-
Bruce Momjian authored
docs that CLIENT/LOG_MIN_MESSAGES now controls debug_* output location. Doc changes included.
Bruce Momjian authoreddocs that CLIENT/LOG_MIN_MESSAGES now controls debug_* output location. Doc changes included.
varbit.c 29.68 KiB
/*-------------------------------------------------------------------------
*
* varbit.c
* Functions for the SQL datatypes BIT() and BIT VARYING().
*
* Code originally contributed by Adriaan Joubert.
*
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/varbit.c,v 1.31 2003/05/27 17:49:46 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "libpq/pqformat.h"
#include "utils/array.h"
#include "utils/fmgroids.h"
#include "utils/memutils.h"
#include "utils/varbit.h"
#define HEXDIG(z) ((z)<10 ? ((z)+'0') : ((z)-10+'A'))
/*----------
* 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
*
* The length of the bitdata vector should always be exactly as many
* bytes as are needed for the given bitlength. If the bitlength is
* not a multiple of 8, the extra low-order padding bits of the last
* byte must be zeroes.
*----------
*/
/*
* bit_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
bit_in(PG_FUNCTION_ARGS)
{
char *input_string = 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;
bits8 x = 0;
/* Check that the first character is a b or an x */
if (input_string[0] == 'b' || input_string[0] == 'B')
{
bit_not_hex = true;
sp = input_string + 1;
}
else if (input_string[0] == 'x' || input_string[0] == 'X')
{
bit_not_hex = false;
sp = input_string + 1;
}
else
{
/*
* Otherwise it's binary. This allows things like cast('1001' as
* bit) to work transparently.
*/
bit_not_hex = true;
sp = input_string;
}
slen = strlen(sp);
/* 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.
*/
if (atttypmod <= 0)
atttypmod = bitlen;
else if (bitlen != atttypmod)
elog(ERROR, "Bit string length %d does not match type BIT(%d)",
bitlen, atttypmod);
len = VARBITTOTALLEN(atttypmod);
/* set to 0 so that *r is always initialised and string is zero-padded */
result = (VarBit *) palloc0(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = atttypmod;
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;
}
}
}
PG_RETURN_VARBIT_P(result);
}
Datum
bit_out(PG_FUNCTION_ARGS)
{
#if 1
/* same as varbit output */
return varbit_out(fcinfo);
#else
/* This is how one would print a hex string, in case someone wants to
write a formatting function. */
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);
#endif
}
/*
* bit_recv - converts external binary format to bit
*/Datum
bit_recv(PG_FUNCTION_ARGS)
{
/* Exactly the same as varbit_recv, so share code */
return varbit_recv(fcinfo);
}
/*
* bit_send - converts bit to binary format
*/
Datum
bit_send(PG_FUNCTION_ARGS)
{
/* Exactly the same as varbit_send, so share code */
return varbit_send(fcinfo);
}
/* bit()
* Converts a bit() type to a specific internal length.
* len is the bitlength specified in the column definition.
*
* If doing implicit cast, raise error when source data is wrong length.
* If doing explicit cast, silently truncate or zero-pad to specified length.
*/
Datum
bit(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 len = PG_GETARG_INT32(1);
bool isExplicit = PG_GETARG_BOOL(2);
VarBit *result;
int rlen;
int ipad;
bits8 mask;
/* No work if typmod is invalid or supplied data matches it already */
if (len <= 0 || len == VARBITLEN(arg))
PG_RETURN_VARBIT_P(arg);
if (!isExplicit)
elog(ERROR, "Bit string length %d does not match type BIT(%d)",
VARBITLEN(arg), len);
rlen = VARBITTOTALLEN(len);
/* set to 0 so that string is zero-padded */
result = (VarBit *) palloc0(rlen);
VARATT_SIZEP(result) = rlen;
VARBITLEN(result) = len;
memcpy(VARBITS(result), VARBITS(arg),
Min(VARBITBYTES(result), VARBITBYTES(arg)));
/*
* Make sure last byte is zero-padded if needed. This is useless but
* safe if source data was shorter than target length (we assume the
* last byte of the source data was itself correctly zero-padded).
*/
ipad = VARBITPAD(result);
if (ipad > 0)
{
mask = BITMASK << ipad;
*(VARBITS(result) + VARBITBYTES(result) - 1) &= mask;
}
PG_RETURN_VARBIT_P(result);
}
/*
* varbit_in -
* converts a string to the internal representation of a bitstring. * This is the same as bit_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 *input_string = 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;
bits8 x = 0;
/* Check that the first character is a b or an x */
if (input_string[0] == 'b' || input_string[0] == 'B')
{
bit_not_hex = true;
sp = input_string + 1;
}
else if (input_string[0] == 'x' || input_string[0] == 'X')
{
bit_not_hex = false;
sp = input_string + 1;
}
else
{
bit_not_hex = true;
sp = input_string;
}
slen = strlen(sp);
/* 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.
