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postgresql/src/backend/utils/adt/varbit.c

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/*-------------------------------------------------------------------------
*
* varbit.c
* Functions for the SQL datatypes BIT() and BIT VARYING().
*
* Code originally contributed by Adriaan Joubert.
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/varbit.c,v 1.9 2000/08/26 21:53:41 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "utils/array.h"
#include "utils/fmgroids.h"
#include "utils/varbit.h"
#define HEXDIG(z) ((z)<10 ? ((z)+'0') : ((z)-10+'A'))
/*----------
* Prefixes:
* zp -- zero-padded fixed length bit string
* var -- varying bit string
*
* attypmod -- contains the length of the bit string in bits, or for
* varying bits the maximum length.
*
* The data structure contains the following elements:
* header -- length of the whole data structure (incl header)
* in bytes. (as with all varying length datatypes)
* data section -- private data section for the bits data structures
* bitlength -- length of the bit string in bits
* bitdata -- bit string, most significant byte first
*----------
*/
/*
* zpbit_in -
* converts a char string to the internal representation of a bitstring.
* The length is determined by the number of bits required plus
* VARHDRSZ bytes or from atttypmod.
*/
Datum
zpbit_in(PG_FUNCTION_ARGS)
{
char *s = PG_GETARG_CSTRING(0);
#ifdef NOT_USED
Oid typelem = PG_GETARG_OID(1);
#endif
int32 atttypmod = PG_GETARG_INT32(2);
VarBit *result; /* The resulting bit string */
char *sp; /* pointer into the character string */
bits8 *r; /* pointer into the result */
int len, /* Length of the whole data structure */
bitlen, /* Number of bits in the bit string */
slen; /* Length of the input string */
bool bit_not_hex; /* false = hex string true = bit string */
int bc,
ipad;
bits8 x = 0;
/* Check that the first character is a b or an x */
if (s[0] == 'b' || s[0] == 'B')
bit_not_hex = true;
else if (s[0] == 'x' || s[0] == 'X')
bit_not_hex = false;
else
{
elog(ERROR, "zpbit_in: %s is not a valid bitstring", s);
bit_not_hex = false; /* keep compiler quiet */
}
slen = strlen(s) - 1;
/* Determine bitlength from input string */
if (bit_not_hex)
bitlen = slen;
else
bitlen = slen * 4;
/*
* Sometimes atttypmod is not supplied. If it is supplied we need to
* make sure that the bitstring fits. Note that the number of infered
* bits can be larger than the number of actual bits needed, but only
* if we are reading a hex string and not by more than 3 bits, as a
* hex string gives an accurate length up to 4 bits
*/
if (atttypmod <= 0)
atttypmod = bitlen;
else if (bit_not_hex ? (bitlen > atttypmod) : (bitlen > atttypmod + 3))
elog(ERROR, "zpbit_in: bit string too long for bit(%d)",
atttypmod);
len = VARBITTOTALLEN(atttypmod);
result = (VarBit *) palloc(len);
/* set to 0 so that *r is always initialised and string is zero-padded */
memset(result, 0, len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = atttypmod;
sp = s + 1;
r = VARBITS(result);
if (bit_not_hex)
{
/* Parse the bit representation of the string */
/* We know it fits, as bitlen was compared to atttypmod */
x = BITHIGH;
for (; *sp; sp++)
{
if (*sp == '1')
*r |= x;
else if (*sp != '0')
