Remove unused extra copy of find_next_document_index

This commit is contained in:
John Keiser 2020-06-09 17:52:13 -07:00
parent 6f90f5dc5f
commit ea08e7d192
1 changed files with 0 additions and 89 deletions

View File

@ -73,8 +73,6 @@ private:
really_inline void step(const uint8_t *block, buf_block_reader<STEP_SIZE> &reader) noexcept;
really_inline void next(simd::simd8x64<uint8_t> in, json_block block, size_t idx);
really_inline error_code finish(dom_parser_implementation &parser, size_t idx, size_t len, bool partial);
static really_inline uint32_t find_next_document_index(dom_parser_implementation &parser);
static really_inline size_t trim_partial_utf8(const uint8_t *buf, size_t len);
json_scanner scanner{};
utf8_checker checker{};
@ -197,91 +195,4 @@ really_inline error_code json_structural_indexer::finish(dom_parser_implementati
return checker.errors();
}
/**
* This algorithm is used to quickly identify the last structural position that
* makes up a complete document.
*
* It does this by going backwards and finding the last *document boundary* (a
* place where one value follows another without a comma between them). If the
* last document (the characters after the boundary) has an equal number of
* start and end brackets, it is considered complete.
*
* Simply put, we iterate over the structural characters, starting from
* the end. We consider that we found the end of a JSON document when the
* first element of the pair is NOT one of these characters: '{' '[' ';' ','
* and when the second element is NOT one of these characters: '}' '}' ';' ','.
*
* This simple comparison works most of the time, but it does not cover cases
* where the batch's structural indexes contain a perfect amount of documents.
* In such a case, we do not have access to the structural index which follows
* the last document, therefore, we do not have access to the second element in
* the pair, and means that we cannot identify the last document. To fix this
* issue, we keep a count of the open and closed curly/square braces we found
* while searching for the pair. When we find a pair AND the count of open and
* closed curly/square braces is the same, we know that we just passed a
* complete
* document, therefore the last json buffer location is the end of the batch
*/
really_inline uint32_t json_structural_indexer::find_next_document_index(dom_parser_implementation &parser) {
// TODO don't count separately, just figure out depth
auto arr_cnt = 0;
auto obj_cnt = 0;
for (auto i = parser.n_structural_indexes - 1; i > 0; i--) {
auto idxb = parser.structural_indexes[i];
switch (parser.buf[idxb]) {
case ':':
case ',':
continue;
case '}':
obj_cnt--;
continue;
case ']':
arr_cnt--;
continue;
case '{':
obj_cnt++;
break;
case '[':
arr_cnt++;
break;
}
auto idxa = parser.structural_indexes[i - 1];
switch (parser.buf[idxa]) {
case '{':
case '[':
case ':':
case ',':
continue;
}
// Last document is complete, so the next document will appear after!
if (!arr_cnt && !obj_cnt) {
return parser.n_structural_indexes;
}
// Last document is incomplete; mark the document at i + 1 as the next one
return i;
}
return 0;
}
// Skip the last character if it is partial
really_inline size_t json_structural_indexer::trim_partial_utf8(const uint8_t *buf, size_t len) {
if (unlikely(len < 3)) {
switch (len) {
case 2:
if (buf[len-1] >= 0b11000000) { return len-1; } // 2-, 3- and 4-byte characters with only 1 byte left
if (buf[len-2] >= 0b11100000) { return len-2; } // 3- and 4-byte characters with only 2 bytes left
return len;
case 1:
if (buf[len-1] >= 0b11000000) { return len-1; } // 2-, 3- and 4-byte characters with only 1 byte left
return len;
case 0:
return len;
}
}
if (buf[len-1] >= 0b11000000) { return len-1; } // 2-, 3- and 4-byte characters with only 1 byte left
if (buf[len-2] >= 0b11100000) { return len-2; } // 3- and 4-byte characters with only 1 byte left
if (buf[len-3] >= 0b11110000) { return len-3; } // 4-byte characters with only 3 bytes left
return len;
}
} // namespace stage1