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

/*-------------------------------------------------------------------------
 *
 * varlena.c--
 *	  Functions for the variable-length built-in types.
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/varlena.c,v 1.29 1998/01/07 18:46:54 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <ctype.h>
#include <string.h>

#include "postgres.h"
#include "utils/palloc.h"
#include "utils/builtins.h"		/* where function declarations go */

/*****************************************************************************
 *	 USER I/O ROUTINES														 *
 *****************************************************************************/


#define VAL(CH)			((CH) - '0')
#define DIG(VAL)		((VAL) + '0')

/*
 *		byteain			- converts from printable representation of byte array
 *
 *		Non-printable characters must be passed as '\nnn' (octal) and are
 *		converted to internal form.  '\' must be passed as '\\'.
 *		elog(ERROR, ...) if bad form.
 *
 *		BUGS:
 *				The input is scaned twice.
 *				The error checking of input is minimal.
 */
text *
byteain(char *inputText)
{
	char	   *tp;
	char	   *rp;
	int			byte;
	text	   *result;

	if (inputText == NULL)
		elog(ERROR, "Bad input string for type bytea");

	for (byte = 0, tp = inputText; *tp != '\0'; byte++)
		if (*tp++ == '\\')
		{
			if (*tp == '\\')
				tp++;
			else if (!isdigit(*tp++) ||
					 !isdigit(*tp++) ||
					 !isdigit(*tp++))
				elog(ERROR, "Bad input string for type bytea");
		}
	tp = inputText;
	byte += VARHDRSZ;
	result = (text *) palloc(byte);
	result->vl_len = byte;		/* varlena? */
	rp = result->vl_dat;
	while (*tp != '\0')
		if (*tp != '\\' || *++tp == '\\')
			*rp++ = *tp++;
		else
		{
			byte = VAL(*tp++);
			byte <<= 3;
			byte += VAL(*tp++);
			byte <<= 3;
			*rp++ = byte + VAL(*tp++);
		}
	return (result);
}

/*
 *		byteaout		- converts to printable representation of byte array
 *
 *		Non-printable characters are inserted as '\nnn' (octal) and '\' as
 *		'\\'.
 *
 *		NULL vlena should be an error--returning string with NULL for now.
 */
char *
byteaout(text *vlena)
{
	char	   *result;

	char	   *vp;
	char	   *rp;
	int			val;			/* holds unprintable chars */
	int			i;
	int			len;

	if (vlena == NULL)
	{
		result = (char *) palloc(2);
		result[0] = '-';
		result[1] = '\0';
		return (result);
	}
	vp = vlena->vl_dat;
	len = 1;					/* empty string has 1 char */
	for (i = vlena->vl_len - VARHDRSZ; i != 0; i--, vp++)
		if (*vp == '\\')
			len += 2;
		else if (isascii(*vp) && isprint(*vp))
			len++;
		else
			len += VARHDRSZ;
	rp = result = (char *) palloc(len);
	vp = vlena->vl_dat;
	for (i = vlena->vl_len - VARHDRSZ; i != 0; i--)
		if (*vp == '\\')
		{
			vp++;
			*rp++ = '\\';
			*rp++ = '\\';
		}
		else if (isascii(*vp) && isprint(*vp))
			*rp++ = *vp++;
		else
		{
			val = *vp++;
			*rp = '\\';
			rp += 3;
			*rp-- = DIG(val & 07);
			val >>= 3;
			*rp-- = DIG(val & 07);
			val >>= 3;
			*rp = DIG(val & 03);
			rp += 3;
		}
	*rp = '\0';
	return (result);
}


/*
 *		textin			- converts "..." to internal representation
 */
text *
textin(char *inputText)
{
	text	   *result;
	int			len;

	if (inputText == NULL)
		return (NULL);

	len = strlen(inputText) + VARHDRSZ;
	result = (text *) palloc(len);
	VARSIZE(result) = len;

	memmove(VARDATA(result), inputText, len - VARHDRSZ);
	return (result);
}

/*
 *		textout			- converts internal representation to "..."
 */
char *
textout(text *vlena)
{
	int			len;
	char	   *result;

