#include "postgres.h"
#include "access/heapam_xlog.h"
#include "access/visibilitymap.h"
#include "access/xlog.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/smgr.h"
#include "utils/inval.h"

Include dependency graph for visibilitymap.c:

Macros
#define	MAPSIZE (BLCKSZ - MAXALIGN(SizeOfPageHeaderData))

#define	HEAPBLOCKS_PER_BYTE (BITS_PER_BYTE / BITS_PER_HEAPBLOCK)

#define	HEAPBLOCKS_PER_PAGE (MAPSIZE * HEAPBLOCKS_PER_BYTE)

#define	HEAPBLK_TO_MAPBLOCK(x) ((x) / HEAPBLOCKS_PER_PAGE)

#define	HEAPBLK_TO_MAPBYTE(x) (((x) % HEAPBLOCKS_PER_PAGE) / HEAPBLOCKS_PER_BYTE)

#define	HEAPBLK_TO_OFFSET(x) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK)

Functions
static Buffer	vm_readbuf (Relation rel, BlockNumber blkno, bool extend)

static void	vm_extend (Relation rel, BlockNumber nvmblocks)

bool	visibilitymap_clear (Relation rel, BlockNumber heapBlk, Buffer buf, uint8 flags)

void	visibilitymap_pin (Relation rel, BlockNumber heapBlk, Buffer *buf)

bool	visibilitymap_pin_ok (BlockNumber heapBlk, Buffer buf)

void	visibilitymap_set (Relation rel, BlockNumber heapBlk, Buffer heapBuf, XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid, uint8 flags)

uint8	visibilitymap_get_status (Relation rel, BlockNumber heapBlk, Buffer *buf)

void	visibilitymap_count (Relation rel, BlockNumber all_visible, BlockNumber all_frozen)

void	visibilitymap_truncate (Relation rel, BlockNumber nheapblocks)

Variables
static const uint8	number_of_ones_for_visible [256]

static const uint8	number_of_ones_for_frozen [256]

Macro Definition Documentation

#define HEAPBLK_TO_MAPBLOCK ( x ) ((x) / HEAPBLOCKS_PER_PAGE)

Definition at line 114 of file visibilitymap.c.

Referenced by visibilitymap_clear(), visibilitymap_get_status(), visibilitymap_pin(), visibilitymap_pin_ok(), visibilitymap_set(), and visibilitymap_truncate().

#define HEAPBLK_TO_MAPBYTE ( x ) (((x) % HEAPBLOCKS_PER_PAGE) / HEAPBLOCKS_PER_BYTE)

Definition at line 115 of file visibilitymap.c.

Referenced by visibilitymap_clear(), visibilitymap_get_status(), visibilitymap_set(), and visibilitymap_truncate().

#define HEAPBLK_TO_OFFSET ( x ) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK)

Definition at line 116 of file visibilitymap.c.

Referenced by visibilitymap_clear(), visibilitymap_get_status(), visibilitymap_set(), and visibilitymap_truncate().

#define HEAPBLOCKS_PER_BYTE (BITS_PER_BYTE / BITS_PER_HEAPBLOCK)

Definition at line 108 of file visibilitymap.c.

#define HEAPBLOCKS_PER_PAGE (MAPSIZE * HEAPBLOCKS_PER_BYTE)

Definition at line 111 of file visibilitymap.c.

#define MAPSIZE (BLCKSZ - MAXALIGN(SizeOfPageHeaderData))

Definition at line 105 of file visibilitymap.c.

Referenced by visibilitymap_count(), and visibilitymap_truncate().

Function Documentation

bool visibilitymap_clear	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer	buf,
		uint8	flags
	)

Definition at line 169 of file visibilitymap.c.

References Assert, BUFFER_LOCK_EXCLUSIVE, BUFFER_LOCK_UNLOCK, BufferGetBlockNumber(), BufferGetPage, BufferIsValid, DEBUG1, elog, ERROR, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, LockBuffer(), MarkBufferDirty(), PageGetContents, RelationGetRelationName, and VISIBILITYMAP_VALID_BITS.

