SqlString.cpp File Reference

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Functions
FENNEL_BEGIN_NAMESPACE int	SqlStrCat (char *dest, int destStorageBytes, int destLenBytes, char const *const str, int strLenBytes)
	Strcat.
int	SqlStrCat (char *dest, int destStorageBytes, char const *const str1, int str1LenBytes, char const *const str2, int str2LenBytes)
	StrCat.
int	SqlStrCmp_Bin (char const *const str1, int str1LenBytes, char const *const str2, int str2LenBytes)
	StrCmp.
int	SqlStrCpy_Var (char *dest, int destStorageBytes, char const *const str, int strLenBytes)
	StrCpy.
int	SqlStrLenBit (int strLenBytes)
	StrLen in bits.
int	SqlStrLenOct (int strLenBytes)
	StrLen in octets.

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Function Documentation

int SqlStrCat	(	char *	dest,
		int	destStorageBytes,
		char const *const	str1,
		int	str1LenBytes,
		char const *const	str2,
		int	str2LenBytes
	)

StrCat.

SQL VARCHAR & CHAR. Ascii & UCS2. dest = str1 || str2. Returns new length in bytes.

This is an optimization for creating a concatenated string from two other strings, eliminating a separate string copy. The assumption is that this is the common case with concatenation. Subsequent concatenations may occur with other form.

If either string is variable width, the result is variable width: per SQL99 Part 2 Section 6.27 Syntax Rule 3.a.i. If both strings are fixed width, the result is fixed width, item ii.

Note: CHAR('1 ') || CHAR('2 ') is CHAR('1 2 ') and is not CHAR('12 ').

When used with CHARs, ignore the return value, and set destLenBytes = destStorageBytes

Definition at line 51 of file SqlString.cpp.

{
    if (str1LenBytes + str2LenBytes > destStorageBytes) {
        // SQL99 Part 2 Section 22.1 22-001
        // "String Data Right truncation"
        throw "22001";
    }

    memcpy(dest, str1, str1LenBytes);
    memcpy(dest + str1LenBytes, str2, str2LenBytes);
    return str1LenBytes + str2LenBytes;
}

FENNEL_BEGIN_NAMESPACE int SqlStrCat	(	char *	dest,
		int	destStorageBytes,
		int	destLenBytes,
		char const *const	str,
		int	strLenBytes
	)

Strcat.

SQL VARCHAR & CHAR. Ascii & UCS2. dest = dest || str. Returns new length in bytes.

If either string is variable width, the result is variable width: per SQL99 Part 2 Section 6.27 Syntax Rule 3.a.i. If both strings are fixed width, the result is fixed width, per item ii.

Note that CHAR('1 ') || CHAR('2 ') = CHAR('1 2 ') and not CHAR('12 ').

When called repeatedly to cat multiple strings together (e.g. A || B || C), the final destLength must be exactly equal to the defined resulting width. (e.g. width of A+B+C) for both VARCHAR & CHAR. Take care that these length semantics are adhered to in the final result, even though intermediate results (say A || B) may not have the correct length.

When used with CHARs, set strLenBytes to strStorageBytes. On intermediate results set destLenBytes = return value of previous call. Final result should/must have return value == destStorage.

Definition at line 33 of file SqlString.cpp.

Referenced by strCatA2(), strCatA3(), SqlStringTest::testSqlStringCat_Fix(), SqlStringTest::testSqlStringCat_Var(), and SqlStringTest::testSqlStringCat_Var2().

{
    if (destLenBytes + strLenBytes > destStorageBytes) {
        // SQL99 Part 2 Section 22.1 22-001 "String Data Right truncation"
        throw "22001";
    }

    memcpy(dest + destLenBytes, str, strLenBytes);
    return destLenBytes + strLenBytes;
}

int SqlStrCmp_Bin	(	char const *const	str1,
		int	str1LenBytes,
		char const *const	str2,
		int	str2LenBytes
	)

StrCmp.

Binary. See SQL2003 Part 2 Section 4.3.2. As an extension to SQL2003, allow inequalities (>,>=, etc.) Follows byte-wise comparison semantics of memcmp().

Returns -1, 0, 1.

Definition at line 71 of file SqlString.cpp.

Referenced by SqlStrCmp(), strCmpOct(), and SqlStringTest::testSqlStringCmp_Bin_Helper().

{
    // First, check for differences in "common" length. If common length
    // are contains same values, declare the longer string "larger".
    int minLenBytes =
        str1LenBytes > str2LenBytes ? str2LenBytes : str1LenBytes;
    int memc = memcmp(str1, str2, minLenBytes);
    if (memc > 0) {
        // Normalize to -1, 0, 1
        return 1;
    } else if (memc < 0) {
        // Normalize to -1, 0, 1
        return -1;
    } else if (str1LenBytes == str2LenBytes) {
        // memc == 0
        // Equal length & contain same data -> equal
        return 0;
    } else if (str1LenBytes > str2LenBytes) {
        // Common contains same data, str1 is longer -> str1 > str2
        return 1;
    } else {
        // Common contains same data, str2 is longer -> str2 > str1
        return -1;
    }
}

int SqlStrCpy_Var	(	char *	dest,
		int	destStorageBytes,
		char const *const	str,
		int	strLenBytes
	)

StrCpy.

String Copy. Variable Width / VARCHAR. Ascii & UCS2. Returns strLenBytes.

This routine may not be compliant with the SQL99 standard.

May be used for Fixed width strings if strLenBytes == destStorageBytes Otherwise use SqlStrCpy_Fix() to get appropriate padding.

Definition at line 102 of file SqlString.cpp.

Referenced by strCpyA(), and SqlStringTest::testSqlStringCpy_Var().

{
    if (strLenBytes > destStorageBytes) {
        // SQL99 Part 2 Section 22.1 22-001
        // "String Data Right truncation"
        throw "22001";
    }
    memcpy(dest, str, strLenBytes);
    return strLenBytes;
}

int SqlStrLenBit

(

int

strLenBytes

)

StrLen in bits.

CHAR/VARCHAR. Ascii & UCS2.

Parameter str is ignored for ascii strings.

Definition at line 118 of file SqlString.cpp.

Referenced by strLenBitA(), and SqlStringTest::testSqlStringLenBit().

{
    return 8 * strLenBytes;
}

int SqlStrLenOct

(

int

strLenBytes

)

StrLen in octets.

CHAR/VARCHAR. Ascii & UCS2.

Parameter str is ignored for ascii strings.

Definition at line 124 of file SqlString.cpp.

Referenced by strLenOctA(), and SqlStringTest::testSqlStringLenOct().

{
    return strLenBytes;
}

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