1 files changed, 123 insertions, 0 deletions
diff --git a/src/prc1/arg.c b/src/prc1/arg.c
new file mode 100644
index 0000000..f61bca7
--- /dev/null
+++ b/src/prc1/arg.c
@@ -0,0 +1,123 @@
+#include "arg.h"
+#include "dbg.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct arg
+{
+    const char *s;
+    int (*f)(struct args *, const char *);
+
+    enum
+    {
+        NOVAL,
+        SPACEVAL = 1,
+        EQVAL = 1 << 1,
+        JOINVAL = 1 << 2
+    } v;
+};
+
+static int debug(struct args *a, const char *arg)
+{
+    dbgen = 1;
+    return 0;
+}
+
+static int inc(struct args *a, const char *arg)
+{
+    struct arg_input *i = &a->incs;
+    size_t n = i->n + 1;
+    const char **v = realloc(i->v, n * sizeof *v);
+
+    if (!v)
+    {
+        perror("realloc(3)");
+        return -1;
+    }
+
+    v[i->n++] = arg;
+    i->v = v;
+    return 0;
+}
+
+static int opt(struct args *args, const struct arg *a, const char *arg)
+{
+    const struct arg *prev = args->arg;
+    const char *v = arg + strlen(a->s);
+
+    if (prev && prev->v)
+    {
+        fprintf(stderr, "%s: option '%s' requires a value\n", args->name,
+            prev->s);
+        return -1;
+    }
+    else if (*v)
+    {
+        if (!(a->v & JOINVAL))
+        {
+            fprintf(stderr, "%s: unrecognized command-line option '%s'\n",
+                args->name, arg);
+            return -1;
+        }
+    }
+    else if (a->v & SPACEVAL)
+    {
+        args->arg = a;
+        return 0;
+    }
+    else
+        v = NULL;
+
+    return a->f(args, v);
+}
+
+int arg(struct args *a, const char *value)
+{
+    static const struct arg args[] =
+    {
+        {"-d", debug},
+        {"-I", inc, SPACEVAL | JOINVAL}
+    };
+
+    const struct arg *prev = a->arg;
+
+    for (size_t i = 0; i < sizeof args / sizeof *args; i++)
+    {
+        const struct arg *arg = &args[i];
+
+        if (!strncmp(value, arg->s, strlen(arg->s)))
+            return opt(a, arg, value);
+    }
+
+    if (prev)
+    {
+        if (*value != '-' && prev->f(a, value))
+            return -1;
+
+        a->arg = NULL;
+    }
+    else if (a->src)
+    {
+        fprintf(stderr, "%s: only one source file allowed\n", a->name);
+        return -1;
+    }
+    else
+        a->src = value;
+
+    return 0;
+}
+
+void arg_defaults(struct args *a)
+{
+}
+
+static void free_input(struct arg_input *i)
+{
+    free(i->v);
+}
+
+void arg_free(struct args *a)
+{
+    free_input(&a->incs);
+}