*/
if (atttypmod <= 0)
atttypmod = bitlen;
else if (bitlen > atttypmod)
elog(ERROR, "Bit string too long for type BIT VARYING(%d)",
atttypmod);
len = VARBITTOTALLEN(bitlen);
/* set to 0 so that *r is always initialised and string is zero-padded */
result = (VarBit *) palloc0(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = Min(bitlen, atttypmod);
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;
}
}
}
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 + 1);
sp = VARBITS(s);
r = result;
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_recv - converts external binary format to varbit
*
* External format is the bitlen as an int32, then the byte array.
*/
Datum
varbit_recv(PG_FUNCTION_ARGS)
{
StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
VarBit *result;
int len,
bitlen;
int ipad;
bits8 mask;
bitlen = pq_getmsgint(buf, sizeof(int32));
if (bitlen < 0)
elog(ERROR, "Invalid length in external bit string");
len = VARBITTOTALLEN(bitlen);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = bitlen;
pq_copymsgbytes(buf, (char *) VARBITS(result), VARBITBYTES(result));
/* Make sure last byte is zero-padded if needed */
ipad = VARBITPAD(result);
if (ipad > 0)
{
mask = BITMASK << ipad;
*(VARBITS(result) + VARBITBYTES(result) - 1) &= mask;
}
PG_RETURN_VARBIT_P(result);
}
/*
* varbit_send - converts varbit to binary format
*/
Datum
varbit_send(PG_FUNCTION_ARGS)
{
VarBit *s = PG_GETARG_VARBIT_P(0);
StringInfoData buf;
pq_begintypsend(&buf);
pq_sendint(&buf, VARBITLEN(s), sizeof(int32));
pq_sendbytes(&buf, VARBITS(s), VARBITBYTES(s));
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}
/* varbit()
* Converts a varbit() type to a specific internal length.
* len is the maximum bitlength specified in the column definition.
*
* If doing implicit cast, raise error when source data is too long.
* If doing explicit cast, silently truncate to max length.
*/
Datumvarbit(PG_FUNCTION_ARGS)
{
VarBit *arg = PG_GETARG_VARBIT_P(0);
int32 len = PG_GETARG_INT32(1);
bool isExplicit = PG_GETARG_BOOL(2);
VarBit *result;
int rlen;
int ipad;
bits8 mask;
/* No work if typmod is invalid or supplied data matches it already */
if (len <= 0 || len >= VARBITLEN(arg))
PG_RETURN_VARBIT_P(arg);
if (!isExplicit)
elog(ERROR, "Bit string too long for type BIT VARYING(%d)", len);
rlen = VARBITTOTALLEN(len);
result = (VarBit *) palloc(rlen);
VARATT_SIZEP(result) = rlen;
VARBITLEN(result) = len;
memcpy(VARBITS(result), VARBITS(arg), VARBITBYTES(result));
/* Make sure last byte is zero-padded if needed */
ipad = VARBITPAD(result);
if (ipad > 0)
{
mask = BITMASK << ipad;
*(VARBITS(result) + VARBITBYTES(result) - 1) &= mask;
}
PG_RETURN_VARBIT_P(result);
}
/*
* 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.
