@section Implementation details


@subsection Internal functions


These routines are used within BFD.
They are not intended for export, but are documented here for
completeness.

@findex bfd_malloc
@subsubsection @code{bfd_malloc}
@deftypefn {Function} void *bfd_malloc (bfd_size_type {*size*}); 
Returns a pointer to an allocated block of memory that is at least
SIZE bytes long.  If SIZE is 0 then it will be treated as if it were
1.  If SIZE is too big then NULL will be returned.
Returns NULL upon error and sets bfd_error.

@end deftypefn
@findex bfd_realloc
@subsubsection @code{bfd_realloc}
@deftypefn {Function} void *bfd_realloc (void *{*mem*}, bfd_size_type {*size*}); 
Returns a pointer to an allocated block of memory that is at least
SIZE bytes long.  If SIZE is 0 then it will be treated as if it were
1.  If SIZE is too big then NULL will be returned.
If MEM is not NULL then it must point to an allocated block of memory.
If this block is large enough then MEM may be used as the return
value for this function, but this is not guaranteed.

If MEM is not returned then the first N bytes in the returned block
will be identical to the first N bytes in region pointed to by MEM,
where N is the lessor of SIZE and the length of the region of memory
currently addressed by MEM.

Returns NULL upon error and sets bfd_error.

@end deftypefn
@findex bfd_realloc_or_free
@subsubsection @code{bfd_realloc_or_free}
@deftypefn {Function} void *bfd_realloc_or_free (void *{*mem*}, bfd_size_type {*size*}); 
Returns a pointer to an allocated block of memory that is at least
SIZE bytes long.  If SIZE is 0 then no memory will be allocated,
MEM will be freed, and NULL will be returned.  This will not cause
bfd_error to be set.

If SIZE is too big then NULL will be returned and bfd_error will be
set. 
If MEM is not NULL then it must point to an allocated block of memory.
If this block is large enough then MEM may be used as the return
value for this function, but this is not guaranteed.

If MEM is not returned then the first N bytes in the returned block
will be identical to the first N bytes in region pointed to by MEM,
where N is the lessor of SIZE and the length of the region of memory
currently addressed by MEM.

@end deftypefn
@findex bfd_zmalloc
@subsubsection @code{bfd_zmalloc}
@deftypefn {Function} void *bfd_zmalloc (bfd_size_type {*size*}); 
Returns a pointer to an allocated block of memory that is at least
SIZE bytes long.  If SIZE is 0 then it will be treated as if it were
1.  If SIZE is too big then NULL will be returned.
Returns NULL upon error and sets bfd_error.

If NULL is not returned then the allocated block of memory will
have been cleared.

@end deftypefn
@findex bfd_alloc
@subsubsection @code{bfd_alloc}
@deftypefn {Function} void *bfd_alloc (bfd *abfd, bfd_size_type wanted); 
Allocate a block of @var{wanted} bytes of memory attached to
@code{abfd} and return a pointer to it.

@end deftypefn
@findex bfd_zalloc
@subsubsection @code{bfd_zalloc}
@deftypefn {Function} void *bfd_zalloc (bfd *abfd, bfd_size_type wanted); 
Allocate a block of @var{wanted} bytes of zeroed memory
attached to @code{abfd} and return a pointer to it.

@end deftypefn
@findex bfd_release
@subsubsection @code{bfd_release}
@deftypefn {Function} void bfd_release (bfd *, void *); 
Free a block allocated for a BFD.
Note: Also frees all more recently allocated blocks!

@end deftypefn
@findex bfd_write_bigendian_4byte_int
@subsubsection @code{bfd_write_bigendian_4byte_int}
@deftypefn {Function} bool bfd_write_bigendian_4byte_int (bfd *, unsigned int); 
Write a 4 byte integer @var{i} to the output BFD @var{abfd}, in big
endian order regardless of what else is going on.  This is useful in
archives.

@end deftypefn
@findex bfd_put_size
@subsubsection @code{bfd_put_size}
@findex bfd_get_size
@subsubsection @code{bfd_get_size}
These macros as used for reading and writing raw data in
sections; each access (except for bytes) is vectored through
the target format of the BFD and mangled accordingly. The
mangling performs any necessary endian translations and
removes alignment restrictions.  Note that types accepted and
returned by these macros are identical so they can be swapped
around in macros---for example, @file{libaout.h} defines @code{GET_WORD}
to either @code{bfd_get_32} or @code{bfd_get_64}.