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


/* ========== PUBLIC ROUTINES ========== */

/*
 * textlen -
 *	  returns the actual length of a text*
 *     (which is less than the VARSIZE of the text*)
 */
int32
textlen(text *t)
{
	if (!PointerIsValid(t))
		elog(ERROR,"Null input to textlen");

	return (VARSIZE(t) - VARHDRSZ);
} /* textlen() */

/*
 * textcat -
 *	  takes two text* and returns a text* that is the concatentation of
 *	  the two.
 *
 * Rewritten by Sapa, sapa@hq.icb.chel.su. 8-Jul-96.
 * Updated by Thomas, Thomas.Lockhart@jpl.nasa.gov 1997-07-10.
 * Allocate space for output in all cases.
 * XXX - thomas 1997-07-10
 * As in previous code, allow concatenation when one string is NULL.
 * Is this OK?
 */
text *
textcat(text *t1, text *t2)
{
	int			len1,
				len2,
				len;
	char	   *ptr;
	text	   *result;

	if (!PointerIsValid(t1) && !PointerIsValid(t2))
		return (NULL);

	len1 = (PointerIsValid(t1) ? (VARSIZE(t1) - VARHDRSZ) : 0);
	if (len1 < 0)
		len1 = 0;
	while (len1 > 0 && VARDATA(t1)[len1 - 1] == '\0')
		len1--;

	len2 = (PointerIsValid(t2) ? (VARSIZE(t2) - VARHDRSZ) : 0);
	if (len2 < 0)
		len2 = 0;
	while (len2 > 0 && VARDATA(t2)[len2 - 1] == '\0')
		len2--;

	result = palloc(len = len1 + len2 + VARHDRSZ);

	/* Fill data field of result string... */
	ptr = VARDATA(result);
	if (PointerIsValid(t1))
		memcpy(ptr, VARDATA(t1), len1);
	if (PointerIsValid(t2))
		memcpy(ptr + len1, VARDATA(t2), len2);

	/* Set size of result string... */
	VARSIZE(result) = len;

	return (result);
} /* textcat() */

/*
 * text_substr()
 * Return a substring starting at the specified position.
 * - thomas 1997-12-31
 *
 * Input:
 *  - string
 *  - starting position (is one-based)
 *  - string length
 *
 * If the starting position is zero or less, then return the entire string.
 * XXX Note that this may not be the right behavior:
 *  if we are calculating the starting position we might want it to start at one.
 * If the length is less than zero, return the remaining string.
 *
 * Note that the arguments operate on octet length,
 *  so not aware of multi-byte character sets.
 */
text *
text_substr(text *string, int32 m, int32 n)
{
	text	   *ret;
	int			len;

	if ((string == (text *) NULL) || (m <= 0))
		return string;

	len = VARSIZE(string) - VARHDRSZ;

	/* m will now become a zero-based starting position */
	if (m >= len)
	{
		m = 0;
		n = 0;
	}
	else
	{
		m--;
		if (((m+n) > len) || (n < 0))
			n = (len-m);
	}

	ret = (text *) palloc(VARHDRSZ + n);
	VARSIZE(ret) = VARHDRSZ + n;

	memcpy(VARDATA(ret), VARDATA(string)+m, n);

	return ret;
} /* text_substr() */

/*
 * textpos -
 *	  Return the position of the specified substring.
 *	  Implements the SQL92 POSITION() function.
 *	  Ref: A Guide To The SQL Standard, Date & Darwen, 1997
 * - thomas 1997-07-27
 */
int32
textpos(text *t1, text *t2)
{
	int			pos;
	int			px,
				p;
	int			len1,
				len2;
	char	   *p1,
			   *p2;

	if (!PointerIsValid(t1) || !PointerIsValid(t2))
		return (0);

	if (VARSIZE(t2) <= 0)
		return (1);

	len1 = (VARSIZE(t1) - VARHDRSZ);
	len2 = (VARSIZE(t2) - VARHDRSZ);
	p1 = VARDATA(t1);
	p2 = VARDATA(t2);
	pos = 0;
	px = (len1 - len2);
	for (p = 0; p <= px; p++)
	{
		if ((*p2 == *p1) && (strncmp(p1, p2, len2) == 0))
		{
			pos = p + 1;
			break;
		};
		p1++;
	};
	return (pos);
} /* textpos() */

