lavu: add av_strtok()

The function strtok_r() is part of the POSIX.1 specification, but is not
available on some platforms. We provide an internal implementation, so we
do not need to rely on a platform implementation.

2 files changed, 53 insertions, 0 deletions

diff --git a/libavutil/avstring.c b/libavutil/avstring.c
index 4c504482da..247cd71745 100644
--- a/libavutil/avstring.c
+++ b/libavutil/avstring.c
@@ -160,6 +160,35 @@ char *av_get_token(const char **buf, const char *term)
     return ret;
 }
 
+char *av_strtok(char *s, const char *delim, char **saveptr)
+{
+    char *tok;
+
+    if (!s && !(s = *saveptr))
+        return NULL;
+
+    /* skip leading delimiters */
+    s += strspn(s, delim);
+
+    /* s now points to the first non delimiter char, or to the end of the string */
+    if (!*s) {
+        *saveptr = NULL;
+        return NULL;
+    }
+    tok = s++;
+
+    /* skip non delimiters */
+    s += strcspn(s, delim);
+    if (*s) {
+        *s = 0;
+        *saveptr = s+1;
+    } else {
+        *saveptr = NULL;
+    }
+
+    return tok;
+}
+
 #ifdef TEST
 
 #undef printf
diff --git a/libavutil/avstring.h b/libavutil/avstring.h
index 2be84a9ed0..0b2205a9be 100644
--- a/libavutil/avstring.h
+++ b/libavutil/avstring.h
@@ -141,4 +141,28 @@ char *av_d2str(double d);
  */
 char *av_get_token(const char **buf, const char *term);
 
+/**
+ * Split the string into several tokens which can be accessed by
+ * successive calls to av_strtok().
+ *
+ * A token is defined as a sequence of characters not belonging to the
+ * set specified in delim.
+ *
+ * On the first call to av_strtok(), s should point to the string to
+ * parse, and the value of saveptr is ignored. In subsequent calls, s
+ * should be NULL, and saveptr should be unchanged since the previous
+ * call.
+ *
+ * This function is similar to strtok_r() defined in POSIX.1.
+ *
+ * @param s the string to parse, may be NULL
+ * @param delim 0-terminated list of token delimiters, must be non-NULL
+ * @param saveptr user-provided pointer which points to stored
+ * information necessary for av_strtok() to continue scanning the same
+ * string. saveptr is updated to point to the next character after the
+ * first delimiter found, or to NULL if the string was terminated
+ * @return the found token, or NULL when no token is found
+ */
+char *av_strtok(char *s, const char *delim, char **saveptr);
+
 #endif /* AVUTIL_AVSTRING_H */