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Make key 64 bits where large shifts may be used.

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This fixes a long-standing issue with large multibit structures.
This commit is contained in:
Justin Viiret
2015-11-27 13:30:59 +11:00
committed by Matthew Barr
parent 205bc1af7f
commit 15c2980948
3 changed files with 66 additions and 56 deletions
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18
src/util/multibit.c
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@@ -142,23 +142,25 @@ const u32 mmbit_root_offset_from_level[7] = {
u32 mmbit_size(u32 total_bits) {
MDEBUG_PRINTF("%u\n", total_bits);
// UE-2228: multibit has bugs in very, very large cases that we should be
// protected against at compile time by resource limits.
assert(total_bits <= 1U << 30);
// Flat model multibit structures are just stored as a bit vector.
if (total_bits <= MMB_FLAT_MAX_BITS) {
return ROUNDUP_N(total_bits, 8) / 8;
}
u32 current_level = 1;
u32 total = 0;
u64a current_level = 1; // Number of blocks on current level.
u64a total = 0; // Total number of blocks.
while (current_level * MMB_KEY_BITS < total_bits) {
total += current_level;
current_level <<= MMB_KEY_SHIFT;
}
total += (total_bits + MMB_KEY_BITS - 1)/MMB_KEY_BITS;
return sizeof(MMB_TYPE) * total;
// Last level is a one-for-one bit vector. It needs room for total_bits
// elements, rounded up to the nearest block.
u64a last_level = ((u64a)total_bits + MMB_KEY_BITS - 1) / MMB_KEY_BITS;
total += last_level;
assert(total * sizeof(MMB_TYPE) <= UINT32_MAX);
return (u32)(total * sizeof(MMB_TYPE));
}
#ifdef DUMP_SUPPORT