diff options
| -rw-r--r-- | byterun/hash.c | 15 | ||||
| -rw-r--r-- | byterun/mlvalues.h | 3 |
2 files changed, 18 insertions, 0 deletions
diff --git a/byterun/hash.c b/byterun/hash.c index af756eaf2..114d9d69c 100644 --- a/byterun/hash.c +++ b/byterun/hash.c @@ -131,3 +131,18 @@ static void hash_aux(value obj) a priori unknown structure. Use its physical address as hash key. */ Combine((long) obj); } + +/* Hashing variant tags */ + +value hash_variant(char * tag) +{ + value accu; + /* Same hashing algorithm as in ../typing/btype.ml, function hash_variant */ + for (accu = Val_int(0); *tag != 0; tag++) + accu = Val_int(223 * Int_val(accu) + *((unsigned char *) tag)); + accu = accu & Val_int((1 << 31) - 1); + /* Force sign extension of bit 31 for compatibility between 32 and 64-bit + platforms */ + return (int32) accu; +} + diff --git a/byterun/mlvalues.h b/byterun/mlvalues.h index cfa06d26d..434adba94 100644 --- a/byterun/mlvalues.h +++ b/byterun/mlvalues.h @@ -176,6 +176,9 @@ typedef opcode_t * code_t; #define Class_val(val) Field(val, 0) #define Oid_val(val) Long_val(Field(val, 1)) +/* Another special case: variants */ +extern value hash_variant(char * tag); + /* 2- If tag >= No_scan_tag : a sequence of bytes. */ /* Pointer to the first byte */ |