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From: "Ezekiel Newren via GitGitGadget" <gitgitgadget@gmail•com>
To: git@vger•kernel.org
Cc: Ezekiel Newren <ezekielnewren@gmail•com>,
	Ezekiel Newren <ezekielnewren@gmail•com>
Subject: [PATCH 15/15] xdiff: implement xdl_trim_ends() in Rust
Date: Fri, 29 Aug 2025 19:42:19 +0000	[thread overview]
Message-ID: <9fdd23acf6613c6f07c8928755ce18b87321911e.1756496539.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.2043.git.git.1756496539.gitgitgadget@gmail.com>

From: Ezekiel Newren <ezekielnewren@gmail•com>

Replace the C implementation of xdl_trim_ends() with a Rust
implementation.

Signed-off-by: Ezekiel Newren <ezekielnewren@gmail•com>
---
 rust/xdiff/src/lib.rs      | 15 +++++++++++++++
 rust/xdiff/src/xprepare.rs | 27 +++++++++++++++++++++++++++
 rust/xdiff/src/xtypes.rs   | 19 +++++++++++++++++++
 xdiff/xprepare.c           | 28 +---------------------------
 4 files changed, 62 insertions(+), 27 deletions(-)
 create mode 100644 rust/xdiff/src/xprepare.rs
 create mode 100644 rust/xdiff/src/xtypes.rs

diff --git a/rust/xdiff/src/lib.rs b/rust/xdiff/src/lib.rs
index e69de29bb2..4cc05a7e6b 100644
--- a/rust/xdiff/src/lib.rs
+++ b/rust/xdiff/src/lib.rs
@@ -0,0 +1,15 @@
+pub mod xprepare;
+pub mod xtypes;
+
+use crate::xprepare::trim_ends;
+use crate::xtypes::xdfile;
+
+#[no_mangle]
+unsafe extern "C" fn xdl_trim_ends(xdf1: *mut xdfile, xdf2: *mut xdfile) -> i32 {
+    let xdf1 = xdf1.as_mut().expect("null pointer");
+    let xdf2 = xdf2.as_mut().expect("null pointer");
+
+    trim_ends(xdf1, xdf2);
+
+    0
+}
diff --git a/rust/xdiff/src/xprepare.rs b/rust/xdiff/src/xprepare.rs
new file mode 100644
index 0000000000..f64f60c099
--- /dev/null
+++ b/rust/xdiff/src/xprepare.rs
@@ -0,0 +1,27 @@
+use crate::xtypes::xdfile;
+
+///
+/// Early trim initial and terminal matching records.
+///
+pub(crate) fn trim_ends(xdf1: &mut xdfile, xdf2: &mut xdfile) {
+    let mut lim = std::cmp::min(xdf1.record.len(), xdf2.record.len());
+
+    for i in 0..lim {
+        if xdf1.record[i].ha != xdf2.record[i].ha {
+            xdf1.dstart = i as isize;
+            xdf2.dstart = i as isize;
+            lim -= i;
+            break;
+        }
+    }
+
+    for i in 0..lim {
+        let f1i = xdf1.record.len() - 1 - i;
+        let f2i = xdf2.record.len() - 1 - i;
+        if xdf1.record[f1i].ha != xdf2.record[f2i].ha {
+            xdf1.dend = f1i as isize;
+            xdf2.dend = f2i as isize;
+            break;
+        }
+    }
+}
diff --git a/rust/xdiff/src/xtypes.rs b/rust/xdiff/src/xtypes.rs
new file mode 100644
index 0000000000..3d1ce9742f
--- /dev/null
+++ b/rust/xdiff/src/xtypes.rs
@@ -0,0 +1,19 @@
+use interop::ivec::IVec;
+
+#[repr(C)]
+pub(crate) struct xrecord {
+    pub(crate) ptr: *const u8,
+    pub(crate) size: usize,
+    pub(crate) ha: u64,
+}
+
+#[repr(C)]
+pub(crate) struct xdfile {
+    pub(crate) record: IVec<xrecord>,
+    pub(crate) dstart: isize,
+    pub(crate) dend: isize,
+    pub(crate) rchg: *mut u8,
+    pub(crate) rindex: *mut usize,
+    pub(crate) nreff: usize,
+    pub(crate) ha: *mut u64,
+}
diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 93370f1c6d..2c7480875f 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -318,33 +318,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 }
 
