Rework hashing, use a more extensible framework similar to n3876 proposal

std::hash specialization is a pain to work with, stop using that, and
just specialize a 'size_t hash_value(const T&)' free function.

1 files changed, 0 insertions, 60 deletions

diff --git a/src/string.cc b/src/string.cc
index 14c680c9..152b90aa 100644
--- a/src/string.cc
+++ b/src/string.cc
@@ -173,64 +173,4 @@ std::vector<StringView> wrap_lines(StringView text, CharCount max_width)
     return lines;
 }
 
-[[gnu::always_inline]]
-static inline uint32_t rotl(uint32_t x, int8_t r)
-{
-    return (x << r) | (x >> (32 - r));
-}
-
-[[gnu::always_inline]]
-static inline uint32_t fmix(uint32_t h)
-{
-    h ^= h >> 16;
-    h *= 0x85ebca6b;
-    h ^= h >> 13;
-    h *= 0xc2b2ae35;
-    h ^= h >> 16;
-
-    return h;
-}
-
-// murmur3 hash, based on https://github.com/PeterScott/murmur3
-size_t hash_data(const char* input, size_t len)
-{
-    const uint8_t* data = reinterpret_cast<const uint8_t*>(input);
-    uint32_t hash = 0x1235678;
-    constexpr uint32_t c1 = 0xcc9e2d51;
-    constexpr uint32_t c2 = 0x1b873593;
-
-    const int nblocks = len / 4;
-    const uint32_t* blocks = reinterpret_cast<const uint32_t*>(data + nblocks*4);
-
-    for (int i = -nblocks; i; ++i)
-    {
-        uint32_t key = blocks[i];
-        key *= c1;
-        key = rotl(key, 15);
-        key *= c2;
-
-        hash ^= key;
-        hash = rotl(hash, 13);
-        hash = hash * 5 + 0xe6546b64;
-    }
-
-    const uint8_t* tail = data + nblocks * 4;
-    uint32_t key = 0;
-    switch (len & 3)
-    {
-        case 3: key ^= tail[2] << 16;
-        case 2: key ^= tail[1] << 8;
-        case 1: key ^= tail[0];
-                key *= c1;
-                key = rotl(key,15);
-                key *= c2;
-                hash ^= key;
-    }
-
-    hash ^= len;
-    hash = fmix(hash);
-
-    return hash;
-}
-
 }