[PATCH 1 of 2] bdiff: extract line record finalization to a macro

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1479000183 28800
#      Sat Nov 12 17:23:03 2016 -0800
# Node ID 99388e747e8f99c7bdcfd2592ed8fc45e885ee55
# Parent  74918cd12b496ab6c975c05a202b334e07ef33c3
bdiff: extract line record finalization to a macro

A subsequent patch will introduce a 2nd call site for this
functionality. It is a bit too much to duplicate. And this is in a
tight loop and we don't want to take the risk that an "inline"
function won't actually be inlined. So we define it is a macro.

diff --git a/mercurial/bdiff.c b/mercurial/bdiff.c
--- a/mercurial/bdiff.c
+++ b/mercurial/bdiff.c
@@ -21,6 +21,16 @@
 #define ROL(v, n) ((v) << (n) | (v) >> (sizeof(v) * CHAR_BIT - (n)))
 #define HASH(h, c) ((c) + ROL(h ,7))
 
+#define FINALIZELINE(l, hash, p, b) { \
+	l->hash = hash; \
+	hash = 0; \
+	l->len = p - b + 1; \
+	l->l = b; \
+	l->n = INT_MAX; \
+	l++; \
+	b = p + 1; \
+}
+
 struct pos {
 	int pos, len;
 };
@@ -51,13 +61,7 @@ int bdiff_splitlines(const char *a, ssiz
 		hash = HASH(hash, *p);
 
 		if (*p == '\n' || p == plast) {
-			l->hash = hash;
-			hash = 0;
-			l->len = p - b + 1;
-			l->l = b;
-			l->n = INT_MAX;
-			l++;
-			b = p + 1;
+			FINALIZELINE(l, hash, p, b);
 		}
 	}