From: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> This is needed to create a merged view multiple reftables Signed-off-by: Han-Wen Nienhuys <hanwen@xxxxxxxxxx> --- Makefile | 2 + reftable/pq.c | 115 ++++++++++++++++++++++++++++++++++++++ reftable/pq.h | 32 +++++++++++ reftable/pq_test.c | 72 ++++++++++++++++++++++++ reftable/reftable-tests.h | 1 + t/helper/test-reftable.c | 1 + 6 files changed, 223 insertions(+) create mode 100644 reftable/pq.c create mode 100644 reftable/pq.h create mode 100644 reftable/pq_test.c diff --git a/Makefile b/Makefile index b23e4a82063a..74560a9605bb 100644 --- a/Makefile +++ b/Makefile @@ -2406,6 +2406,7 @@ REFTABLE_OBJS += reftable/block.o REFTABLE_OBJS += reftable/blocksource.o REFTABLE_OBJS += reftable/iter.o REFTABLE_OBJS += reftable/publicbasics.o +REFTABLE_OBJS += reftable/pq.o REFTABLE_OBJS += reftable/reader.o REFTABLE_OBJS += reftable/record.o REFTABLE_OBJS += reftable/reftable.o @@ -2415,6 +2416,7 @@ REFTABLE_OBJS += reftable/zlib-compat.o REFTABLE_TEST_OBJS += reftable/basics_test.o REFTABLE_TEST_OBJS += reftable/block_test.o +REFTABLE_TEST_OBJS += reftable/pq_test.o REFTABLE_TEST_OBJS += reftable/record_test.o REFTABLE_TEST_OBJS += reftable/reftable_test.o REFTABLE_TEST_OBJS += reftable/test_framework.o diff --git a/reftable/pq.c b/reftable/pq.c new file mode 100644 index 000000000000..8918d158e2d4 --- /dev/null +++ b/reftable/pq.c @@ -0,0 +1,115 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#include "pq.h" + +#include "reftable-record.h" +#include "system.h" +#include "basics.h" + +static int pq_less(struct pq_entry a, struct pq_entry b) +{ + struct strbuf ak = STRBUF_INIT; + struct strbuf bk = STRBUF_INIT; + int cmp = 0; + reftable_record_key(&a.rec, &ak); + reftable_record_key(&b.rec, &bk); + + cmp = strbuf_cmp(&ak, &bk); + + strbuf_release(&ak); + strbuf_release(&bk); + + if (cmp == 0) + return a.index > b.index; + + return cmp < 0; +} + +struct pq_entry merged_iter_pqueue_top(struct merged_iter_pqueue pq) +{ + return pq.heap[0]; +} + +int merged_iter_pqueue_is_empty(struct merged_iter_pqueue pq) +{ + return pq.len == 0; +} + +void merged_iter_pqueue_check(struct merged_iter_pqueue pq) +{ + int i = 0; + for (i = 1; i < pq.len; i++) { + int parent = (i - 1) / 2; + + assert(pq_less(pq.heap[parent], pq.heap[i])); + } +} + +struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq) +{ + int i = 0; + struct pq_entry e = pq->heap[0]; + pq->heap[0] = pq->heap[pq->len - 1]; + pq->len--; + + i = 0; + while (i < pq->len) { + int min = i; + int j = 2 * i + 1; + int k = 2 * i + 2; + if (j < pq->len && pq_less(pq->heap[j], pq->heap[i])) { + min = j; + } + if (k < pq->len && pq_less(pq->heap[k], pq->heap[min])) { + min = k; + } + + if (min == i) { + break; + } + + SWAP(pq->heap[i], pq->heap[min]); + i = min; + } + + return e; +} + +void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e) +{ + int i = 0; + if (pq->len == pq->cap) { + pq->cap = 2 * pq->cap + 1; + pq->heap = reftable_realloc(pq->heap, + pq->cap * sizeof(struct pq_entry)); + } + + pq->heap[pq->len++] = e; + i = pq->len - 1; + while (i > 0) { + int j = (i - 1) / 2; + if (pq_less(pq->heap[j], pq->heap[i])) { + break; + } + + SWAP(pq->heap[j], pq->heap[i]); + + i = j; + } +} + +void merged_iter_pqueue_release(struct merged_iter_pqueue *pq) +{ + int i = 0; + for (i = 0; i < pq->len; i++) { + reftable_record_destroy(&pq->heap[i].rec); + } + FREE_AND_NULL(pq->heap); + pq->len = pq->cap = 0; +} diff --git a/reftable/pq.h b/reftable/pq.h new file mode 100644 index 000000000000..385d2fb139a6 --- /dev/null +++ b/reftable/pq.h @@ -0,0 +1,32 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#ifndef PQ_H +#define PQ_H + +#include "record.h" + +struct pq_entry { + int index; + struct reftable_record rec; +}; + +struct merged_iter_pqueue { + struct pq_entry *heap; + size_t len; + size_t cap; +}; + +struct pq_entry merged_iter_pqueue_top(struct merged_iter_pqueue pq); +int merged_iter_pqueue_is_empty(struct merged_iter_pqueue pq); +void merged_iter_pqueue_check(struct merged_iter_pqueue pq); +struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq); +void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e); +void merged_iter_pqueue_release(struct merged_iter_pqueue *pq); + +#endif diff --git a/reftable/pq_test.c b/reftable/pq_test.c new file mode 100644 index 000000000000..5178980b37ed --- /dev/null +++ b/reftable/pq_test.c @@ -0,0 +1,72 @@ +/* +Copyright 2020 Google LLC + +Use of this source code is governed by a BSD-style +license that can be found in the LICENSE file or at +https://developers.google.com/open-source/licenses/bsd +*/ + +#include "system.h" + +#include "basics.h" +#include "constants.h" +#include "pq.h" +#include "record.h" +#include "reftable-tests.h" +#include "test_framework.h" + +static void test_pq(void) +{ + char *names[54] = { NULL }; + int N = ARRAY_SIZE(names) - 1; + + struct merged_iter_pqueue pq = { NULL }; + const char *last = NULL; + + int i = 0; + for (i = 0; i < N; i++) { + char name[100]; + snprintf(name, sizeof(name), "%02d", i); + names[i] = xstrdup(name); + } + + i = 1; + do { + struct reftable_record rec = + reftable_new_record(BLOCK_TYPE_REF); + struct pq_entry e = { 0 }; + + reftable_record_as_ref(&rec)->refname = names[i]; + e.rec = rec; + merged_iter_pqueue_add(&pq, e); + merged_iter_pqueue_check(pq); + i = (i * 7) % N; + } while (i != 1); + + while (!merged_iter_pqueue_is_empty(pq)) { + struct pq_entry e = merged_iter_pqueue_remove(&pq); + struct reftable_ref_record *ref = + reftable_record_as_ref(&e.rec); + + merged_iter_pqueue_check(pq); + + if (last != NULL) { + assert(strcmp(last, ref->refname) < 0); + } + last = ref->refname; + ref->refname = NULL; + reftable_free(ref); + } + + for (i = 0; i < N; i++) { + reftable_free(names[i]); + } + + merged_iter_pqueue_release(&pq); +} + +int pq_test_main(int argc, const char *argv[]) +{ + RUN_TEST(test_pq); + return 0; +} diff --git a/reftable/reftable-tests.h b/reftable/reftable-tests.h index 5e7698ae654e..495556572e20 100644 --- a/reftable/reftable-tests.h +++ b/reftable/reftable-tests.h @@ -12,6 +12,7 @@ license that can be found in the LICENSE file or at int basics_test_main(int argc, const char **argv); int block_test_main(int argc, const char **argv); int merged_test_main(int argc, const char **argv); +int pq_test_main(int argc, const char **argv); int record_test_main(int argc, const char **argv); int refname_test_main(int argc, const char **argv); int reftable_test_main(int argc, const char **argv); diff --git a/t/helper/test-reftable.c b/t/helper/test-reftable.c index fdf925867375..368eb7339eb7 100644 --- a/t/helper/test-reftable.c +++ b/t/helper/test-reftable.c @@ -5,6 +5,7 @@ int cmd__reftable(int argc, const char **argv) { basics_test_main(argc, argv); block_test_main(argc, argv); + pq_test_main(argc, argv); record_test_main(argc, argv); reftable_test_main(argc, argv); tree_test_main(argc, argv); -- gitgitgadget
