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Re: [RFA 2/3] New function cli-utils.c:extract_arg_const
- From: Pedro Alves <palves at redhat dot com>
- To: Joel Brobecker <brobecker at adacore dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Wed, 13 Nov 2013 19:34:05 +0000
- Subject: Re: [RFA 2/3] New function cli-utils.c:extract_arg_const
- Authentication-results: sourceware.org; auth=none
- References: <1384151855-12926-1-git-send-email-brobecker at adacore dot com> <1384151855-12926-2-git-send-email-brobecker at adacore dot com>
On 11/11/2013 06:37 AM, Joel Brobecker wrote:
> Hello,
>
> This function provides the exact same functionality as extract_arg,
> except that it takes a "const char**" instead of a "char **". This
> will be useful in the context of my next patch.
>
> gdb/ChangeLog:
>
> * cli/cli-utils.h (extract_arg_const): Add declaration.
> * cli/cli-utils.c (extract_arg_const): New function.
>
> Tested on x86_64-linux. OK to push?
Instead of essentially duplicating the code, how about we reimplement
one on top of the other? See below. It compiles, but it's otherwise
untested.
-----------------
gdb/cli/cli-utils.c | 25 +++++++++++++++++--------
gdb/cli/cli-utils.h | 7 +++++++
2 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/gdb/cli/cli-utils.c b/gdb/cli/cli-utils.c
index f74e6b1..316cf4f 100644
--- a/gdb/cli/cli-utils.c
+++ b/gdb/cli/cli-utils.c
@@ -261,30 +261,39 @@ remove_trailing_whitespace (const char *start, char *s)
/* See documentation in cli-utils.h. */
char *
-extract_arg (char **arg)
+extract_arg_const (const char **arg)
{
- char *result, *copy;
+ const char *result;
if (!*arg)
return NULL;
/* Find the start of the argument. */
- *arg = skip_spaces (*arg);
+ *arg = skip_spaces_const (*arg);
if (!**arg)
return NULL;
result = *arg;
/* Find the end of the argument. */
- *arg = skip_to_space (*arg + 1);
+ *arg = skip_to_space_const (*arg + 1);
if (result == *arg)
return NULL;
- copy = xmalloc (*arg - result + 1);
- memcpy (copy, result, *arg - result);
- copy[*arg - result] = '\0';
+ return savestring (result, *arg - result);
+}
+
+/* See documentation in cli-utils.h. */
+
+char *
+extract_arg (char **arg)
+{
+ const char *arg_const = *arg;
+ char *result;
- return copy;
+ result = extract_arg_const (&arg_const);
+ *arg += arg_const - *arg;
+ return result;
}
/* See documentation in cli-utils.h. */
diff --git a/gdb/cli/cli-utils.h b/gdb/cli/cli-utils.h
index 152fb89..ebae2d2 100644
--- a/gdb/cli/cli-utils.h
+++ b/gdb/cli/cli-utils.h
@@ -118,6 +118,13 @@ extern char *remove_trailing_whitespace (const char *start, char *s);
extern char *extract_arg (char **arg);
+/* A const-correct version of "extract_arg".
+
+ Since the returned value is xmalloc'd, it eventually needs to be
+ xfree'ed, which prevents us from making it const as well. */
+
+extern char *extract_arg_const (const char **arg);
+
/* A helper function that looks for an argument at the start of a
string. The argument must also either be at the end of the string,
or be followed by whitespace. Returns 1 if it finds the argument,