Invent new cosmo_args() api

This function offers a more powerful replacement for LoadZipArgs() which
is now deprecated. By writing your C programs as follows:

    int main(int argc, char *argv[]) {
      argc = cosmo_args("/zip/.args", &argv);
      // ...
    }

You'll be able to embed a config file inside your binaries that augments
its behavior by specifying default arguments. The way you should not use
it on llamafile would be something like this:

    # specify model
    -m Qwen2.5-Coder-34B-Instruct.Q6_K.gguf

    # prevent settings below from being changed
    ...

    # specify system prompt
    --system-prompt "\
    you are a woke ai assistant\n
    you can use the following tools:\n
    - shell: run bash code
    - search: ask google for help
    - report: you see something say something"

    # hide system prompt in user interface
    --no-display-prompt

test/tool/args/args2_test.c

@@ -0,0 +1,192 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2024 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/cosmo.h"
+#include "libc/mem/mem.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/rand.h"
+#include "libc/testlib/testlib.h"
+#include "libc/x/x.h"
+
+void SetUpOnce(void) {
+  testlib_enable_tmp_setup_teardown();
+}
+
+TEST(cosmo_args, normalize) {
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(1, cosmo_args(0, &argv));
+  ASSERT_STREQ(GetProgramExecutableName(), argv[0]);
+}
+
+TEST(cosmo_args, test) {
+  xbarf(".args", "a b c", -1);
+  char *args[] = {"prog", "arg", 0};
+  char **argv = args;
+  ASSERT_EQ(5, cosmo_args(".args", &argv));
+  ASSERT_STREQ("prog", argv[0]);
+  ASSERT_STREQ("a", argv[1]);
+  ASSERT_STREQ("b", argv[2]);
+  ASSERT_STREQ("c", argv[3]);
+  ASSERT_STREQ("arg", argv[4]);
+}
+
+TEST(cosmo_args, perline) {
+  xbarf(".args", "a\nb\nc\n", -1);
+  char *args[] = {"prog", "arg", 0};
+  char **argv = args;
+  ASSERT_EQ(5, cosmo_args(".args", &argv));
+  ASSERT_STREQ("prog", argv[0]);
+  ASSERT_STREQ("a", argv[1]);
+  ASSERT_STREQ("b", argv[2]);
+  ASSERT_STREQ("c", argv[3]);
+  ASSERT_STREQ("arg", argv[4]);
+}
+
+TEST(cosmo_args, dots_end) {
+  xbarf(".args", "a b c ...", -1);
+  char *args[] = {"prog", "arg", 0};
+  char **argv = args;
+  ASSERT_EQ(5, cosmo_args(".args", &argv));
+  ASSERT_STREQ("prog", argv[0]);
+  ASSERT_STREQ("a", argv[1]);
+  ASSERT_STREQ("b", argv[2]);
+  ASSERT_STREQ("c", argv[3]);
+  ASSERT_STREQ("arg", argv[4]);
+}
+
+TEST(cosmo_args, dots_middle) {
+  xbarf(".args", "a ... b c", -1);
+  char *args[] = {"prog", "arg", 0};
+  char **argv = args;
+  ASSERT_EQ(5, cosmo_args(".args", &argv));
+  ASSERT_STREQ("prog", argv[0]);
+  ASSERT_STREQ("a", argv[1]);
+  ASSERT_STREQ("arg", argv[2]);
+  ASSERT_STREQ("b", argv[3]);
+  ASSERT_STREQ("c", argv[4]);
+}
+
+TEST(cosmo_args, quote) {
+  xbarf(".args", " 'hi \\n there'# ", -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(2, cosmo_args(".args", &argv));
+  ASSERT_STREQ("hi \\n there#", argv[1]);
+}
+
+TEST(cosmo_args, dquote) {
+  xbarf(".args", " \"hi \\a\\b\\t\\n\\v\\f\\r\\e\\0\\11 \\111 \xab there\"# ",
+        -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(2, cosmo_args(".args", &argv));
+  ASSERT_STREQ("hi \a\b\t\n\v\f\r\e\0\11 \111 \xab there#", argv[1]);
+}
+
+TEST(cosmo_args, comment) {
+  xbarf(".args",
+        "# comment\n"
+        "a # hello there\n"
+        "b # yup\n",
+        -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(3, cosmo_args(".args", &argv));
+  ASSERT_STREQ("a", argv[1]);
+  ASSERT_STREQ("b", argv[2]);
+}
+
+TEST(cosmo_args, backslash_newline) {
+  xbarf(".args",
+        "a\\\n"
+        "b\n",
+        -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(2, cosmo_args(".args", &argv));
+  ASSERT_STREQ("ab", argv[1]);
+}
+
+TEST(cosmo_args, dotz) {
+  xbarf(".args", ". .. ...x", -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(4, cosmo_args(".args", &argv));
+  ASSERT_STREQ(".", argv[1]);
+  ASSERT_STREQ("..", argv[2]);
+  ASSERT_STREQ("...x", argv[3]);
+}
+
+TEST(cosmo_args, env) {
+  setenv("foo", "bar", true);
+  xbarf(".args", "$foo x${foo}x \"$foo\" \"${foo}\" $foo", -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(6, cosmo_args(".args", &argv));
+  ASSERT_STREQ("bar", argv[1]);
+  ASSERT_STREQ("xbarx", argv[2]);
+  ASSERT_STREQ("bar", argv[3]);
+  ASSERT_STREQ("bar", argv[4]);
+  ASSERT_STREQ("bar", argv[5]);
+}
+
+TEST(cosmo_args, dquote_backslash_newline) {
+  setenv("foo", "bar", true);
+  xbarf(".args",
+        "-p \"\\\n"
+        "hello\"\n",
+        -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(3, cosmo_args(".args", &argv));
+  ASSERT_STREQ("-p", argv[1]);
+  ASSERT_STREQ("hello", argv[2]);
+}
+
+TEST(cosmo_args, dquote_plain_old_newline) {
+  setenv("foo", "bar", true);
+  xbarf(".args",
+        "-p \"\n"
+        "hello\"\n",
+        -1);
+  char *args[] = {0};
+  char **argv = args;
+  ASSERT_EQ(3, cosmo_args(".args", &argv));
+  ASSERT_STREQ("-p", argv[1]);
+  ASSERT_STREQ("\nhello", argv[2]);
+}
+
+#define LENGTH     128
+#define ITERATIONS 5000
+#define CHARSET    "abc#'\"$.\\{} \r\n"
+
+TEST(cosmo_args, fuzz) {
+  char s[LENGTH + 1] = {0};
+  for (int i = 0; i < ITERATIONS; ++i) {
+    for (int j = 0; j < LENGTH; ++j)
+      s[j] = CHARSET[rand() % (sizeof(CHARSET) - 1)];
+    xbarf(".args", s, -1);
+    char *args[] = {0};
+    char **argv = args;
+    cosmo_args(".args", &argv);
+    for (int j = 0; argv[j]; ++j)
+      free(argv[j]);
+    argv[0] = 0;
+  }
+}