atotime.cpp

linux下的一款播放器

/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: atotime.cpp,v 1.1.2.1 2004/07/09 01:50:20 hubbe Exp $
 * 
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/////////////////////////////////////////////////////////////////////////////
//
//  ATOTIME.CPP
//
//
//  This file contains the functions that are used in RealText rendering to
//	convert a string of characters into a time value, in milliseconds.
//
//  (1) BOOL convertTimeStringToULONG32(
//		_CHAR* pTimeBuf,
//		ULONG32 timeBufLen, 
//		ULONG32& timeValInMillisec);
//	Converts a string, like "0:00:02.341", into a ULONG32 "time" value,
//  	in milliseconds, and returns FALSE, with timeValInMillisec
//	undefined if pTimeBuf is not in the correct time format which is:
//	"[[[[[[d:]h]h:]m]m:]s]s[.a[b[c]]]" where d is any number of days
//	up to 49 days (which is the max that 32 bits can hold, in msec),
//	hh is the number of hours (a two-digit # if following a ':'),
//	mm is the number of minutes (a two-digit # if following a ':'),
//	ss is the number of seconds (a two-digit # if following a ':'),
//	(noting that the lowest digit of seconds must exist in the
//	string and can stand alone as a time value), and
//	a, b, and c are tenths of seconds, hundredths of seconds, and
//	thousandths of seconds, respectively.
//	timeBufLen is equivalent to strlen(pTimeBuffer), i.e.,
//	it does not take into account the terminating '\0' char.
//
//	Returned is FALSE with timeValInMillisec undefined if error in
//	expected format is found.  Also, the pTimeBuf's contents can be
//	changed by this function (with '\0's where '.' and ':'s used to
//	be, but length of pTimeBuf is guaranteed to stay the same.
//
//  (2) BOOL IsTimeAMoreRecentThanTimeB(
//		ULONG32 ulTimeA, ULONG32 ulTimeB,
//		BOOL bIsLiveSource=TRUE,
//		ULONG32* pULTimeDiff=NULL /* OUT */,
//		ULONG32 ulAcceptableMaxTimeDiff=
//			    MAX_ALLOWED_TIME_DIFFERENCE_IN_MSEC)
//	If bIsLiveSource is FALSE (defaultable to TRUE), this simply
//	returns (A>B), else it's live & ULONG32 wrap-around can occur so...
//	this function tells whether or not time A is later (more recent)
//	than time B even with ULONG32 wrap-around, e.g., if A is 1234
//	and B is 4000001234, then we can guess that A is actually more
//	recent than B because A<B and B-A>ulAcceptableMaxTimeDiff,
//	so it looks like the clock wrapped around after B and before A.
//	Conversely, if A>B and A-B>ulAcceptableMaxTimeDiff, then it looks
//	like the clock wrapped around after A and before B, so A is NOT
//	more recent.  Returned is a BOOL that contains the answer.
//	NOTE: there is a concept of "infinity", defined as
//	TIME_INFINITY (which is 0xfffffffe), and there is a concept
//	of invalid time, defined as TIME_INVALID (0xffffffff).  The following
//	chart shows how these values are handled:
//	    A is:		B is:		return value will be:
//	    -----		-----		---------------------
//	    Infinity		Infinity	FALSE
//	    Infinity		Invalid		FALSE
//	    Infinity		< 0xfffffffe	TRUE
//	    Invalid		Infinity	TRUE
//	    Invalid		Invalid		FALSE
//	    Invalid		< 0xfffffffe	TRUE
//	    < 0xfffffffe	Infinity	FALSE
//	    < 0xfffffffe	Invalid		FALSE
//	    < 0xfffffffe	< 0xfffffffe	depends; see above algorithm
//
//	If pULTimeDiff is sent in as NULL, it remains NULL, otherwise it will
//	exit this function containing A minus B, regardless of which is
//	greater or more recent, noting that A & B are ULONG32s so the result
//	is always the equivalent of adding 0x100000000 to A and then
//	subtracting B and then truncating it by removing that 33rd bit, if
//	still 1:
//
//  (3) BOOL IsTimeASameOrMoreRecentThanTimeB(
//		ULONG32 ulTimeA, ULONG32 ulTimeB,
//		BOOL bIsLiveSource=TRUE,
//		ULONG32* pULTimeDiff=NULL /* OUT */,
//		ULONG32 ulAcceptableMaxTimeDiff=
//			    MAX_ALLOWED_TIME_DIFFERENCE_IN_MSEC)
//	This function first checks if time A is == to time B, and, if not
//	returns the return value from a call to (2), above.
//
//


#include "hxtypes.h"
#include "hxassert.h"
#include "rt_types.h" //for _CHAR

#include <stdlib.h>
#include <ctype.h>

#include "atotime.h"

#include "hxheap.h"
#ifdef _DEBUG
#undef HX_THIS_FILE		
static char HX_THIS_FILE[] = __FILE__;
#endif


#define NUM_DECIMAL_DIGITS_OF_SECONDS	3

BOOL convertTimeStringToULONG32(_CHAR* pTimeBuf, ULONG32 timeBufLen, 
	ULONG32& timeValInMillisec)
{
    _CHAR* pTimeBuffer = pTimeBuf;
    ULONG32 timeBufferLen = timeBufLen;

    // /Fixes PR 43536:  get rid of leading white spaces now; logic below
    // counts on no leading spaces:
    if (pTimeBuffer  &&  timeBufferLen)
    {
	while (' ' == *pTimeBuffer  &&  timeBufferLen)
	{
	    pTimeBuffer++;
	    timeBufferLen--;
	}
    }



    _CHAR savedEndChar = '\0';	//for restoring '\"' char at end, if found.

