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v0.1.10
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biojppm committed Aug 20, 2022
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2 changes: 1 addition & 1 deletion CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ project(c4core
LANGUAGES CXX)
include(./compat.cmake)

c4_project(VERSION 0.1.9
c4_project(VERSION 0.1.10
AUTHOR "Joao Paulo Magalhaes <[email protected]>")

option(C4CORE_WITH_FASTFLOAT "use fastfloat to parse floats" ON)
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106 changes: 106 additions & 0 deletions changelog/0.1.10.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,106 @@
### Changes

Improved the performance of `c4/charconv.hpp` functions ([PR#77](https://github.com/biojppm/c4core/pull/77)):
- Added `digits_dec/hex/oct/bin()`.
- Optimized `write_dec/hex/oct/bin()`:
- these functions now return immediately without entering the loop if the output buffer is smaller than respectively `digits_dec/hex/oct/bin()`. This enables both:
- writing every character in its final position without having to revert the string at the end
- the need to check the buffer size on appending every character.
- `write_dec()` now writes two digits at once, thus halving the number of integer divisions.
- Added `write_dec/hex/oct/bin_unchecked()`, which receive precomputed `digits_dec/hex/oct/bin()`, thus speeding up the radix `itoa()/utoa()` overloads.
- Added `xtoa()` radix+digits overloads:
- `size_t xtoa(substr s, T v, T radix)`
- `size_t xtoa(substr s, T v, T radix, size_t num_digits)`
- `read_dec/hex/oct/bin()`: these functions no longer allow an empty input buffer.
- Use intrinsic functions `__builtin_clz()` (gcc) / `_BitScanReverse()` (msvc) in `c4::msb()` and `__builtin_ctz()` (gcc) / `_BitScanForward()` (msvc) in `c4::lsb()` when they are available. `msb()` is used by `digits_hex()/digits_bin()`.
- Refactored the charconv tests to improve consistency and thoroughness.
- Improved the charconv benchmarks to ensure full consistency across benchmarks.
- Special thanks and kudos to @fargies for being attentive and pinpointing several issues throughout the PR!
- Finding the best approach involved [writing a R&D benchmark for the several algorithm components](https://github.com/biojppm/c4core/tree/master/bm/bm_xtoa.cpp). This benchmark is disabled by default, and can be enabled with the flag `C4CORE_BM_XTOA_RND`.
- With the changes from this PR, the [charconv benchmark](https://github.com/biojppm/c4core/tree/master/bm_charconv.cpp) results show that on Linux/g++11.2, with integral types:
- `c4::to_chars()` can be expected to be roughly...
- ~40% to 2x faster than `std::to_chars()`
- ~10x-30x faster than `sprintf()`
- ~50x-100x faster than a naive `stringstream::operator<<()` followed by `stringstream::str()`
- `c4::from_chars()` can be expected to be roughly...
- ~10%-30% faster than `std::from_chars()`
- ~10x faster than `scanf()`
- ~30x-50x faster than a naive `stringstream::str()` followed by `stringstream::operator>>()`
- Here are the results from the run:
| Write throughput | | Read throughput | |
|:-------------------------|--------:|:-------------------------|---------:|
| **write `uint8_t`** | **MB/s**| **read `uint8_t`** | **MB/s**|
| `c4::to_chars<u8>` | 526.86 | `c4::from_chars<u8>` | 163.06 |
| `std::to_chars<u8>` | 379.03 | `std::from_chars<u8>` | 154.85 |
| `std::sprintf<u8>` | 20.49 | `std::scanf<u8>` | 15.75 |
| `std::stringstream<u8>` | 3.82 | `std::stringstream<u8>` | 3.83 |
| **write `int8_t`** | **MB/s**| **read `int8_t`** | **MB/s**|
| `c4::to_chars<i8>` | 599.98 | `c4::from_chars<i8>` | 184.20 |
| `std::to_chars<i8>` | 246.32 | `std::from_chars<i8>` | 156.40 |
| `std::sprintf<i8>` | 19.15 | `std::scanf<i8>` | 16.44 |
| `std::stringstream<i8>` | 3.83 | `std::stringstream<i8>` | 3.89 |
| **write `uint16_t`** | **MB/s**| **read `uint16_t`** | **MB/s**|
| `c4::to_chars<u16>` | 486.40 | `c4::from_chars<u16>` | 349.48 |
| `std::to_chars<u16>` | 454.24 | `std::from_chars<u16>` | 319.13 |
| `std::sprintf<u16>` | 38.74 | `std::scanf<u16>` | 28.12 |
| `std::stringstream<u16>` | 7.08 | `std::stringstream<u16>`| 6.73 |
| **write `int16_t`** | **MB/s**| **read `int16_t`** | **MB/s**|
| `c4::to_chars<i16>` | 507.44 | `c4::from_chars<i16>` | 282.95 |
| `std::to_chars<i16>` | 297.49 | `std::from_chars<i16>` | 186.18 |
| `std::sprintf<i16>` | 39.03 | `std::scanf<i16>` | 28.45 |
| `std::stringstream<i16>` | 6.98 | `std::stringstream<i16>`| 6.49 |
| **write `uint32_t`** | **MB/s**| **read `uint32_t`** | **MB/s**|
| `c4::to_chars<u32>` | 730.12 | `c4::from_chars<u32>` | 463.95 |
| `std::to_chars<u32>` | 514.76 | `std::from_chars<u32>` | 329.42 |
| `std::sprintf<u32>` | 71.19 | `std::scanf<u32>` | 44.97 |
| `std::stringstream<u32>` | 14.05 | `std::stringstream<u32>`| 12.57 |
| **write `int32_t`** | **MB/s**| **read `int32_t`** | **MB/s**|
| `c4::to_chars<i32>` | 618.76 | `c4::from_chars<i32>` | 345.53 |
| `std::to_chars<i32>` | 394.72 | `std::from_chars<i32>` | 224.46 |
| `std::sprintf<i32>` | 71.14 | `std::scanf<i32>` | 43.49 |
| `std::stringstream<i32>` | 13.91 | `std::stringstream<i32>`| 12.03 |
| **write `uint64_t`** | **MB/s**| **read `uint64_t`** | **MB/s**|
| `c4::to_chars<u64>` | 1118.87 | `c4::from_chars<u64>` | 928.49 |
| `std::to_chars<u64>` | 886.58 | `std::from_chars<u64>` | 759.03 |
| `std::sprintf<u64>` | 140.96 | `std::scanf<u64>` | 91.60 |
| `std::stringstream<u64>` | 28.01 | `std::stringstream<u64>`| 25.00 |
| **write `int64_t`** | **MB/s**| **read `int64_t`** | **MB/s**|
| `c4::to_chars<i64>` | 1198.78 | `c4::from_chars<i64>` | 713.76 |
| `std::to_chars<i64>` | 882.17 | `std::from_chars<i64>` | 646.18 |
| `std::sprintf<i64>` | 138.79 | `std::scanf<i64>` | 90.07 |
| `std::stringstream<i64>` | 27.62 | `std::stringstream<i64>`| 25.12 |

