Implement basic padding support in libsa so we can do zero-padding

in bootloader printfs.

Feedback from and ok gerhard@

diff --git a/sys/lib/libsa/printf.c b/sys/lib/libsa/printf.c
index 0b3b540..a1183b2 100644 (file)
--- a/sys/lib/libsa/printf.c
+++ b/sys/lib/libsa/printf.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: printf.c,v 1.27 2015/06/14 10:55:50 miod Exp $        */
+/*     $OpenBSD: printf.c,v 1.28 2018/01/17 08:46:15 patrick Exp $     */
 /*     $NetBSD: printf.c,v 1.10 1996/11/30 04:19:21 gwr Exp $  */
 
 /*-
@@ -60,9 +60,16 @@
 
 #include "stand.h"
 
-void kprintn(void (*)(int), u_long, int);
+/*
+ * macros for converting digits to letters and vice versa
+ */
+#define        to_digit(c)     ((c) - '0')
+#define        is_digit(c)     ((unsigned)to_digit(c) <= 9)
+#define        to_char(n)      ((n) + '0')
+
+void kprintn(void (*)(int), u_long, int, int, char);
 #ifdef LIBSA_LONGLONG_PRINTF
-void kprintn64(void (*)(int), u_int64_t, int);
+void kprintn64(void (*)(int), u_int64_t, int, int, char);
 #endif
 void kdoprnt(void (*)(int), const char *, va_list);
 
@@ -91,8 +98,8 @@ kdoprnt(void (*put)(int), const char *fmt, va_list ap)
        u_int64_t ull;
 #endif
        unsigned long ul;
-       int ch, lflag;
-       char *p;
+       int ch, lflag, width, n;
+       char *p, padchar;
 
        for (;;) {
                while ((ch = *fmt++) != '%') {
@@ -101,10 +108,30 @@ kdoprnt(void (*put)(int), const char *fmt, va_list ap)
                        put(ch);
                }
                lflag = 0;
-reswitch:      switch (ch = *fmt++) {
+               padchar = ' ';
+               width = 0;
+rflag:         ch = *fmt++;
+reswitch:      switch (ch) {
+               case '0':
+                       /*
+                        * ``Note that 0 is taken as a flag, not as the
+                        * beginning of a field width.''
+                        *      -- ANSI X3J11
+                        */
+                       padchar = '0';
+                       goto rflag;
+               case '1': case '2': case '3': case '4':
+               case '5': case '6': case '7': case '8': case '9':
+                       n = 0;
+                       do {
+                               n = 10 * n + to_digit(ch);
+                               ch = *fmt++;
+                       } while (is_digit(ch));
+                       width = n;
+                       goto reswitch;
                case 'l':
                        lflag++;
-                       goto reswitch;
+                       goto rflag;
 #ifndef        STRIPPED
                case 'b':
                {
@@ -112,7 +139,7 @@ reswitch:   switch (ch = *fmt++) {
 
                        ul = va_arg(ap, int);
                        p = va_arg(ap, char *);
-                       kprintn(put, ul, *p++);
+                       kprintn(put, ul, *p++, width, padchar);
 
                        if (!ul)
                                break;
@@ -149,7 +176,7 @@ reswitch:   switch (ch = *fmt++) {
                                        put('-');
                                        ull = -(int64_t)ull;
                                }
-                               kprintn64(put, ull, 10);
+                               kprintn64(put, ull, 10, width, padchar);
                                break;
                        } 
 #endif
@@ -159,31 +186,31 @@ reswitch: switch (ch = *fmt++) {
                                put('-');
                                ul = -(long)ul;
                        }
-                       kprintn(put, ul, 10);
+                       kprintn(put, ul, 10, width, padchar);
                        break;
                case 'o':
 #ifdef LIBSA_LONGLONG_PRINTF
                        if (lflag > 1) {
                                ull = va_arg(ap, u_int64_t);
-                               kprintn64(put, ull, 8);
+                               kprintn64(put, ull, 8, width, padchar);
                                break;
                        } 
 #endif
                        ul = lflag ?
                            va_arg(ap, u_long) : va_arg(ap, u_int);
-                       kprintn(put, ul, 8);
+                       kprintn(put, ul, 8, width, padchar);
                        break;
                case 'u':
 #ifdef LIBSA_LONGLONG_PRINTF
                        if (lflag > 1) {
                                ull = va_arg(ap, u_int64_t);
-                               kprintn64(put, ull, 10);
+                               kprintn64(put, ull, 10, width, padchar);
                                break;
                        } 
 #endif
                        ul = lflag ?
                            va_arg(ap, u_long) : va_arg(ap, u_int);
-                       kprintn(put, ul, 10);
+                       kprintn(put, ul, 10, width, padchar);
                        break;
                case 'p':
                        put('0');
@@ -193,7 +220,7 @@ reswitch:   switch (ch = *fmt++) {
 #ifdef LIBSA_LONGLONG_PRINTF
                        if (lflag > 1) {
                                ull = va_arg(ap, u_int64_t);
-                               kprintn64(put, ull, 16);
+                               kprintn64(put, ull, 16, width, padchar);
                                break;
                        }
 #else
@@ -207,6 +234,10 @@ reswitch:  switch (ch = *fmt++) {
                                do {
                                        *p++ = hexdig[ull & 15];
                                } while (ull >>= 4);
+                               while ((p - buf) < width &&
+                                   (p - buf) < sizeof(buf)) {
+                                       *p++ = padchar;
+                               }
                                do {
                                        put(*--p);
                                } while (p > buf);
@@ -215,7 +246,7 @@ reswitch:   switch (ch = *fmt++) {
 #endif
                        ul = lflag ?
                            va_arg(ap, u_long) : va_arg(ap, u_int);
-                       kprintn(put, ul, 16);
+                       kprintn(put, ul, 16, width, padchar);
                        break;
                default:
                        put('%');
@@ -231,7 +262,7 @@ reswitch:   switch (ch = *fmt++) {
 }
 
 void
-kprintn(void (*put)(int), unsigned long ul, int base)
+kprintn(void (*put)(int), unsigned long ul, int base, int width, char padchar)
 {
        /* hold a long in base 8 */
        char *p, buf[(sizeof(long) * NBBY / 3) + 1];
@@ -240,6 +271,9 @@ kprintn(void (*put)(int), unsigned long ul, int base)
        do {
                *p++ = hexdig[ul % base];
        } while (ul /= base);
+       while ((p - buf) < width && (p - buf) < sizeof(buf)) {
+               *p++ = padchar;
+       }
        do {
                put(*--p);
        } while (p > buf);
@@ -247,7 +281,7 @@ kprintn(void (*put)(int), unsigned long ul, int base)
 
 #ifdef LIBSA_LONGLONG_PRINTF
 void
-kprintn64(void (*put)(int), u_int64_t ull, int base)
+kprintn64(void (*put)(int), u_int64_t ull, int base, int width, char padchar)
 {
        /* hold an int64_t in base 8 */
        char *p, buf[(sizeof(u_int64_t) * NBBY / 3) + 1];
@@ -256,6 +290,9 @@ kprintn64(void (*put)(int), u_int64_t ull, int base)
        do {
                *p++ = hexdig[ull % base];
        } while (ull /= base);
+       while ((p - buf) < width && (p - buf) < sizeof(buf)) {
+               *p++ = padchar;
+       }
        do {
                put(*--p);
        } while (p > buf);