Patchwork Add a string_view version of startswith

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Submitter Doug Evans via gdb-patches
Date Oct. 1, 2019, 7:17 p.m.
Message ID <20191001191743.239208-1-cbiesinger@google.com>
Download mbox | patch
Permalink /patch/34771/
State New
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Comments

Doug Evans via gdb-patches - Oct. 1, 2019, 7:17 p.m.
[Thanks Pedro, both comments are fixed now. Note that this patch depends on
https://sourceware.org/ml/gdb-patches/2019-10/msg00032.html]

Makes sure that the string is longer than prefix, so that strncmp will
do the right thing even if the string is not null-terminated.

For use in my string_view conversion patch:
https://sourceware.org/ml/gdb-patches/2019-10/msg00030.html

gdb/ChangeLog:

2019-10-01  Christian Biesinger  <cbiesinger@google.com>

	* gdbsupport/common-utils.h (startswith): Add an overloaded version
	that takes gdb::string_view arguments.
---
 gdb/gdbsupport/common-utils.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

Patch

diff --git a/gdb/gdbsupport/common-utils.h b/gdb/gdbsupport/common-utils.h
index a5312cb0c4..4a20a665cc 100644
--- a/gdb/gdbsupport/common-utils.h
+++ b/gdb/gdbsupport/common-utils.h
@@ -23,6 +23,7 @@ 
 #include <string>
 #include <vector>
 
+#include "gdb_string_view.h"
 #include "poison.h"
 
 /* If possible, define FUNCTION_NAME, a macro containing the name of
@@ -110,15 +111,25 @@  std::string extract_string_maybe_quoted (const char **arg);
 
 extern char *safe_strerror (int);
 
-/* Return non-zero if the start of STRING matches PATTERN, zero
+/* Return true if the start of STRING matches PATTERN, false
    otherwise.  */
 
-static inline int
+static inline bool
 startswith (const char *string, const char *pattern)
 {
   return strncmp (string, pattern, strlen (pattern)) == 0;
 }
 
+/* Version of startswith that takes string_view arguments.  See comment
+   above.  */
+
+static inline bool
+startswith (gdb::string_view string, gdb::string_view pattern)
+{
+  return (string.length() >= pattern.length ()
+	  && strncmp (string.data (), pattern.data (), pattern.length ()) == 0);
+}
+
 ULONGEST strtoulst (const char *num, const char **trailer, int base);
 
 /* Skip leading whitespace characters in INP, returning an updated