elog(ERROR, "Cannot parse %c as a binary digit", *sp);
x >>= 1;
if (x == 0)
{
x = BITHIGH;
r++;
}
}
}
else
{
/* Parse the hex representation of the string */
for (bc = 0; *sp; sp++)
{
if (*sp >= '0' && *sp <= '9')
x = (bits8) (*sp - '0');
else if (*sp >= 'A' && *sp <= 'F')
x = (bits8) (*sp - 'A') + 10;
else if (*sp >= 'a' && *sp <= 'f')
x = (bits8) (*sp - 'a') + 10;
else
elog(ERROR, "Cannot parse %c as a hex digit", *sp);
if (bc)
{
*r++ |= x;
bc = 0;
}
else
{
*r = x << 4;
bc = 1;
}
}
}
if (bitlen > atttypmod)
{
/* Check that this fitted */
r = VARBITEND(result) - 1;
ipad = VARBITPAD(result);
/*
* The bottom ipad bits of the byte pointed to by r need to be
* zero
*/
if (((*r << (BITS_PER_BYTE - ipad)) & BITMASK) != 0)
elog(ERROR, "zpbit_in: bit string too long for bit(%d)",
atttypmod);
}
PG_RETURN_VARBIT_P(result);
}
/* zpbit_out -
* for the time being we print everything as hex strings, as this is likely
* to be more compact than bit strings, and consequently much more efficient
* for long strings
*/
Datum
zpbit_out(PG_FUNCTION_ARGS)
{
VarBit *s = PG_GETARG_VARBIT_P(0);
char *result,
*r;
bits8 *sp;
int i,
len,
bitlen;
bitlen = VARBITLEN(s);
len = (bitlen + 3) / 4;
result = (char *) palloc(len + 2);
sp = VARBITS(s);
r = result;
*r++ = 'X';
/* we cheat by knowing that we store full bytes zero padded */
for (i = 0; i < len; i += 2, sp++)
{
*r++ = HEXDIG((*sp) >> 4);
*r++ = HEXDIG((*sp) & 0xF);
}
/*
* Go back one step if we printed a hex number that was not part
* of the bitstring anymore
*/
if (i > len)
r--;
*r = '\0';
PG_RETURN_CSTRING(result);
}
/* zpbit()
* Converts a bit() type to a specific internal length.
* len is the bitlength specified in the column definition.
*/
Datum
zpbit(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 len = PG_GETARG_INT32(1);
VarBit *result;
int rlen;
/* No work if typmod is invalid or supplied data matches it already */
if (len <= 0 || len == VARBITLEN(arg))
PG_RETURN_VARBIT_P(arg);
rlen = VARBITTOTALLEN(len);
result = (VarBit *) palloc(rlen);
/* set to 0 so that result is zero-padded if input is shorter */
memset(result, 0, rlen);
VARATT_SIZEP(result) = rlen;
VARBITLEN(result) = len;
memcpy(VARBITS(result), VARBITS(arg),
Min(VARBITBYTES(result), VARBITBYTES(arg)));
PG_RETURN_VARBIT_P(result);
}
/* _zpbit()
* Converts an array of bit() elements to a specific internal length.
* len is the bitlength specified in the column definition.
*/
Datum
_zpbit(PG_FUNCTION_ARGS)
{
ArrayType *v = (ArrayType *) PG_GETARG_VARLENA_P(0);
int32 len = PG_GETARG_INT32(1);
FunctionCallInfoData locfcinfo;
/*
* Since zpbit() is a built-in function, we should only need to
* look it up once per run.
*/
static FmgrInfo zpbit_finfo;
if (zpbit_finfo.fn_oid == InvalidOid)
fmgr_info(F_ZPBIT, &zpbit_finfo);
MemSet(&locfcinfo, 0, sizeof(locfcinfo));
locfcinfo.flinfo = &zpbit_finfo;
locfcinfo.nargs = 2;
/* We assume we are "strict" and need not worry about null inputs */
locfcinfo.arg[0] = PointerGetDatum(v);
locfcinfo.arg[1] = Int32GetDatum(len);
return array_map(&locfcinfo, ZPBITOID, ZPBITOID);
}
/*
* varbit_in -
* converts a string to the internal representation of a bitstring.
* This is the same as zpbit_in except that atttypmod is taken as
* the maximum length, not the exact length to force the bitstring to.
