diff --git a/media/libmediametrics/include/media/MediaMetricsItem.h b/media/libmediametrics/include/media/MediaMetricsItem.h
index 9d1b9b3..7ce75ed 100644
--- a/media/libmediametrics/include/media/MediaMetricsItem.h
+++ b/media/libmediametrics/include/media/MediaMetricsItem.h
@@ -467,17 +467,16 @@
     template <> // static
     status_t extract(std::string *val, const char **bufferpptr, const char *bufferptrmax) {
         const char *ptr = *bufferpptr;
-        while (*ptr != 0) {
+        do {
             if (ptr >= bufferptrmax) {
                 ALOGE("%s: buffer exceeded", __func__);
                 android_errorWriteLog(0x534e4554, "204445255");
                 return BAD_VALUE;
             }
-            ++ptr;
-        }
-        const size_t size = (ptr - *bufferpptr) + 1;
+        } while (*ptr++ != 0);
+        // ptr is terminator+1, == bufferptrmax if we finished entire buffer
         *val = *bufferpptr;
-        *bufferpptr += size;
+        *bufferpptr = ptr;
         return NO_ERROR;
     }
     template <> // static