chsprintf minimal @p sprintf() patch

[tdwebste]

We have added chsprint to implement a minimal @p sprintf() like functionality with
output to a string.


Your feed back is appreciated.

How do I attach a patch file? I am getting The extension " " is not allowed for everything I have tried.


From 8a4411d184dc884a9a3e03a1a7fa54356d6d0dbd Mon Sep 17 00:00:00 2001
From: Timothy Webster <[email protected]>
Date: Sun, 1 Dec 2013 23:33:22 -0500
Subject: [PATCH] chibios sprint

chsprintf
This function implements a minimal @p sprintf() like functionality with
output to a string.
---
os/various/chprintf.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 176 insertions(+)

diff --git a/os/various/chprintf.c b/os/various/chprintf.c
index 5d3d38e..0960eaa 100644
--- a/os/various/chprintf.c
+++ b/os/various/chprintf.c
@@ -259,4 +259,180 @@ unsigned_common:
}
}

+/**
+ * @brief Formatted string function.
+ * @details This function implements a minimal @p sprintf() like functionality
+ * with output to a string.
+ * The general parameters format is: %[-][width|*][.precision|*][l|L]p.
+ * The following parameter types (p) are supported:
+ * - <b>x</b> hexadecimal integer.
+ * - <b>X</b> hexadecimal long.
+ * - <b>o</b> octal integer.
+ * - <b>O</b> octal long.
+ * - <b>d</b> decimal signed integer.
+ * - <b>D</b> decimal signed long.
+ * - <b>u</b> decimal unsigned integer.
+ * - <b>U</b> decimal unsigned long.
+ * - <b>c</b> character.
+ * - <b>s</b> string.
+ * .
+ *
+ * @param[in] buf pointer to a string buffer
+ * @param[in] fmt formatting string
+ */
+void chsprintf(char *buf, const char *fmt, ...) {
+ va_list ap;
+ char *p, *s, c, filler;
+ int i, precision, width;
+ bool_t is_long, left_align;
+ long l;
+#if CHPRINTF_USE_FLOAT
+ float f;
+ char tmpbuf[2*MAX_FILLER + 1];
+#else
+ char tmpbuf[MAX_FILLER + 1];
+#endif
+
+ va_start(ap, fmt);
+ while (TRUE) {
+ c = *fmt++;
+ if (c == 0) {
+ va_end(ap);
+ *(buf++) = 0;
+ return;
+ }
+ if (c != '%') {
+ *(buf++) = (uint8_t)c;
+ continue;
+ }
+ p = tmpbuf;
+ s = tmpbuf;
+ left_align = FALSE;
+ if (*fmt == '-') {
+ fmt++;
+ left_align = TRUE;
+ }
+ filler = ' ';
+ if (*fmt == '.') {
+ fmt++;
+ filler = '0';
+ }
+ width = 0;
+ while (TRUE) {
+ c = *fmt++;
+ if (c >= '0' && c <= '9')
+ c -= '0';
+ else if (c == '*')
+ c = va_arg(ap, int);
+ else
+ break;
+ width = width * 10 + c;
+ }
+ precision = 0;
+ if (c == '.') {
+ while (TRUE) {
+ c = *fmt++;
+ if (c >= '0' && c <= '9')
+ c -= '0';
+ else if (c == '*')
+ c = va_arg(ap, int);
+ else
+ break;
+ precision *= 10;
+ precision += c;
+ }
+ }
+ /* Long modifier.*/
+ if (c == 'l' || c == 'L') {
+ is_long = TRUE;
+ if (*fmt)
+ c = *fmt++;
+ }
+ else
+ is_long = (c >= 'A') && (c <= 'Z');
+
+ /* Command decoding.*/
+ switch (c) {
+ case 'c':
+ filler = ' ';
+ *p++ = va_arg(ap, int);
+ break;
+ case 's':
+ filler = ' ';
+ if ((s = va_arg(ap, char *)) == 0)
+ s = "(null)";
+ if (precision == 0)
+ precision = 32767;
+ for (p = s; *p && (--precision >= 0); p++)
+ ;
+ break;
+ case 'D':
+ case 'd':
+ case 'I':
+ case 'i':
+ if (is_long)
+ l = va_arg(ap, long);
+ else
+ l = va_arg(ap, int);
+ if (l < 0) {
+ *p++ = '-';
+ l = -l;
+ }
+ p = ltoa(p, l, 10);
+ break;
+#if CHPRINTF_USE_FLOAT
+ case 'f':
+ f = (float) va_arg(ap, double);
+ if (f < 0) {
+ *p++ = '-';
+ f = -f;
+ }
+ p = ftoa(p, f);
+ break;
+#endif
+ case 'X':
+ case 'x':
+ c = 16;
+ goto unsigned_common;
+ case 'U':
+ case 'u':
+ c = 10;
+ goto unsigned_common;
+ case 'O':
+ case 'o':
+ c = 8;
+unsigned_common:
+ if (is_long)
+ l = va_arg(ap, unsigned long);
+ else
+ l = va_arg(ap, unsigned int);
+ p = ltoa(p, l, c);
+ break;
+ default:
+ *p++ = c;
+ break;
+ }
+ i = (int)(p - s);
+ if ((width -= i) < 0)
+ width = 0;
+ if (left_align == FALSE)
+ width = -width;
+ if (width < 0) {
+ if (*s == '-' && filler == '0') {
+ *(buf++) = (uint8_t)*s++;
+ i--;
+ }
+ do
+ *(buf++) = (uint8_t)filler;
+ while (++width != 0);
+ }
+ while (--i >= 0)
+ *(buf++) = (uint8_t)*s++;
+
+ while (width) {
+ *(buf++) = (uint8_t)filler;
+ width--;
+ }
+ }
+}
/** @} */
--
1.8.1.2

[Giovanni]

Hi,

I need to verify if there is an easier way to implement chsprintf(), duplicating all the code looks a bit wasteful. Probably it is possible to create a string writer implementing a stream and using the normal chprintf() for printing.

Giovanni

[Giovanni]

Hi,

I added an alternate implementation of chsnprintf() that uses memstreams internally. Note the "N", I prefer this variant for safety reasons.

Please let me go if it works for you.

Giovanni

[tdwebste]

Thx
Which release repository did you add it to? 2.6 or 2.7.
We are still on 2.6, But we are looking to migrate to 2.7

[Giovanni]

Hi,

Both, it will be in 2.6.2 and 2.7.0.

Note that 2.7.0 probably will never be released and replaced by the 3.0.0 branch. Everything is going in 2.6.2 anyway.

Giovanni

[tdwebste]

I know I am missing something easy.

git grep include -- 'chprintf.[ch]'
chprintf.c:#include "ch.h"
chprintf.c:#include "chprintf.h"
chprintf.c:#include "memstreams.h"
chprintf.h:#include <stdarg.h>


chprintf.c:297: undefined reference to `msObjectInit'

ideas?

[tdwebste]

Forgot to add
$(CHIBIOS)/os/various/memstreams.c \
to my Makefile.