Referenced by heap_delete(), heap_insert(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_multi_insert(), heap_update(), heap_xlog_delete(), heap_xlog_insert(), heap_xlog_lock(), heap_xlog_lock_updated(), heap_xlog_multi_insert(), heap_xlog_update(), and lazy_scan_heap().

 {
     BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
     int         mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
     int         mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
     uint8       mask = flags << mapOffset;
     char       *map;
     bool        cleared = false;
 
     Assert(flags & VISIBILITYMAP_VALID_BITS);
 
 #ifdef TRACE_VISIBILITYMAP
     elog(DEBUG1, "vm_clear %s %d", RelationGetRelationName(rel), heapBlk);
 #endif
 
     if (!BufferIsValid(buf) || BufferGetBlockNumber(buf) != mapBlock)
         elog(ERROR, "wrong buffer passed to visibilitymap_clear");
 
     LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
     map = PageGetContents(BufferGetPage(buf));
 
     if (map[mapByte] & mask)
     {
         map[mapByte] &= ~mask;
 
         MarkBufferDirty(buf);
         cleared = true;
     }
 
     LockBuffer(buf, BUFFER_LOCK_UNLOCK);
 
     return cleared;
 }

void visibilitymap_count	(	Relation	rel,
		BlockNumber *	all_visible,
		BlockNumber *	all_frozen
	)

Definition at line 408 of file visibilitymap.c.

References Assert, BufferGetPage, BufferIsValid, i, MAPSIZE, number_of_ones_for_frozen, number_of_ones_for_visible, PageGetContents, ReleaseBuffer(), and vm_readbuf().

Referenced by do_analyze_rel(), index_update_stats(), and lazy_vacuum_rel().

 {
     BlockNumber mapBlock;
 
     /* all_visible must be specified */
     Assert(all_visible);
 
     *all_visible = 0;
     if (all_frozen)
         *all_frozen = 0;
 
     for (mapBlock = 0;; mapBlock++)
     {
         Buffer      mapBuffer;
         unsigned char *map;
         int         i;
 
         /*
          * Read till we fall off the end of the map.  We assume that any extra
          * bytes in the last page are zeroed, so we don't bother excluding
          * them from the count.
          */
         mapBuffer = vm_readbuf(rel, mapBlock, false);
         if (!BufferIsValid(mapBuffer))
             break;
 
         /*
          * We choose not to lock the page, since the result is going to be
          * immediately stale anyway if anyone is concurrently setting or
          * clearing bits, and we only really need an approximate value.
          */
         map = (unsigned char *) PageGetContents(BufferGetPage(mapBuffer));
 
         for (i = 0; i < MAPSIZE; i++)
         {
             *all_visible += number_of_ones_for_visible[map[i]];
             if (all_frozen)
                 *all_frozen += number_of_ones_for_frozen[map[i]];
         }
 
         ReleaseBuffer(mapBuffer);
     }
 }

uint8 visibilitymap_get_status	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer *	buf
	)

Definition at line 360 of file visibilitymap.c.

References BufferGetBlockNumber(), BufferGetPage, BufferIsValid, DEBUG1, elog, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InvalidBuffer, PageGetContents, RelationGetRelationName, ReleaseBuffer(), VISIBILITYMAP_VALID_BITS, and vm_readbuf().

Referenced by collect_visibility_data(), lazy_scan_heap(), lazy_vacuum_page(), pg_visibility(), pg_visibility_map(), and pg_visibility_map_summary().