 
-/*
- * Early trim initial and terminal matching records.
- */
-static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
-	long i, lim;
-	xrecord_t *recs1, *recs2;
-
-	recs1 = xdf1->record.ptr;
-	recs2 = xdf2->record.ptr;
-	for (i = 0, lim = XDL_MIN(xdf1->record.length, xdf2->record.length); i < lim;
-	     i++, recs1++, recs2++)
-		if (recs1->ha != recs2->ha)
-			break;
-
-	xdf1->dstart = xdf2->dstart = i;
-
-	recs1 = xdf1->record.ptr + xdf1->record.length - 1;
-	recs2 = xdf2->record.ptr + xdf2->record.length - 1;
-	for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
-		if (recs1->ha != recs2->ha)
-			break;
-
-	xdf1->dend = xdf1->record.length - i - 1;
-	xdf2->dend = xdf2->record.length - i - 1;
-
-	return 0;
-}
+extern i32 xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
 
 
 static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) {
-- 
gitgitgadget

  parent reply	other threads:[~2025-08-29 19:42 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-29 19:42 [PATCH 00/15] Introduce rust: In xdiff Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 01/15] doc: add a policy for using Rust brian m. carlson via GitGitGadget
2025-08-29 20:00   ` brian m. carlson
2025-08-29 20:11     ` Ezekiel Newren
2025-09-02 16:39       ` brian m. carlson
2025-09-02 18:39         ` Ezekiel Newren
2025-09-04 22:55           ` Ezekiel Newren
2025-08-29 19:42 ` [PATCH 02/15] xdiff: introduce rust Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 03/15] github workflows: install rust Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 04/15] win+Meson: do allow linking with the Rust-built xdiff Johannes Schindelin via GitGitGadget
2025-08-29 19:42 ` [PATCH 05/15] github workflows: upload Cargo.lock Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 06/15] ivec: create a vector type that is interoperable between C and Rust Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 07/15] xdiff/xprepare: remove superfluous forward declarations Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 08/15] xdiff: delete unnecessary fields from xrecord_t and xdfile_t Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 09/15] xdiff: make fields of xrecord_t Rust friendly Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 10/15] xdiff: use one definition for freeing xdfile_t Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 11/15] xdiff: replace chastore with an ivec in xdfile_t Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 12/15] xdiff: delete nrec field from xdfile_t Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 13/15] xdiff: delete recs " Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` [PATCH 14/15] xdiff: make xdfile_t more rust friendly Ezekiel Newren via GitGitGadget
2025-08-29 19:42 ` Ezekiel Newren via GitGitGadget [this message]
2025-09-17  1:16 ` [PATCH v2 00/18] Introduce rust: In xdiff Ezekiel Newren via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 01/18] cleanup: rename variables that collide with Rust primitive type names Ezekiel Newren via GitGitGadget
2025-09-17  7:42     ` Eric Sunshine
2025-09-17 14:32       ` Junio C Hamano
2025-09-19 19:36         ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 02/18] make: add -fPIE flag Ezekiel Newren via GitGitGadget
2025-09-17  7:44     ` Eric Sunshine
2025-09-19 19:48       ` Ezekiel Newren
2025-09-19 20:07         ` Junio C Hamano
2025-09-19 21:52           ` Ezekiel Newren
2025-09-19 23:43             ` Junio C Hamano
2025-09-19 23:59               ` Collin Funk
2025-09-20 16:44                 ` Junio C Hamano
2025-09-21  1:14                   ` Ramsay Jones
2025-09-17  1:16   ` [PATCH v2 03/18] make: merge xdiff lib into libgit.a Ezekiel Newren via GitGitGadget
2025-09-17  7:46     ` Eric Sunshine
