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Adding example.

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This commit is contained in:
Daniel Lemire 2022-07-29 11:42:20 -04:00
parent cfb44c2592
commit d797a3a05d
3 changed files with 100 additions and 24 deletions
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26
README.md
View File

@ -97,6 +97,32 @@ int main() {
}
```
You can parse delimited numbers:
```C++
const std::string input = "234532.3426362,7869234.9823,324562.645";
double result;
auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
if(answer.ec != std::errc()) {
// check error
}
// we have result == 234532.3426362.
if(answer.ptr[0] != ',') {
// unexpected delimiter
}
answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
if(answer.ec != std::errc()) {
// check error
}
// we have result == 7869234.9823.
if(answer.ptr[0] != ',') {
// unexpected delimiter
}
answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
if(answer.ec != std::errc()) {
// check error
}
// we have result == 324562.645.
```
## Reference

27
tests/basictest.cpp
View File

@ -224,6 +224,33 @@ TEST_CASE("decimal_point_parsing") {
}
}
TEST_CASE("issue19") {
const std::string input = "234532.3426362,7869234.9823,324562.645";
double result;
auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
CHECK_MESSAGE(answer.ec == std::errc(), "We want to parse up to 234532.3426362\n");
CHECK_MESSAGE(answer.ptr == input.data() + 14,
"Parsed the number " << result
<< " and stopped at the wrong character: after " << (answer.ptr - input.data()) << " characters");
CHECK_MESSAGE(result == 234532.3426362, "We want to parse234532.3426362\n");
CHECK_MESSAGE(answer.ptr[0] == ',', "We want to parse up to the comma\n");
answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
CHECK_MESSAGE(answer.ec == std::errc(), "We want to parse 7869234.9823\n");
CHECK_MESSAGE(answer.ptr == input.data() + 27,
"Parsed the number " << result
<< " and stopped at the wrong character " << (answer.ptr - input.data()));
CHECK_MESSAGE(answer.ptr[0] == ',', "We want to parse up to the comma\n");
CHECK_MESSAGE(result == 7869234.9823, "We want to parse up 7869234.9823\n");
answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
CHECK_MESSAGE(answer.ec == std::errc(), "We want to parse 324562.645\n");
CHECK_MESSAGE(answer.ptr == input.data() + 38,
"Parsed the number " << result
<< " and stopped at the wrong character " << (answer.ptr - input.data()));
CHECK_MESSAGE(result == 324562.645, "We want to parse up 7869234.9823\n");
}
TEST_CASE("issue19") {
const std::string input = "3.14e";
double result;

23
tests/example_test.cpp
View File

@ -4,11 +4,34 @@
#include <string>
#include <system_error>
bool many() {
const std::string input = "234532.3426362,7869234.9823,324562.645";
double result;
auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
if(answer.ec != std::errc()) { return false; }
if(result != 234532.3426362) { return false; }
if(answer.ptr[0] != ',') { return false; }
answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
if(answer.ec != std::errc()) { return false; }
if(result != 7869234.9823) { return false; }
if(answer.ptr[0] != ',') { return false; }
answer = fast_float::from_chars(answer.ptr + 1, input.data()+input.size(), result);
if(answer.ec != std::errc()) { return false; }
if(result != 324562.645) { return false; }
return true;
}
int main() {
const std::string input = "3.1416 xyz ";
double result;
auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
if((answer.ec != std::errc()) || ((result != 3.1416))) { std::cerr << "parsing failure\n"; return EXIT_FAILURE; }
std::cout << "parsed the number " << result << std::endl;
if(!many()) {
printf("Bug\n");
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}