pike.git/ src/ builtin_functions.c

2016-06-29

2016-06-29 13:00:50 by Henrik Grubbström (Grubba) <grubba@grubba.org>

• 1565da60446ff14a23071bd51a588e3ec841617b (59 lines) (+52/-7) ^{[ Show | Annotate ]}
  Branch: 8.1

Efuns: Fixed multiple issues with the new hash().

It now follows the same API as the old hash() (ie the second argument
is a modulo). It now also has the same value range as the old hash (eg
it no longer returns negative values), and returns the same value on
both 32-bit and 64-bit platforms.

As a side-effect this fixes a buffer read overrun when the second argument
was larger than the length of the string.

It no longer leaves droppings on the stack.

Updated the testsuite.

433:    push_int64(i);   }    + /*! @decl int hash(string s) +  *! @decl int hash(string s, int max) +  *! +  *! Return an integer derived from the string @[s]. The same string +  *! always hashes to the same value, also between processes, +  *! architectures, and Pike versions (see compatibility notes below, +  *! though). +  *! +  *! If @[max] is given, the result will be >= 0 and < @[max], +  *! otherwise the result will be >= 0 and <= 0x7fffffff. +  *! +  *! @note +  *! The hash algorithm was changed in Pike 8.1. If you want a hash +  *! that is compatible with Pike 8.0 and earlier, use @[hash_7_8()]. +  *! +  *! The hash algorithm was also changed in Pike 7.5. If you want a hash +  *! that is compatible with Pike 7.4 and earlier, use @[hash_7_4()]. +  *! The difference with regards to @[hash_8_0()] only affects wide strings. +  *! +  *! The hash algorithm was also changed in Pike 7.1. If you want a hash +  *! that is compatible with Pike 7.0 and earlier, use @[hash_7_0()]. +  *! +  *! @note +  *! This hash function differs from the one provided by @[hash_value()], +  *! in that @[hash_value()] returns a process specific value. +  *! +  *! @seealso +  *! @[hash_7_0()], @[hash_7_4()], @[hash_7_8()], @[hash_value] +  */   static void f_hash( INT32 args )   { -  int len = 0; +  size_t res; +  ptrdiff_t len = 0; +     if( TYPEOF(Pike_sp[-args]) != PIKE_T_STRING )    PIKE_ERROR("hash","Argument is not a string\n",Pike_sp,args); -  if( args > 1 ) -  len = Pike_sp[-args+1].u.integer; -  else -  len = Pike_sp[-1].u.string->len; -  push_int( hashmem_siphash24( Pike_sp[-1].u.string->str, -  len << Pike_sp[-1].u.string->size_shift)); +  +  len = Pike_sp[-args].u.string->len; +  +  res = hashmem_siphash24( Pike_sp[-args].u.string->str, +  len << Pike_sp[-args].u.string->size_shift) & +  0x7fffffff; +  +  if( args > 1 ) { +  if(TYPEOF(Pike_sp[1-args]) != T_INT) +  SIMPLE_ARG_TYPE_ERROR("hash",2,"int"); +  +  if(Pike_sp[1-args].u.integer <= 0) +  PIKE_ERROR("hash", "Modulo < 1.\n", Pike_sp, args); +  +  res %= Pike_sp[1-args].u.integer;    }    -  +  pop_n_elems(args); +  push_int(res); + } +    /*! @decl int hash_value (mixed value)    *!    *! Return a hash value for the argument. It's an integer in the