2025-09-19 19:54       ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 04/18] make: merge reftable " Ezekiel Newren via GitGitGadget
2025-09-17  7:46     ` Eric Sunshine
2025-09-19 19:02     ` Junio C Hamano
2025-09-19 20:00       ` Ezekiel Newren
2025-09-19 20:14         ` Junio C Hamano
2025-09-19 23:02           ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 05/18] doc: add a policy for using Rust brian m. carlson via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 06/18] BreakingChanges: announce Rust becoming mandatory Patrick Steinhardt via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 07/18] build: introduce rust Ezekiel Newren via GitGitGadget
2025-09-17  8:26     ` Eric Sunshine
2025-09-17 14:54       ` Junio C Hamano
2025-09-18  7:06         ` Eric Sunshine
2025-09-19 20:11       ` Ezekiel Newren
2025-09-19 20:24         ` Eric Sunshine
2025-09-19 21:28           ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 08/18] help: report on whether or not Rust is enabled Patrick Steinhardt via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 09/18] github workflows: install rust Ezekiel Newren via GitGitGadget
2025-09-17  8:01     ` Eric Sunshine
2025-09-17  1:16   ` [PATCH v2 10/18] win+Meson: do allow linking with the Rust-built xdiff Johannes Schindelin via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 11/18] github workflows: upload Cargo.lock Ezekiel Newren via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 12/18] build: new crate, build-helper Ezekiel Newren via GitGitGadget
2025-09-17  8:58     ` Eric Sunshine
2025-09-17  1:16   ` [PATCH v2 13/18] build-helper: link against libgit.a and any other required C libraries Ezekiel Newren via GitGitGadget
2025-09-17  8:51     ` Eric Sunshine
2025-09-17 23:07       ` D. Ben Knoble
2025-09-17 23:31         ` Eric Sunshine
2025-09-19 20:25       ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 14/18] build-helper: cbindgen, let crates generate a header file Ezekiel Newren via GitGitGadget
2025-09-17  9:08     ` Eric Sunshine
2025-09-19 20:34       ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 15/18] varint: use explicit width for integers Patrick Steinhardt via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 16/18] build: new crate, misc Ezekiel Newren via GitGitGadget
2025-09-17  9:16     ` Eric Sunshine
2025-09-19 20:42     ` Ezekiel Newren
2025-09-19 20:50       ` Eric Sunshine
2025-09-19 21:54         ` Ezekiel Newren
2025-09-17  1:16   ` [PATCH v2 17/18] misc: use BuildHelper Ezekiel Newren via GitGitGadget
2025-09-17  1:16   ` [PATCH v2 18/18] misc::varint: reimplement as test balloon for Rust Patrick Steinhardt via GitGitGadget
2025-09-17  5:58   ` [PATCH v2 00/18] Introduce rust: In xdiff Patrick Steinhardt
2025-09-19 20:57     ` Ezekiel Newren
2025-09-22 13:01       ` Patrick Steinhardt
2025-09-22 15:31         ` Ezekiel Newren
2025-09-22 16:08           ` Patrick Steinhardt
2025-09-22 16:47           ` Junio C Hamano
2025-09-22 17:23             ` Ezekiel Newren
2025-09-22 17:32               ` Ezekiel Newren
2025-09-22 18:17                 ` Junio C Hamano
2025-09-22 18:33                   ` Ezekiel Newren
2025-09-22 18:41                     ` Junio C Hamano
2025-09-22 18:12               ` Junio C Hamano
2025-09-17 17:07   ` Junio C Hamano
2025-09-17 20:44     ` Junio C Hamano
2025-09-17 21:34     ` Elijah Newren
2025-09-17 22:48       ` Junio C Hamano
2025-09-22 13:01         ` Patrick Steinhardt
2025-09-22 15:18           ` Ezekiel Newren
2025-09-22 16:15             ` Patrick Steinhardt
2025-09-22 16:27               ` Ezekiel Newren
2025-09-23  5:11                 ` Patrick Steinhardt
2025-09-23 16:32                   ` Ezekiel Newren
2025-09-23 18:05   ` Ezekiel Newren
2025-09-23 21:04     ` Junio C Hamano

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