If you feel suspicious about these bold claims, you can browse through [c4core's CI benchmark results](https://github.com/biojppm/c4core/actions/workflows/benchmarks.yml) which will hopefully give these more substance.


### New features

- Added `bool c4::overflows<T>(csubstr s)` for detecting whether a string overflows a given integral type. See [PR#78](https://github.com/biojppm/c4core/pull/78).
- Also, added `c4::fmt::overflow_checked()` (and the corresponding `from_chars()` overload) to enable a check for overflow before parsing from string:
```c++
c4::from_chars(str, &val); // no overflow check
c4::from_chars(str, c4::fmt::overflow_checked(val)); // enable overflow check
// as an example, the implementation looks like:
template<class T>
bool c4::from_chars(c4::csubstr str, c4::fmt::overflow_checked<T> oc)
{
if(overflows<T>(str))
return false;
return c4::from_chars(str, oc.val);
}
```
### Fixes
- Fix missing endianess macro on windows arm/arm64 compilations [PR #76](https://github.com/biojppm/c4core/pull/76)
- Add missing `#define` for the include guard of the amalgamated header (see [rapidyaml#246](https://github.com/biojppm/rapidyaml/issues/246)).
- Fix CPU detection with ARMEL [PR #86](https://github.com/biojppm/c4core/pull/86).
- Fix GCC version detection [PR #87](https://github.com/biojppm/c4core/pull/87).
- Fix [cmake#8](https://github.com/biojppm/cmake/issues/8): `SOVERSION` missing from shared libraries.
- Update fastfloat to 3.5.1.
### Thanks
- @fargies
- @daichifukui
- @janisozaur
106 changes: 0 additions & 106 deletions changelog/current.md
Original file line number Diff line number Diff line change
@@ -1,106 +0,0 @@
### Changes