 {
     BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
     uint32      mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
     uint8       mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
     char       *map;
     uint8       result;
 
 #ifdef TRACE_VISIBILITYMAP
     elog(DEBUG1, "vm_get_status %s %d", RelationGetRelationName(rel), heapBlk);
 #endif
 
     /* Reuse the old pinned buffer if possible */
     if (BufferIsValid(*buf))
     {
         if (BufferGetBlockNumber(*buf) != mapBlock)
         {
             ReleaseBuffer(*buf);
             *buf = InvalidBuffer;
         }
     }
 
     if (!BufferIsValid(*buf))
     {
         *buf = vm_readbuf(rel, mapBlock, false);
         if (!BufferIsValid(*buf))
             return false;
     }
 
     map = PageGetContents(BufferGetPage(*buf));
 
     /*
      * A single byte read is atomic.  There could be memory-ordering effects
      * here, but for performance reasons we make it the caller's job to worry
      * about that.
      */
     result = ((map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS);
     return result;
 }

void visibilitymap_pin	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer *	buf
	)

Definition at line 220 of file visibilitymap.c.

References BufferGetBlockNumber(), BufferIsValid, HEAPBLK_TO_MAPBLOCK, ReleaseBuffer(), and vm_readbuf().

Referenced by GetVisibilityMapPins(), heap_delete(), heap_lock_tuple(), heap_lock_updated_tuple_rec(), heap_update(), heap_xlog_delete(), heap_xlog_insert(), heap_xlog_lock(), heap_xlog_lock_updated(), heap_xlog_multi_insert(), heap_xlog_update(), heap_xlog_visible(), lazy_scan_heap(), and RelationGetBufferForTuple().

 {
     BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
 
     /* Reuse the old pinned buffer if possible */
     if (BufferIsValid(*buf))
     {
         if (BufferGetBlockNumber(*buf) == mapBlock)
             return;
 
         ReleaseBuffer(*buf);
     }
     *buf = vm_readbuf(rel, mapBlock, true);
 }

bool visibilitymap_pin_ok	(	BlockNumber	heapBlk,
		Buffer	buf
	)

Definition at line 244 of file visibilitymap.c.

References BufferGetBlockNumber(), BufferIsValid, and HEAPBLK_TO_MAPBLOCK.

Referenced by GetVisibilityMapPins().

 {
     BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
 
     return BufferIsValid(buf) && BufferGetBlockNumber(buf) == mapBlock;
 }

void visibilitymap_set	(	Relation	rel,
		BlockNumber	heapBlk,
		Buffer	heapBuf,
		XLogRecPtr	recptr,
		Buffer	vmBuf,
		TransactionId	cutoff_xid,
		uint8	flags
	)

Definition at line 273 of file visibilitymap.c.

References Assert, BUFFER_LOCK_EXCLUSIVE, BUFFER_LOCK_UNLOCK, BufferGetBlockNumber(), BufferGetPage, BufferIsValid, DEBUG1, elog, END_CRIT_SECTION, ERROR, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InRecovery, LockBuffer(), log_heap_visible(), MarkBufferDirty(), PageGetContents, PageIsAllVisible, PageSetLSN, RelationData::rd_node, RelationGetRelationName, RelationNeedsWAL, START_CRIT_SECTION, VISIBILITYMAP_VALID_BITS, XLogHintBitIsNeeded, and XLogRecPtrIsInvalid.

Referenced by heap_xlog_visible(), lazy_scan_heap(), and lazy_vacuum_page().

 {
     BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
     uint32      mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
     uint8       mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
     Page        page;
     uint8      *map;
 
 #ifdef TRACE_VISIBILITYMAP
     elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk);
 #endif
 
     Assert(InRecovery || XLogRecPtrIsInvalid(recptr));
     Assert(InRecovery || BufferIsValid(heapBuf));
     Assert(flags & VISIBILITYMAP_VALID_BITS);
 
     /* Check that we have the right heap page pinned, if present */
     if (BufferIsValid(heapBuf) && BufferGetBlockNumber(heapBuf) != heapBlk)
         elog(ERROR, "wrong heap buffer passed to visibilitymap_set");
 
