Add vu-arithm

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 157 insertions, 0 deletions

diff --git a/src/vu-arithm.c b/src/vu-arithm.c
new file mode 100644
index 0000000..61f60fd
--- /dev/null
+++ b/src/vu-arithm.c
@@ -0,0 +1,157 @@
+/* See LICENSE file for copyright and license details. */
+#include "arg.h"
+#include "stream.h"
+#include "util.h"
+
+#include <fcntl.h>
+#include <math.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Because the syntax for a function returning a function pointer is disgusting. */
+typedef void (*process_func)(struct stream *left, struct stream *right, size_t n);
+
+static void
+usage(void)
+{
+	eprintf("usage: %s operation right-hand-stream\n", argv0);
+}
+
+#define LIST_OPERATORS\
+	X(add, *lh += rh)\
+	X(sub, *lh -= rh)\
+	X(mul, *lh *= rh)\
+	X(div, *lh /= rh)\
+	X(exp, *lh = pow(*lh, rh))\
+	X(log, *lh = log(*lh) / log(rh))\
+	X(min, *lh = *lh < rh ? *lh : rh)\
+	X(max, *lh = *lh > rh ? *lh : rh)
+
+#define X(NAME, ALGO)\
+	static void\
+	process_lf_##NAME(struct stream *left, struct stream *right, size_t n)\
+	{\
+		size_t i;\
+		double *lh, rh;\
+		for (i = 0; i < n; i += 4 * sizeof(double)) {\
+			lh = ((double *)(left->buf + i)) + 0, rh = ((double *)(right->buf + i))[0];\
+			ALGO;\
+			lh = ((double *)(left->buf + i)) + 1, rh = ((double *)(right->buf + i))[1];\
+			ALGO;\
+			lh = ((double *)(left->buf + i)) + 2, rh = ((double *)(right->buf + i))[2];\
+			ALGO;\
+			lh = ((double *)(left->buf + i)) + 3, rh = ((double *)(right->buf + i))[3];\
+			ALGO;\
+		}\
+	}
+LIST_OPERATORS
+#undef X
+
+static process_func
+get_lf_process(const char *operation)
+{
+#define X(NAME, ALGO)\
+	if (!strcmp(operation, #NAME)) return process_lf_##NAME;
+LIST_OPERATORS
+#undef X
+	eprintf("algorithm not recognised: %s\n", operation);
+	return NULL;
+}
+
+int
+main(int argc, char *argv[])
+{
+	struct stream left;
+	struct stream right;
+	ssize_t r;
+	size_t i, n;
+	process_func process = NULL;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc != 2)
+		usage();
+
+	left.file = "<stdin>";
+	left.fd = STDIN_FILENO;
+	einit_stream(&left);
+
+	right.file = argv[1];
+	right.fd = open(right.file, O_RDONLY);
+	if (right.fd < 0)
+		eprintf("open %s:", right.file);
+	einit_stream(&right);
+
+	if (left.width != right.width || left.height != right.height)
+		eprintf("videos do not have the same geometry\n");
+	if (left.pixel_size != right.pixel_size)
+		eprintf("videos use incompatible pixel formats\n");
+
+	if (!strcmp(left.pixfmt, "xyza"))
+		process = get_lf_process(argv[0]);
+	else
+		eprintf("pixel format %s is not supported, try xyza\n", left.pixfmt);
+
+	for (;;) {
+		if (left.ptr < sizeof(left.buf) && !eread_stream(&left, SIZE_MAX)) {
+			close(left.fd);
+			left.fd = -1;
+			break;
+		}
+		if (right.ptr < sizeof(right.buf) && !eread_stream(&right, SIZE_MAX)) {
+			close(right.fd);
+			right.fd = -1;
+			break;
+		}
+
+		n = left.ptr < right.ptr ? left.ptr : right.ptr;
+		n -= n % left.pixel_size;
+		left.ptr -= n;
+		right.ptr -= n;
+
+		process(&left, &right, n);
+
+		for (i = 0; i < n; i += (size_t)r) {
+			r = write(STDOUT_FILENO, left.buf + i, n - i);
+			if (r < 0)
+				eprintf("write <stdout>:");
+		}
+
+		if ((n & 3) || left.ptr != right.ptr) {
+			memmove(left.buf,  left.buf  + n, left.ptr);
+			memmove(right.buf, right.buf + n, right.ptr);
+		}
+	}
+
+	if (right.fd >= 0)
+		close(right.fd);
+
+	for (i = 0; i < left.ptr; i += (size_t)r) {
+		r = write(STDOUT_FILENO, left.buf + i, left.ptr - i);
+		if (r < 0)
+			eprintf("write <stdout>:");
+	}
+
+	if (left.fd >= 0) {
+		for (;;) {
+			left.ptr = 0;
+			if (!eread_stream(&left, SIZE_MAX)) {
+				close(left.fd);
+				left.fd = -1;
+				break;
+			}
+
+			for (i = 0; i < left.ptr; i += (size_t)r) {
+				r = write(STDOUT_FILENO, left.buf + i, left.ptr - i);
+				if (r < 0)
+					eprintf("write <stdout>:");
+			}
+		}
+	}
+
+	return 0;
+}