*/
Datum
varbit_in(PG_FUNCTION_ARGS)
{
char *s = PG_GETARG_CSTRING(0);
#ifdef NOT_USED
Oid typelem = PG_GETARG_OID(1);
#endif
int32 atttypmod = PG_GETARG_INT32(2);
VarBit *result; /* The resulting bit string */
char *sp; /* pointer into the character string */
bits8 *r; /* pointer into the result */
int len, /* Length of the whole data structure */
bitlen, /* Number of bits in the bit string */
slen; /* Length of the input string */
bool bit_not_hex; /* false = hex string true = bit string */
int bc,
ipad;
bits8 x = 0;
/* Check that the first character is a b or an x */
if (s[0] == 'b' || s[0] == 'B')
bit_not_hex = true;
else if (s[0] == 'x' || s[0] == 'X')
bit_not_hex = false;
else
{
elog(ERROR, "varbit_in: %s is not a valid bitstring", s);
bit_not_hex = false; /* keep compiler quiet */
}
slen = strlen(s) - 1;
/* Determine bitlength from input string */
if (bit_not_hex)
bitlen = slen;
else
bitlen = slen * 4;
/*
* Sometimes atttypmod is not supplied. If it is supplied we need to
* make sure that the bitstring fits. Note that the number of infered
* bits can be larger than the number of actual bits needed, but only
* if we are reading a hex string and not by more than 3 bits, as a
* hex string gives an accurate length up to 4 bits
*/
if (atttypmod <= 0)
atttypmod = bitlen;
else if (bit_not_hex ? (bitlen > atttypmod) : (bitlen > atttypmod + 3))
elog(ERROR, "varbit_in: bit string too long for bit varying(%d)",
atttypmod);
len = VARBITTOTALLEN(bitlen);
result = (VarBit *) palloc(len);
/* set to 0 so that *r is always initialised and string is zero-padded */
memset(result, 0, len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = Min(bitlen, atttypmod);
sp = s + 1;
r = VARBITS(result);
if (bit_not_hex)
{
/* Parse the bit representation of the string */
/* We know it fits, as bitlen was compared to atttypmod */
x = BITHIGH;
for (; *sp; sp++)
{
if (*sp == '1')
*r |= x;
else if (*sp != '0')
elog(ERROR, "Cannot parse %c as a binary digit", *sp);
x >>= 1;
if (x == 0)
{
x = BITHIGH;
r++;
}
}
}
else
{
/* Parse the hex representation of the string */
for (bc = 0; *sp; sp++)
{
if (*sp >= '0' && *sp <= '9')
x = (bits8) (*sp - '0');
else if (*sp >= 'A' && *sp <= 'F')
x = (bits8) (*sp - 'A') + 10;
else if (*sp >= 'a' && *sp <= 'f')
x = (bits8) (*sp - 'a') + 10;
else
elog(ERROR, "Cannot parse %c as a hex digit", *sp);
if (bc)
{
*r++ |= x;
bc = 0;
}
else
{
*r = x << 4;
bc = 1;
}
}
}
if (bitlen > atttypmod)
{
/* Check that this fitted */
r = VARBITEND(result) - 1;
ipad = VARBITPAD(result);
/*
* The bottom ipad bits of the byte pointed to by r need to be
* zero
*/
if (((*r << (BITS_PER_BYTE - ipad)) & BITMASK) != 0)
elog(ERROR, "varbit_in: bit string too long for bit varying(%d)",
atttypmod);
}
PG_RETURN_VARBIT_P(result);
}
/* varbit_out -
* Prints the string as bits to preserve length accurately
*/
Datum
varbit_out(PG_FUNCTION_ARGS)
{
VarBit *s = PG_GETARG_VARBIT_P(0);
char *result,
*r;
bits8 *sp;
bits8 x;
int i,
k,
len;
len = VARBITLEN(s);
result = (char *) palloc(len + 2);
sp = VARBITS(s);
r = result;
*r++ = 'B';
for (i = 0; i < len - BITS_PER_BYTE; i += BITS_PER_BYTE, sp++)
{
x = *sp;
for (k = 0; k < BITS_PER_BYTE; k++)
{
*r++ = (x & BITHIGH) ? '1' : '0';
x <<= 1;
}
}
x = *sp;
for (k = i; k < len; k++)
{
*r++ = (x & BITHIGH) ? '1' : '0';
x <<= 1;
}
*r = '\0';
PG_RETURN_CSTRING(result);
}
/* varbit()
* Converts a varbit() type to a specific internal length.
