From 8a9e379465d2f60cec5ff91811db1eb661e4c9e3 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@tuebingen.mpg.de>
Date: Wed, 27 Oct 2021 20:40:07 +0200
Subject: [PATCH] string: Introduce arr_zalloc().

Adjust all callers which pass a product of two integers to zalloc()
to call the new function instead and reduce zalloc() to a one-line
wrapper.
---
 fecdec_filter.c |  2 +-
 play.c          |  2 +-
 string.c        | 55 +++++++++++++++++++++++++++++++++----------------
 string.h        |  1 +
 write.c         |  2 +-
 5 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/fecdec_filter.c b/fecdec_filter.c
index a720a7a7..a3498e02 100644
--- a/fecdec_filter.c
+++ b/fecdec_filter.c
@@ -226,7 +226,7 @@ static int add_slice(char *buf, struct fecdec_group *fg)
 	if (fg->num_slices == 0) {
 		fg->num_slices = fg->h.slices_per_group;
 		fg->idx = arr_alloc(fg->num_slices, sizeof(int));
-		fg->data = zalloc(fg->num_slices * sizeof(unsigned char *));
+		fg->data = arr_zalloc(fg->num_slices, sizeof(unsigned char *));
 	}
 	r = fg->num_received_slices;
 	/* Check if we already have this slice. */
diff --git a/play.c b/play.c
index 92685013..69b463ac 100644
--- a/play.c
+++ b/play.c
@@ -1259,7 +1259,7 @@ int main(int argc, char *argv[])
 	session_open();
 	num_inputs = lls_num_inputs(play_lpr);
 	init_shuffle_map();
-	pt->invalid = zalloc(sizeof(*pt->invalid) * num_inputs);
+	pt->invalid = arr_zalloc(num_inputs, sizeof(*pt->invalid));
 	pt->rq = CRT_FILE_CHANGE;
 	pt->playing = true;
 	pt->task = task_register(&(struct task_info){
diff --git a/string.c b/string.c
index f01c8392..7c8b2f00 100644
--- a/string.c
+++ b/string.c
@@ -62,6 +62,43 @@ __must_check __malloc void *arr_alloc(size_t nmemb, size_t size)
 	return arr_realloc(NULL, nmemb, size);
 }
 
+/**
+ * Allocate and initialize an array, abort on failure or bugs.
+ *
+ * \param nmemb See \ref arr_realloc().
+ * \param size See \ref arr_realloc().
+ *
+ * This calls \ref arr_alloc() and zeroes-out the array.
+ *
+ * \return See \ref arr_alloc().
+ */
+__must_check __malloc void *arr_zalloc(size_t nmemb, size_t size)
+{
+	void *ptr = arr_alloc(nmemb, size);
+
+	/*
+	 * This multiplication can not overflow because the above call to \ref
+	 * arr_alloc() aborts on overflow.
+	 */
+	memset(ptr, 0, nmemb * size);
+	return ptr;
+}
+
+/**
+ * Allocate and initialize memory.
+ *
+ * \param size The desired new size.
+ *
+ * \return A pointer to the allocated and zeroed-out memory, which is suitably
+ * aligned for any kind of variable.
+ *
+ * \sa \ref alloc(), calloc(3).
+ */
+__must_check void *zalloc(size_t size)
+{
+	return arr_zalloc(1, size);
+}
+
 /**
  * Paraslash's version of realloc().
  *
@@ -98,24 +135,6 @@ __must_check __malloc void *alloc(size_t size)
 	return arr_alloc(1, size);
 }
 
-/**
- * Allocate and initialize memory.
- *
- * \param size The desired new size.
- *
- * \return A pointer to the allocated and zeroed-out memory, which is suitably
- * aligned for any kind of variable.
- *
- * \sa \ref alloc(), calloc(3).
- */
-__must_check __malloc void *zalloc(size_t size)
-{
-	void *ret = alloc(size);
-
-	memset(ret, 0, size);
-	return ret;
-}
-
 /**
  * Paraslash's version of strdup().
  *
diff --git a/string.h b/string.h
index 3efe6878..ef7c3ee8 100644
--- a/string.h
+++ b/string.h
@@ -72,6 +72,7 @@ __must_check void *para_realloc(void *p, size_t size);
 __must_check __malloc void *alloc(size_t size);
 __must_check __malloc void *zalloc(size_t size);
 __must_check __malloc void *arr_alloc(size_t nmemb, size_t size);
+__must_check __malloc void *arr_zalloc(size_t nmemb, size_t size);
 __must_check __malloc char *para_strdup(const char *s);
 
 __printf_2_0 unsigned xvasprintf(char **result, const char *fmt, va_list ap);
diff --git a/write.c b/write.c
index 9e0f22bd..356f35d4 100644
--- a/write.c
+++ b/write.c
@@ -89,7 +89,7 @@ static int setup_and_schedule(struct lls_parse_result *lpr)
 	}, &s);
 
 	n = writer_given? writer_given : 1;
-	wns = zalloc(n * sizeof(*wns));
+	wns = arr_zalloc(n, sizeof(*wns));
 	for (i = 0; i < n; i++) {
 		const char *arg = i < writer_given?
 			lls_string_val(i, OPT_RESULT(WRITER, lpr)) : NULL;
-- 
2.39.2