1 files changed, 108 insertions, 0 deletions
diff --git a/src/util/option.c b/src/util/option.c
new file mode 100644
index 0000000..ef7a398
--- /dev/null
+++ b/src/util/option.c
@@ -0,0 +1,108 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include "option.h"
+#include "util/versie.h"
+#include "util/debug.h"
+
+
+/* static void debug_argv(int argc, char **argv) {
+  fprintf(stderr, "argv: <");
+  for (int i = 0; i < argc; i++) {
+    if (i != 0) fputc(',', stderr);
+    fprintf(stderr, "'%s'", argv[i]);
+  }
+  fprintf(stderr, ">\n");
+} */
+
+char** option_parse(int argc, char **argv, const struct option_spec *speclist) {
+  // fill table of specs
+  const struct option_spec *spectable[256] = {0};
+  for (const struct option_spec *spec = speclist; spec->kind != OPTSPECKIND_END; spec++) {
+    if (spectable[(uint8_t)spec->optc] != NULL) {
+      fprintf(stderr, "option_parse: dubbele specs\n");
+      abort();
+    }
+    spectable[(uint8_t)spec->optc] = spec;
+  }
+
+  // parse options
+  int last_option_index = 0;  // index of last option argument, treating '--' as option arg
+  int npos_before_opts = 0;  // number of positional arguments before last_option_index
+  int opti;
+  for (opti = 1; opti < argc; opti++) {
+    if (argv[opti][0] != '-') continue;  // skip non-options
+
+    // count an option argument even if it's '--'
+    npos_before_opts += opti - (last_option_index + 1);
+    last_option_index = opti;
+
+    if (strcmp(argv[opti], "--") == 0) break;  // but don't try to parse '--'
+
+    for (int j = 1; argv[opti][j]; j++) {
+      const struct option_spec *spec = spectable[(uint8_t)argv[opti][j]];
+      if (!spec) {
+        fprintf(stderr, "%s: Ongeldige optie: -%c\n", argv[0], argv[opti][j]);
+        exit(1);
+      }
+
+      switch (spec->kind) {
+        case OPTSPECKIND_SETBOOL:
+          *spec->spec_sub.setbool.ptr = true;
+          break;
+
+        case OPTSPECKIND_CALL:
+          spec->spec_sub.call.fun();
+          break;
+
+        case OPTSPECKIND_CALLP:
+          spec->spec_sub.callp.fun(spec->spec_sub.callp.data);
+          break;
+
+        case OPTSPECKIND_HELPUSAGE:
+          printf(spec->spec_sub.helpusage.usagestr, argv[0]);
+          exit(0);
+
+        case OPTSPECKIND_VERSION:
+          drukkedoos_print_versie(stdout, argv[0]);
+          exit(0);
+
+        case OPTSPECKIND_END: abort(); // unreachable
+      }
+    }
+  }
+
+  DEBUG("last_option_index=%d npos_before_opts=%d\n", last_option_index, npos_before_opts);
+
+  // debug_argv(argc, argv);
+
+  // collect positional arguments that need to be reshuffled
+  char *posargs[npos_before_opts];
+  for (int i = 1, posi = 0; i < last_option_index; i++) {
+    // don't need to check for '--' here because '--' is an option argument and
+    // this loop doesn't go beyond it
+    if (argv[i][0] == '-') continue;
+
+    posargs[posi++] = argv[i];
+  }
+
+  // move option arguments to the beginning
+  int noptargs = 0;
+  for (int readi = 1; readi <= last_option_index; readi++) {
+    // no need to check for '--' here
+    if (argv[readi][0] == '-') {
+      if (readi > noptargs + 1) argv[noptargs + 1] = argv[readi];
+      noptargs++;
+    }
+  }
+
+  // debug_argv(argc, argv);
+
+  // write positional arguments after the option arguments
+  memcpy(argv + 1 + noptargs, posargs, npos_before_opts * sizeof(char*));
+
+  // debug_argv(argc, argv);
+
+  return argv + 1 + noptargs;
+}