/*
 *		texteq			- returns 1 iff arguments are equal
 *		textne			- returns 1 iff arguments are not equal
 */
bool
texteq(text *arg1, text *arg2)
{
	int			len;
	char	   *a1p,
			   *a2p;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) NULL);
	if ((len = arg1->vl_len) != arg2->vl_len)
		return ((bool) 0);
	a1p = arg1->vl_dat;
	a2p = arg2->vl_dat;

	/*
	 * Varlenas are stored as the total size (data + size variable)
	 * followed by the data. Use VARHDRSZ instead of explicit sizeof() -
	 * thomas 1997-07-10
	 */
	len -= VARHDRSZ;
	while (len-- != 0)
		if (*a1p++ != *a2p++)
			return ((bool) 0);
	return ((bool) 1);
} /* texteq() */

bool
textne(text *arg1, text *arg2)
{
	return ((bool) !texteq(arg1, arg2));
}

/* text_lt()
 * Comparison function for text strings.
 * Includes locale support, but must copy strings to temporary memory
 *	to allow null-termination for inputs to strcoll().
 * XXX HACK code for textlen() indicates that there can be embedded nulls
 *	but it appears that most routines (incl. this one) assume not! - tgl 97/04/07
 */
bool
text_lt(text *arg1, text *arg2)
{
	bool		result;

#ifdef USE_LOCALE
	int			cval;

#endif
	int			len;
	unsigned char *a1p,
			   *a2p;

	if (arg1 == NULL || arg2 == NULL)
		return ((bool) FALSE);

	len = (((VARSIZE(arg1) <= VARSIZE(arg2)) ? VARSIZE(arg1) : VARSIZE(arg2)) - VARHDRSZ);

#ifdef USE_LOCALE
	a1p = (unsigned char *) palloc(len + 1);
	a2p = (unsigned char *) palloc(len + 1);

	memcpy(a1p, VARDATA(arg1), len);
	*(a1p + len) = '\0';
	memcpy(a2p, VARDATA(arg2), len);
	*(a2p + len) = '\0';

	cval = strcoll(a1p, a2p);
	result = ((cval < 0) || ((cval == 0) && (VARSIZE(arg1) < VARSIZE(arg2))));

	pfree(a1p);
	pfree(a2p);
#else
	a1p = (unsigned char *) VARDATA(arg1);
	a2p = (unsigned char *) VARDATA(arg2);

	while (len != 0 && *a1p == *a2p)
	{
		a1p++;
		a2p++;
		len--;
	};

	result = (len ? (*a1p < *a2p) : (VARSIZE(arg1) < VARSIZE(arg2)));
#endif

	return (result);
} /* text_lt() */

/* text_le()
 * Comparison function for text strings.
 * Includes locale support, but must copy strings to temporary memory
 *	to allow null-termination for inputs to strcoll().
 * XXX HACK code for textlen() indicates that there can be embedded nulls
 *	but it appears that most routines (incl. this one) assume not! - tgl 97/04/07
 */
bool
text_le(text *arg1, text *arg2)
{
	bool		result;

#ifdef USE_LOCALE
	int			cval;

#endif
	int			len;
	unsigned char *a1p,
			   *a2p;

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

	len = (((VARSIZE(arg1) <= VARSIZE(arg2)) ? VARSIZE(arg1) : VARSIZE(arg2)) - VARHDRSZ);

#ifdef USE_LOCALE
	a1p = (unsigned char *) palloc(len + 1);
	a2p = (unsigned char *) palloc(len + 1);

	memcpy(a1p, VARDATA(arg1), len);
	*(a1p + len) = '\0';
	memcpy(a2p, VARDATA(arg2), len);
	*(a2p + len) = '\0';

	cval = strcoll(a1p, a2p);
	result = ((cval < 0) || ((cval == 0) && (VARSIZE(arg1) <= VARSIZE(arg2))));

	pfree(a1p);
	pfree(a2p);
#else
	a1p = (unsigned char *) VARDATA(arg1);
	a2p = (unsigned char *) VARDATA(arg2);

