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magicka/deps/odoors/ODUtil.c
2017-03-19 07:49:46 +10:00

462 lines
14 KiB
C

/* OpenDoors Online Software Programming Toolkit
* (C) Copyright 1991 - 1999 by Brian Pirie.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* File: ODUtil.c
*
* Description: Implements the non-platform specific utility functions that
* are defined in odutil.h. Platform specific utility functions
* are implemented in odplat.c.
*
*
* Revisions: Date Ver Who Change
* ---------------------------------------------------------------
* Nov 01, 1994 6.00 BP Created.
* Dec 31, 1994 6.00 BP Added ODMakeFilename().
* Nov 13, 1995 6.00 BP 32-bit portability.
* Nov 23, 1995 6.00 BP Added ODDWordDivide().
* Nov 23, 1995 6.00 BP Added ODDStringHasTail().
* Nov 23, 1995 6.00 BP Added ODFileSize().
* Nov 24, 1995 6.00 BP ODMakeFilename(): handle empty path.
* Feb 19, 1996 6.00 BP Changed version number to 6.00.
* Mar 03, 1996 6.10 BP Begin version 6.10.
* Mar 06, 1996 6.10 BP Added ODDWordMultiply().
* Aug 10, 2003 6.23 SH *nix support
*/
#define BUILDING_OPENDOORS
#include <string.h>
#include <stdio.h>
#include "OpenDoor.h"
#include "ODStr.h"
#include "ODUtil.h"
#include "ODGen.h"
/* ========================================================================= */
/* General string manipulation functions. */
/* ========================================================================= */
/* ----------------------------------------------------------------------------
* ODStringCopy()
*
* Safely copies one string to another. Unlike strncpy(), ODStringCopy()
* ensures that the destination string is always '\0' terminated.
*
* Parameters: pszDest - Pointer to destination string to which to copy
* characters.
*
* pszSource - Pointer to source string from which to copy
* characters.
*
* nSizeOfDest - Maximum number of characters to place in pszDest,
* INCLUDING the '\0' string terminator.
*
* Return: void
*/
void ODStringCopy(char *pszDest, CONST char *pszSource, INT nSizeofDest)
{
ASSERT(pszDest != NULL);
ASSERT(pszSource != NULL);
ASSERT(nSizeofDest > 0);
/* Copy at most the specified number of bytes from source to dest, using */
/* (presumably well optimized) strncpy(). */
strncpy(pszDest, pszSource, nSizeofDest);
/* Ensure that destination string is '\0' terminated. This will not */
/* already be the case if strlen(pszSource) >= nSizeofDest. */
pszDest[nSizeofDest - 1] = '\0';
}
/* ----------------------------------------------------------------------------
* ODStringCToPascal()
*
* Converts a string from C's zero-terminated string format to Pascal's
* length byte + string data format.
*
* Parameters: psPascalString - Pointer to the destination string.
*
* btMaxPascalLength - Size of the destination string, as declared
* in Pascal.
*
* pszCString - Pointer to the source string, in C format.
*
* Return: A pointer to psPascalString.
*/
char *ODStringCToPascal(char *psPascalString, BYTE btMaxPascalLength,
char *pszCString)
{
BYTE btCStringLength = strlen(pszCString);
ASSERT(psPascalString != NULL);
ASSERT(btMaxPascalLength > 0);
ASSERT(pszCString != NULL);
memcpy((char *)psPascalString + 1,
pszCString, *psPascalString = (btCStringLength < btMaxPascalLength)
? btCStringLength : btMaxPascalLength);
return(psPascalString);
}
/* ----------------------------------------------------------------------------
* ODStringPascalToC()
*
* Converts a string from Pascal's length byte + string data format to C's
* zero-terminated string format.
*
* Parameters: pszCString - Pointer to destination string.
*
* psPascalString - Pointer to Pascal format source string.
*
* btMaxLength - Length of C string.
*
* Return: A pointer to pszCString.
*/
char *ODStringPascalToC(char *pszCString, char *psPascalString,
BYTE btMaxLength)
{
ASSERT(pszCString != NULL);
ASSERT(psPascalString != NULL);
ASSERT(btMaxLength > 0);
if(*(BYTE *)psPascalString <= btMaxLength)
{
memcpy(pszCString, (char *)psPascalString + 1, *psPascalString);
pszCString[(int)psPascalString[0]] = '\0';
}
else
{
pszCString[0] = '\0';
}
return(pszCString);
}
/* ----------------------------------------------------------------------------
* ODStringHasTail()
*
* Determines whether a string ends in exactly the specified sequence of
* characters.
