-
/*
- * $Id$
- *
- * DEBUG: section 8 Swap File Bitmap
+ * DEBUG: section 08 Swap File Bitmap
* AUTHOR: Harvest Derived
*
* SQUID Web Proxy Cache http://www.squid-cache.org/
*/
#include "squid.h"
+#include "Debug.h"
+#include "FileMap.h"
/* Number of bits in a long */
#if SIZEOF_LONG == 8
#define FM_INITIAL_NUMBER (1<<14)
-fileMap *
-file_map_create(void)
+FileMap::FileMap() :
+ capacity_(FM_INITIAL_NUMBER), usedSlots_(0),
+ nwords(capacity_ >> LONG_BIT_SHIFT)
{
- fileMap *fm = (fileMap *)xcalloc(1, sizeof(fileMap));
- fm->max_n_files = FM_INITIAL_NUMBER;
- fm->nwords = fm->max_n_files >> LONG_BIT_SHIFT;
- debugs(8, 3, "file_map_create: creating space for " << fm->max_n_files << " files");
- debugs(8, 5, "--> " << fm->nwords << " words of " << sizeof(*fm->file_map) << " bytes each");
- fm->file_map = (unsigned long *)xcalloc(fm->nwords, sizeof(*fm->file_map));
- /* XXX account fm->file_map */
- return fm;
+ debugs(8, 3, HERE << "creating space for " << capacity_ << " files");
+ debugs(8, 5, "--> " << nwords << " words of " << sizeof(*bitmap) << " bytes each");
+ bitmap = (unsigned long *)xcalloc(nwords, sizeof(*bitmap));
}
-static void
-file_map_grow(fileMap * fm)
+void
+FileMap::grow()
{
- int old_sz = fm->nwords * sizeof(*fm->file_map);
- void *old_map = fm->file_map;
- fm->max_n_files <<= 1;
- assert(fm->max_n_files <= (1 << 24)); /* swap_filen is 25 bits, signed */
- fm->nwords = fm->max_n_files >> LONG_BIT_SHIFT;
- debugs(8, 3, "file_map_grow: creating space for " << fm->max_n_files << " files");
- fm->file_map = (unsigned long *)xcalloc(fm->nwords, sizeof(*fm->file_map));
+ int old_sz = nwords * sizeof(*bitmap);
+ void *old_map = bitmap;
+ capacity_ <<= 1;
+ assert(capacity_ <= (1 << 24)); /* swap_filen is 25 bits, signed */
+ nwords = capacity_ >> LONG_BIT_SHIFT;
+ debugs(8, 3, HERE << " creating space for " << capacity_ << " files");
+ debugs(8, 5, "--> " << nwords << " words of " << sizeof(*bitmap) << " bytes each");
+ bitmap = (unsigned long *)xcalloc(nwords, sizeof(*bitmap));
debugs(8, 3, "copying " << old_sz << " old bytes");
- xmemcpy(fm->file_map, old_map, old_sz);
+ memcpy(bitmap, old_map, old_sz);
xfree(old_map);
- /* XXX account fm->file_map */
+ /* XXX account fm->bitmap */
}
-int
-file_map_bit_set(fileMap * fm, int file_number)
+bool
+FileMap::setBit(sfileno file_number)
{
unsigned long bitmask = (1L << (file_number & LONG_BIT_MASK));
- while (file_number >= fm->max_n_files)
- file_map_grow(fm);
+ while (file_number >= capacity_)
+ grow();
- fm->file_map[file_number >> LONG_BIT_SHIFT] |= bitmask;
+ bitmap[file_number >> LONG_BIT_SHIFT] |= bitmask;
- fm->n_files_in_map++;
+ usedSlots_++;
return file_number;
}
/*
- * WARNING: file_map_bit_reset does not perform array bounds
+ * WARNING: clearBit does not perform array bounds
* checking! It assumes that 'file_number' is valid, and that the
* bit is already set. The caller must verify both of those
- * conditions by calling file_map_bit_test() first.
+ * conditions by calling testBit
+ * () first.
*/
void
-file_map_bit_reset(fileMap * fm, int file_number)
+FileMap::clearBit(sfileno file_number)
{
unsigned long bitmask = (1L << (file_number & LONG_BIT_MASK));
- fm->file_map[file_number >> LONG_BIT_SHIFT] &= ~bitmask;
- fm->n_files_in_map--;
+ bitmap[file_number >> LONG_BIT_SHIFT] &= ~bitmask;
+ usedSlots_--;
}
-int
-file_map_bit_test(fileMap * fm, int file_number)
+bool
+FileMap::testBit(sfileno file_number) const
{
unsigned long bitmask = (1L << (file_number & LONG_BIT_MASK));
- if (file_number >= fm->max_n_files)
+ if (file_number >= capacity_)
return 0;
/* be sure the return value is an int, not a u_long */
- return (fm->file_map[file_number >> LONG_BIT_SHIFT] & bitmask ? 1 : 0);
+ return (bitmap[file_number >> LONG_BIT_SHIFT] & bitmask ? 1 : 0);
}
-int
-file_map_allocate(fileMap * fm, int suggestion)
+sfileno
+FileMap::allocate(sfileno suggestion)
{
int word;
- int bit;
- int count;
- if (suggestion >= fm->max_n_files)
+ if (suggestion >= capacity_)
suggestion = 0;
- if (!file_map_bit_test(fm, suggestion))
+ if (!testBit(suggestion))
return suggestion;
word = suggestion >> LONG_BIT_SHIFT;
- for (count = 0; count < fm->nwords; count++) {
- if (fm->file_map[word] != ALL_ONES)
+ for (unsigned int count = 0; count < nwords; count++) {
+ if (bitmap[word] != ALL_ONES)
break;
- word = (word + 1) % fm->nwords;
+ word = (word + 1) % nwords;
}
- for (bit = 0; bit < BITS_IN_A_LONG; bit++) {
+ for (unsigned char bit = 0; bit < BITS_IN_A_LONG; bit++) {
suggestion = ((unsigned long) word << LONG_BIT_SHIFT) | bit;
- if (!file_map_bit_test(fm, suggestion)) {
+ if (!testBit(suggestion)) {
return suggestion;
}
}
- debugs(8, 3, "growing from file_map_allocate");
- file_map_grow(fm);
- return file_map_allocate(fm, fm->max_n_files >> 1);
+ grow();
+ return allocate(capacity_ >> 1);
}
-void
-filemapFreeMemory(fileMap * fm)
+FileMap::~FileMap()
{
- safe_free(fm->file_map);
- safe_free(fm);
+ safe_free(bitmap);
}
-
-#ifdef TEST
-
-#define TEST_SIZE 1<<16
-main(argc, argv)
-{
- int i;
-
- fm = file_map_create(TEST_SIZE);
-
- for (i = 0; i < TEST_SIZE; ++i) {
- file_map_bit_set(i);
- assert(file_map_bit_test(i));
- file_map_bit_reset(i);
- }
-}
-
-#endif