rcx

commit b3a948898f49969297d2ce5ea5e712e2fc807ca0
parent 44255b350222f624c42b4aa5ca59c72898365753
Author: Robert Russell <robertrussell.72001@gmail.com>
Date:   Fri, 24 Mar 2023 17:40:42 -0700

string: printf constructors

Diffstat:
M
inc/string.h
 | 
4
++++
M
src/string.c
 | 
36
++++++++++++++++++++++++++++++++++++

2 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/inc/string.h b/inc/string.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <stdarg.h>
 #include <string.h>
 
 #include "debug.h"
@@ -29,6 +30,9 @@ struct str {
 		.data = buf_static(s,##__VA_ARGS__) \
 	}
 
+int str_printf(Str *str, char *fmt, ...);
+int str_vprintf(Str *str, char *fmt, va_list args);
+
 static inline usize
 str_off(Str s) {
 	return s.off;
diff --git a/src/string.c b/src/string.c
@@ -1,7 +1,43 @@
+#include <stdio.h>
+
 #include "debug.h"
 #include "rcx.h"
 #include "string.h"
 
+int
+str_printf(Str *str, char *fmt, ...) {
+	va_list args;
+	va_start(args, fmt);
+	int ret = str_vprintf(str, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+str_vprintf(Str *str, char *fmt, va_list args) {
+	/* XXX: Using stdlib printf means we waste 1 byte for null term. */
+
+	va_list args2;
+	va_copy(args2, args);
+	int ret = vsnprintf(0, 0, fmt, args2);
+	va_end(args2);
+	if (ret < 0) return -1;
+	usize len = (usize)ret + 1u;
+
+	Buf buf = buf_alloc(len);
+	if (!buf) return -1;
+
+	ret = vsnprintf((char *)buf, len, fmt, args);
+	if (ret < 0) {
+		buf_drop(buf);
+		return -1;
+	}
+
+	*str = buf_slice(buf, 0);
+	return 0;
+
+}
+
 Str
 str_slice_(Str s, isize l, isize u) {
 	if (l < 0) l += s.len;