	while (len != 0 && *a1p == *a2p)
	{
		a1p++;
		a2p++;
		len--;
	};

	result = (len ? (*a1p <= *a2p) : (VARSIZE(arg1) <= VARSIZE(arg2)));
#endif

	return (result);
} /* text_le() */

bool
text_gt(text *arg1, text *arg2)
{
	return ((bool) !text_le(arg1, arg2));
}

bool
text_ge(text *arg1, text *arg2)
{
	return ((bool) !text_lt(arg1, arg2));
}

/*-------------------------------------------------------------
 * byteaGetSize
 *
 * get the number of bytes contained in an instance of type 'bytea'
 *-------------------------------------------------------------
 */
int32
byteaGetSize(text *v)
{
	int			len;

	len = v->vl_len - sizeof(v->vl_len);

	return (len);
}

/*-------------------------------------------------------------
 * byteaGetByte
 *
 * this routine treats "bytea" as an array of bytes.
 * It returns the Nth byte (a number between 0 and 255) or
 * it dies if the length of this array is less than n.
 *-------------------------------------------------------------
 */
int32
byteaGetByte(text *v, int32 n)
{
	int			len;
	int			byte;

	len = byteaGetSize(v);

	if (n >= len)
	{
		elog(ERROR, "byteaGetByte: index (=%d) out of range [0..%d]",
			 n, len - 1);
	}

	byte = (unsigned char) (v->vl_dat[n]);

	return ((int32) byte);
}

/*-------------------------------------------------------------
 * byteaGetBit
 *
 * This routine treats a "bytea" type like an array of bits.
 * It returns the value of the Nth bit (0 or 1).
 * If 'n' is out of range, it dies!
 *
 *-------------------------------------------------------------
 */
int32
byteaGetBit(text *v, int32 n)
{
	int			byteNo,
				bitNo;
	int			byte;

	byteNo = n / 8;
	bitNo = n % 8;

	byte = byteaGetByte(v, byteNo);

	if (byte & (1 << bitNo))
	{
		return ((int32) 1);
	}
	else
	{
		return ((int32) 0);
	}
}

/*-------------------------------------------------------------
 * byteaSetByte
 *
 * Given an instance of type 'bytea' creates a new one with
 * the Nth byte set to the given value.
 *
 *-------------------------------------------------------------
 */
text *
byteaSetByte(text *v, int32 n, int32 newByte)
{
	int			len;
	text	   *res;

	len = byteaGetSize(v);

	if (n >= len)
	{
		elog(ERROR,
			 "byteaSetByte: index (=%d) out of range [0..%d]",
			 n, len - 1);
	}

	/*
	 * Make a copy of the original varlena.
	 */
	res = (text *) palloc(VARSIZE(v));
	if (res == NULL)
	{
		elog(ERROR, "byteaSetByte: Out of memory (%d bytes requested)",
			 VARSIZE(v));
	}
	memmove((char *) res, (char *) v, VARSIZE(v));

	/*
	 * Now set the byte.
	 */
	res->vl_dat[n] = newByte;

	return (res);
}

/*-------------------------------------------------------------
 * byteaSetBit
 *
 * Given an instance of type 'bytea' creates a new one with
 * the Nth bit set to the given value.
 *
 *-------------------------------------------------------------
 */
text *
byteaSetBit(text *v, int32 n, int32 newBit)
{
	text	   *res;
	int			oldByte,
				newByte;
	int			byteNo,
				bitNo;

	/*
	 * sanity check!
	 */
	if (newBit != 0 && newBit != 1)
	{
		elog(ERROR, "byteaSetByte: new bit must be 0 or 1");
	}

	/*
	 * get the byte where the bit we want is stored.
	 */
	byteNo = n / 8;
	bitNo = n % 8;
	oldByte = byteaGetByte(v, byteNo);

	/*
	 * calculate the new value for that byte
	 */
	if (newBit == 0)
	{
		newByte = oldByte & (~(1 << bitNo));
	}
	else
	{
		newByte = oldByte | (1 << bitNo);
	}

	/*
	 * NOTE: 'byteaSetByte' creates a copy of 'v' & sets the byte.
	 */
	res = byteaSetByte(v, byteNo, newByte);

	return (res);
}