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

/*-------------------------------------------------------------------------
 *
 * varchar.c--
 *	  Functions for the built-in type char() and varchar().
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/varchar.c,v 1.21 1998/01/08 04:19:16 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <stdio.h>				/* for sprintf() */
#include <string.h>
#include "postgres.h"
#include "utils/builtins.h"

/*
 * CHAR() and VARCHAR() types are part of the ANSI SQL standard. CHAR()
 * is for blank-padded string whose length is specified in CREATE TABLE.
 * VARCHAR is for storing string whose length is at most the length specified
 * at CREATE TABLE time.
 *
 * It's hard to implement these types because we cannot figure out what
 * the length of the type from the type itself. I change (hopefully all) the
 * fmgr calls that invoke input functions of a data type to supply the
 * length also. (eg. in INSERTs, we have the tupleDescriptor which contains
 * the length of the attributes and hence the exact length of the char() or
 * varchar(). We pass this to bpcharin() or varcharin().) In the case where
 * we cannot determine the length, we pass in -1 instead and the input string
 * must be null-terminated.
 *
 * We actually implement this as a varlena so that we don't have to pass in
 * the length for the comparison functions. (The difference between "text"
 * is that we truncate and possibly blank-pad the string at insertion time.)
 *
 *															  - ay 6/95
 */


/*****************************************************************************
 *	 bpchar - char()														 *
 *****************************************************************************/

/*
 * bpcharin -
 *	  converts a string of char() type to the internal representation.
 *	  len is the length specified in () plus VARHDRSZ bytes. (XXX dummy is here
 *	  because we pass typelem as the second argument for array_in.)
 */
char *
bpcharin(char *s, int dummy, int typlen)
{
	char	   *result,
			   *r;
	int			len;
	int			i;

	if (s == NULL)
		return ((char *) NULL);

	if (typlen == -1)
	{

		/*
		 * this is here because some functions can't supply the typlen
		 */
		len = strlen(s);
		typlen = len + VARHDRSZ;
	}
	else
		len = typlen - VARHDRSZ;

	if (len > 4096)
		elog(ERROR, "bpcharin: length of char() must be less than 4096");

	result = (char *) palloc(typlen);
	VARSIZE(result) = typlen;
	r = VARDATA(result);
	for (i = 0; i < len; i++, r++, s++)
	{
		*r = *s;
		if (*r == '\0')
			break;
	}
	/* blank pad the string if necessary */
	for (; i < len; i++)
	{
		*r++ = ' ';
	}
	return (result);
}

char *
bpcharout(char *s)
{
	char	   *result;
	int			len;

	if (s == NULL)
	{
		result = (char *) palloc(2);
		result[0] = '-';
		result[1] = '\0';
	}
	else
	{
		len = VARSIZE(s) - VARHDRSZ;
		result = (char *) palloc(len + 1);
		StrNCpy(result, VARDATA(s), len+1);	/* these are blank-padded */
	}
	return (result);
}

/*****************************************************************************
 *	 varchar - varchar()													 *
 *****************************************************************************/

/*
 * vcharin -
 *	  converts a string of varchar() type to the internal representation.
 *	  len is the length specified in () plus VARHDRSZ bytes. (XXX dummy is here
 *	  because we pass typelem as the second argument for array_in.)
 */
char *
varcharin(char *s, int dummy, int typlen)
{
	char	   *result;
	int			len;

	if (s == NULL)
		return ((char *) NULL);

	if (typlen == -1)	/* we will remove this soon to make compact storage */
						/* change varcharlen at the same time to use VARSIZE */
		len = strlen(s) + VARHDRSZ;
/*	if (typlen != -1 && len > typlen) */
	else
		len = typlen;	/* clip the string at max length */

	if (len > 4096)
		elog(ERROR, "varcharin: length of char() must be less than 4096");

	result = (char *) palloc(len);
	VARSIZE(result) = len;
	strncpy(VARDATA(result), s, len - VARHDRSZ);

	return (result);
}

char *
varcharout(char *s)
{
	char	   *result;
	int			len;

	if (s == NULL)
	{
		result = (char *) palloc(2);
		result[0] = '-';
		result[1] = '\0';
	}
	else
	{
		len = VARSIZE(s) - VARHDRSZ;
		result = (char *) palloc(len + 1);
		StrNCpy(result, VARDATA(s), len+1);
	}
	return (result);
}

