1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
/*
* This source code is released into the public domain.
*/
module;
#include <array>
#include <charconv>
#include <cstdlib>
#include <iterator>
#include <span>
#include <string>
#include <utility>
#include <ucl.h>
export module nihil.ucl:emit;
import :object;
namespace nihil::ucl {
export enum struct emitter {
configuration = UCL_EMIT_CONFIG,
compact_json = UCL_EMIT_JSON_COMPACT,
json = UCL_EMIT_JSON,
yaml = UCL_EMIT_YAML,
};
/*
* Wrap ucl_emitter_functions for a particular output iterator type.
*
* We can't throw exceptions here since we're called from C code. The emit
* functions return an integer value, but it's not really clear what this is
* for (for example, returning errors?) and the C API seems to mostly ignore
* it. So, we just eat errors and keep going.
*/
template<std::output_iterator<char> Iterator>
struct emit_wrapper {
emit_wrapper(Iterator iterator_)
: iterator(std::move(iterator_))
{}
static auto append_character(unsigned char c, std::size_t nchars,
void *ud)
noexcept -> int
try {
auto *self = static_cast<emit_wrapper *>(ud);
while (nchars--)
*self->iterator++ = static_cast<char>(c);
return 0;
} catch (...) {
return 0;
}
static auto append_len(unsigned char const *str, std::size_t len,
void *ud)
noexcept -> int
try {
auto *self = static_cast<emit_wrapper *>(ud);
for (auto c : std::span(str, len))
*self->iterator++ = static_cast<char>(c);
return 0;
} catch (...) {
return 0;
}
static auto append_int(std::int64_t value, void *ud)
noexcept -> int
try {
auto constexpr bufsize =
std::numeric_limits<std::int64_t>::digits10;
auto buf = std::array<char, bufsize>();
auto *self = static_cast<emit_wrapper *>(ud);
auto result = std::to_chars(buf.data(), buf.data() + buf.size(),
value, 10);
if (result.ec == std::errc())
for (auto c : std::span(buf.data(), result.ptr))
*self->iterator++ = c;
return 0;
} catch (...) {
return 0;
}
static auto append_double(double value, void *ud)
noexcept -> int
try {
auto constexpr bufsize =
std::numeric_limits<double>::digits10;
auto buf = std::array<char, bufsize>();
auto *self = static_cast<emit_wrapper *>(ud);
auto result = std::to_chars(buf.data(), buf.data() + buf.size(),
value);
if (result.ec == std::errc())
for (auto c : std::span(buf.data(), result.ptr))
*self->iterator++ = c;
return 0;
} catch (...) {
return 0;
}
auto get_functions(this emit_wrapper &self) -> ucl_emitter_functions
{
auto ret = ucl_emitter_functions{};
ret.ucl_emitter_append_character = &emit_wrapper::append_character;
ret.ucl_emitter_append_len = &emit_wrapper::append_len;
ret.ucl_emitter_append_int = &emit_wrapper::append_int;
ret.ucl_emitter_append_double = &emit_wrapper::append_double;
ret.ud = &self;
return ret;
}
private:
Iterator iterator{};
};
export auto emit(object const &object, emitter format,
std::output_iterator<char> auto &&it)
-> void
{
auto ucl_format = static_cast<ucl_emitter>(format);
auto wrapper = emit_wrapper(it);
auto functions = wrapper.get_functions();
::ucl_object_emit_full(object.get_ucl_object(), ucl_format,
&functions, nullptr);
}
} // namespace nihil::ucl
|
