Implements %[flags][width]type
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177
printf.c
177
printf.c
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@ -1,39 +1,94 @@
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/* printf.c -- format and print data */
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/* Copyright (c) 2020 Renaud Fivet */
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/* printf.c -- format and print data
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** Copyright (c) 2020-2021 Renaud Fivet
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** v3: %[flags][width]type
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** v2: zero padding and uppercase/lowercase for hexadecimal
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** v1: type=c,u,x,X,i,d,s,%
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*/
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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#include "system.h" /* kputc(), kputs() */
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static int kputu( unsigned u, unsigned d, int padlen, char fmt) {
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char s[ 12] ; /* room for 11 octal digit + EOS */
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char *p = &s[ sizeof s - 1] ; /* point to last byte */
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size_t strlen( const char *s) {
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const char *end = s - 1 ;
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while( *++end) ;
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*p = 0 ; /* null terminated string */
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fmt = fmt & 0x20 ; /* set uppercase bit */
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do {
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unsigned r = u % d ;
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u /= d ;
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*--p = "0123456789ABCDEF"[ r] | fmt ;
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padlen -= 1 ;
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} while( u) ;
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while( padlen-- > 0) {
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kputc( '0') ;
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u += 1 ; /* use u to calculate output length */
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}
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return u + kputs( p) ;
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return end - s ;
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}
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static int kputi( int i) {
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int flag = i < 0 ;
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if( flag) {
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i = -i ;
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kputc( '-') ;
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#define ZEROPAD (1 << 3)
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#define LEFTALIGN (3 << 2)
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#define LEFTMASK 4
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#define PLUSSIGN (1 << 1)
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#define BLANKSIGN (1 << 0)
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static const unsigned char base[] = {
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16, /* Xx 0x58 0x78 */
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10, /* iu 0x69 0x75 */
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2, /* b 0x62 unused */
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8, /* o 0x6F */
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} ;
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static const char signs[] = { 0, ' ', '+', '+'} ;
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static int kputpad( char c, int len) {
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int cnt ;
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if( len > 0) {
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cnt = len ;
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while( len--)
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kputc( c) ;
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} else
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cnt = 0 ;
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return cnt ;
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}
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static int kputu( unsigned u, int padlen, char fmt) {
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char s[ 12] ; /* room for 11 octal digit + EOS */
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char *p = &s[ sizeof s - 1] ; /* point to last byte */
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char signprefix ;
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*p = 0 ; /* null terminated string */
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int flags = padlen >> 28 ;
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padlen &= 0x0FFFFFFF ; /* clear flags */
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if( fmt == 'i' && (0 > (int) u)) {
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u = - (int) u ;
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signprefix = '-' ;
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} else
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signprefix = signs[ flags & 3] ;
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if( signprefix)
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padlen -= 1 ;
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unsigned d = base[ fmt & 3] ;
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fmt = fmt & 0x20 ; /* set uppercase bit */
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do {
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*--p = "0123456789ABCDEF"[ u % d] | fmt ;
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padlen -= 1 ;
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u /= d ;
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} while( u) ;
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/* reuse u to calculate output length */
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flags >>= 2 ;
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if( !flags) /* Right align */
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u += kputpad( ' ', padlen) ;
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if( signprefix) {
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kputc( signprefix) ;
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u += 1 ;
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}
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return flag + kputu( i, 10, 0, 'u') ;
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if( flags == (ZEROPAD >> 2))
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u += kputpad( '0', padlen) ;
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u += kputs( p) ;
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if( flags == (LEFTALIGN >> 2))
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u += kputpad( ' ', padlen) ;
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return u ;
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}
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int printf( const char *fmt, ...) {
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@ -46,37 +101,77 @@ int printf( const char *fmt, ...) {
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if( c != '%') {
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cnt += 1 ; kputc( c) ;
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} else {
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int len = 0 ;
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/* %[flags][width]type */
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int flags = 0 ;
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int width = 0 ;
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c = *fmt++ ;
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while( c >= '0' && c <= '9') {
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len = len * 10 + ( c - '0') ;
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/* flags and width */
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for( ;;) {
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c = *fmt++ ;
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switch( c) {
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case ' ':
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flags |= BLANKSIGN ;
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continue ;
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case '+':
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flags |= PLUSSIGN ;
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continue ;
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case '-':
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flags |= LEFTALIGN ;
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continue ;
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case '0':
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flags |= ZEROPAD ;
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continue ;
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case '*':
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width = va_arg( ap, int) ;
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c = *fmt++ ;
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break ;
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default:
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while( c >= '0' && c <= '9') {
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width = width * 10 + ( c - '0') ;
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c = *fmt++ ;
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}
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}
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break ;
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}
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/* type */
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if( c == 0)
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break ;
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switch( c) {
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case 'c':
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flags >>= 2 ;
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if( !flags) /* right aligned */
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cnt += kputpad( ' ', width - 1) ;
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cnt += 1 ; kputc( va_arg( ap, int /* char */)) ;
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if( flags == (LEFTALIGN >> 2))
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cnt += kputpad( ' ', width - 1) ;
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break ;
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case 'd':
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c = 'i' ;
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/* fallthrough */
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case 'i':
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case 'o':
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cnt += kputu( va_arg( ap, unsigned), 8, len, c) ;
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break ;
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case 'u':
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cnt += kputu( va_arg( ap, unsigned), 10, len, c) ;
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break ;
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case 'x':
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case 'X':
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cnt += kputu( va_arg( ap, unsigned), 16, len, c) ;
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cnt += kputu( va_arg( ap, unsigned), width | flags << 28, c) ;
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break ;
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case 'i':
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case 'd':
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cnt += kputi( va_arg( ap, int)) ;
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break ;
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case 's':
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cnt += kputs( va_arg( ap, char *)) ;
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case 's': {
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char *argp = va_arg( ap, char *) ;
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flags >>= 2 ;
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if( !flags) /* right aligned */
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cnt += kputpad( ' ', width - strlen( argp)) ;
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int size = kputs( argp) ;
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cnt += size ;
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if( flags == (LEFTMASK >> 2))
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cnt += kputpad( ' ', width - size) ;
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}
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break ;
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default:
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cnt += 1 ; kputc( '%') ;
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