* len is the maximum bitlength specified in the column definition.
*/
Datum
varbit(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 len = PG_GETARG_INT32(1);
VarBit *result;
int rlen;
/* No work if typmod is invalid or supplied data matches it already */
if (len <= 0 || len >= VARBITLEN(arg))
PG_RETURN_VARBIT_P(arg);
rlen = VARBITTOTALLEN(len);
result = (VarBit *) palloc(rlen);
VARATT_SIZEP(result) = rlen;
VARBITLEN(result) = len;
memcpy(VARBITS(result), VARBITS(arg), VARBITBYTES(result));
PG_RETURN_VARBIT_P(result);
}
/* _varbit()
* Converts an array of bit() elements to a specific internal length.
* len is the maximum bitlength specified in the column definition.
*/
Datum
_varbit(PG_FUNCTION_ARGS)
{
ArrayType *v = (ArrayType *) PG_GETARG_VARLENA_P(0);
int32 len = PG_GETARG_INT32(1);
FunctionCallInfoData locfcinfo;
/*
* Since varbit() is a built-in function, we should only need to
* look it up once per run.
*/
static FmgrInfo varbit_finfo;
if (varbit_finfo.fn_oid == InvalidOid)
fmgr_info(F_VARBIT, &varbit_finfo);
MemSet(&locfcinfo, 0, sizeof(locfcinfo));
locfcinfo.flinfo = &varbit_finfo;
locfcinfo.nargs = 2;
/* We assume we are "strict" and need not worry about null inputs */
locfcinfo.arg[0] = PointerGetDatum(v);
locfcinfo.arg[1] = Int32GetDatum(len);
return array_map(&locfcinfo, VARBITOID, VARBITOID);
}
/*
* Comparison operators
*
* We only need one set of comparison operators for bitstrings, as the lengths
* are stored in the same way for zero-padded and varying bit strings.
*
* Note that the standard is not unambiguous about the comparison between
* zero-padded bit strings and varying bitstrings. If the same value is written
* into a zero padded bitstring as into a varying bitstring, but the zero
* padded bitstring has greater length, it will be bigger.
*
* Zeros from the beginning of a bitstring cannot simply be ignored, as they
* may be part of a bit string and may be significant.
*
* Note: btree indexes need these routines not to leak memory; therefore,
* be careful to free working copies of toasted datums. Most places don't
* need to be so careful.
*/
Datum
biteq(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
bool result;
int bitlen1,
bitlen2;
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
if (bitlen1 != bitlen2)
result = false;
else
{
/* bit strings are always stored in a full number of bytes */
result = memcmp(VARBITS(arg1), VARBITS(arg2), VARBITBYTES(arg1)) == 0;
}
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
Datum
bitne(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
bool result;
int bitlen1,
bitlen2;
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
if (bitlen1 != bitlen2)
result = true;
else
{
/* bit strings are always stored in a full number of bytes */
result = memcmp(VARBITS(arg1), VARBITS(arg2), VARBITBYTES(arg1)) != 0;
}
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
/* bit_cmp
*
* Compares two bitstrings and returns <0, 0, >0 depending on whether the first
* string is smaller, equal, or bigger than the second. All bits are considered
* and additional zero bits may make one string smaller/larger than the other,
* even if their zero-padded values would be the same.
