Add a bytecode interpreter.

I wrote it in C because I actually like programming in C. Turns out
setting up a Makefile is really easy too.

1 files changed, 71 insertions, 0 deletions

diff --git a/bytecode/bytecode.c b/bytecode/bytecode.c
new file mode 100644
index 0000000..a21231b
--- /dev/null
+++ b/bytecode/bytecode.c
@@ -0,0 +1,71 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "oper.h"
+#include "panic.h"
+#include "slice.h"
+
+static struct slice xmalloc(size_t size)
+{
+	void *p = malloc(size);
+	if (!p) {
+		panicf("Out of memory!\n");
+	}
+	return (struct slice) {
+		.buf = p,
+		.size = size,
+	};
+}
+
+static struct slice xrealloc(void *ptr, size_t size)
+{
+	void *p = realloc(ptr, size);
+	if (!p) {
+		panicf("Out of memory!\n");
+	}
+	return (struct slice) {
+		.buf = p,
+		.size = size,
+	};
+}
+
+void read_file(struct slice *out, char *filename)
+{
+	FILE *f = fopen(filename, "r");
+	if (!f) {
+		panicf("File %s does not exit!\n", filename);
+	}
+	size_t offset = 0;
+	while (true) {
+		if (offset >= out->size) {
+			size_t new_size = 2 * out->size;
+			*out = xrealloc(out->buf, new_size);
+		}
+		size_t read_size = out->size - offset;
+		size_t n = fread(out->buf + offset, 1, read_size, f);
+		if (n < read_size) {
+			if (ferror(f)) {
+				panicf("Read error!\n");
+			}
+			out->size = offset + n;
+			return;
+		}
+		offset += n;
+	}
+}
+
+int main(int argc, char **argv)
+{
+	if (argc < 2) {
+		printf("Usage error: need a filename.\n");
+		return 1;
+	}
+
+	struct slice program = xmalloc(1);
+	read_file(&program, argv[1]);
+
+	run(program);
+
+	free(program.buf);
+}