1 /*
2 * Copyright 2019 The Hafnium Authors.
3 *
4 * Use of this source code is governed by a BSD-style
5 * license that can be found in the LICENSE file or at
6 * https://opensource.org/licenses/BSD-3-Clause.
7 */
8
9 #include "hf/string.h"
10
11 #include "hf/static_assert.h"
12 #include "hf/std.h"
13
string_init_empty(struct string * str)14 void string_init_empty(struct string *str)
15 {
16 static_assert(sizeof(str->data) >= 1, "String buffer too small");
17 str->data[0] = '\0';
18 }
19
20 /**
21 * Caller must guarantee that `data` points to a NULL-terminated string.
22 * The constructor checks that it fits into the internal buffer and copies
23 * the string there.
24 */
string_init(struct string * str,const struct memiter * data)25 enum string_return_code string_init(struct string *str,
26 const struct memiter *data)
27 {
28 const char *base = memiter_base(data);
29 size_t size = memiter_size(data);
30
31 /*
32 * Require that the value contains exactly one NULL character and that
33 * it is the last byte.
34 */
35 if (size < 1 || memchr(base, '\0', size) != &base[size - 1]) {
36 return STRING_ERROR_INVALID_INPUT;
37 }
38
39 if (size > sizeof(str->data)) {
40 return STRING_ERROR_TOO_LONG;
41 }
42
43 memcpy_s(str->data, sizeof(str->data), base, size);
44 return STRING_SUCCESS;
45 }
46
string_is_empty(const struct string * str)47 bool string_is_empty(const struct string *str)
48 {
49 return str->data[0] == '\0';
50 }
51
string_data(const struct string * str)52 const char *string_data(const struct string *str)
53 {
54 return str->data;
55 }
56
57 /**
58 * Returns true if the iterator `data` contains string `str`.
59 * Only characters until the first null terminator are compared.
60 */
string_eq(const struct string * str,const struct memiter * data)61 bool string_eq(const struct string *str, const struct memiter *data)
62 {
63 const char *base = memiter_base(data);
64 size_t len = memiter_size(data);
65
66 return (len <= sizeof(str->data)) &&
67 (strncmp(str->data, base, len) == 0);
68 }
69