rb_integer_pack

rb_sys::bindings::uncategorized

Function rb_integer_pack 

Source 
pub unsafe extern "C" fn rb_integer_pack(
    val: VALUE,
    words: *mut c_void,
    numwords: size_t,
    wordsize: size_t,
    nails: size_t,
    flags: c_int,
) -> c_int
Expand description

Exports an integer into a buffer. This function fills the buffer specified by words and numwords as val in the format specified by wordsize, nails and flags.

@param[in] val Integer or integer-like object which has #to_int method. @param[out] words Return buffer. @param[in] numwords Number of words of words. @param[in] wordsize Number of bytes per word. @param[in] nails Number of padding bits in a word. Most significant nails bits of each word are filled by zero. @param[in] flags Bitwise or of constants whose name starts “INTEGER_PACK_”. @exception rb_eTypeError val doesn’t respond to #to_int.

Possible flags are:

  • #INTEGER_PACK_MSWORD_FIRST: Stores the most significant word as the first word.

  • #INTEGER_PACK_LSWORD_FIRST: Stores the least significant word as the first word.

  • #INTEGER_PACK_MSBYTE_FIRST: Stores the most significant byte in a word as the first byte in the word.

  • #INTEGER_PACK_LSBYTE_FIRST: Stores the least significant byte in a word as the first byte in the word.

  • #INTEGER_PACK_NATIVE_BYTE_ORDER: Either #INTEGER_PACK_MSBYTE_FIRST or #INTEGER_PACK_LSBYTE_FIRST corresponding to the host’s endian.

  • #INTEGER_PACK_2COMP: Uses 2’s complement representation.

  • #INTEGER_PACK_LITTLE_ENDIAN: Shorthand of INTEGER_PACK_LSWORD_FIRST|INTEGER_PACK_LSBYTE_FIRST.

  • #INTEGER_PACK_BIG_ENDIAN: Shorthand of INTEGER_PACK_MSWORD_FIRST|INTEGER_PACK_MSBYTE_FIRST.

  • #INTEGER_PACK_FORCE_GENERIC_IMPLEMENTATION: Uses generic implementation (for test and debug).

This function fills the buffer specified by words as val’s 2’s complement representation if #INTEGER_PACK_2COMP is specified in flags. Otherwise it fills words as abs(val) and signedness is returned via the return value.

@return The signedness and overflow condition. The overflow condition depends on #INTEGER_PACK_2COMP.

When #INTEGER_PACK_2COMP is not specified:

  • -2 : Negative overflow. val <= -2**(numwords*(wordsize*CHAR_BIT-nails))

  • -1 : Negative without overflow. -2**(numwords*(wordsize*CHAR_BIT-nails)) < val < 0

  • 0 : zero. val == 0

  • 1 : Positive without overflow. 0 < val < 2**(numwords*(wordsize*CHAR_BIT-nails))

  • 2 : Positive overflow. 2**(numwords*(wordsize*CHAR_BIT-nails)) <= val

When #INTEGER_PACK_2COMP is specified:

  • -2 : Negative overflow. val < -2**(numwords*(wordsize*CHAR_BIT-nails))

  • -1 : Negative without overflow. -2**(numwords*(wordsize*CHAR_BIT-nails)) <= val < 0

  • 0 : zero. val == 0

  • 1 : Positive without overflow. 0 < val < 2**(numwords*(wordsize*CHAR_BIT-nails))

  • 2 : Positive overflow. 2**(numwords*(wordsize*CHAR_BIT-nails)) <= val

The value, -2**(numwords*(wordsize*CHAR_BIT-nails)), is representable in 2’s complement representation but not representable in absolute value. So -1 is returned for the value if #INTEGER_PACK_2COMP is specified but returns -2 if #INTEGER_PACK_2COMP is not specified.

§The least significant words are filled in the buffer when overflow occur.

Generated by rb-sys for Ruby mri-x86_64-linux-gnu-3.2.3