*/
static int32
bit_cmp(VarBit *arg1, VarBit *arg2)
{
int bitlen1,
bytelen1,
bitlen2,
bytelen2;
int32 cmp;
bytelen1 = VARBITBYTES(arg1);
bytelen2 = VARBITBYTES(arg2);
cmp = memcmp(VARBITS(arg1), VARBITS(arg2), Min(bytelen1, bytelen2));
if (cmp == 0)
{
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
if (bitlen1 != bitlen2)
cmp = (bitlen1 < bitlen2) ? -1 : 1;
}
return cmp;
}
Datum
bitlt(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
bool result;
result = (bit_cmp(arg1, arg2) < 0);
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
Datum
bitle(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
bool result;
result = (bit_cmp(arg1, arg2) <= 0);
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
Datum
bitgt(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
bool result;
result = (bit_cmp(arg1, arg2) > 0);
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
Datum
bitge(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
bool result;
result = (bit_cmp(arg1, arg2) >= 0);
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
Datum
bitcmp(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
int32 result;
result = bit_cmp(arg1, arg2);
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_INT32(result);
}
/* bitcat
* Concatenation of bit strings
*/
Datum
bitcat(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
VarBit *result;
int bitlen1,
bitlen2,
bytelen,
bit1pad,
bit2shift;
bits8 *pr,
*pa;
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
bytelen = VARBITTOTALLEN(bitlen1 + bitlen2);
result = (VarBit *) palloc(bytelen);
VARATT_SIZEP(result) = bytelen;
VARBITLEN(result) = bitlen1 + bitlen2;
/* Copy the first bitstring in */
memcpy(VARBITS(result), VARBITS(arg1), VARBITBYTES(arg1));
/* Copy the second bit string */
bit1pad = VARBITPAD(arg1);
if (bit1pad == 0)
{
memcpy(VARBITS(result) + VARBITBYTES(arg1), VARBITS(arg2),
VARBITBYTES(arg2));
}
else if (bitlen2 > 0)
{
/* We need to shift all the bits to fit */
bit2shift = BITS_PER_BYTE - bit1pad;
pr = VARBITS(result) + VARBITBYTES(arg1) - 1;
for (pa = VARBITS(arg2); pa < VARBITEND(arg2); pa++)
{
*pr |= ((*pa >> bit2shift) & BITMASK);
pr++;
if (pr < VARBITEND(result))
*pr = (*pa << bit1pad) & BITMASK;
}
}
PG_RETURN_VARBIT_P(result);
}
/* bitsubstr
* retrieve a substring from the bit string.
* Note, s is 1-based.
* SQL draft 6.10 9)
*/
Datum
bitsubstr(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 s = PG_GETARG_INT32(1);
int32 l = PG_GETARG_INT32(2);
VarBit *result;
int bitlen,
rbitlen,
len,
ipad = 0,
ishift,
i;
int e,
s1,
e1;
bits8 mask,
*r,
*ps;
bitlen = VARBITLEN(arg);
e = s + l;
s1 = Max(s, 1);
e1 = Min(e, bitlen + 1);
if (s1 > bitlen || e1 < 1)
{
/* Need to return a zero-length bitstring */
len = VARBITTOTALLEN(0);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = 0;
}
else
{
/*
* OK, we've got a true substring starting at position s1-1 and
* ending at position e1-1
*/
rbitlen = e1 - s1;
len = VARBITTOTALLEN(rbitlen);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = rbitlen;
len -= VARHDRSZ + VARBITHDRSZ;
/* Are we copying from a byte boundary? */
if ((s1 - 1) % BITS_PER_BYTE == 0)
{
/* Yep, we are copying bytes */
memcpy(VARBITS(result), VARBITS(arg) + (s1 - 1) / BITS_PER_BYTE,
len);
}
else
{
/* Figure out how much we need to shift the sequence by */
ishift = (s1 - 1) % BITS_PER_BYTE;
r = VARBITS(result);
ps = VARBITS(arg) + (s1 - 1) / BITS_PER_BYTE;
for (i = 0; i < len; i++)
{
*r = (*ps << ishift) & BITMASK;
if ((++ps) < VARBITEND(arg))
*r |= *ps >> (BITS_PER_BYTE - ishift);
r++;
}
}
/* Do we need to pad at the end? */
ipad = VARBITPAD(result);
if (ipad > 0)
{
mask = BITMASK << ipad;
*(VARBITS(result) + len - 1) &= mask;
}
}
PG_RETURN_VARBIT_P(result);
}
/* bitlength, bitoctetlength
* Return the length of a bit string
*/
Datum
bitlength(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
PG_RETURN_INT32(VARBITLEN(arg));
}
Datum
bitoctetlength(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
PG_RETURN_INT32(VARBITBYTES(arg));
}
/* bitand
* perform a logical AND on two bit strings.
