add: command-line argument parser

3 files changed, 163 insertions, 2 deletions

diff --git a/src/cli/args.c b/src/cli/args.c
new file mode 100644
index 0000000..501406f
--- /dev/null
+++ b/src/cli/args.c
@@ -0,0 +1,119 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include "cli/args.h"
+
+#define HDASS_VERSION "0.1.0"
+
+static bool match_assembler(const char* name, enum Assembler* out)
+{
+	if (strcmp(name, "nasm") == 0)
+	{
+		*out = ASSEMBLER_NASM;
+		return true;
+	}
+	if (strcmp(name, "fasm") == 0)
+	{
+		*out = ASSEMBLER_FASM;
+		return true;
+	}
+	if (strcmp(name, "masm") == 0)
+	{
+		*out = ASSEMBLER_MASM;
+		return true;
+	}
+	return false;
+}
+
+void print_version(void)
+{
+	printf("hdass %s\n", HDASS_VERSION);
+}
+
+void print_usage(const char* program)
+{
+	printf("hachem's dumb assembly super set\n\n");
+	printf("usage: %s <input.hdass> [options]\n\n", program);
+	printf("options:\n");
+	printf("  -o, --output <file>   write output to <file> (default: stdout)\n");
+	printf("  -t, --target <name>   target assembler: nasm, fasm, masm (default: nasm)\n");
+	printf("  -h, --help            print this help and exit\n");
+	printf("  -v, --version         print version and exit\n");
+}
+
+enum ParseResult parse_args(int argc, char** argv, struct Args* args)
+{
+	const char* program = argv[0];
+
+	args->input_path = NULL;
+	args->output_path = NULL;
+	args->target = ASSEMBLER_NASM;
+
+	for (int i = 1; i < argc; i += 1)
+	{
+		const char* arg = argv[i];
+
+		if (strcmp(arg, "-h") == 0 || strcmp(arg, "--help") == 0)
+		{
+			print_usage(program);
+			return PARSE_EXIT;
+		}
+
+		if (strcmp(arg, "-v") == 0 || strcmp(arg, "--version") == 0)
+		{
+			print_version();
+			return PARSE_EXIT;
+		}
+
+		if (strcmp(arg, "-o") == 0 || strcmp(arg, "--output") == 0)
+		{
+			i += 1;
+			if (i >= argc)
+			{
+				fprintf(stderr, "error: '%s' requires an argument\n", arg);
+				return PARSE_ERROR;
+			}
+			args->output_path = argv[i];
+			continue;
+		}
+
+		if (strcmp(arg, "-t") == 0 || strcmp(arg, "--target") == 0)
+		{
+			i += 1;
+			if (i >= argc)
+			{
+				fprintf(stderr, "error: '%s' requires an argument\n", arg);
+				return PARSE_ERROR;
+			}
+			if (!match_assembler(argv[i], &args->target))
+			{
+				fprintf(stderr, "error: unknown target '%s'\n", argv[i]);
+				return PARSE_ERROR;
+			}
+			continue;
+		}
+
+		if (arg[0] == '-')
+		{
+			fprintf(stderr, "error: unknown option '%s'\n", arg);
+			return PARSE_ERROR;
+		}
+
+		if (args->input_path != NULL)
+		{
+			fprintf(stderr, "error: multiple input files given ('%s' and '%s')\n", args->input_path, arg);
+			return PARSE_ERROR;
+		}
+
+		args->input_path = arg;
+	}
+
+	if (args->input_path == NULL)
+	{
+		fprintf(stderr, "error: no input file given\n");
+		return PARSE_ERROR;
+	}
+
+	return PARSE_OK;
+}
diff --git a/src/cli/args.h b/src/cli/args.h
new file mode 100644
index 0000000..f80b736
--- /dev/null
+++ b/src/cli/args.h
@@ -0,0 +1,26 @@
+#pragma once
+
+enum Assembler
+{
+	ASSEMBLER_NASM,
+	ASSEMBLER_FASM,
+	ASSEMBLER_MASM,
+};
+
+enum ParseResult
+{
+	PARSE_OK,
+	PARSE_EXIT,
+	PARSE_ERROR,
+};
+
+struct Args
+{
+	const char* input_path;
+	const char* output_path;
+	enum Assembler target;
+};
+
+enum ParseResult parse_args(int argc, char** argv, struct Args* args);
+void print_usage(const char* program);
+void print_version(void);
diff --git a/src/main.c b/src/main.c
index 902e18a..a14d2ba 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,6 +1,22 @@
 #include <stdio.h>
 
-int main(void)
+#include "cli/args.h"
+
+int main(int argc, char** argv)
 {
-    puts("type shi");
+	struct Args args;
+
+	enum ParseResult result = parse_args(argc, argv, &args);
+	if (result == PARSE_EXIT)
+		return 0;
+	if (result == PARSE_ERROR)
+		return 1;
+
+	static const char* target_names[] = { "nasm", "fasm", "masm" };
+
+	printf("input:  %s\n", args.input_path);
+	printf("output: %s\n", args.output_path != NULL ? args.output_path : "<stdout>");
+	printf("target: %s\n", target_names[args.target]);
+
+	return 0;
 }