[PATCH v2 01/31] Introduce string_printf

Pedro Alves
2016-10-19T01:12:25Z

This introduces the string_printf function. Like asprintf, but
returns a std::string.

gdb/ChangeLog:
yyyy-mm-yy Pedro Alves <palves@redhat.com>

* common/common-utils.c (string_printf): New function.
* common/common-utils.h: Include <string>.
(string_printf): Declare.
---
gdb/common/common-utils.c | 30 ++++++++++++++++++++++++++++++
gdb/common/common-utils.h | 6 ++++++
2 files changed, 36 insertions(+)

diff --git a/gdb/common/common-utils.c b/gdb/common/common-utils.c
index 5a346ec..05ba3aa 100644
--- a/gdb/common/common-utils.c
+++ b/gdb/common/common-utils.c
@@ -150,6 +150,36 @@ xsnprintf (char *str, size_t size, const char *format, ...)
return ret;
}

+/* See documentation in common-utils.h. */
+
+std::string
+string_printf (const char* fmt, ...)
+{
+ std::string str;
+ va_list vp;
+
+ /* Start by assuming some reasonable size will be sufficient. */
+ str.resize (1024);
+
+ while (1)
+ {
+ size_t size;
+ int result;
+
+ va_start (vp, fmt);
+ size = str.size ();
+ result = vsnprintf (&str[0], size, fmt, vp);
+ va_end (vp);
+
+ str.resize (result);
+
+ if (result < size)
+ break;
+ }
+
+ return str;
+}
+
char *
savestring (const char *ptr, size_t len)
{
diff --git a/gdb/common/common-utils.h b/gdb/common/common-utils.h
index 47def11..a9053ff 100644
--- a/gdb/common/common-utils.h
+++ b/gdb/common/common-utils.h
@@ -20,6 +20,8 @@
#ifndef COMMON_UTILS_H
#define COMMON_UTILS_H

+#include <string>
+
/* If possible, define FUNCTION_NAME, a macro containing the name of
the function being defined. Since this macro may not always be
defined, all uses must be protected by appropriate macro definition
@@ -56,6 +58,10 @@ char *xstrvprintf (const char *format, va_list ap)
int xsnprintf (char *str, size_t size, const char *format, ...)
ATTRIBUTE_PRINTF (3, 4);

+/* Returns a std::string built from a printf-style format string. */
+std::string string_printf (const char* fmt, ...)
+ ATTRIBUTE_PRINTF (1, 2);
+
/* Make a copy of the string at PTR with LEN characters
(and add a null character at the end in the copy).
Uses malloc to get the space. Returns the address of the copy. */
--
2.5.5