ensure that SLINEAR volume adjustments don't wrap around short integer maximums

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6882 65c4cc65-6c06-0410-ace0-fbb531ad65f3

frame.c

@@ -1263,9 +1263,9 @@ int ast_frame_adjust_volume(struct ast_frame *f, int adjustment)
 
 	for (count = 0; count < f->samples; count++) {
 		if (adjustment > 0) {
-			fdata[count] *= abs(adjustment);
+			ast_slinear_saturated_multiply(&fdata[count], abs(adjustment));
 		} else if (adjustment < 0) {
-			fdata[count] /= abs(adjustment);
+			ast_slinear_saturated_divide(&fdata[count], abs(adjustment));
 		}
 	}
 

include/asterisk/utils.h

@@ -168,7 +168,37 @@ char *ast_uri_encode(char *string, char *outbuf, int buflen, int doreserved);
 	\param s	String to be decoded 
  */
 void ast_uri_decode(char *s);
+
+static inline void ast_slinear_saturated_add(short *input, short value)
+{
+	int res;
+
+	res = *input + value;
+	if (res > 32767)
+		*input = 32767;
+	else if (res < -32767)
+		*input = -32767;
+	else
+		*input = (short) res;
+}
 	
+static inline void ast_slinear_saturated_multiply(short *input, short value)
+{
+	int res;
+
+	res = *input * value;
+	if (res > 32767)
+		*input = 32767;
+	else if (res < -32767)
+		*input = -32767;
+	else
+		*input = (short) res;
+}
+
+static inline void ast_slinear_saturated_divide(short *input, short value)
+{
+	*input /= value;
+}
 
 extern int test_for_thread_safety(void);