Initial import

libc/calls/hefty/sortenvp.c

@@ -0,0 +1,68 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/alg/alg.h"
+#include "libc/alg/arraylist.h"
+#include "libc/calls/hefty/ntspawn.h"
+#include "libc/dce.h"
+#include "libc/nexgen32e/tinystrcmp.h"
+#include "libc/str/str.h"
+
+static int sortenvpcb(const char **a, const char **b) { return strcmp(*a, *b); }
+
+static void slowsort(char **a, int n) {
+  size_t i, j;
+  const char *t;
+  for (i = 1; i < n; ++i) {
+    j = i;
+    t = a[i];
+    while (j > 0 && tinystrcmp(t, a[j - 1]) < 0) {
+      a[j] = a[j - 1];
+      --j;
+    }
+    a[j] = t;
+  }
+}
+
+/**
+ * Copies environment variable pointers and sorts them.
+ *
+ * This is useful for (a) binary searching; and (b) keeping the NT
+ * Executive happy, which wants strings to be ordered by UNICODE
+ * codepoint identifiers. That's basically what uint8_t comparisons on
+ * UTF8-encoded data gives us.
+ *
+ * @param envp is a NULL-terminated string array
+ * @return newly allocated sorted copy of envp pointer array
+ */
+hidden textwindows nodiscard char **sortenvp(char *const envp[]) {
+  size_t count = 0;
+  while (envp[count]) count++;
+  size_t bytesize = (count + 1) * sizeof(char *);
+  char **copy = malloc(bytesize);
+  if (copy) {
+    memcpy(copy, envp, bytesize);
+    if (IsTiny()) {
+      slowsort(copy, count);
+    } else {
+      qsort(copy, count, sizeof(char *), (void *)sortenvpcb);
+    }
+  }
+  return copy;
+}