Improved the performance of `c4/charconv.hpp` functions ([PR#77](https://github.com/biojppm/c4core/pull/77)):
- Added `digits_dec/hex/oct/bin()`.
- Optimized `write_dec/hex/oct/bin()`:
- these functions now return immediately without entering the loop if the output buffer is smaller than respectively `digits_dec/hex/oct/bin()`. This enables both:
- writing every character in its final position without having to revert the string at the end
- the need to check the buffer size on appending every character.
- `write_dec()` now writes two digits at once, thus halving the number of integer divisions.
- Added `write_dec/hex/oct/bin_unchecked()`, which receive precomputed `digits_dec/hex/oct/bin()`, thus speeding up the radix `itoa()/utoa()` overloads.
- Added `xtoa()` radix+digits overloads:
- `size_t xtoa(substr s, T v, T radix)`
- `size_t xtoa(substr s, T v, T radix, size_t num_digits)`
- `read_dec/hex/oct/bin()`: these functions no longer allow an empty input buffer.
- Use intrinsic functions `__builtin_clz()` (gcc) / `_BitScanReverse()` (msvc) in `c4::msb()` and `__builtin_ctz()` (gcc) / `_BitScanForward()` (msvc) in `c4::lsb()` when they are available. `msb()` is used by `digits_hex()/digits_bin()`.
- Refactored the charconv tests to improve consistency and thoroughness.
- Improved the charconv benchmarks to ensure full consistency across benchmarks.
- Special thanks and kudos to @fargies for being attentive and pinpointing several issues throughout the PR!
- Finding the best approach involved [writing a R&D benchmark for the several algorithm components](https://github.com/biojppm/c4core/tree/master/bm/bm_xtoa.cpp). This benchmark is disabled by default, and can be enabled with the flag `C4CORE_BM_XTOA_RND`.
- With the changes from this PR, the [charconv benchmark](https://github.com/biojppm/c4core/tree/master/bm_charconv.cpp) results show that on Linux/g++11.2, with integral types:
- `c4::to_chars()` can be expected to be roughly...
- ~40% to 2x faster than `std::to_chars()`
- ~10x-30x faster than `sprintf()`
- ~50x-100x faster than a naive `stringstream::operator<<()` followed by `stringstream::str()`
- `c4::from_chars()` can be expected to be roughly...
- ~10%-30% faster than `std::from_chars()`
- ~10x faster than `scanf()`
- ~30x-50x faster than a naive `stringstream::str()` followed by `stringstream::operator>>()`
- Here are the results from the run:
| Write throughput | | Read throughput | |
|:-------------------------|--------:|:-------------------------|---------:|
| **write `uint8_t`** | **MB/s**| **read `uint8_t`** | **MB/s**|
| `c4::to_chars<u8>` | 526.86 | `c4::from_chars<u8>` | 163.06 |
| `std::to_chars<u8>` | 379.03 | `std::from_chars<u8>` | 154.85 |
| `std::sprintf<u8>` | 20.49 | `std::scanf<u8>` | 15.75 |
| `std::stringstream<u8>` | 3.82 | `std::stringstream<u8>` | 3.83 |
| **write `int8_t`** | **MB/s**| **read `int8_t`** | **MB/s**|
| `c4::to_chars<i8>` | 599.98 | `c4::from_chars<i8>` | 184.20 |
| `std::to_chars<i8>` | 246.32 | `std::from_chars<i8>` | 156.40 |
| `std::sprintf<i8>` | 19.15 | `std::scanf<i8>` | 16.44 |
| `std::stringstream<i8>` | 3.83 | `std::stringstream<i8>` | 3.89 |
| **write `uint16_t`** | **MB/s**| **read `uint16_t`** | **MB/s**|
| `c4::to_chars<u16>` | 486.40 | `c4::from_chars<u16>` | 349.48 |
| `std::to_chars<u16>` | 454.24 | `std::from_chars<u16>` | 319.13 |
| `std::sprintf<u16>` | 38.74 | `std::scanf<u16>` | 28.12 |
| `std::stringstream<u16>` | 7.08 | `std::stringstream<u16>`| 6.73 |
| **write `int16_t`** | **MB/s**| **read `int16_t`** | **MB/s**|
| `c4::to_chars<i16>` | 507.44 | `c4::from_chars<i16>` | 282.95 |
| `std::to_chars<i16>` | 297.49 | `std::from_chars<i16>` | 186.18 |
| `std::sprintf<i16>` | 39.03 | `std::scanf<i16>` | 28.45 |
| `std::stringstream<i16>` | 6.98 | `std::stringstream<i16>`| 6.49 |
| **write `uint32_t`** | **MB/s**| **read `uint32_t`** | **MB/s**|
| `c4::to_chars<u32>` | 730.12 | `c4::from_chars<u32>` | 463.95 |
| `std::to_chars<u32>` | 514.76 | `std::from_chars<u32>` | 329.42 |
| `std::sprintf<u32>` | 71.19 | `std::scanf<u32>` | 44.97 |
| `std::stringstream<u32>` | 14.05 | `std::stringstream<u32>`| 12.57 |
| **write `int32_t`** | **MB/s**| **read `int32_t`** | **MB/s**|
| `c4::to_chars<i32>` | 618.76 | `c4::from_chars<i32>` | 345.53 |
| `std::to_chars<i32>` | 394.72 | `std::from_chars<i32>` | 224.46 |
| `std::sprintf<i32>` | 71.14 | `std::scanf<i32>` | 43.49 |
| `std::stringstream<i32>` | 13.91 | `std::stringstream<i32>`| 12.03 |
| **write `uint64_t`** | **MB/s**| **read `uint64_t`** | **MB/s**|
| `c4::to_chars<u64>` | 1118.87 | `c4::from_chars<u64>` | 928.49 |
| `std::to_chars<u64>` | 886.58 | `std::from_chars<u64>` | 759.03 |
| `std::sprintf<u64>` | 140.96 | `std::scanf<u64>` | 91.60 |
| `std::stringstream<u64>` | 28.01 | `std::stringstream<u64>`| 25.00 |
| **write `int64_t`** | **MB/s**| **read `int64_t`** | **MB/s**|
| `c4::to_chars<i64>` | 1198.78 | `c4::from_chars<i64>` | 713.76 |
| `std::to_chars<i64>` | 882.17 | `std::from_chars<i64>` | 646.18 |
| `std::sprintf<i64>` | 138.79 | `std::scanf<i64>` | 90.07 |
| `std::stringstream<i64>` | 27.62 | `std::stringstream<i64>`| 25.12 |

