Implement most forward-facing CLI stuff.

README.md

@@ -25,6 +25,19 @@ Only OS X and Linux are tested. You'll need a decent compiler that supports C11
 (gcc, clang) and SDL 2. Using Homebrew, you can `brew install sdl2`; using apt,
 you can `apt-get install libsdl2-dev`.
 
-Run `make` and then `./crater`. To build the development version with debug
-symbols (they can exist simultaneously), run `make DEBUG=1` and then
+Run `make` to create `./crater`. To build the development version with debug
+symbols (they can exist simultaneously), run `make DEBUG=1`, which creates
 `./crater-dev`.
+
+Usage
+-----
+
+Running `./crater`  without arguments will display a list of ROM images located
+in the `roms/` directory, and then ask the user to pick one, or enter their own
+ROM path. You can provide a path directly with `./crater path/to/rom`.
+
+Add or symlink ROMs to `roms/` at your leisure. Note that they should end in
+`.gg` or `.bin`.
+
+`./crater -h` gives (fairly basic) command-line usage, and `./crater -v` gives
+the current version.

crater.c

@@ -1,10 +1,160 @@
 /* Copyright (C) 2014 Ben Kurtovic <ben.kurtovic@gmail.com>
    Released under the terms of the MIT License. See LICENSE for details. */
 
+#include <dirent.h>
+#include <errno.h>
+#include <stdbool.h>
 #include <stdio.h>
-#include <SDL.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
 
-int main(int argc, char* argv[]) {
-    printf("Hello, world!\n");
+#include "src/errors.h"
+#include "src/rom.h"
+#include "src/version.h"
+
+#define ROMS_DIR "roms"
+
+/* Print command-line help/usage. */
+static void print_help(char *arg1)
+{
+    printf("%s [--help|-h] [--version|-v] [rom_path]\n", arg1);
+}
+
+/* Print crater's version. */
+static void print_version()
+{
+    printf("crater %s\n", CRATER_VERSION);
+}
+
+/* Parse the command-line arguments for any special flags. */
+static void parse_args(int argc, char *argv[])
+{
+    char *arg;
+    int i;
+
+    for (i = 1; i < argc; i++) {
+        arg = argv[i];
+        if (arg[0] != '-')
+            continue;
+        do
+            arg++;
+        while (arg[0] == '-');
+
+        if (!strcmp(arg, "h") || !strcmp(arg, "help")) {
+            print_help(argv[0]);
+            exit(0);
+        } else if (!strcmp(arg, "v") || !strcmp(arg, "version")) {
+            print_version();
+            exit(0);
+        } else {
+            printf("Error: unknown argument: %s\n", argv[i]);
+            exit(1);
+        }
+    }
+}
+
+/* Return whether the given string ends with the given suffix. */
+static bool ends_with(char *input, char *suffix)
+{
+    size_t ilen = strlen(input), slen = strlen(suffix);
+
+    if (ilen < slen)
+        return false;
+    return strcmp(input + (ilen - slen), suffix) == 0;
+}
+
+/* Load all potential ROM files in roms/ into a data structure. */
+static int load_rom_paths(char ***path_ptr)
+{
+    DIR *dirp;
+    struct dirent *entry;
+    char **paths = NULL, *path;
+    int psize = 8, npaths = 0;
+
+    dirp = opendir(ROMS_DIR);
+    if (dirp) {
+        paths = malloc(sizeof(char*) * psize);
+        if (!paths)
+            out_of_memory();
+        while ((entry = readdir(dirp))) {
+            path = entry->d_name;
+            if (ends_with(path, ".gg") || ends_with(path, ".bin")) {
+                if (npaths >= psize) {
+                    paths = realloc(paths, sizeof(char*) * (psize *= 2));
+                    if (!paths)
+                        out_of_memory();
+                }
+                paths[npaths] = malloc(sizeof(char*) *
+                        (strlen(path) + strlen(ROMS_DIR) + 1));
+                if (!paths[npaths])
+                    out_of_memory();
+                strcpy(paths[npaths], ROMS_DIR "/");
+                strcat(paths[npaths], path);
+                npaths++;
+            }
+        }
+        closedir(dirp);
+    } else {
+        if (errno == ENOENT)
+            printf("Warning: couldn't find roms/ directory.\n");
+        else
+            perror("Warning: couldn't open roms/ directory");
+    }
+    *path_ptr = paths;
+    return npaths;
+}
+
+/* Find all potential ROM files in the roms/ directory, then ask the user which
+ * one they want to run.
+ */
+static char* get_rom_path_from_user()
+{
+    char **paths, *path, *input = NULL;
+    int npaths, i;
+    long int index;
+    size_t size = 0;
+    ssize_t len;
+
+    npaths = load_rom_paths(&paths);
+    for (i = 0; i < npaths; i++)
+        printf("[%2d] %s\n", i + 1, paths[i]);
+    if (npaths)
+        printf("Enter a ROM number from above, or the path to a ROM image: ");
+    else
+        printf("Enter the path to a ROM image: ");
+
+    len = getline(&input, &size, stdin);
+    if (!input)
+        out_of_memory();
+    if (len > 0 && input[len - 1] == '\n')
+        input[len - 1] = '\0';
+    index = strtol(input, NULL, 10);
+    if (index < 1 || index > npaths)
+        path = input;
+    else
+        path = paths[index - 1];
+
+    for (i = 0; i < npaths; i++) {
+        if (paths[i] != path)
+            free(paths[i]);
+    }
+    if (paths)
+        free(paths);
+    return path;
+}
+
+int main(int argc, char *argv[])
+{
+    char *rom_path;
+
+    parse_args(argc, argv);
+    rom_path = argc > 1 ? argv[1] : get_rom_path_from_user();
+
+    // TODO: main logic hook here
+    printf("Loading ROM: %s\n", rom_path);
+
+    if (argc <= 1)
+        free(rom_path);
     return 0;
 }

src/errors.c

@@ -0,0 +1,13 @@
+/* Copyright (C) 2014 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "errors.h"
+
+/* Called after an out-of-memory error. Prints a message and dies. */
+void out_of_memory() {
+    printf("Error: couldn't allocate memory.\n");
+    exit(1);
+}

src/errors.h

@@ -0,0 +1,6 @@
+/* Copyright (C) 2014 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#pragma once
+
+void out_of_memory();

src/rom.c

@@ -0,0 +1,22 @@
+/* Copyright (C) 2014 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#include <stdlib.h>
+
+#include "rom.h"
+#include "errors.h"
+
+rom_type* load_rom(char *path)
+{
+    rom_type *rom;
+
+    rom = malloc(sizeof(rom_type));
+    if (!rom)
+        out_of_memory();
+    return rom;
+}
+
+void unload_rom(rom_type *rom)
+{
+    free(rom);
+}

src/rom.h

@@ -0,0 +1,9 @@
+/* Copyright (C) 2014 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#pragma once
+
+typedef struct {
+    char* name;
+    char* data;
+} rom_type;

src/version.h

@@ -0,0 +1,6 @@
+/* Copyright (C) 2014 Ben Kurtovic <ben.kurtovic@gmail.com>
+   Released under the terms of the MIT License. See LICENSE for details. */
+
+#pragma once
+
+#define CRATER_VERSION "0.1.dev"

src/z80.h

@@ -3,6 +3,6 @@
 
 #pragma once
 
-struct register_t {
+typedef struct {
     int pc;
-};
+} register_type;