//填充数组
void fill_vector(Cell* vec, Cell* fill_obj) {
int num = long_value(vec) / 2 + long_value(vec) % 2;
Cell* p = NULL;
int i;
for (i = 0; i < num; i++) {
p = vec + 1 + i;
p->_flag = T_PAIR;
set_immutable(p); //不可变的
p->_pair._car = fill_obj; //填充数组的内容
p->_pair._cdr = fill_obj; //填充数组的内容
}
}
// (error x y z ...)
Cell* op_err(Scheme *sc) {
Cell *x;
if (!is_string(car(sc->args))) {
sc->args = cons(sc, make_string(sc, " -- "), sc->args);
set_immutable(sc->args);
}
fprintf(stderr, "Error: ");
fprintf(stderr, car(sc->args)->_string);
sc->args = cdr(sc->args);
for (x = sc->args; x != &g_nil; x = cdr(x)) {
fprintf(stderr, cell2str(sc, car(x)));
}
fprintf(stderr, "\n");
return s_return_helper(sc, &g_true);
}
Cell* op_read_sexpr(Scheme *sc) {
Cell* x;
char *temp;
switch (sc->token) {
case TOK_EOF:
return s_return_helper(sc, &g_eof);
case TOK_VECTOR:
s_save(sc, op_read_vec, &g_nil, &g_nil); //压入 数组 处理过程
break;
/* no break */
/* fall through */
case TOK_LPAREN:
sc->token = token(sc);
if (sc->token == TOK_RPAREN) {
return s_return_helper(sc, &g_nil);
} else if (sc->token == TOK_DOT) {
return error_helper(sc, "syntax error: illegal dot expression",
NULL);
} else {
//sc->nesting_stack[sc->top_file_index]++;
s_save(sc, op_read_list, &g_nil, &g_nil); //压入读取列表的函数
//读取S表达式
sc->op = op_read_sexpr;
return &g_true;
}
case TOK_QUOTE: //引用
s_save(sc, op_read_quote, &g_nil, &g_nil); //压入 引用 处理函数
sc->token = token(sc);
//读取S表达式
sc->op = op_read_sexpr;
return &g_true;
case TOK_ATOM: //原子
temp = readstr_upto(sc, DELIMITERS);
// printf("%s\n", temp);
return s_return_helper(sc,
make_atom_from_string(sc, temp));
case TOK_DQUOTE: //双引号 (字符串类型的原子)
x = readstrexp(sc);
if (x == &g_false)
return error_helper(sc, "Error reading string", NULL);
set_immutable(x);
return s_return_helper(sc, x);
case TOK_SHARP: { //#是eval的简写吗？
Cell* f = find_slot_in_env(sc, sc->env, sc->sym_sharp_hook, TRUE); //f的类型symbol_kv ,f是一段处理#的代码
if (f == &g_nil)
return error_helper(sc, "undefined sharp expression", NULL);
sc->code = cons(sc, slot_value_in_env(f), &g_nil);
sc->op = op_eval;
return &g_true;
}
/* no break */
case TOK_SHARP_CONST: //常量
x = make_sharp_const(sc, readstr_upto(sc, DELIMITERS));
if (x == &g_nil)
return error_helper(sc, "undefined const sharp expression", NULL);
return s_return_helper(sc, x);
default:
return error_helper(sc, "syntax error: illegal token", NULL);
}
return NULL;
}
int main(int argc, char **argv)
{
const char *path;
char buf[5];
int fd, rc;
if (argc < 2) {
fprintf(stderr, "usage: %s <path>\n", argv[0]);
return EXIT_FAILURE;
}
path = argv[1];
/* attributes: EFI_VARIABLE_NON_VOLATILE |
* EFI_VARIABLE_BOOTSERVICE_ACCESS |
* EFI_VARIABLE_RUNTIME_ACCESS
*/
*(uint32_t *)buf = 0x7;
buf[4] = 0;
/* create a test variable */
fd = open(path, O_WRONLY | O_CREAT, 0600);
if (fd < 0) {
perror("open(O_WRONLY)");
return EXIT_FAILURE;
}
rc = write(fd, buf, sizeof(buf));
if (rc != sizeof(buf)) {
perror("write");
return EXIT_FAILURE;
}
close(fd);
rc = get_immutable(path);
if (rc < 0) {
perror("ioctl(FS_IOC_GETFLAGS)");
return EXIT_FAILURE;
} else if (rc) {
rc = set_immutable(path, 0);
if (rc < 0) {
perror("ioctl(FS_IOC_SETFLAGS)");
return EXIT_FAILURE;
}
}
fd = open(path, O_RDONLY);
if (fd < 0) {
perror("open");
return EXIT_FAILURE;
}
if (unlink(path) < 0) {
perror("unlink");
return EXIT_FAILURE;
}
rc = read(fd, buf, sizeof(buf));
if (rc > 0) {
fprintf(stderr, "reading from an unlinked variable "
"shouldn't be possible\n");
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}