     /* Check that we have the right VM page pinned */
     if (!BufferIsValid(vmBuf) || BufferGetBlockNumber(vmBuf) != mapBlock)
         elog(ERROR, "wrong VM buffer passed to visibilitymap_set");
 
     page = BufferGetPage(vmBuf);
     map = (uint8 *) PageGetContents(page);
     LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE);
 
     if (flags != (map[mapByte] >> mapOffset & VISIBILITYMAP_VALID_BITS))
     {
         START_CRIT_SECTION();
 
         map[mapByte] |= (flags << mapOffset);
         MarkBufferDirty(vmBuf);
 
         if (RelationNeedsWAL(rel))
         {
             if (XLogRecPtrIsInvalid(recptr))
             {
                 Assert(!InRecovery);
                 recptr = log_heap_visible(rel->rd_node, heapBuf, vmBuf,
                                           cutoff_xid, flags);
 
                 /*
                  * If data checksums are enabled (or wal_log_hints=on), we
                  * need to protect the heap page from being torn.
                  */
                 if (XLogHintBitIsNeeded())
                 {
                     Page        heapPage = BufferGetPage(heapBuf);
 
                     /* caller is expected to set PD_ALL_VISIBLE first */
                     Assert(PageIsAllVisible(heapPage));
                     PageSetLSN(heapPage, recptr);
                 }
             }
             PageSetLSN(page, recptr);
         }
 
         END_CRIT_SECTION();
     }
 
     LockBuffer(vmBuf, BUFFER_LOCK_UNLOCK);
 }

void visibilitymap_truncate	(	Relation	rel,
		BlockNumber	nheapblocks
	)

Definition at line 462 of file visibilitymap.c.

References BUFFER_LOCK_EXCLUSIVE, BufferGetPage, BufferIsValid, DEBUG1, elog, END_CRIT_SECTION, HEAPBLK_TO_MAPBLOCK, HEAPBLK_TO_MAPBYTE, HEAPBLK_TO_OFFSET, InRecovery, LockBuffer(), log_newpage_buffer(), MAPSIZE, MarkBufferDirty(), MemSet, PageGetContents, RelationData::rd_smgr, RelationGetRelationName, RelationNeedsWAL, RelationOpenSmgr, SMgrRelationData::smgr_vm_nblocks, smgrexists(), smgrnblocks(), smgrtruncate(), START_CRIT_SECTION, UnlockReleaseBuffer(), VISIBILITYMAP_FORKNUM, vm_readbuf(), and XLogHintBitIsNeeded.

Referenced by pg_truncate_visibility_map(), RelationTruncate(), and smgr_redo().

 {
     BlockNumber newnblocks;
 
     /* last remaining block, byte, and bit */
     BlockNumber truncBlock = HEAPBLK_TO_MAPBLOCK(nheapblocks);
     uint32      truncByte = HEAPBLK_TO_MAPBYTE(nheapblocks);
     uint8       truncOffset = HEAPBLK_TO_OFFSET(nheapblocks);
 
 #ifdef TRACE_VISIBILITYMAP
     elog(DEBUG1, "vm_truncate %s %d", RelationGetRelationName(rel), nheapblocks);
 #endif
 
     RelationOpenSmgr(rel);
 
     /*
      * If no visibility map has been created yet for this relation, there's
      * nothing to truncate.
      */
     if (!smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
         return;
 
     /*
      * Unless the new size is exactly at a visibility map page boundary, the
      * tail bits in the last remaining map page, representing truncated heap
      * blocks, need to be cleared. This is not only tidy, but also necessary
      * because we don't get a chance to clear the bits if the heap is extended
      * again.
      */
     if (truncByte != 0 || truncOffset != 0)
     {
         Buffer      mapBuffer;
         Page        page;
         char       *map;
 
         newnblocks = truncBlock + 1;
 
         mapBuffer = vm_readbuf(rel, truncBlock, false);
         if (!BufferIsValid(mapBuffer))
         {
             /* nothing to do, the file was already smaller */
             return;
         }
 
         page = BufferGetPage(mapBuffer);
         map = PageGetContents(page);
 