*/
/* 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
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);
/* fast path for different-length inputs */
if (bitlen1 != bitlen2)
result = false;
else
result = (bit_cmp(arg1, arg2) == 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);
/* fast path for different-length inputs */
if (bitlen1 != bitlen2)
result = true;
else
result = (bit_cmp(arg1, arg2) != 0);
PG_FREE_IF_COPY(arg1, 0);
PG_FREE_IF_COPY(arg2, 1);
PG_RETURN_BOOL(result);
}
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);
/* If we do not have an upper bound, set bitlen */
if (l == -1)
l = bitlen;
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
*/
Datumbitlength(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, "Cannot AND bit strings 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, "Cannot OR bit strings 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, "Cannot XOR bit strings 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 type integer");
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);
}
Datum
bitfromint8(PG_FUNCTION_ARGS)
{
#ifndef INT64_IS_BUSTED
int64 a = PG_GETARG_INT64(0); VarBit *result;
bits8 *r;
int len;
/* allocate enough space for the bits in an int64 */
len = VARBITTOTALLEN(sizeof(a) * BITS_PER_BYTE);
result = (VarBit *) palloc(len);
VARATT_SIZEP(result) = len;
VARBITLEN(result) = sizeof(a) * BITS_PER_BYTE;
/*
* masks and shifts here are just too painful and we know that an
* int64 has got 8 bytes
*/
r = VARBITS(result);
r[0] = (bits8) ((a >> (7 * BITS_PER_BYTE)) & BITMASK);
r[1] = (bits8) ((a >> (6 * BITS_PER_BYTE)) & BITMASK);
r[2] = (bits8) ((a >> (5 * BITS_PER_BYTE)) & BITMASK);
r[3] = (bits8) ((a >> (4 * BITS_PER_BYTE)) & BITMASK);
r[4] = (bits8) ((a >> (3 * BITS_PER_BYTE)) & BITMASK);
r[5] = (bits8) ((a >> (2 * BITS_PER_BYTE)) & BITMASK);
r[6] = (bits8) ((a >> (1 * BITS_PER_BYTE)) & BITMASK);
r[7] = (bits8) (a & BITMASK);
PG_RETURN_VARBIT_P(result);
#else
elog(ERROR, "INT64 is not supported on this platform");
PG_RETURN_NULL();
#endif
}
Datum
bittoint8(PG_FUNCTION_ARGS)
{
#ifndef INT64_IS_BUSTED
VarBit *arg = PG_GETARG_VARBIT_P(0);
uint64 result;
bits8 *r;
/* Check that the bit string is not too long */
if (VARBITLEN(arg) > sizeof(result) * BITS_PER_BYTE)
elog(ERROR, "Bit string is too large to fit in type int64");
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_INT64(result);
#else
elog(ERROR, "INT64 is not supported on this platform");
PG_RETURN_NULL();
#endif
}
/* Determines the position of S2 in the bitstring S1 (1-based string).
* If S2 does not appear in S1 this function returns 0.
* If S2 is of length 0 this function returns 1.
* Compatible in usage with POSITION() functions for other data types.
*/
Datum
bitposition(PG_FUNCTION_ARGS)
{
VarBit *str = PG_GETARG_VARBIT_P(0);
VarBit *substr = PG_GETARG_VARBIT_P(1);
int substr_length, str_length,
i,
is;
bits8 *s, /* pointer into substring */
*p; /* pointer into str */
bits8 cmp, /* shifted substring byte to compare */
mask1, /* mask for substring byte shifted right */
mask2, /* mask for substring byte shifted left */
end_mask, /* pad mask for last substring byte */
str_mask; /* pad mask for last string byte */
bool is_match;
/* Get the substring length */
substr_length = VARBITLEN(substr);
str_length = VARBITLEN(str);
/* String has zero length or substring longer than string, return 0 */
if ((str_length == 0) || (substr_length > str_length))
PG_RETURN_INT32(0);
/* zero-length substring means return 1 */
if (substr_length == 0)
PG_RETURN_INT32(1);
/* Initialise the padding masks */
end_mask = BITMASK << VARBITPAD(substr);
str_mask = BITMASK << VARBITPAD(str);
for (i = 0; i < VARBITBYTES(str) - VARBITBYTES(substr) + 1; i++)
{
for (is = 0; is < BITS_PER_BYTE; is++)
{
is_match = true;
p = VARBITS(str) + i;
mask1 = BITMASK >> is;
mask2 = ~mask1;
for (s = VARBITS(substr);
is_match && s < VARBITEND(substr); s++)
{
cmp = *s >> is;
if (s == VARBITEND(substr) - 1)
{
mask1 &= end_mask >> is;
if (p == VARBITEND(str) - 1)
{
/* Check that there is enough of str left */
if (mask1 & ~str_mask)
{
is_match = false;
break;
}
mask1 &= str_mask;
}
}
is_match = ((cmp ^ *p) & mask1) == 0;
if (!is_match)
break;
/* Move on to the next byte */
p++;
if (p == VARBITEND(str))
{
mask2 = end_mask << (BITS_PER_BYTE - is);
is_match = mask2 == 0;
#if 0
elog(DEBUG4, "S. %d %d em=%2x sm=%2x r=%d",
i, is, end_mask, mask2, is_match);
#endif
break;
}
cmp = *s << (BITS_PER_BYTE - is);
if (s == VARBITEND(substr) - 1) {
mask2 &= end_mask << (BITS_PER_BYTE - is);
if (p == VARBITEND(str) - 1)
{
if (mask2 & ~str_mask)
{
is_match = false;
break;
}
mask2 &= str_mask;
}
}
is_match = ((cmp ^ *p) & mask2) == 0;
}
/* Have we found a match? */
if (is_match)
PG_RETURN_INT32(i * BITS_PER_BYTE + is + 1);
}
}
PG_RETURN_INT32(0);
}