gbranden pushed a commit to branch master
in repository groff.
commit 5164bc1a0dd747df4d1b8b36c4df0f8c5da14234
Author: G. Branden Robinson <[email protected]>
AuthorDate: Wed Jun 10 05:54:04 2026 -0500
[libgroff]: Rewrite `string::move()`.
* src/libs/libgroff/string.cpp: Continue refactoring to implement new
invariant: any existing `string` object is backed by "clean" storage.
(string::move): Rewrite. Use `sfree_alloc()`, which also backs
`operator=()`, on destination string to perform replacement
allocation. Use memcpy(3) to copy contents from source string to
destination. Use member function `clear()` on source string. Add
assert(3)ion enforcing new invariant.
Performance analysis
====================
Impact seems negligible. I timed a full groff build from "distclean" to
completion, using a single core.
Before
------
real 2m48.029s
user 2m53.073s
sys 0m21.077s
After
-----
real 2m48.352s
user 2m53.379s
sys 0m21.279s
---
ChangeLog | 11 +++++++++++
src/libs/libgroff/string.cpp | 10 ++++------
2 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 4e506cd15..1b1904395 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2026-06-10 G. Branden Robinson <[email protected]>
+
+ * src/libs/libgroff/string.cpp: Continue refactoring to
+ implement new invariant: any existing `string` object is backed
+ by "clean" storage.
+ (string::move): Rewrite. Use `sfree_alloc()`, which also backs
+ `operator=()`, on destination string to perform replacement
+ allocation. Use memcpy(3) to copy contents from source string
+ to destination. Use member function `clear()` on source string.
+ Add assert(3)ion enforcing new invariant.
+
2026-06-10 G. Branden Robinson <[email protected]>
* src/libs/libgroff/string.cpp (string::operator=)
diff --git a/src/libs/libgroff/string.cpp b/src/libs/libgroff/string.cpp
index 6fca589be..891070488 100644
--- a/src/libs/libgroff/string.cpp
+++ b/src/libs/libgroff/string.cpp
@@ -231,13 +231,11 @@ string &string::operator=(char c)
void string::move(string &s)
{
- sfree(ptr);
- ptr = s.ptr;
+ sfree_alloc(ptr, sz, s.len, &sz);
+ memcpy(ptr, s.ptr, s.len);
len = s.len;
- sz = s.sz;
- s.ptr = 0 /* nullptr */;
- s.len = 0;
- s.sz = 0;
+ s.clear();
+ assert(ptr != 0 /* nullptr */);
}
void string::grow1()
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