diff options
Diffstat (limited to 'kernel/hashlib.h')
| -rw-r--r-- | kernel/hashlib.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/kernel/hashlib.h b/kernel/hashlib.h index 24a1dbf6d..021cc66ee 100644 --- a/kernel/hashlib.h +++ b/kernel/hashlib.h @@ -31,6 +31,20 @@ inline unsigned int mkhash_add(unsigned int a, unsigned int b) { return ((a << 5) + a) + b; } +inline unsigned int mkhash_xorshift(unsigned int a) { + if (sizeof(a) == 4) { + a ^= a << 13; + a ^= a >> 17; + a ^= a << 5; + } else if (sizeof(a) == 8) { + a ^= a << 13; + a ^= a >> 7; + a ^= a << 17; + } else + throw std::runtime_error("mkhash_xorshift() only implemented for 32 bit and 64 bit ints"); + return a; +} + template<typename T> struct hash_ops { bool cmp(const T &a, const T &b) const { return a == b; @@ -122,7 +136,11 @@ inline int hashtable_size(int old_size) if (old_size < 250999999) return 250999999; if (old_size < 503000009) return 503000009; if (old_size < 1129999999) return 1129999999; - throw std::length_error("hash table exceeded maximum size"); + + if (sizeof(old_size) == 4) + throw std::length_error("hash table exceeded maximum size. recompile with -mint64."); + + return old_size * 2; } template<typename K, typename T, typename OPS = hash_ops<K>> |