/*
?*?%CopyrightBegin%
?*
?*?Copyright?Ericsson?AB?1996-2018.?All?Rights?Reserved.
?*
?*?Licensed?under?the?Apache?License?Version?2.0?（the?“License“）;
?*?you?may?not?use?this?file?except?in?compliance?with?the?License.
?*?You?may?obtain?a?copy?of?the?License?at
?*
?*?????http://www.apache.org/licenses/LICENSE-2.0
?*
?*?Unless?required?by?applicable?law?or?agreed?to?in?writing?software
?*?distributed?under?the?License?is?distributed?on?an?“AS?IS“?BASIS
?*?WITHOUT?WARRANTIES?OR?CONDITIONS?OF?ANY?KIND?either?express?or?implied.
?*?See?the?License?for?the?specific?language?governing?permissions?and
?*?limitations?under?the?License.
?*
?*?%CopyrightEnd%
?*/

#ifdef?HAVE_CONFIG_H
#??include?“config.h“
#endif

#include?“sys.h“
#include?“erl_sys_driver.h“
#include?“erl_vm.h“
#include?“global.h“
#include?“hash.h“
#include?“atom.h“


#define?ATOM_SIZE??3000

IndexTable?erts_atom_table;	/*?The?index?table?*/

static?erts_rwmtx_t?atom_table_lock;

#define?atom_read_lock（）	erts_rwmtx_rlock（&atom_table_lock）
#define?atom_read_unlock（）	erts_rwmtx_runlock（&atom_table_lock）
#define?atom_write_lock（）	erts_rwmtx_rwlock（&atom_table_lock）
#define?atom_write_unlock（）	erts_rwmtx_rwunlock（&atom_table_lock）

#if?0
#define?ERTS_ATOM_PUT_OPS_STAT
#endif
#ifdef?ERTS_ATOM_PUT_OPS_STAT
static?erts_atomic_t?atom_put_ops;
#endif

/*?Functions?for?allocating?space?for?the?ext?of?atoms.?We?do?not
?*?use?malloc?for?each?atom?to?prevent?excessive?memory?fragmentation
?*/

typedef?struct?_atom_text?{
????struct?_atom_text*?next;
????unsigned?char?text[ATOM_TEXT_SIZE];
}?AtomText;

static?AtomText*?text_list;	/*?List?of?text?buffers?*/
static?byte?*atom_text_pos;
static?byte?*atom_text_end;
static?Uint?reserved_atom_space;	/*?Total?amount?of?atom?text?space?*/
static?Uint?atom_space;		/*?Amount?of?atom?text?space?used?*/

/*
?*?Print?info?about?atom?tables
?*/
void?atom_info（fmtfn_t?to?void?*to_arg）
{
????int?lock?=?!ERTS_IS_CRASH_DUMPING;
????if?（lock）
	atom_read_lock（）;
????index_info（to?to_arg?&erts_atom_table）;
#ifdef?ERTS_ATOM_PUT_OPS_STAT
????erts_print（to?to_arg?“atom_put_ops:?%ld\n“
	???????erts_atomic_read_nob（&atom_put_ops））;
#endif

????if?（lock）
	atom_read_unlock（）;
}

/*
?*?Allocate?an?atom?text?segment.
?*/
static?void
more_atom_space（void）
{
????AtomText*?ptr;

????ptr?=?（AtomText*）?erts_alloc（ERTS_ALC_T_ATOM_TXT?sizeof（AtomText））;

????ptr->next?=?text_list;
????text_list?=?ptr;

????atom_text_pos?=?ptr->text;
????atom_text_end?=?atom_text_pos?+?ATOM_TEXT_SIZE;
????reserved_atom_space?+=?sizeof（AtomText）;

????VERBOSE（DEBUG_SYSTEM（“Allocated?%d?atom?space\n“ATOM_TEXT_SIZE））;
}

/*
?*?Allocate?string?space?within?an?atom?text?segment.
?*/

static?byte*
atom_text_alloc（int?bytes）
{
????byte?*res;

????ASSERT（bytes?<=?MAX_ATOM_SZ_LIMIT）;
????if?（atom_text_pos?+?bytes?>=?atom_text_end）?{
	more_atom_space（）;
????}
????res?=?atom_text_pos;
????atom_text_pos?+=?bytes;
????atom_space????+=?bytes;
????return?res;
}

/*
?*?Calculate?atom?hash?value?（using?the?hash