If you feel suspicious about these bold claims, you can browse through [c4core's CI benchmark results](https://github.com/biojppm/c4core/actions/workflows/benchmarks.yml) which will hopefully give these more substance.


### New features

- Added `bool c4::overflows<T>(csubstr s)` for detecting whether a string overflows a given integral type. See [PR#78](https://github.com/biojppm/c4core/pull/78).
- Also, added `c4::fmt::overflow_checked()` (and the corresponding `from_chars()` overload) to enable a check for overflow before parsing from string:
```c++
c4::from_chars(str, &val); // no overflow check
c4::from_chars(str, c4::fmt::overflow_checked(val)); // enable overflow check
// as an example, the implementation looks like:
template<class T>
bool c4::from_chars(c4::csubstr str, c4::fmt::overflow_checked<T> oc)
{
if(overflows<T>(str))
return false;
return c4::from_chars(str, oc.val);
}
```
### Fixes
- Fix missing endianess macro on windows arm/arm64 compilations [PR #76](https://github.com/biojppm/c4core/pull/76)
- Add missing `#define` for the include guard of the amalgamated header (see [rapidyaml#246](https://github.com/biojppm/rapidyaml/issues/246)).
- Fix CPU detection with ARMEL [PR #86](https://github.com/biojppm/c4core/pull/86).
- Fix GCC version detection [PR #87](https://github.com/biojppm/c4core/pull/87).
- Fix [cmake#8](https://github.com/biojppm/cmake/issues/8): `SOVERSION` missing from shared libraries.
- Update fastfloat to 3.5.1.
### Thanks
- @fargies
- @daichifukui
- @janisozaur
2 changes: 1 addition & 1 deletion tbump.toml
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
# github_url = "https://github.com/<user or organization>/<project>/"

[version]
current = "0.1.9"
current = "0.1.10"

# Example of a semver regexp.
# Make sure this matches current_version before
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2 changes: 1 addition & 1 deletion test/test_install/CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ project(c4core
HOMEPAGE_URL "https://github.com/biojppm/c4core"
LANGUAGES CXX)
include(../../cmake/c4Project.cmake)
c4_project(VERSION 0.1.9
c4_project(VERSION 0.1.10
AUTHOR "Joao Paulo Magalhaes <[email protected]>")

if(C4CORE_TEST_INSTALL_PACKAGE_MODE)
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2 changes: 1 addition & 1 deletion test/test_singleheader/CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ project(c4core
HOMEPAGE_URL "https://github.com/biojppm/c4core"
LANGUAGES CXX)
include(../../cmake/c4Project.cmake)
c4_project(VERSION 0.1.9
c4_project(VERSION 0.1.10
AUTHOR "Joao Paulo Magalhaes <[email protected]>")

# amalgamate c4core to get the single header
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