From 18aae7e21e1a88c75adb38aa2555e0b1928b137d Mon Sep 17 00:00:00 2001
From: Phillip Wood <phillip.wood@dunelm.org.uk>
Date: Fri, 8 Jul 2022 16:25:17 +0000
Subject: xdiff: introduce xdl_calloc

In preparation for introducing XDL_CALLOC_ARRAY() use calloc() to
obtain zeroed out memory rather than malloc() followed by memset(). To
try and keep the lines a reasonable length this commit also stops
casting the pointer returned by calloc() as this is unnecessary.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 72e25a9..bb56b23 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -120,6 +120,7 @@ typedef struct s_bdiffparam {
 
 
 #define xdl_malloc(x) xmalloc(x)
+#define xdl_calloc(n, sz) xcalloc(n, sz)
 #define xdl_free(ptr) free(ptr)
 #define xdl_realloc(ptr,x) xrealloc(ptr,x)
 
diff --git a/xdiff/xhistogram.c b/xdiff/xhistogram.c
index 01decff..c97edc1 100644
--- a/xdiff/xhistogram.c
+++ b/xdiff/xhistogram.c
@@ -251,7 +251,7 @@ static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
 		    int line1, int count1, int line2, int count2)
 {
 	int b_ptr;
-	int sz, ret = -1;
+	int ret = -1;
 	struct histindex index;
 
 	memset(&index, 0, sizeof(index));
@@ -265,23 +265,19 @@ static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
 	index.rcha.head = NULL;
 
 	index.table_bits = xdl_hashbits(count1);
-	sz = index.records_size = 1 << index.table_bits;
-	sz *= sizeof(struct record *);
-	if (!(index.records = (struct record **) xdl_malloc(sz)))
+	index.records_size = 1 << index.table_bits;
+	if (!(index.records = xdl_calloc(index.records_size,
+					 sizeof(*index.records))))
 		goto cleanup;
-	memset(index.records, 0, sz);
 
-	sz = index.line_map_size = count1;
-	sz *= sizeof(struct record *);
-	if (!(index.line_map = (struct record **) xdl_malloc(sz)))
+	index.line_map_size = count1;
+	if (!(index.line_map = xdl_calloc(index.line_map_size,
+					  sizeof(*index.line_map))))
 		goto cleanup;
-	memset(index.line_map, 0, sz);
 
-	sz = index.line_map_size;
-	sz *= sizeof(unsigned int);
-	if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz)))
+	if (!(index.next_ptrs = xdl_calloc(index.line_map_size,
+					   sizeof(*index.next_ptrs))))
 		goto cleanup;
-	memset(index.next_ptrs, 0, sz);
 
 	/* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
 	if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)
diff --git a/xdiff/xpatience.c b/xdiff/xpatience.c
index ce87b90..94f8886 100644
--- a/xdiff/xpatience.c
+++ b/xdiff/xpatience.c
@@ -151,11 +151,9 @@ static int fill_hashmap(mmfile_t *file1, mmfile_t *file2,
 
 	/* We know exactly how large we want the hash map */
 	result->alloc = count1 * 2;
-	result->entries = (struct entry *)
-		xdl_malloc(result->alloc * sizeof(struct entry));
+	result->entries = xdl_calloc(result->alloc, sizeof(*result->entries));
 	if (!result->entries)
 		return -1;
-	memset(result->entries, 0, result->alloc * sizeof(struct entry));
 
 	/* First, fill with entries from the first file */
 	while (count1--)
diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 25866a1..45190e5 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -78,12 +78,11 @@ static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
 
 		return -1;
 	}
-	if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
+	if (!(cf->rchash = xdl_calloc(cf->hsize, sizeof(*cf->rchash)))) {
 
 		xdl_cha_free(&cf->ncha);
 		return -1;
 	}
-	memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *));
 
 	cf->alloc = size;
 	if (!XDL_ALLOC_ARRAY(cf->rcrecs, cf->alloc)) {
@@ -183,9 +182,8 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 
 	hbits = xdl_hashbits((unsigned int) narec);
 	hsize = 1 << hbits;
-	if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *))))
+	if (!(rhash = xdl_calloc(hsize, sizeof(*rhash))))
 		goto abort;
-	memset(rhash, 0, hsize * sizeof(xrecord_t *));
 
 	nrec = 0;
 	if ((cur = blk = xdl_mmfile_first(mf, &bsize))) {
@@ -209,9 +207,8 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
 		}
 	}
 
-	if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char))))
+	if (!(rchg = xdl_calloc((nrec + 2), sizeof(*rchg))))
 		goto abort;
-	memset(rchg, 0, (nrec + 2) * sizeof(char));
 
 	if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
 	    (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
@@ -383,11 +380,10 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
 	xdlclass_t *rcrec;
 	char *dis, *dis1, *dis2;
 
-	if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) {
+	if (!(dis = xdl_calloc(xdf1->nrec + xdf2->nrec + 2, sizeof(*dis)))) {
 
 		return -1;
 	}
-	memset(dis, 0, xdf1->nrec + xdf2->nrec + 2);
 	dis1 = dis;
 	dis2 = dis1 + xdf1->nrec + 1;
 
-- 
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