*/
Datum
bitand(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
VarBit *result;
int len,
bitlen1,
bitlen2,
i;
bits8 *p1,
*p2,
*r;
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
if (bitlen1 != bitlen2)
elog(ERROR, "bitand: Cannot AND bitstrings of different sizes");
len = VARSIZE(arg1);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = bitlen1;
p1 = VARBITS(arg1);
p2 = VARBITS(arg2);
r = VARBITS(result);
for (i = 0; i < VARBITBYTES(arg1); i++)
*r++ = *p1++ & *p2++;
/* Padding is not needed as & of 0 pad is 0 */
PG_RETURN_VARBIT_P(result);
}
/* bitor
* perform a logical OR on two bit strings.
*/
Datum
bitor(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
VarBit *result;
int len,
bitlen1,
bitlen2,
i;
bits8 *p1,
*p2,
*r;
bits8 mask;
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
if (bitlen1 != bitlen2)
elog(ERROR, "bitor: Cannot OR bitstrings of different sizes");
len = VARSIZE(arg1);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = bitlen1;
p1 = VARBITS(arg1);
p2 = VARBITS(arg2);
r = VARBITS(result);
for (i = 0; i < VARBITBYTES(arg1); i++)
*r++ = *p1++ | *p2++;
/* Pad the result */
mask = BITMASK << VARBITPAD(result);
if (mask)
{
r--;
*r &= mask;
}
PG_RETURN_VARBIT_P(result);
}
/* bitxor
* perform a logical XOR on two bit strings.
*/
Datum
bitxor(PG_FUNCTION_ARGS)
{
VarBit *arg1 = PG_GETARG_VARBIT_P(0);
VarBit *arg2 = PG_GETARG_VARBIT_P(1);
VarBit *result;
int len,
bitlen1,
bitlen2,
i;
bits8 *p1,
*p2,
*r;
bits8 mask;
bitlen1 = VARBITLEN(arg1);
bitlen2 = VARBITLEN(arg2);
if (bitlen1 != bitlen2)
elog(ERROR, "bitxor: Cannot XOR bitstrings of different sizes");
len = VARSIZE(arg1);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = bitlen1;
p1 = VARBITS(arg1);
p2 = VARBITS(arg2);
r = VARBITS(result);
for (i = 0; i < VARBITBYTES(arg1); i++)
*r++ = *p1++ ^ *p2++;
/* Pad the result */
mask = BITMASK << VARBITPAD(result);
if (mask)
{
r--;
*r &= mask;
}
PG_RETURN_VARBIT_P(result);
}
/* bitnot
* perform a logical NOT on a bit string.
*/
Datum
bitnot(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
VarBit *result;
bits8 *p,
*r;
bits8 mask;
result = (VarBit *) palloc(VARSIZE(arg));
VARATT_SIZEP(result) = VARSIZE(arg);
VARBITLEN(result) = VARBITLEN(arg);
p = VARBITS(arg);
r = VARBITS(result);
for (; p < VARBITEND(arg); p++)
*r++ = ~ *p;
/* Pad the result */
mask = BITMASK << VARBITPAD(result);
if (mask)
{
r--;
*r &= mask;
}
PG_RETURN_VARBIT_P(result);
}
/* bitshiftleft
* do a left shift (i.e. towards the beginning of the string)
*/
Datum
bitshiftleft(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 shft = PG_GETARG_INT32(1);
VarBit *result;
int byte_shift,
ishift,
len;
bits8 *p,
*r;
/* Negative shift is a shift to the right */
if (shft < 0)
PG_RETURN_DATUM(DirectFunctionCall2(bitshiftright,
VarBitPGetDatum(arg),
Int32GetDatum(-shft)));
result = (VarBit *) palloc(VARSIZE(arg));
VARATT_SIZEP(result) = VARSIZE(arg);
VARBITLEN(result) = VARBITLEN(arg);
r = VARBITS(result);
/* If we shifted all the bits out, return an all-zero string */