         LockBuffer(mapBuffer, BUFFER_LOCK_EXCLUSIVE);
 
         /* NO EREPORT(ERROR) from here till changes are logged */
         START_CRIT_SECTION();
 
         /* Clear out the unwanted bytes. */
         MemSet(&map[truncByte + 1], 0, MAPSIZE - (truncByte + 1));
 
         /*----
          * Mask out the unwanted bits of the last remaining byte.
          *
          * ((1 << 0) - 1) = 00000000
          * ((1 << 1) - 1) = 00000001
          * ...
          * ((1 << 6) - 1) = 00111111
          * ((1 << 7) - 1) = 01111111
          *----
          */
         map[truncByte] &= (1 << truncOffset) - 1;
 
         /*
          * Truncation of a relation is WAL-logged at a higher-level, and we
          * will be called at WAL replay. But if checksums are enabled, we need
          * to still write a WAL record to protect against a torn page, if the
          * page is flushed to disk before the truncation WAL record. We cannot
          * use MarkBufferDirtyHint here, because that will not dirty the page
          * during recovery.
          */
         MarkBufferDirty(mapBuffer);
         if (!InRecovery && RelationNeedsWAL(rel) && XLogHintBitIsNeeded())
             log_newpage_buffer(mapBuffer, false);
 
         END_CRIT_SECTION();
 
         UnlockReleaseBuffer(mapBuffer);
     }
     else
         newnblocks = truncBlock;
 
     if (smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM) <= newnblocks)
     {
         /* nothing to do, the file was already smaller than requested size */
         return;
     }
 
     /* Truncate the unused VM pages, and send smgr inval message */
     smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks);
 
     /*
      * We might as well update the local smgr_vm_nblocks setting. smgrtruncate
      * sent an smgr cache inval message, which will cause other backends to
      * invalidate their copy of smgr_vm_nblocks, and this one too at the next
      * command boundary.  But this ensures it isn't outright wrong until then.
      */
     if (rel->rd_smgr)
         rel->rd_smgr->smgr_vm_nblocks = newnblocks;
 }

static void vm_extend	(	Relation	rel,
		BlockNumber	nvmblocks
	)

static

Definition at line 626 of file visibilitymap.c.

References CacheInvalidateSmgr(), ExclusiveLock, InvalidBlockNumber, LockRelationForExtension(), PageInit(), PageSetChecksumInplace(), palloc(), pfree(), RelationData::rd_smgr, RelationOpenSmgr, SMgrRelationData::smgr_rnode, SMgrRelationData::smgr_vm_nblocks, smgrcreate(), smgrexists(), smgrextend(), smgrnblocks(), UnlockRelationForExtension(), and VISIBILITYMAP_FORKNUM.

Referenced by vm_readbuf().

 {
     BlockNumber vm_nblocks_now;
     Page        pg;
 
     pg = (Page) palloc(BLCKSZ);
     PageInit(pg, BLCKSZ, 0);
 
     /*
      * We use the relation extension lock to lock out other backends trying to
      * extend the visibility map at the same time. It also locks out extension
      * of the main fork, unnecessarily, but extending the visibility map
      * happens seldom enough that it doesn't seem worthwhile to have a
      * separate lock tag type for it.
      *
      * Note that another backend might have extended or created the relation
      * by the time we get the lock.
      */
     LockRelationForExtension(rel, ExclusiveLock);
 
     /* Might have to re-open if a cache flush happened */
     RelationOpenSmgr(rel);
 
     /*
      * Create the file first if it doesn't exist.  If smgr_vm_nblocks is
      * positive then it must exist, no need for an smgrexists call.
      */
     if ((rel->rd_smgr->smgr_vm_nblocks == 0 ||
          rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber) &&
         !smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
         smgrcreate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, false);
 
     vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
 
     /* Now extend the file */
     while (vm_nblocks_now < vm_nblocks)
     {
         PageSetChecksumInplace(pg, vm_nblocks_now);
 
         smgrextend(rel->rd_smgr, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
                    (char *) pg, false);
         vm_nblocks_now++;
     }
 
