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storeInitialRingTopPatch: fix large delta bug

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Check for staleness up front, so that it is safe to use u32 values to
handle adding more tops.

Adds LargeGap unit tests.
This commit is contained in:
Justin Viiret 2015-11-03 14:58:01 +11:00 committed by Matthew Barr
parent a083bcfa8d
commit 2603be3924
2 changed files with 60 additions and 15 deletions
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38
src/nfa/repeat.c
View File

@ -1165,7 +1165,7 @@ static
void storeInitialRingTopPatch(const struct RepeatInfo *info,
struct RepeatRingControl *xs,
u8 *state, u64a offset) {
DEBUG_PRINTF("set the first patch\n");
DEBUG_PRINTF("set the first patch, offset=%llu\n", offset);
xs->offset = offset;
u8 *active = state;
@ -1340,21 +1340,33 @@ void repeatStoreSparseOptimalP(const struct RepeatInfo *info,
union RepeatControl *ctrl, void *state,
u64a offset, char is_alive) {
struct RepeatRingControl *xs = &ctrl->ring;
u64a delta = offset - xs->offset;
u32 patch_size = info->patchSize;
u32 patch_count = info->patchCount;
u32 encoding_size = info->encodingSize;
u32 patch = delta / patch_size;
DEBUG_PRINTF("offset: %llu encoding_size: %u\n", offset, encoding_size);
u8 *active = (u8 *)state;
if (!is_alive) {
DEBUG_PRINTF("offset: %llu encoding_size: %u\n", offset,
info->encodingSize);
// If (a) this is the first top, or (b) the ring is stale, initialize the
// ring and write this offset in as the first top.
if (!is_alive ||
offset >
repeatLastTopSparseOptimalP(info, ctrl, state) + info->repeatMax) {
storeInitialRingTopPatch(info, xs, active, offset);
return;
}
assert(offset >= xs->offset);
// Tops should arrive in order, with no duplicates.
assert(offset > repeatLastTopSparseOptimalP(info, ctrl, state));
// As the ring is not stale, our delta should fit within a u32.
assert(offset - xs->offset <= UINT32_MAX);
u32 delta = (u32)(offset - xs->offset);
u32 patch_size = info->patchSize;
u32 patch_count = info->patchCount;
u32 encoding_size = info->encodingSize;
u32 patch = delta / patch_size;
DEBUG_PRINTF("delta=%u, patch_size=%u, patch=%u\n", delta, patch_size,
patch);
u8 *ring = active + info->patchesOffset;
u32 occ = ringOccupancy(xs, patch_count);
@ -1365,10 +1377,6 @@ void repeatStoreSparseOptimalP(const struct RepeatInfo *info,
patch, patch_count, occ);
if (patch >= patch_count) {
u32 patch_shift_count = patch - patch_count + 1;
if (patch_shift_count >= patch_count) {
storeInitialRingTopPatch(info, xs, active, offset);
return;
}
assert(patch >= patch_shift_count);
DEBUG_PRINTF("shifting by %u\n", patch_shift_count);
xs->offset += patch_size * patch_shift_count;

37
unit/internal/repeat.cpp
View File

@ -448,6 +448,25 @@ TEST_P(RepeatTest, Pack) {
}
}
TEST_P(RepeatTest, LargeGap) {
SCOPED_TRACE(testing::Message() << "Repeat: " << info);
if (info.repeatMax == REPEAT_INF) {
return; // Test not valid for FIRST-type repeats.
}
for (int i = 0; i < 64; i++) {
u64a top1 = 1000;
repeatStore(&info, ctrl, state, top1, 0); // first top
ASSERT_EQ(top1, repeatLastTop(&info, ctrl, state));
// Add a second top after a gap of 2^i bytes.
u64a top2 = top1 + (1ULL << i);
repeatStore(&info, ctrl, state, top2, 1); // second top
ASSERT_EQ(top2, repeatLastTop(&info, ctrl, state));
}
}
static
const u32 sparsePeriods[] = {
2,
@ -895,6 +914,24 @@ TEST_P(SparseOptimalTest, Simple3e) {
test_sparse3entryExpire(info, ctrl, state, 2 * info->minPeriod - 1);
}
TEST_P(SparseOptimalTest, LargeGap) {
SCOPED_TRACE(testing::Message() << "Repeat: " << *info);
for (int i = 0; i < 64; i++) {
u64a top1 = 1000;
repeatStore(info, ctrl, state, top1, 0); // first top
ASSERT_EQ(top1, repeatLastTop(info, ctrl, state));
// Add a second top after a gap of 2^i bytes.
u64a top2 = top1 + (1ULL << i);
if (top2 - top1 < info->minPeriod) {
continue; // not a valid top
}
repeatStore(info, ctrl, state, top2, 1); // second top
ASSERT_EQ(top2, repeatLastTop(info, ctrl, state));
}
}
TEST_P(SparseOptimalTest, ThreeTops) {
SCOPED_TRACE(testing::Message() << "Repeat: " << *info);