/*****************************************************************************
 *	Comparison Functions used for bpchar
 *****************************************************************************/

static int
bcTruelen(char *arg)
{
	char	   *s = VARDATA(arg);
	int			i;
	int			len;

	len = VARSIZE(arg) - VARHDRSZ;
	for (i = len - 1; i >= 0; i--)
	{
		if (s[i] != ' ')
			break;
	}
	return (i + 1);
}

int32
bpcharlen(char *arg)
{
	if (!PointerIsValid(arg))
		elog(ERROR, "Bad (null) char() external representation", NULL);

	return(bcTruelen(arg));
}

bool
bpchareq(char *arg1, char *arg2)
{
	int			len1,
				len2;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	if (len1 != len2)
		return 0;

	return (strncmp(VARDATA(arg1), VARDATA(arg2), len1) == 0);
}

bool
bpcharne(char *arg1, char *arg2)
{
	int			len1,
				len2;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	if (len1 != len2)
		return 1;

	return (strncmp(VARDATA(arg1), VARDATA(arg2), len1) != 0);
}

bool
bpcharlt(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (cmp == 0)
		return (len1 < len2);
	else
		return (cmp < 0);
}

bool
bpcharle(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (0 == cmp)
		return (bool) (len1 <= len2 ? 1 : 0);
	else
		return (bool) (cmp <= 0);
}

bool
bpchargt(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (cmp == 0)
		return (len1 > len2);
	else
		return (cmp > 0);
}

bool
bpcharge(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (0 == cmp)
		return (bool) (len1 >= len2 ? 1 : 0);
	else
		return (bool) (cmp >= 0);
}

int32
bpcharcmp(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	len1 = bcTruelen(arg1);
	len2 = bcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if ((0 == cmp) && (len1 != len2))
		return (int32) (len1 < len2 ? -1 : 1);
	else
		return cmp;
}

/*****************************************************************************
 *	Comparison Functions used for varchar
 *****************************************************************************/

static int
vcTruelen(char *arg)
{
	char	   *s = VARDATA(arg);
	int			i;
	int			len;

	len = VARSIZE(arg) - VARHDRSZ;
	for (i = 0; i < len; i++)
	{
		if (*s++ == '\0')
			break;
	}
	return i;
}

int32
varcharlen(char *arg)
{
	if (!PointerIsValid(arg))
		elog(ERROR, "Bad (null) varchar() external representation", NULL);

	return(vcTruelen(arg));
}

bool
varchareq(char *arg1, char *arg2)
{
	int			len1,
				len2;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);

	if (len1 != len2)
		return 0;

	return (strncmp(VARDATA(arg1), VARDATA(arg2), len1) == 0);
}

bool
varcharne(char *arg1, char *arg2)
{
	int			len1,
				len2;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);

	if (len1 != len2)
		return 1;

	return (strncmp(VARDATA(arg1), VARDATA(arg2), len1) != 0);
}

bool
varcharlt(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (cmp == 0)
		return (len1 < len2);
	else
		return (cmp < 0);
}

bool
varcharle(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (0 == cmp)
		return (bool) (len1 <= len2 ? 1 : 0);
	else
		return (bool) (cmp <= 0);
}

bool
varchargt(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (cmp == 0)
		return (len1 > len2);
	else
		return (cmp > 0);
}

bool
varcharge(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) 0);
	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);

	cmp = strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2));
	if (0 == cmp)
		return (bool) (len1 >= len2 ? 1 : 0);
	else
		return (bool) (cmp >= 0);

}

int32
varcharcmp(char *arg1, char *arg2)
{
	int			len1,
				len2;
	int			cmp;

	len1 = vcTruelen(arg1);
	len2 = vcTruelen(arg2);
	cmp = (strncmp(VARDATA(arg1), VARDATA(arg2), Min(len1, len2)));
	if ((0 == cmp) && (len1 != len2))
		return (int32) (len1 < len2 ? -1 : 1);
	else
		return (int32) (cmp);
}

/*****************************************************************************
 * Hash functions (modified from hashtext in access/hash/hashfunc.c)
 *****************************************************************************/

uint32
hashbpchar(struct varlena * key)
{
	int			keylen;
	char	   *keydata;
	uint32		n;
	int			loop;

	keydata = VARDATA(key);
	keylen = bcTruelen((char *) key);

#define HASHC	n = *keydata++ + 65599 * n

	n = 0;
	if (keylen > 0)
	{
		loop = (keylen + 8 - 1) >> 3;

		switch (keylen & (8 - 1))
		{
			case 0:
				do
				{				/* All fall throughs */
					HASHC;
			case 7:
					HASHC;
			case 6:
					HASHC;
			case 5:
					HASHC;
			case 4:
					HASHC;
			case 3:
					HASHC;
			case 2:
					HASHC;
			case 1:
					HASHC;
				} while (--loop);
		}
	}
	return (n);
}

uint32
hashvarchar(struct varlena * key)
{
	int			keylen;
	char	   *keydata;
	uint32		n;
	int			loop;

	keydata = VARDATA(key);
	keylen = vcTruelen((char *) key);

#define HASHC	n = *keydata++ + 65599 * n

	n = 0;
	if (keylen > 0)
	{
		loop = (keylen + 8 - 1) >> 3;

		switch (keylen & (8 - 1))
		{
			case 0:
				do
				{				/* All fall throughs */
					HASHC;
			case 7:
					HASHC;
			case 6:
					HASHC;
			case 5:
					HASHC;
			case 4:
					HASHC;
			case 3:
					HASHC;
			case 2:
					HASHC;
			case 1:
					HASHC;
				} while (--loop);
		}
	}
	return (n);
}