Add parse_args

1 files changed, 106 insertions, 13 deletions

diff --git a/repl.c b/repl.c
index 32f2bee..edac70f 100644
--- a/repl.c
+++ b/repl.c
@@ -69,13 +69,6 @@ syntax_error:
     return 1;
 }
 
-/*
-static int
-parse_args(const char *fname, const char *types, int argc, char **args, ...)
-{
-}
-*/
-
 static int
 repl_write(int fd, const struct param *param, int argc, char **args)
 {
@@ -160,12 +153,6 @@ repl_echo(int fd, const struct param *param, int argc, char **args)
 }
 
 static int
-repl_io_read(int fd, const struct param *param, int argc, char **args)
-{
-    return 0;
-}
-
-static int
 repl_io_write(int fd, const struct param *param, int argc, char **args)
 {
     return 0;
@@ -183,6 +170,112 @@ interrupt_handler(int signal)
 }
 */
 
+enum args_type {
+    A_END,
+    A_BYTE,
+    A_DBYTE,
+    A_QBYTE,
+    A_OBYTE,
+    A_STRING,
+    A_OPTIONAL = 16
+};
+
+struct command;
+
+typedef int (*fptr)(int, const struct command *, struct param *, int, char **);
+
+struct command {
+    char alias;
+    const char *name;
+    int *args_spec;
+    const char *usage;
+    fptr fptr;
+    int quit;
+};
+
+static int
+parse_args(const struct command *cmd, int argc, char **args, ...)
+{
+    int i = 0;
+    int opt = 0;
+    int err = 0;
+    va_list ap;
+    va_start(ap, args);
+
+    void *ptr = NULL;
+    int *p = cmd->args_spec;
+
+    for ( ; *p != A_END; ++p) {
+        // Avoid runaway p
+        assert(i < MAX_ARGS);
+
+        if (*p == A_OPTIONAL) {
+            opt = 1;
+            continue;
+        }
+
+        if (i == argc && !opt)
+            goto syntax_error;
+
+        ptr = va_arg(ap, void *);
+        errno = 0;
+        char *end = NULL;
+
+        switch (*p) {
+        case A_BYTE:
+            *((uint8_t *)ptr) = strtoul(args[i], &end, 16);
+            break;
+
+        case A_DBYTE:
+            *((uint16_t *)ptr) = strtoul(args[i], &end, 16);
+            break;
+
+        case A_STRING:
+            *((const char **)ptr) = args[i];
+            break;
+        }
+
+        if (errno || args[i] == end) {
+            fprintf(stderr, "Invalid argument: %s\n", args[i]);
+            goto syntax_error;
+        }
+
+        ++i;
+    }
+
+    va_end(ap);
+    return i;
+
+syntax_error:
+    va_end(ap);
+    fputs(cmd->usage, stderr);
+    return -1;
+}
+
+#define ARGS(...) (int []){__VA_ARGS__}
+
+static int
+repl_io_read(int fd, const struct param *param, int argc, char **args)
+{
+    uint8_t bank;
+    uint16_t address;
+    const char *filename = NULL;
+
+    struct command cmd = {
+        .alias = 'i',
+        .name = "io_read",
+        .usage = "",
+        .fptr = NULL,
+        .quit = 0,
+        .args_spec = ARGS(A_BYTE, A_DBYTE, A_OPTIONAL, A_STRING, A_END),
+        .usage = "Usage: read <bank> <address> <length> [pathname]\n"
+    };
+
+    parse_args(&cmd, argc, args, &bank, &address, &filename);
+    printf("result: %hhx %hx %s\n", bank, address, filename);
+    return 0;
+}
+
 // TODO: Handle signals (CTRL-C)
 // TODO: Print errors when in repl and crash if from terminal
 void