if (shft >= VARBITLEN(arg))
{
memset(r, 0, VARBITBYTES(arg));
PG_RETURN_VARBIT_P(result);
}
byte_shift = shft / BITS_PER_BYTE;
ishift = shft % BITS_PER_BYTE;
p = VARBITS(arg) + byte_shift;
if (ishift == 0)
{
/* Special case: we can do a memcpy */
len = VARBITBYTES(arg) - byte_shift;
memcpy(r, p, len);
memset(r + len, 0, byte_shift);
}
else
{
for (; p < VARBITEND(arg); r++)
{
*r = *p << ishift;
if ((++p) < VARBITEND(arg))
*r |= *p >> (BITS_PER_BYTE - ishift);
}
for (; r < VARBITEND(result); r++)
*r = 0;
}
PG_RETURN_VARBIT_P(result);
}
/* bitshiftright
* do a right shift (i.e. towards the end of the string)
*/
Datum
bitshiftright(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 shft = PG_GETARG_INT32(1);
VarBit *result;
int byte_shift,
ishift,
len;
bits8 *p,
*r;
/* Negative shift is a shift to the left */
if (shft < 0)
PG_RETURN_DATUM(DirectFunctionCall2(bitshiftleft,
VarBitPGetDatum(arg),
Int32GetDatum(-shft)));
result = (VarBit *) palloc(VARSIZE(arg));
VARATT_SIZEP(result) = VARSIZE(arg);
VARBITLEN(result) = VARBITLEN(arg);
r = VARBITS(result);
/* If we shifted all the bits out, return an all-zero string */
if (shft >= VARBITLEN(arg))
{
memset(r, 0, VARBITBYTES(arg));
PG_RETURN_VARBIT_P(result);
}
byte_shift = shft / BITS_PER_BYTE;
ishift = shft % BITS_PER_BYTE;
p = VARBITS(arg);
/* Set the first part of the result to 0 */
memset(r, 0, byte_shift);
r += byte_shift;
if (ishift == 0)
{
/* Special case: we can do a memcpy */
len = VARBITBYTES(arg) - byte_shift;
memcpy(r, p, len);
}
else
{
if (r < VARBITEND(result))
*r = 0; /* initialize first byte */
for (; r < VARBITEND(result); p++)
{
*r |= *p >> ishift;
if ((++r) < VARBITEND(result))
*r = (*p << (BITS_PER_BYTE - ishift)) & BITMASK;
}
}
PG_RETURN_VARBIT_P(result);
}
/* This is not defined in any standard. We retain the natural ordering of
* bits here, as it just seems more intuitive.
*/
Datum
bitfromint4(PG_FUNCTION_ARGS)
{
int32 a = PG_GETARG_INT32(0);
VarBit *result;
bits8 *r;
int len;
/* allocate enough space for the bits in an int4 */
len = VARBITTOTALLEN(sizeof(int4)*BITS_PER_BYTE);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = sizeof(int4)*BITS_PER_BYTE;
/* masks and shifts here are just too painful and we know that an int4 has
* got 4 bytes
*/
r = VARBITS(result);
r[0] = (bits8) ((a >> (3*BITS_PER_BYTE)) & BITMASK);
r[1] = (bits8) ((a >> (2*BITS_PER_BYTE)) & BITMASK);
r[2] = (bits8) ((a >> (1*BITS_PER_BYTE)) & BITMASK);
r[3] = (bits8) (a & BITMASK);
PG_RETURN_VARBIT_P(result);
}
Datum
bittoint4(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
uint32 result;
bits8 *r;
/* Check that the bit string is not too long */
if (VARBITLEN(arg) > sizeof(int4)*BITS_PER_BYTE)
elog(ERROR, "Bit string is too large to fit in an int4");
result = 0;
for (r = VARBITS(arg); r < VARBITEND(arg); r++)
{
result <<= BITS_PER_BYTE;
result |= *r;
}
/* Now shift the result to take account of the padding at the end */
result >>= VARBITPAD(arg);
PG_RETURN_INT32(result);
}
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