Commit 4a32dce92a0ff00d824b3ec512b8f6dff28dcaa2
2017-03-14T19:32:12
[sfnt] Implement PS names for font instances [1/3]. Add 128bit MurmurHash 3 function. Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT. * src/sfnt/sfdriver.c (ROTL32): New macro. (fmix32, murmur_hash_3_128): New functions.
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diff --git a/ChangeLog b/ChangeLog
index 091724f..181ade9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2017-03-14 Werner Lemberg <wl@gnu.org>
+
+ [sfnt] Implement PS names for font instances [1/3].
+
+ Add 128bit MurmurHash 3 function.
+
+ Everything is guarded with TT_CONFIG_OPTION_GX_VAR_SUPPORT.
+
+ * src/sfnt/sfdriver.c (ROTL32): New macro.
+ (fmix32, murmur_hash_3_128): New functions.
+
2017-03-13 Werner Lemberg <wl@gnu.org>
[truetype] Ignore invalid MVAR tags.
diff --git a/src/sfnt/sfdriver.c b/src/sfnt/sfdriver.c
index f132669..455c490 100644
--- a/src/sfnt/sfdriver.c
+++ b/src/sfnt/sfdriver.c
@@ -250,6 +250,195 @@
}
+#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
+
+ /* the implementation of MurmurHash3 is taken and adapted from */
+ /* https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp */
+
+#define ROTL32( x, r ) ( x << r ) | ( x >> ( 32 - r ) )
+
+
+ FT_UInt32
+ fmix32( FT_UInt32 h )
+ {
+ h ^= h >> 16;
+ h *= 0x85ebca6b;
+ h ^= h >> 13;
+ h *= 0xc2b2ae35;
+ h ^= h >> 16;
+
+ return h;
+ }
+
+
+ void
+ murmur_hash_3_128( const void* key,
+ const int len,
+ FT_UInt32 seed,
+ void* out )
+ {
+ const FT_Byte* data = (const FT_Byte*)key;
+ const int nblocks = len / 16;
+
+ FT_UInt32 h1 = seed;
+ FT_UInt32 h2 = seed;
+ FT_UInt32 h3 = seed;
+ FT_UInt32 h4 = seed;
+
+ const FT_UInt32 c1 = 0x239b961b;
+ const FT_UInt32 c2 = 0xab0e9789;
+ const FT_UInt32 c3 = 0x38b34ae5;
+ const FT_UInt32 c4 = 0xa1e38b93;
+
+ const FT_UInt32* blocks = (const FT_UInt32*)( data + nblocks * 16 );
+
+ int i;
+
+
+ for( i = -nblocks; i; i++ )
+ {
+ FT_UInt32 k1 = blocks[i * 4 + 0];
+ FT_UInt32 k2 = blocks[i * 4 + 1];
+ FT_UInt32 k3 = blocks[i * 4 + 2];
+ FT_UInt32 k4 = blocks[i * 4 + 3];
+
+
+ k1 *= c1;
+ k1 = ROTL32( k1, 15 );
+ k1 *= c2;
+ h1 ^= k1;
+
+ h1 = ROTL32( h1, 19 );
+ h1 += h2;
+ h1 = h1 * 5 + 0x561ccd1b;
+
+ k2 *= c2;
+ k2 = ROTL32( k2, 16 );
+ k2 *= c3;
+ h2 ^= k2;
+
+ h2 = ROTL32( h2, 17 );
+ h2 += h3;
+ h2 = h2 * 5 + 0x0bcaa747;
+
+ k3 *= c3;
+ k3 = ROTL32( k3, 17 );
+ k3 *= c4;
+ h3 ^= k3;
+
+ h3 = ROTL32( h3, 15 );
+ h3 += h4;
+ h3 = h3 * 5 + 0x96cd1c35;
+
+ k4 *= c4;
+ k4 = ROTL32( k4, 18 );
+ k4 *= c1;
+ h4 ^= k4;
+
+ h4 = ROTL32( h4, 13 );
+ h4 += h1;
+ h4 = h4 * 5 + 0x32ac3b17;
+ }
+
+ {
+ const FT_Byte* tail = (const FT_Byte*)( data + nblocks * 16 );
+
+ FT_UInt32 k1 = 0;
+ FT_UInt32 k2 = 0;
+ FT_UInt32 k3 = 0;
+ FT_UInt32 k4 = 0;
+
+
+ switch ( len & 15 )
+ {
+ case 15:
+ k4 ^= tail[14] << 16;
+ case 14:
+ k4 ^= tail[13] << 8;
+ case 13:
+ k4 ^= tail[12] << 0;
+ k4 *= c4;
+ k4 = ROTL32( k4, 18 );
+ k4 *= c1;
+ h4 ^= k4;
+
+ case 12:
+ k3 ^= tail[11] << 24;
+ case 11:
+ k3 ^= tail[10] << 16;
+ case 10:
+ k3 ^= tail[9] << 8;
+ case 9:
+ k3 ^= tail[8] << 0;
+ k3 *= c3;
+ k3 = ROTL32( k3, 17 );
+ k3 *= c4;
+ h3 ^= k3;
+
+ case 8:
+ k2 ^= tail[7] << 24;
+ case 7:
+ k2 ^= tail[6] << 16;
+ case 6:
+ k2 ^= tail[5] << 8;
+ case 5:
+ k2 ^= tail[4] << 0;
+ k2 *= c2;
+ k2 = ROTL32( k2, 16 );
+ k2 *= c3;
+ h2 ^= k2;
+
+ case 4:
+ k1 ^= tail[3] << 24;
+ case 3:
+ k1 ^= tail[2] << 16;
+ case 2:
+ k1 ^= tail[1] << 8;
+ case 1:
+ k1 ^= tail[0] << 0;
+ k1 *= c1;
+ k1 = ROTL32( k1, 15 );
+ k1 *= c2;
+ h1 ^= k1;
+ }
+ }
+
+ h1 ^= len;
+ h2 ^= len;
+ h3 ^= len;
+ h4 ^= len;
+
+ h1 += h2;
+ h1 += h3;
+ h1 += h4;
+
+ h2 += h1;
+ h3 += h1;
+ h4 += h1;
+
+ h1 = fmix32( h1 );
+ h2 = fmix32( h2 );
+ h3 = fmix32( h3 );
+ h4 = fmix32( h4 );
+
+ h1 += h2;
+ h1 += h3;
+ h1 += h4;
+
+ h2 += h1;
+ h3 += h1;
+ h4 += h1;
+
+ ((FT_UInt32*)out)[0] = h1;
+ ((FT_UInt32*)out)[1] = h2;
+ ((FT_UInt32*)out)[2] = h3;
+ ((FT_UInt32*)out)[3] = h4;
+ }
+
+
+#endif /* TT_CONFIG_OPTION_GX_VAR_SUPPORT */
+
+
typedef int (*char_type_func)( int c );