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| author | Patrick Steinhardt <ps@pks.im> | 2025-04-07 15:16:16 +0200 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2025-04-07 14:53:09 -0700 |
| commit | ba620d296ab7bcd93fcedfe13b265f84df1ed1eb (patch) | |
| tree | a64e7d6f200f86ea9e8a32ca621de1c487836c4f /reftable/block.c | |
| parent | 1ac4e5e83d997887dcd051c89861292a45a3db8c (diff) | |
| download | git-ba620d296ab7bcd93fcedfe13b265f84df1ed1eb.tar.gz | |
reftable/block: simplify how we track restart points
Restart points record the location of reftable records that do not use
prefix compression and are used to perform a binary search inside of a
block. These restart points are encoded at the end of a block, between
the record data and the footer of a table.
The block structure contains three different variables related to these
restart points:
- The block length contains the length of the reftable block up to the
restart points.
- The restart count contains the number of restart points contained in
the block.
- The restart bytes variable tracks where the restart point data
begins.
Tracking all three of these variables is unnecessary though as the data
can be derived from one another: the block length without restart points
is the exact same as the offset of the restart count data, which we
already track via the `restart_bytes` data.
Refactor the code so that we track the location of restart bytes not as
a pointer, but instead as an offset. This allows us to trivially get rid
of the `block_len` variable as described above. This avoids having the
confusing `block_len` variable and allows us to do less bookkeeping
overall.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'reftable/block.c')
| -rw-r--r-- | reftable/block.c | 25 |
1 files changed, 12 insertions, 13 deletions
diff --git a/reftable/block.c b/reftable/block.c index 9774018725..f2567a8f0f 100644 --- a/reftable/block.c +++ b/reftable/block.c @@ -216,10 +216,9 @@ int block_reader_init(struct block_reader *br, struct reftable_block *block, uint32_t full_block_size = table_block_size; uint8_t typ = block->data[header_off]; uint32_t sz = reftable_get_be24(block->data + header_off + 1); - int err = 0; - uint16_t restart_count = 0; - uint32_t restart_start = 0; - uint8_t *restart_bytes = NULL; + uint16_t restart_count; + uint32_t restart_off; + int err; block_source_return_block(&br->block); @@ -300,8 +299,7 @@ int block_reader_init(struct block_reader *br, struct reftable_block *block, } restart_count = reftable_get_be16(block->data + sz - 2); - restart_start = sz - 2 - 3 * restart_count; - restart_bytes = block->data + restart_start; + restart_off = sz - 2 - 3 * restart_count; /* transfer ownership. */ br->block = *block; @@ -309,11 +307,12 @@ int block_reader_init(struct block_reader *br, struct reftable_block *block, block->len = 0; br->hash_size = hash_size; - br->block_len = restart_start; + br->restart_off = restart_off; br->full_block_size = full_block_size; br->header_off = header_off; br->restart_count = restart_count; - br->restart_bytes = restart_bytes; + + err = 0; done: return err; @@ -337,7 +336,7 @@ int block_reader_first_key(const struct block_reader *br, struct reftable_buf *k int off = br->header_off + 4, n; struct string_view in = { .buf = br->block.data + off, - .len = br->block_len - off, + .len = br->restart_off - off, }; uint8_t extra = 0; @@ -354,13 +353,13 @@ int block_reader_first_key(const struct block_reader *br, struct reftable_buf *k static uint32_t block_reader_restart_offset(const struct block_reader *br, size_t idx) { - return reftable_get_be24(br->restart_bytes + 3 * idx); + return reftable_get_be24(br->block.data + br->restart_off + 3 * idx); } void block_iter_seek_start(struct block_iter *it, const struct block_reader *br) { it->block = br->block.data; - it->block_len = br->block_len; + it->block_len = br->restart_off; it->hash_size = br->hash_size; reftable_buf_reset(&it->last_key); it->next_off = br->header_off + 4; @@ -378,7 +377,7 @@ static int restart_needle_less(size_t idx, void *_args) uint32_t off = block_reader_restart_offset(args->reader, idx); struct string_view in = { .buf = args->reader->block.data + off, - .len = args->reader->block_len - off, + .len = args->reader->restart_off - off, }; uint64_t prefix_len, suffix_len; uint8_t extra; @@ -505,7 +504,7 @@ int block_iter_seek_key(struct block_iter *it, const struct block_reader *br, else it->next_off = br->header_off + 4; it->block = br->block.data; - it->block_len = br->block_len; + it->block_len = br->restart_off; it->hash_size = br->hash_size; err = reftable_record_init(&rec, block_reader_type(br)); |