libperf: Adopt xyarray class from perf

Move the xyarray class from perf to libperf, because it's going to be
used in both.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-58-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/lib/Build

@@ -4,6 +4,7 @@ libperf-y += threadmap.o
 libperf-y += evsel.o
 libperf-y += evlist.o
 libperf-y += zalloc.o
+libperf-y += xyarray.o
 
 $(OUTPUT)zalloc.o: ../../lib/zalloc.c FORCE
 	$(call rule_mkdir)

tools/perf/lib/include/internal/xyarray.h

@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LIBPERF_INTERNAL_XYARRAY_H
+#define __LIBPERF_INTERNAL_XYARRAY_H
+
+#include <sys/types.h>
+
+struct xyarray {
+	size_t row_size;
+	size_t entry_size;
+	size_t entries;
+	size_t max_x;
+	size_t max_y;
+	char contents[];
+};
+
+struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size);
+void xyarray__delete(struct xyarray *xy);
+void xyarray__reset(struct xyarray *xy);
+
+static inline void *xyarray__entry(struct xyarray *xy, int x, int y)
+{
+	return &xy->contents[x * xy->row_size + y * xy->entry_size];
+}
+
+static inline int xyarray__max_y(struct xyarray *xy)
+{
+	return xy->max_y;
+}
+
+static inline int xyarray__max_x(struct xyarray *xy)
+{
+	return xy->max_x;
+}
+
+#endif /* __LIBPERF_INTERNAL_XYARRAY_H */

tools/perf/lib/xyarray.c

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <internal/xyarray.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size)
+{
+	size_t row_size = ylen * entry_size;
+	struct xyarray *xy = zalloc(sizeof(*xy) + xlen * row_size);
+
+	if (xy != NULL) {
+		xy->entry_size = entry_size;
+		xy->row_size   = row_size;
+		xy->entries    = xlen * ylen;
+		xy->max_x      = xlen;
+		xy->max_y      = ylen;
+	}
+
+	return xy;
+}
+
+void xyarray__reset(struct xyarray *xy)
+{
+	size_t n = xy->entries * xy->entry_size;
+
+	memset(xy->contents, 0, n);
+}
+
+void xyarray__delete(struct xyarray *xy)
+{
+	free(xy);
+}