In the put routines, @var{val} must be a @code{bfd_vma}.  If we are on a
system without prototypes, the caller is responsible for making
sure that is true, with a cast if necessary.  We don't cast
them in the macro definitions because that would prevent @code{lint}
or @code{gcc -Wall} from detecting sins such as passing a pointer.
To detect calling these with less than a @code{bfd_vma}, use
@code{gcc -Wconversion} on a host with 64 bit @code{bfd_vma}'s.
@example

/* Byte swapping macros for user section data.  */

#define bfd_put_8(abfd, val, ptr) \
  ((void) (*((bfd_byte *) (ptr)) = (val) & 0xff))
#define bfd_put_signed_8 \
  bfd_put_8
#define bfd_get_8(abfd, ptr) \
  ((bfd_vma) *(const bfd_byte *) (ptr) & 0xff)
#define bfd_get_signed_8(abfd, ptr) \
  ((((bfd_signed_vma) *(const bfd_byte *) (ptr) & 0xff) ^ 0x80) - 0x80)

#define bfd_put_16(abfd, val, ptr) \
  BFD_SEND (abfd, bfd_putx16, ((val),(ptr)))
#define bfd_put_signed_16 \
  bfd_put_16
#define bfd_get_16(abfd, ptr) \
  BFD_SEND (abfd, bfd_getx16, (ptr))
#define bfd_get_signed_16(abfd, ptr) \
  BFD_SEND (abfd, bfd_getx_signed_16, (ptr))

#define bfd_put_24(abfd, val, ptr) \
  do                                   \
    if (bfd_big_endian (abfd))         \
      bfd_putb24 ((val), (ptr));       \
    else                               \
      bfd_putl24 ((val), (ptr));       \
  while (0)

bfd_vma bfd_getb24 (const void *p);
bfd_vma bfd_getl24 (const void *p);

#define bfd_get_24(abfd, ptr) \
  (bfd_big_endian (abfd) ? bfd_getb24 (ptr) : bfd_getl24 (ptr))

#define bfd_put_32(abfd, val, ptr) \
  BFD_SEND (abfd, bfd_putx32, ((val),(ptr)))
#define bfd_put_signed_32 \
  bfd_put_32
#define bfd_get_32(abfd, ptr) \
  BFD_SEND (abfd, bfd_getx32, (ptr))
#define bfd_get_signed_32(abfd, ptr) \
  BFD_SEND (abfd, bfd_getx_signed_32, (ptr))

#define bfd_put_64(abfd, val, ptr) \
  BFD_SEND (abfd, bfd_putx64, ((val), (ptr)))
#define bfd_put_signed_64 \
  bfd_put_64
#define bfd_get_64(abfd, ptr) \
  BFD_SEND (abfd, bfd_getx64, (ptr))
#define bfd_get_signed_64(abfd, ptr) \
  BFD_SEND (abfd, bfd_getx_signed_64, (ptr))

#define bfd_get(bits, abfd, ptr)                       \
  ((bits) == 8 ? bfd_get_8 (abfd, ptr)                 \
   : (bits) == 16 ? bfd_get_16 (abfd, ptr)             \
   : (bits) == 32 ? bfd_get_32 (abfd, ptr)             \
   : (bits) == 64 ? bfd_get_64 (abfd, ptr)             \
   : (abort (), (bfd_vma) - 1))

#define bfd_put(bits, abfd, val, ptr)                  \
  ((bits) == 8 ? bfd_put_8  (abfd, val, ptr)           \
   : (bits) == 16 ? bfd_put_16 (abfd, val, ptr)        \
   : (bits) == 32 ? bfd_put_32 (abfd, val, ptr)        \
   : (bits) == 64 ? bfd_put_64 (abfd, val, ptr)        \
   : (abort (), (void) 0))

@end example

@findex bfd_h_put_size
@subsubsection @code{bfd_h_put_size}
These macros have the same function as their @code{bfd_get_x}
brethren, except that they are used for removing information
for the header records of object files. Believe it or not,
some object files keep their header records in big endian
order and their data in little endian order.
@example

/* Byte swapping macros for file header data.  */

#define bfd_h_put_8(abfd, val, ptr) \
  bfd_put_8 (abfd, val, ptr)
#define bfd_h_put_signed_8(abfd, val, ptr) \
  bfd_put_8 (abfd, val, ptr)
#define bfd_h_get_8(abfd, ptr) \
  bfd_get_8 (abfd, ptr)
#define bfd_h_get_signed_8(abfd, ptr) \
  bfd_get_signed_8 (abfd, ptr)

