Removes is_at_container_start() and documents is_at_iterator_start(), move_at_start(), enter_at_container_start() (#1638)

* Removes is_at_container_start() and documents is_at_iterator_start()

* More documentation.
This commit is contained in:
Daniel Lemire 2021-06-25 13:26:43 -04:00 committed by GitHub
parent e607958a7b
commit 1fd3e32051
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4 changed files with 24 additions and 16 deletions

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@ -3,5 +3,8 @@
{"column": 95 },
{"column": 120 }
],
"files.trimTrailingWhitespace": true
"files.trimTrailingWhitespace": true,
"files.associations": {
"array": "cpp"
}
}

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@ -76,13 +76,6 @@ simdjson_really_inline simdjson_result<size_t> array::count_elements() & noexcep
// If the array is empty (i.e., we already scanned past it), then we use a
// fast path and return 0.
if(!iter.is_open()) { return 0; }
// The count_elements method should always be called before you have begun
// iterating through the array.
// To open a new array you need to be at a `[`.
#ifdef SIMDJSON_DEVELOPMENT_CHECKS
// array::begin() makes the same check.
if(!iter.is_at_container_start()) { return OUT_OF_ORDER_ITERATION; }
#endif
size_t count{0};
// Important: we do not consume any of the values.
for(simdjson_unused auto v : *this) { count++; }

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@ -604,9 +604,6 @@ simdjson_really_inline error_code value_iterator::incorrect_type_error(const cha
simdjson_really_inline bool value_iterator::is_at_start() const noexcept {
return _json_iter->token.index == _start_position;
}
simdjson_really_inline bool value_iterator::is_at_container_start() const noexcept {
return _json_iter->token.index == _start_position + 1;
}
simdjson_really_inline bool value_iterator::is_at_iterator_start() const noexcept {
// We can legitimately be either at the first value ([1]), or after the array if it's empty ([]).
auto delta = _json_iter->token.index - _start_position;

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@ -281,12 +281,22 @@ public:
/** @} */
protected:
/* updates the index so that at_start() is true and syncs the depth. */
/**
* move_at_start(): moves us so that we are pointing at the beginning of
* the container. It updates the index so that at_start() is true and it
* syncs the depth. The user can then create a new container instance.
*
* Usage: used with value::count_elements()
**/
simdjson_really_inline void move_at_start() noexcept;
/**
* enter_at_container_start is similar to move_at_start()
* except that it sets the depth to indicate that we are inside the
* container and then it accesses the first element
* enter_at_container_start moves at the beginning of the container
* and sets the depth to indicate that we are inside the
* container and ready to access the first element. It is only
* safely used with non-empty containers. The caller is responsible
* to ensure that the container is not empty!
*
* Usage: used with array::count_elements().
**/
simdjson_really_inline void enter_at_container_start() noexcept;
/* Useful for debugging and logging purposes. */
@ -306,7 +316,12 @@ protected:
simdjson_really_inline error_code incorrect_type_error(const char *message) const noexcept;
simdjson_really_inline bool is_at_start() const noexcept;
simdjson_really_inline bool is_at_container_start() const noexcept;
/**
* is_at_iterator_start() returns true on an array or object after it has just been
* created, whether the instance is empty or not.
*
* Usage: used by array::begin() in debug mode (SIMDJSON_DEVELOPMENT_CHECKS)
*/
simdjson_really_inline bool is_at_iterator_start() const noexcept;
inline void assert_at_start() const noexcept;
inline void assert_at_container_start() const noexcept;