    ULONG32 days_, hours_, minutes_, seconds_, milliseconds_;
    days_ = hours_ = minutes_ = seconds_ = milliseconds_ = 0L;

    LONG32 bufIndx=0L;

    BOOL bDotEncounteredAlready = FALSE;
    LONG32 indexOfDot = -1;
    BOOL endCharWasChanged = FALSE;

    timeValInMillisec=0;

    HX_ASSERT_VALID_PTR(pTimeBuffer);
    HX_ASSERT(MIN_TIMEBUFFERLENGTH >= 1);
    if(!pTimeBuffer  ||  MIN_TIMEBUFFERLENGTH > timeBufferLen)
    {
	return FALSE;
    }

    savedEndChar = pTimeBuffer[timeBufferLen-1];

    //Get rid of start & terminating quotation mark, if they exist:
    if('\"' == pTimeBuffer[0])
    {
	pTimeBuffer++;
	timeBufferLen--;
	//Added this check to kill bug if (pTimeBuffer==")
	// and got shortened to an empty string:
	if(!timeBufferLen)
	{
	    return FALSE;
	}
    }
    if('\"' == pTimeBuffer[timeBufferLen-1])
    {
	pTimeBuffer[timeBufferLen-1] = '\0'; //get rid of end '\"'.
	timeBufferLen--;
	endCharWasChanged = TRUE;
    }
    
    //Work from right to left, searching first for milliseconds and then for
    //	seconds (or seconds only if no '.' found):
    BOOL bColonWasFound = FALSE;
    for(bufIndx=timeBufferLen-1; 0L<=bufIndx; bufIndx--)
    {
	_CHAR ch = toupper(pTimeBuffer[bufIndx]);
	if('0' > ch  ||  '9' < ch)
	{
	    if(' '==ch  ||  '\t'==ch  ||  '\n'==ch  ||  '\r'==ch)
	    {
		//Added everything up to "break;" to
		// handle (valid) strings with leading space(s) like " 39":
		//previous found was seconds_, so translate into ULONG:
		seconds_ = atol(&pTimeBuffer[bufIndx+1L]);
		timeValInMillisec += seconds_*1000; //converts seconds to ms.
		break; //we're done; we found seconds only.
	    }
	    else if('.' == ch)
	    {
		if(bDotEncounteredAlready)
		{
		    //Make sure pTimeBuffer is in original state:
		    if(endCharWasChanged)
		    {
			timeBufferLen++;
			pTimeBuffer[timeBufferLen-1] = savedEndChar;
		    }
		    if(indexOfDot >= 0)
		    {
			pTimeBuffer[indexOfDot] = '.';
		    }
		    //this second '.' is unexpected, so return with
		    //  timeValInMillisec set to whatever was read so far:
		    return FALSE;
		}

		bDotEncounteredAlready = TRUE;
		indexOfDot = bufIndx;
		pTimeBuffer[bufIndx] = '\0'; //end the buffr at the '.' .

		//previously-read #'s are milliseconds, so count them:
		//added "-1" to fix bug if buf ends with ".":
		if(1L > timeBufferLen-bufIndx-1) 
		{
		    milliseconds_ = 0L;
		}
		else
		{
		    //Now, make sure that more than three digits (base 10)
		    //	are not present, e.g., reduce "46371" to "463" since
		    //	we only allow millisecond precision (3 digits past
		    //	the decimal point:
		    _CHAR chTmp = '\0';
		    ULONG32 ulNumDecimalDigitsFound = timeBufferLen-1 - bufIndx;
		    if(NUM_DECIMAL_DIGITS_OF_SECONDS <
			    ulNumDecimalDigitsFound)
		    {
			chTmp = pTimeBuffer[bufIndx+1L];
			pTimeBuffer[bufIndx+NUM_DECIMAL_DIGITS_OF_SECONDS+1]=
				'\0';
		    }
		    milliseconds_ = atol(&pTimeBuffer[bufIndx+1L]);
		    //Added this to fix "y.x" being converted
		    // to y00x instead of yx00 milliseconds:
		    if(ulNumDecimalDigitsFound < NUM_DECIMAL_DIGITS_OF_SECONDS)
		    {
			for(ULONG32 ulDiff=NUM_DECIMAL_DIGITS_OF_SECONDS
				-ulNumDecimalDigitsFound; ulDiff>0; ulDiff--)
			{
			    milliseconds_ *= 10;
			}
		    }

		    if(NUM_DECIMAL_DIGITS_OF_SECONDS <
			    ulNumDecimalDigitsFound)
		    {
			//restore the changed char in the pTimeBuffer:
			pTimeBuffer[
				bufIndx+NUM_DECIMAL_DIGITS_OF_SECONDS+1]=
				chTmp;
		    }
		}
		
		timeValInMillisec = milliseconds_;
	    } //end "else if('.' == ch)".
	    else if(':' == ch)
	    {
		bColonWasFound = TRUE;
		//previous found was seconds_, so translate into ULONG:
		seconds_ = atol(&pTimeBuffer[bufIndx+1L]);
		timeValInMillisec += seconds_*1000; //converts seconds to ms.
		break; //done with "seconds_[.milliseconds_]" part.
	    }
	    else  //unexpected char found, so quit parsing:
	    {
		//Make sure pTimeBuffer is in original state:
		if(endCharWasChanged)
		{
		    timeBufferLen++;
		    pTimeBuffer[timeBufferLen-1] = savedEndChar;
		}