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156 lines (135 loc) · 6.9 KB
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#include "simdjson.h"
#include "isadetection.h"
#include "simdprune_tables.h"
#include <initializer_list>
// Static array of known implementations. We're hoping these get baked into the executable
// without requiring a static initializer.
#if SIMDJSON_IMPLEMENTATION_HASWELL
#include "haswell/implementation.h"
namespace simdjson { namespace internal { const haswell::implementation haswell_singleton{}; } }
#endif // SIMDJSON_IMPLEMENTATION_HASWELL
#if SIMDJSON_IMPLEMENTATION_WESTMERE
#include "westmere/implementation.h"
namespace simdjson { namespace internal { const westmere::implementation westmere_singleton{}; } }
#endif // SIMDJSON_IMPLEMENTATION_WESTMERE
#if SIMDJSON_IMPLEMENTATION_ARM64
#include "arm64/implementation.h"
namespace simdjson { namespace internal { const arm64::implementation arm64_singleton{}; } }
#endif // SIMDJSON_IMPLEMENTATION_ARM64
#if SIMDJSON_IMPLEMENTATION_FALLBACK
#include "fallback/implementation.h"
namespace simdjson { namespace internal { const fallback::implementation fallback_singleton{}; } }
#endif // SIMDJSON_IMPLEMENTATION_FALLBACK
namespace simdjson {
namespace internal {
/**
* @private Detects best supported implementation on first use, and sets it
*/
class detect_best_supported_implementation_on_first_use final : public implementation {
public:
const std::string &name() const noexcept final { return set_best()->name(); }
const std::string &description() const noexcept final { return set_best()->description(); }
uint32_t required_instruction_sets() const noexcept final { return set_best()->required_instruction_sets(); }
WARN_UNUSED error_code create_dom_parser_implementation(
size_t capacity,
size_t max_length,
std::unique_ptr<internal::dom_parser_implementation>& dst
) const noexcept final {
return set_best()->create_dom_parser_implementation(capacity, max_length, dst);
}
WARN_UNUSED error_code minify(const uint8_t *buf, size_t len, uint8_t *dst, size_t &dst_len) const noexcept final {
return set_best()->minify(buf, len, dst, dst_len);
}
WARN_UNUSED bool validate_utf8(const char * buf, size_t len) const noexcept final override {
return set_best()->validate_utf8(buf, len);
}
really_inline detect_best_supported_implementation_on_first_use() noexcept : implementation("best_supported_detector", "Detects the best supported implementation and sets it", 0) {}
private:
const implementation *set_best() const noexcept;
};
const detect_best_supported_implementation_on_first_use detect_best_supported_implementation_on_first_use_singleton;
internal::atomic_ptr<const implementation> active_implementation{&internal::detect_best_supported_implementation_on_first_use_singleton};
const std::initializer_list<const implementation *> available_implementation_pointers {
#if SIMDJSON_IMPLEMENTATION_HASWELL
&haswell_singleton,
#endif
#if SIMDJSON_IMPLEMENTATION_WESTMERE
&westmere_singleton,
#endif
#if SIMDJSON_IMPLEMENTATION_ARM64
&arm64_singleton,
#endif
#if SIMDJSON_IMPLEMENTATION_FALLBACK
&fallback_singleton,
#endif
}; // available_implementation_pointers
// So we can return UNSUPPORTED_ARCHITECTURE from the parser when there is no support
class unsupported_implementation final : public implementation {
public:
WARN_UNUSED error_code create_dom_parser_implementation(
size_t,
size_t,
std::unique_ptr<internal::dom_parser_implementation>&
) const noexcept final {
return UNSUPPORTED_ARCHITECTURE;
}
WARN_UNUSED error_code minify(const uint8_t *, size_t, uint8_t *, size_t &) const noexcept final override {
return UNSUPPORTED_ARCHITECTURE;
}
WARN_UNUSED bool validate_utf8(const char *, size_t) const noexcept final override {
return false; // Just refuse to validate. Given that we have a fallback implementation
// it seems unlikely that unsupported_implementation will ever be used. If it is used,
// then it will flag all strings as invalid. The alternative is to return an error_code
// from which the user has to figure out whether the string is valid UTF-8... which seems
// like a lot of work just to handle the very unlikely case that we have an unsupported
// implementation. And, when it does happen (that we have an unsupported implementation),
// what are the chances that the programmer has a fallback? Given that *we* provide the
// fallback, it implies that the programmer would need a fallback for our fallback.
}
unsupported_implementation() : implementation("unsupported", "Unsupported CPU (no detected SIMD instructions)", 0) {}
};
const unsupported_implementation unsupported_singleton{};
size_t available_implementation_list::size() const noexcept {
return internal::available_implementation_pointers.size();
}
const implementation * const *available_implementation_list::begin() const noexcept {
return internal::available_implementation_pointers.begin();
}
const implementation * const *available_implementation_list::end() const noexcept {
return internal::available_implementation_pointers.end();
}
const implementation *available_implementation_list::detect_best_supported() const noexcept {
// They are prelisted in priority order, so we just go down the list
uint32_t supported_instruction_sets = detect_supported_architectures();
for (const implementation *impl : internal::available_implementation_pointers) {
uint32_t required_instruction_sets = impl->required_instruction_sets();
if ((supported_instruction_sets & required_instruction_sets) == required_instruction_sets) { return impl; }
}
return &unsupported_singleton; // this should never happen?
}
const implementation *detect_best_supported_implementation_on_first_use::set_best() const noexcept {
SIMDJSON_PUSH_DISABLE_WARNINGS
SIMDJSON_DISABLE_DEPRECATED_WARNING // Disable CRT_SECURE warning on MSVC: manually verified this is safe
char *force_implementation_name = getenv("SIMDJSON_FORCE_IMPLEMENTATION");
SIMDJSON_POP_DISABLE_WARNINGS
if (force_implementation_name) {
auto force_implementation = available_implementations[force_implementation_name];
if (force_implementation) {
return active_implementation = force_implementation;
} else {
// Note: abort() and stderr usage within the library is forbidden.
return active_implementation = &unsupported_singleton;
}
}
return active_implementation = available_implementations.detect_best_supported();
}
} // namespace internal
SIMDJSON_DLLIMPORTEXPORT const internal::available_implementation_list available_implementations{};
SIMDJSON_DLLIMPORTEXPORT internal::atomic_ptr<const implementation> active_implementation{&internal::detect_best_supported_implementation_on_first_use_singleton};
WARN_UNUSED error_code minify(const char *buf, size_t len, char *dst, size_t &dst_len) noexcept {
return active_implementation->minify((const uint8_t *)buf, len, (uint8_t *)dst, dst_len);
}
WARN_UNUSED bool validate_utf8(const char *buf, size_t len) noexcept {
return active_implementation->validate_utf8(buf, len);
}
} // namespace simdjson