*
* Parameters: pszFullString - String to examine.
*
* pszTail - String to look for at the end of
* pszFullString.
*
* Return: TRUE if the pszFullString does end with pszTail, FALSE if
* it does not.
*/
BOOL ODStringHasTail(char *pszFullString, char *pszTail)
{
INT nTailLength = strlen(pszTail);
INT nFullStringLength = strlen(pszFullString);
ASSERT(pszFullString != NULL);
ASSERT(pszTail != NULL);
if(nFullStringLength < nTailLength)
{
return(FALSE);
}
return(stricmp(pszFullString + (nFullStringLength - nTailLength), pszTail) == 0);
}
/* ========================================================================= */
/* File-related functions. */
/* ========================================================================= */
/* ----------------------------------------------------------------------------
* ODMakeFilename()
*
* Generates a fully-qualified filename from a path and base filename.
*
* Parameters: pszOut - String to store generated filename in.
*
* pszPath - Directory name. May be the same as pszOut, or
* may be different.
*
* pszFilename - Base filename.
*
* nMaxOutSize - Size of pszOut. This value should be one more
* than the maximum number of characters to be
* stored in the output string.
*
* Return: kODRCSuccess on success, or an error code on failure.
*/
tODResult ODMakeFilename(char *pszOut, CONST char *pszPath,
CONST char *pszFilename, INT nMaxOutSize)
{
/* Validate parameters in debug mode */
ASSERT(pszPath != NULL);
ASSERT(pszFilename != NULL);
ASSERT(pszOut != NULL);
ASSERT(pszFilename != pszOut);
ASSERT(nMaxOutSize > 0);
/* Check that there is enough room in the destination string to hold */
/* both source strings plus possibly an additional \-seperator. */
if((INT)(strlen(pszPath) + strlen(pszFilename) + 1) > nMaxOutSize - 1)
{
return(kODRCFilenameTooLong);
}
/* Copy path to output filename, if the addresses are different. */
if(pszPath != pszOut)
{
strcpy(pszOut, pszPath);
}
/* Ensure there is a trailing backslash, if path was not empty. */
#ifdef ODPLAT_NIX
#else
if(pszOut[strlen(pszOut) - 1] != DIRSEP && strlen(pszOut) > 0)
{
strcat(pszOut, DIRSEP_STR);
}
#endif
/* Append base filename. */
strcat(pszOut, pszFilename);
return(kODRCSuccess);
}
/* ----------------------------------------------------------------------------
* ODFileSize()
*
* Determines the size of a currently open file.
*
* Parameters: pfFile - Pointer to an already open file to examine.
*
* Return: The size of the file. In the case of a file that is open in
* binary mode, this will be the file length in bytes.
*/
DWORD ODFileSize(FILE *pfFile)
{
DWORD dwOriginal;
DWORD dwFileSize;
ASSERT(pfFile != NULL);
dwOriginal = ftell(pfFile);
fseek(pfFile, 0L, SEEK_END);
dwFileSize = ftell(pfFile);
fseek(pfFile, dwOriginal, SEEK_SET);
return(dwFileSize);
}
/* ========================================================================= */
/* DWORD math functions. */
/* ========================================================================= */
/* ----------------------------------------------------------------------------
* ODDWordShiftLeft()
*
* Shifts a DWORD to the left by the specified number of bits.
*
* Parameters: dwValue - Value to be shifted.
*
* btDistance - Distance to shift dwValue by.
*
* Return: Result of the shift operation.
*/
DWORD ODDWordShiftLeft(DWORD dwValue, BYTE btDistance)
{
WORD wUpper;
WORD wLower;
wLower = (WORD)dwValue;
wUpper = *(WORD *)(((BYTE *)(&dwValue)) + 2);
while(btDistance--)
{
wUpper <<= 1;
wUpper |= (wLower & 0x8000) >> 15;
wLower <<= 1;
}
dwValue = wLower;
*(WORD *)(((BYTE *)(&dwValue)) + 2) = wUpper;
return(dwValue);
}
/* ----------------------------------------------------------------------------
* ODDWordShiftRight()
*
* Shifts a DWORD to the right by the specified number of bits.
