program: implement support for precompiling source files

 - Introduce new command line flags `-o` and `-O` to write compiled program
   code into the specified output file

 - Add support for transparently executing precompiled files, the
   lexical analyzing and com,pilation phase is skipped in this case

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 19 insertions, 6 deletions

diff --git a/source.c b/source.c
index aa73efd..3b35b70 100644
--- a/source.c
+++ b/source.c
@@ -16,6 +16,7 @@
 
 #include <string.h>
 #include <errno.h>
+#include <endian.h>
 
 #include "ucode/source.h"
 
@@ -124,7 +125,8 @@ uc_source_type_test(uc_source_t *source)
 	union { char s[sizeof(uint32_t)]; uint32_t n; } buf;
 	uc_source_type_t type = UC_SOURCE_TYPE_PLAIN;
 	FILE *fp = source->fp;
-	int c;
+	size_t rlen;
+	int c = 0;
 
 	if (fread(buf.s, 1, 2, fp) == 2 && !strncmp(buf.s, "#!", 2)) {
 		source->off += 2;
@@ -132,12 +134,8 @@ uc_source_type_test(uc_source_t *source)
 		while ((c = fgetc(fp)) != EOF) {
 			source->off++;
 
-			if (c == '\n') {
-				uc_source_line_update(source, source->off);
-				uc_source_line_next(source);
-
+			if (c == '\n')
 				break;
-			}
 		}
 	}
 	else {
@@ -145,6 +143,21 @@ uc_source_type_test(uc_source_t *source)
 			fprintf(stderr, "Failed to rewind source buffer: %s\n", strerror(errno));
 	}
 
+	rlen = fread(buf.s, 1, 4, fp);
+
+	if (rlen == 4 && buf.n == htobe32(UC_PRECOMPILED_BYTECODE_MAGIC)) {
+		type = UC_SOURCE_TYPE_PRECOMPILED;
+	}
+	else {
+		uc_source_line_update(source, source->off);
+
+		if (c == '\n')
+			uc_source_line_next(source);
+	}
+
+	if (fseek(fp, -(long)rlen, SEEK_CUR) == -1)
+		fprintf(stderr, "Failed to rewind source buffer: %s\n", strerror(errno));
+
 	return type;
 }