#define bfd_h_put_16(abfd, val, ptr) \
  BFD_SEND (abfd, bfd_h_putx16, (val, ptr))
#define bfd_h_put_signed_16 \
  bfd_h_put_16
#define bfd_h_get_16(abfd, ptr) \
  BFD_SEND (abfd, bfd_h_getx16, (ptr))
#define bfd_h_get_signed_16(abfd, ptr) \
  BFD_SEND (abfd, bfd_h_getx_signed_16, (ptr))

#define bfd_h_put_32(abfd, val, ptr) \
  BFD_SEND (abfd, bfd_h_putx32, (val, ptr))
#define bfd_h_put_signed_32 \
  bfd_h_put_32
#define bfd_h_get_32(abfd, ptr) \
  BFD_SEND (abfd, bfd_h_getx32, (ptr))
#define bfd_h_get_signed_32(abfd, ptr) \
  BFD_SEND (abfd, bfd_h_getx_signed_32, (ptr))

#define bfd_h_put_64(abfd, val, ptr) \
  BFD_SEND (abfd, bfd_h_putx64, (val, ptr))
#define bfd_h_put_signed_64 \
  bfd_h_put_64
#define bfd_h_get_64(abfd, ptr) \
  BFD_SEND (abfd, bfd_h_getx64, (ptr))
#define bfd_h_get_signed_64(abfd, ptr) \
  BFD_SEND (abfd, bfd_h_getx_signed_64, (ptr))

/* Aliases for the above, which should eventually go away.  */

#define H_PUT_64  bfd_h_put_64
#define H_PUT_32  bfd_h_put_32
#define H_PUT_16  bfd_h_put_16
#define H_PUT_8   bfd_h_put_8
#define H_PUT_S64 bfd_h_put_signed_64
#define H_PUT_S32 bfd_h_put_signed_32
#define H_PUT_S16 bfd_h_put_signed_16
#define H_PUT_S8  bfd_h_put_signed_8
#define H_GET_64  bfd_h_get_64
#define H_GET_32  bfd_h_get_32
#define H_GET_16  bfd_h_get_16
#define H_GET_8   bfd_h_get_8
#define H_GET_S64 bfd_h_get_signed_64
#define H_GET_S32 bfd_h_get_signed_32
#define H_GET_S16 bfd_h_get_signed_16
#define H_GET_S8  bfd_h_get_signed_8


@end example

@findex Byte swapping routines.
@subsubsection @code{Byte swapping routines.}
@deftypefn {Function} uint64_t bfd_getb64 (const void *); uint64_t bfd_getl64 (const void *); int64_t bfd_getb_signed_64 (const void *); int64_t bfd_getl_signed_64 (const void *); bfd_vma bfd_getb32 (const void *); bfd_vma bfd_getl32 (const void *); bfd_signed_vma bfd_getb_signed_32 (const void *); bfd_signed_vma bfd_getl_signed_32 (const void *); bfd_vma bfd_getb16 (const void *); bfd_vma bfd_getl16 (const void *); bfd_signed_vma bfd_getb_signed_16 (const void *); bfd_signed_vma bfd_getl_signed_16 (const void *); void bfd_putb64 (uint64_t, void *); void bfd_putl64 (uint64_t, void *); void bfd_putb32 (bfd_vma, void *); void bfd_putl32 (bfd_vma, void *); void bfd_putb24 (bfd_vma, void *); void bfd_putl24 (bfd_vma, void *); void bfd_putb16 (bfd_vma, void *); void bfd_putl16 (bfd_vma, void *); uint64_t bfd_get_bits (const void *, int, bool); void bfd_put_bits (uint64_t, void *, int, bool); 
Read and write integers in a particular endian order.  getb
and putb functions handle big-endian, getl and putl handle
little-endian.  bfd_get_bits and bfd_put_bits specify
big-endian by passing TRUE in the last parameter,
little-endian by passing FALSE.

@end deftypefn
@findex bfd_log2
@subsubsection @code{bfd_log2}
@deftypefn {Function} unsigned int bfd_log2 (bfd_vma x); 
Return the log base 2 of the value supplied, rounded up.  E.g., an
@var{x} of 1025 returns 11.  A @var{x} of 0 returns 0.

@end deftypefn