mirror of
https://github.com/fmtlib/fmt.git
synced 2024-11-02 11:28:20 +00:00
101 lines
2.4 KiB
C++
101 lines
2.4 KiB
C++
// Formatting library for C++ - scanning API proof of concept
|
|
//
|
|
// Copyright (c) 2012 - present, Victor Zverovich
|
|
// All rights reserved.
|
|
//
|
|
// For the license information refer to format.h.
|
|
|
|
#include <array>
|
|
#include <climits>
|
|
|
|
#include "fmt/format.h"
|
|
#include "gmock.h"
|
|
#include "gtest-extra.h"
|
|
|
|
FMT_BEGIN_NAMESPACE
|
|
namespace internal {
|
|
|
|
struct scan_arg {
|
|
int* value;
|
|
// TODO: more types
|
|
};
|
|
|
|
template <typename Handler>
|
|
void parse_scan_format(string_view format_str, Handler&& handler) {
|
|
const char* p = format_str.data();
|
|
const char* end = p + format_str.size();
|
|
while (p != end) {
|
|
char c = *p++;
|
|
if (c != '{' || p == end || *p++ != '}')
|
|
throw format_error("invalid format string");
|
|
handler.on_arg();
|
|
}
|
|
}
|
|
} // namespace internal
|
|
|
|
struct scan_args {
|
|
int size;
|
|
const internal::scan_arg* data;
|
|
|
|
template <size_t N>
|
|
scan_args(const std::array<internal::scan_arg, N>& store)
|
|
: size(N), data(store.data()) {
|
|
static_assert(N < INT_MAX, "too many arguments");
|
|
}
|
|
};
|
|
|
|
namespace internal {
|
|
struct scan_handler {
|
|
const char* begin;
|
|
const char* end;
|
|
scan_args args;
|
|
int next_arg_id;
|
|
|
|
scan_handler(string_view input, scan_args args)
|
|
: begin(input.data()),
|
|
end(begin + input.size()),
|
|
args(args),
|
|
next_arg_id(0) {}
|
|
|
|
void on_arg() {
|
|
int value = 0;
|
|
while (begin != end) {
|
|
char c = *begin++;
|
|
if (c < '0' || c > '9') throw format_error("invalid input");
|
|
value = value * 10 + (c - '0');
|
|
}
|
|
if (next_arg_id >= args.size)
|
|
throw format_error("argument index out of range");
|
|
*args.data[0].value = value;
|
|
}
|
|
};
|
|
} // namespace internal
|
|
|
|
void vscan(string_view input, string_view format_str, scan_args args) {
|
|
internal::parse_scan_format(format_str, internal::scan_handler(input, args));
|
|
}
|
|
|
|
template <typename... Args>
|
|
std::array<internal::scan_arg, sizeof...(Args)> make_scan_args(Args&... args) {
|
|
return std::array<internal::scan_arg, sizeof...(Args)>{&args...};
|
|
}
|
|
|
|
template <typename... Args>
|
|
void scan(string_view input, string_view format_str, Args&... args) {
|
|
vscan(input, format_str, make_scan_args(args...));
|
|
}
|
|
FMT_END_NAMESPACE
|
|
|
|
TEST(ScanTest, ReadInt) {
|
|
int n = 0;
|
|
fmt::scan("42", "{}", n);
|
|
EXPECT_EQ(n, 42);
|
|
}
|
|
|
|
TEST(ScanTest, InvalidFormat) {
|
|
EXPECT_THROW_MSG(fmt::scan("", "{}"), fmt::format_error,
|
|
"argument index out of range");
|
|
EXPECT_THROW_MSG(fmt::scan("", "{"), fmt::format_error,
|
|
"invalid format string");
|
|
}
|