diff --git a/include/asterisk/strings.h b/include/asterisk/strings.h index 2a8b0e4905..5827dda9ba 100644 --- a/include/asterisk/strings.h +++ b/include/asterisk/strings.h @@ -498,14 +498,20 @@ char * attribute_pure ast_str_buffer(const struct ast_str *buf), /*!\brief Truncates the enclosed string to the given length. * \param buf A pointer to the ast_str structure. - * \param len Maximum length of the string. + * \param len Maximum length of the string. If len is larger than the + * current maximum length, things will explode. If it is negative + * at most -len characters will be trimmed off the end. * \retval A pointer to the resulting string. */ AST_INLINE_API( char *ast_str_truncate(struct ast_str *buf, ssize_t len), { if (len < 0) { - buf->__AST_STR_USED += ((ssize_t) abs(len)) > (ssize_t) buf->__AST_STR_USED ? -buf->__AST_STR_USED : len; + if ((typeof(buf->__AST_STR_USED)) -len >= buf->__AST_STR_USED) { + buf->__AST_STR_USED = 0; + } else { + buf->__AST_STR_USED += len; + } } else { buf->__AST_STR_USED = len; }