*
* Parameters: dwValue - Value to be shifted.
*
* btDistance - Distance to shift dwValue by.
*
* Return: Result of the shift operation.
*/
DWORD ODDWordShiftRight(DWORD dwValue, BYTE btDistance)
{
WORD wUpper;
WORD wLower;
wLower = (WORD)dwValue;
wUpper = *(WORD *)(((BYTE *)(&dwValue)) + 2);
while(btDistance--)
{
wLower >>= 1;
wLower |= (wUpper & 0x0001) << 15;
wUpper >>= 1;
}
dwValue=wLower;
*(WORD *)(((BYTE *)(&dwValue)) + 2) = wUpper;
return(dwValue);
}
/* ----------------------------------------------------------------------------
* ODDWordDivide()
*
* Divides one DWORD by another DWORD, calculating the quotient and remainder.
*
* Parameters: pdwQuotient - Location where the quotient should be stored,
* or NULL if quotient is not required.
*
* pdwRemainder - Location where remainder should be stored,
* or NULL if remainder is not required.
*
* dwDividend - Dividend to be divided by divisor.
*
* dwDivisor - Divisor to divide dividend by.
*
* Return: TRUE on success or FALSE on failure.
*/
BOOL ODDWordDivide(DWORD *pdwQuotient, DWORD *pdwRemainder,
DWORD dwDividend, DWORD dwDivisor)
{
INT nTimes = 0;
DWORD dwQuotient;
DWORD dwRemainder;
/* Check for divide by zero in debug versions. */
ASSERT(dwDivisor != 0);
/* Check that divisor is not zero. (An attempt to divide by zero will */
/* put this algorithm into an infinite loop, rather than triggering */
/* a divide fault.) */
if(dwDivisor == 0L)
{
return(FALSE);
}
/* Initialize remainder to be entire dividend */
dwRemainder = dwDividend;
/* Initialize quotient to 0 */
dwQuotient = 0L;
/* Determine largest required multiple of divisor */
while(dwRemainder >= dwDivisor)
{
dwDivisor = ODDWordShiftLeft(dwDivisor, 1);
++nTimes;
}
/* Loop across for all multiples of divisor, beginning with the largest */
do
{
dwQuotient = ODDWordShiftLeft(dwQuotient, 1);
/* If current remainder is >= this multiple of the divisor */
if(dwRemainder >= dwDivisor)
{
/* Subtract the multiple of the divisor from the remainder */
dwRemainder -= dwDivisor;
/* The next bit of the quotient should be a 1 */
dwQuotient |= 1L;
}
/* Divide current multiple of divisor by two */
dwDivisor = ODDWordShiftRight(dwDivisor, 1);
/* Repeat for all multiples of the divisor */
} while(nTimes--);
/* If caller asked for quotient, then return it */
if(pdwQuotient != NULL)
{
*pdwQuotient = dwQuotient;
}
/* If caller asked for remainder, then return it */
if(pdwRemainder != NULL)
{
*pdwRemainder = dwRemainder;
}
return(TRUE);
}
/* ----------------------------------------------------------------------------
* ODDWordDivide()
*
* Multiplies one DWORD by another, returning the product. Multiplication
* is performed by using at most 32 additions.
*
* Parameters: dwMultiplicand - The multiplicand.
*
* dwMultiplier - The multiplier.
*
* Return: Result of the multiplication.
*/
DWORD ODDWordMultiply(DWORD dwMultiplicand, DWORD dwMultiplier)
{
DWORD dwResult = 0;
/* Loop while multiplier is not zero */
while(dwMultiplier != 0)
{
/* If least significant bit of multiplier is set */
if(dwMultiplier & 0x00000001)
{
/* Add multiplicand to product */
dwResult += dwMultiplicand;
}
/* Shift multiplicand left one bit */
dwMultiplicand = ODDWordShiftLeft(dwMultiplicand, 1);
/* Shift multiplier right one bit */
dwMultiplier = ODDWordShiftRight(dwMultiplier, 1);
}
/* Return the final result to the caller. */
return(dwResult);
}