/**
* Get information about a key: length of its value and index within the page.
*
* @return TRUE if key was found, value length via *length, index via *idx,
* and whether value is stored in a .dat file via *big.
*/
bool
infopair(DBM *db, char *pag, datum key, size_t *length, int *idx, bool *big)
{
int i;
unsigned n;
size_t dsize;
const unsigned short *ino = (const unsigned short *) pag;
if ((n = ino[0]) == 0)
return FALSE;
if ((i = seepair(db, pag, n, key.dptr, key.dsize)) == 0)
return FALSE;
dsize = offset(ino[i]) - offset(ino[i + 1]);
#ifdef BIGDATA
if (is_big(ino[i + 1])) {
g_assert(dsize >= sizeof(uint32));
dsize = big_length(pag + offset(ino[i + 1]));
}
#endif
if (length != NULL)
*length = dsize;
if (idx != NULL)
*idx = i;
if (big != NULL)
*big = is_big(ino[i + 1]);
return TRUE; /* Key exists */
}
datum
getpair(DBM *db, char *pag, datum key)
{
int i;
unsigned n;
datum val;
const unsigned short *ino = (const unsigned short *) pag;
if ((n = ino[0]) == 0)
return nullitem;
if ((i = seepair(db, pag, n, key.dptr, key.dsize)) == 0)
return nullitem;
val.dptr = pag + offset(ino[i + 1]);
val.dsize = offset(ino[i]) - offset(ino[i + 1]);
#ifdef BIGDATA
if (is_big(ino[i + 1])) {
size_t dsize = big_length(val.dptr);
val.dptr = bigval_get(db, val.dptr, val.dsize);
val.dsize = (NULL == val.dptr) ? 0 : dsize;
}
#endif
return val;
}
bool
exipair(DBM *db, const char *pag, datum key)
{
const unsigned short *ino = (const unsigned short *) pag;
if (ino[0] == 0)
return FALSE;
return seepair(db, pag, ino[0], key.dptr, key.dsize) != 0;
}
int
exipair(char *pag, datum key)
{
register short *ino = (short *) pag;
if (ino[0] == 0)
return 0;
return (seepair(pag, ino[0], key.dptr, key.dsize) != 0);
}
int
delpair(char *pag, datum key)
{
int n;
int i;
short *ino = (short *) pag;
if ((n = ino[0]) == 0)
return 0;
if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
return 0;
/*
* found the key. if it is the last entry
* [i.e. i == n - 1] we just adjust the entry count.
* hard case: move all data down onto the deleted pair,
* shift offsets onto deleted offsets, and adjust them.
* [note: 0 < i < n]
*/
if (i < n - 1) {
int m;
char *dst = pag + (i == 1 ? PBLKSIZ : ino[i - 1]);
char *src = pag + ino[i + 1];
int zoo = dst - src;
debug(("free-up %d ", zoo));
/*
* shift data/keys down
*/
m = ino[i + 1] - ino[n];
#ifdef DUFF
#define MOVB *--dst = *--src
if (m > 0) {
int loop = (m + 8 - 1) >> 3;
switch (m & (8 - 1)) {
case 0: do {
MOVB; case 7: MOVB;
case 6: MOVB; case 5: MOVB;
case 4: MOVB; case 3: MOVB;
case 2: MOVB; case 1: MOVB;
} while (--loop);
}
}
datum
getpair(char *pag, datum key)
{
register int i;
register int n;
datum val;
register short *ino = (short *) pag;
if ((n = ino[0]) == 0)
return nullitem;
if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
return nullitem;
val.dptr = pag + ino[i + 1];
val.dsize = ino[i] - ino[i + 1];
return val;
}
bool
duppair(DBM *db, const char *pag, datum key)
{
const unsigned short *ino = (const unsigned short *) pag;
return ino[0] > 0 && seepair(db, pag, ino[0], key.dptr, key.dsize) > 0;
}
int
delpair(char *pag, datum key)
{
register int n;
register int i;
register short *ino = (short *) pag;
if ((n = ino[0]) == 0)
return 0;
if ((i = seepair(pag, n, key.dptr, key.dsize)) == 0)
return 0;
/*
* found the key. if it is the last entry
* [i.e. i == n - 1] we just adjust the entry count.
* hard case: move all data down onto the deleted pair,
* shift offsets onto deleted offsets, and adjust them.
* [note: 0 < i < n]
*/
if (i < n - 1) {
register int m;
register char *dst = pag + (i == 1 ? PBLKSIZ : ino[i - 1]);
register char *src = pag + ino[i + 1];
register int zoo = dst - src;
debug(("free-up %d ", zoo));
/*
* shift data/keys down
*/
m = ino[i + 1] - ino[n];
#ifdef DUFF
#define MOVB *--dst = *--src
if (m > 0) {
register int loop = (m + 8 - 1) >> 3;
switch (m & (8 - 1)) {
case 0: do {
MOVB; case 7: MOVB;
case 6: MOVB; case 5: MOVB;
case 4: MOVB; case 3: MOVB;
case 2: MOVB; case 1: MOVB;
} while (--loop);
}
}
#else
#ifdef HAS_MEMMOVE
dst -= m;
src -= m;
memmove(dst, src, m);
#else
while (m--)
*--dst = *--src;
#endif
#endif
/*
* adjust offset index up
*/
while (i < n - 1) {
ino[i] = ino[i + 2] + zoo;
i++;
}
}
ino[0] -= 2;
return 1;
}
int
duppair(char *pag, datum key)
{
register short *ino = (short *) pag;
return ino[0] > 0 && seepair(pag, ino[0], key.dptr, key.dsize) > 0;
}
