[PATCH 4/5] Make strmatch() return 1 only if the string compared against the prefix does not contain other characters which may belong to an identifier.

[Stefano Sabatini]

This allows to distinguish for example to have different constants
with the same prefix (e.g. "foo" and "foobar").
---
 libavutil/eval.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/libavutil/eval.c b/libavutil/eval.c
index 98917fa..97af022 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -103,13 +103,16 @@ double av_strtod(const char *numstr, char **tail)
     return d;
 }
 
+#define IS_IDENTIFIER_CHAR(c) ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
+
 static int strmatch(const char *s, const char *prefix)
 {
     int i;
     for (i=0; prefix[i]; i++) {
         if (prefix[i] != s[i]) return 0;
     }
-    return 1;
+    /* return 1 only if the s identifier is terminated */
+    return !IS_IDENTIFIER_CHAR(s[i]);
 }
 
 struct AVExpr {
-- 
1.7.1


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