     /*
      * Send a shared-inval message to force other backends to close any smgr
      * references they may have for this rel, which we are about to change.
      * This is a useful optimization because it means that backends don't have
      * to keep checking for creation or extension of the file, which happens
      * infrequently.
      */
     CacheInvalidateSmgr(rel->rd_smgr->smgr_rnode);
 
     /* Update local cache with the up-to-date size */
     rel->rd_smgr->smgr_vm_nblocks = vm_nblocks_now;
 
     UnlockRelationForExtension(rel, ExclusiveLock);
 
     pfree(pg);
 }

static Buffer vm_readbuf	(	Relation	rel,
		BlockNumber	blkno,
		bool	extend
	)

static

Definition at line 574 of file visibilitymap.c.

References buf, BufferGetPage, InvalidBlockNumber, InvalidBuffer, PageInit(), PageIsNew, RBM_ZERO_ON_ERROR, RelationData::rd_smgr, ReadBufferExtended(), RelationOpenSmgr, SMgrRelationData::smgr_vm_nblocks, smgrexists(), smgrnblocks(), VISIBILITYMAP_FORKNUM, and vm_extend().

Referenced by visibilitymap_count(), visibilitymap_get_status(), visibilitymap_pin(), and visibilitymap_truncate().

 {
     Buffer      buf;
 
     /*
      * We might not have opened the relation at the smgr level yet, or we
      * might have been forced to close it by a sinval message.  The code below
      * won't necessarily notice relation extension immediately when extend =
      * false, so we rely on sinval messages to ensure that our ideas about the
      * size of the map aren't too far out of date.
      */
     RelationOpenSmgr(rel);
 
     /*
      * If we haven't cached the size of the visibility map fork yet, check it
      * first.
      */
     if (rel->rd_smgr->smgr_vm_nblocks == InvalidBlockNumber)
     {
         if (smgrexists(rel->rd_smgr, VISIBILITYMAP_FORKNUM))
             rel->rd_smgr->smgr_vm_nblocks = smgrnblocks(rel->rd_smgr,
                                                         VISIBILITYMAP_FORKNUM);
         else
             rel->rd_smgr->smgr_vm_nblocks = 0;
     }
 
     /* Handle requests beyond EOF */
     if (blkno >= rel->rd_smgr->smgr_vm_nblocks)
     {
         if (extend)
             vm_extend(rel, blkno + 1);
         else
             return InvalidBuffer;
     }
 
     /*
      * Use ZERO_ON_ERROR mode, and initialize the page if necessary. It's
      * always safe to clear bits, so it's better to clear corrupt pages than
      * error out.
      */
     buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
                              RBM_ZERO_ON_ERROR, NULL);
     if (PageIsNew(BufferGetPage(buf)))
         PageInit(BufferGetPage(buf), BLCKSZ, 0);
     return buf;
 }

Variable Documentation

const uint8 number_of_ones_for_frozen[256]

static

Initial value:

= {
    0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
    0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
    0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4,
    2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3,
    2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4,
    2, 2, 3, 3, 2, 2, 3, 3, 3, 3, 4, 4, 3, 3, 4, 4
}

Definition at line 137 of file visibilitymap.c.

Referenced by visibilitymap_count().

const uint8 number_of_ones_for_visible[256]

static

Initial value:

= {
    0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4,
    0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    0, 1, 0, 1, 1, 2, 1, 2, 0, 1, 0, 1, 1, 2, 1, 2,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4,
    1, 2, 1, 2, 2, 3, 2, 3, 1, 2, 1, 2, 2, 3, 2, 3,
    2, 3, 2, 3, 3, 4, 3, 4, 2, 3, 2, 3, 3, 4, 3, 4
}

Definition at line 119 of file visibilitymap.c.

Referenced by visibilitymap_count().

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