From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Sat, 24 Jul 2021 02:13:45 +0000 (-0700)
Subject: eval: avoid sfprintf in float-to-string dynamic
X-Git-Tag: 2.49.0~31^2~6
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=676acbab0dd00b3d5b6c4d683bdaaa1bac5d4beb;p=graphviz

eval: avoid sfprintf in float-to-string dynamic

Instead of constructing a string in the `tmp` buffer and then eventually
allocating vmalloc space to copy this into, we can simply compute the number of
bytes in advance, allocate vmalloc space, and then directly emit the output into
the vmalloc buffer. Related to #1873, #1998.
---

diff --git a/lib/expr/exeval.c b/lib/expr/exeval.c
index 602a4f343..926567bfc 100644
--- a/lib/expr/exeval.c
+++ b/lib/expr/exeval.c
@@ -1615,8 +1615,7 @@ eval(Expr_t* ex, Exnode_t* expr, void* env)
 				tmp.data.constant.value.string = exprintf(ex->ve, "%g", v.floating);
 			}
 			else if ((*ex->disc->convertf)(ex, &tmp, STRING, expr->data.operand.right ? expr->data.operand.right->data.variable.symbol : (Exid_t*)0, 0, ex->disc)) {
-				sfprintf(ex->tmp, "%g", v.floating);
-				tmp.data.constant.value.string = exstash(ex->tmp, ex->ve);
+				tmp.data.constant.value.string = exprintf(ex->ve, "%g", v.floating);
 			}
 			tmp.type = STRING;
 			return tmp.data.constant.value;