Commit d4aaffc6 authored by Nick Mathewson's avatar Nick Mathewson 🦀
Browse files

r11824@catbus: nickm | 2007-02-16 13:16:47 -0500 

 Move all struct-offset-manipulation macros into util.h, and use them consistently.  Because there are days when "SUBTYPE_P(handle, subtype, _base)" is just easier to read and write than "(basetp*)(((handle) - STRUCT_OFFSET(subtype, _base))".


svn:r9592
parent e5d3269b

src/common/compat.c

+2 −4
Original line number Diff line number Diff line
@@ -174,8 +174,7 @@ tor_mmap_file(const char *filename) 
void

tor_munmap_file(tor_mmap_t *handle)

{

  tor_mmap_impl_t *h = (tor_mmap_impl_t*)

    (((char*)handle) - STRUCT_OFFSET(tor_mmap_impl_t, base));

  tor_mmap_impl_t *h = SUBTYPE_P(handle, tor_mmap_impl_t, base);

  munmap((char*)h->base.data, h->mapping_size);

  tor_free(h);

}
@@ -244,8 +243,7 @@ tor_mmap_file(const char *filename) 
void

tor_munmap_file(tor_mmap_t *handle)

{

  win_mmap_t *h = (win_mmap_t*)

    (((char*)handle) - STRUCT_OFFSET(win_mmap_t, base));

  win_mmap_t *h = SUBTYPE_P(handle, win_mmap_t, base);

  if (handle->data)

    /* This is an ugly cast, but without it, "data" in struct tor_mmap_t would

       have to be redefined as non-const. */

src/common/util.h

+23 −0
Original line number Diff line number Diff line
@@ -110,6 +110,29 @@ extern int dmalloc_free(const char *file, const int line, void *pnt, 
   ((off_t) (((char*)&((tp*)0)->member)-(char*)0))

#endif



/** Macro: yield a pointer to the field at position <b>off</b> within the

 * structure <b>st</b>.  Example:

 * <pre>

 *   struct a { int foo; int bar; } x;

 *   off_t bar_offset = STRUCT_OFFSET(struct a, bar);

 *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);

 *   *bar_p = 3;

 * </pre>

 */

#define STRUCT_VAR_P(st, off) ((void*) ( ((char*)(st)) + (off) ) )



/** Macro: yield a pointer to an enclosing structure given a pointer to

 * a substructure at offset <b>off</b>. Example:

 * <pre>

 *   struct base { ... };

 *   struct subtype { int x; struct base b; } x;

 *   struct base *bp = &x.base;

 *   struct *sp = SUBTYPE_P(bp, struct subtype, b);

 * </pre>

 */

#define SUBTYPE_P(p, subtype, basemember) \

  ((void*) ( ((char*)(p)) - STRUCT_OFFSET(subtype, basemember) ))



/* String manipulation */



/** Allowable characters in a hexadecimal string. */

src/or/config.c

+0 −12
Original line number Diff line number Diff line
@@ -102,18 +102,6 @@ typedef struct config_var_t { 
  const char *initvalue; /**< String (or null) describing initial value. */

} config_var_t;



/** Macro: yield a pointer to the field at position <b>off</b> within the

 * structure <b>st</b>.  Example:

 * <pre>

 *   struct a { int foo; int bar; } x;

 *   off_t bar_offset = STRUCT_OFFSET(struct a, bar);

 *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);

 *   *bar_p = 3;

 * </pre>

 */

#define STRUCT_VAR_P(st, off) \

  ((void*) ( ((char*)st) + off ) )



/** An entry for config_vars: "The option <b>name</b> has type

 * CONFIG_TYPE_<b>conftype</b>, and corresponds to

 * or_options_t.<b>member</b>"

src/or/or.h

+1 −5
Original line number Diff line number Diff line
@@ -928,8 +928,7 @@ typedef struct control_connection_t { 
/** Cast a connection_t subtype pointer to a connection_t **/

#define TO_CONN(c) (&(((c)->_base)))

/** Helper macro: Given a pointer to to._base, of type from*, return &to. */

#define DOWNCAST(to, ptr) \

  (to*) (((char*)(ptr)) - STRUCT_OFFSET(to, _base))

#define DOWNCAST(to, ptr) ((to*)SUBTYPE_P(ptr, to, _base))



/** Convert a connection_t* to an or_connection_t*; assert if the cast is

 * invalid. */
@@ -1515,14 +1514,11 @@ static origin_circuit_t *TO_ORIGIN_CIRCUIT(circuit_t *); 
static INLINE or_circuit_t *TO_OR_CIRCUIT(circuit_t *x)

{

  tor_assert(x->magic == OR_CIRCUIT_MAGIC);

  //return (or_circuit_t*) (((char*)x) - STRUCT_OFFSET(or_circuit_t, _base));

  return DOWNCAST(or_circuit_t, x);

}

static INLINE origin_circuit_t *TO_ORIGIN_CIRCUIT(circuit_t *x)

{

  tor_assert(x->magic == ORIGIN_CIRCUIT_MAGIC);

  //return (origin_circuit_t*)

  //  (((char*)x) - STRUCT_OFFSET(origin_circuit_t, _base));

  return DOWNCAST(origin_circuit_t, x);

}