Initial import

libc/runtime/getdosenviron.h

@@ -0,0 +1,67 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=8 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                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#ifndef COSMOPOLITAN_LIBC_DOSENVIRON_H_
+#define COSMOPOLITAN_LIBC_DOSENVIRON_H_
+#include "libc/bits/safemacros.h"
+#include "libc/str/appendchar.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+
+/**
+ * Transcodes NT environment variable block from UTF-16 to UTF-8.
+ *
+ * @param env is a double NUL-terminated block of key=values
+ * @param buf is the new environment
+ * @param size is the byte capacity of buf
+ * @param envp stores NULL-terminated string pointer list
+ * @param max is the pointer count capacity of envp
+ * @return number of variables decoded, excluding NULL-terminator
+ */
+static inline int getdosenviron(const char16_t *env, char *buf, size_t size,
+                                char **envp, size_t max) {
+  const char16_t *s = env;
+  size_t envc = 0;
+  if (size) {
+    wint_t wc;
+    char *p = buf;
+    char *pe = buf + size - 1;
+    if (p < pe) {
+      s += getutf16(s, &wc);
+      while (wc) {
+        if (++envc < max) {
+          envp[envc - 1] = p < pe ? p : NULL;
+        }
+        bool endstring;
+        do {
+          AppendChar(&p, pe, wc);
+          endstring = !wc;
+          s += getutf16(s, &wc);
+        } while (!endstring);
+        buf[min(p - buf, size - 2)] = u'\0';
+      }
+    }
+    AppendChar(&p, pe, '\0');
+    buf[min(p - buf, size - 1)] = u'\0';
+  }
+  if (max) envp[min(envc, max - 1)] = NULL;
+  return envc;
+}
+
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_DOSENVIRON_H_ */