
* @v buf Buffer into which to write the string
* @v size Size of buffer
* @v fmt Format string
* @v ... Arguments corresponding to the format string
* @ret len Length of formatted string
*/
int snprintf ( char *buf, size_t size, const char *fmt, ... ) {
va_list args;
int i;
va_start ( args, fmt );
i = vsnprintf ( buf, size, fmt, args );
va_end ( args );
return i;
}
/**
* Write character to console
*
* @v ctx Context
* @v c Character
*/
static void printf_putchar ( struct printf_context *ctx __unused,
unsigned int c ) {
putchar ( c );
}
/**
* Write a formatted string to the console
*
* @v fmt Format string
* @v args Arguments corresponding to the format string
* @ret len Length of formatted string
*/
int vprintf ( const char *fmt, va_list args ) {
struct printf_context ctx;
/* Hand off to vcprintf */
ctx.handler = printf_putchar;
return vcprintf ( &ctx, fmt, args );
}
/**
* Write a formatted string to the console.
*
* @v fmt Format string
* @v ... Arguments corresponding to the format string
* @ret len Length of formatted string
*/
int printf ( const char *fmt, ... ) {
va_list args;
int i;
va_start ( args, fmt );
i = vprintf ( fmt, args );
va_end ( args );
return i;
}