/**
* Compares two sets of lines from the two files.
*
* @returns true if they matches, false if they don't.
* @param pState The diff state.
* @param iLeft Where to start in the left stream.
* @param iRight Where to start in the right stream.
* @param cLines How many lines to compare.
*/
static bool scmDiffCompareLines(PSCMDIFFSTATE pState, size_t iLeft, size_t iRight, size_t cLines)
{
for (size_t iLine = 0; iLine < cLines; iLine++)
{
SCMEOL enmEolLeft;
size_t cchLeft;
const char *pchLeft = ScmStreamGetLineByNo(pState->pLeft, iLeft + iLine, &cchLeft, &enmEolLeft);
SCMEOL enmEolRight;
size_t cchRight;
const char *pchRight = ScmStreamGetLineByNo(pState->pRight, iRight + iLine, &cchRight, &enmEolRight);
if (!scmDiffCompare(pState, pchLeft, cchLeft, enmEolLeft, pchRight, cchRight, enmEolRight))
return false;
}
return true;
}
/**
* Prints a range of lines with a prefix.
*
* @param pState The diff state.
* @param chPrefix The prefix.
* @param pStream The stream to get the lines from.
* @param iLine The first line.
* @param cLines The number of lines.
*/
static void scmDiffPrintLines(PSCMDIFFSTATE pState, char chPrefix, PSCMSTREAM pStream, size_t iLine, size_t cLines)
{
while (cLines-- > 0)
{
SCMEOL enmEol;
size_t cchLine;
const char *pchLine = ScmStreamGetLineByNo(pStream, iLine, &cchLine, &enmEol);
RTStrmPutCh(pState->pDiff, chPrefix);
if (pchLine && cchLine)
{
if (!pState->fSpecialChars)
RTStrmWrite(pState->pDiff, pchLine, cchLine);
else
{
size_t offVir = 0;
const char *pchStart = pchLine;
const char *pchTab = (const char *)memchr(pchLine, '\t', cchLine);
while (pchTab)
{
RTStrmWrite(pState->pDiff, pchStart, pchTab - pchStart);
offVir += pchTab - pchStart;
size_t cchTab = pState->cchTab - offVir % pState->cchTab;
switch (cchTab)
{
case 1: RTStrmPutStr(pState->pDiff, "."); break;
case 2: RTStrmPutStr(pState->pDiff, ".."); break;
case 3: RTStrmPutStr(pState->pDiff, "[T]"); break;
case 4: RTStrmPutStr(pState->pDiff, "[TA]"); break;
case 5: RTStrmPutStr(pState->pDiff, "[TAB]"); break;
default: RTStrmPrintf(pState->pDiff, "[TAB%.*s]", cchTab - 5, g_szTabSpaces); break;
}
offVir += cchTab;
/* next */
pchStart = pchTab + 1;
pchTab = (const char *)memchr(pchStart, '\t', cchLine - (pchStart - pchLine));
}
size_t cchLeft = cchLine - (pchStart - pchLine);
if (cchLeft)
RTStrmWrite(pState->pDiff, pchStart, cchLeft);
}
}
if (!pState->fSpecialChars)
RTStrmPutCh(pState->pDiff, '\n');
else if (enmEol == SCMEOL_LF)
RTStrmPutStr(pState->pDiff, "[LF]\n");
else if (enmEol == SCMEOL_CRLF)
RTStrmPutStr(pState->pDiff, "[CRLF]\n");
else
RTStrmPutStr(pState->pDiff, "[NONE]\n");
iLine++;
}
}
/**
* Checks if the given line is empty or full of white space.
*
* @returns true if white space only, false if not (or if non-existant).
* @param pStream The stream. Must be in read mode.
* @param iLine The line in question.
*/
bool ScmStreamIsWhiteLine(PSCMSTREAM pStream, size_t iLine)
{
SCMEOL enmEol;
size_t cchLine;
const char *pchLine = ScmStreamGetLineByNo(pStream, iLine, &cchLine, &enmEol);
if (!pchLine)
return false;
while (cchLine && RT_C_IS_SPACE(*pchLine))
pchLine++, cchLine--;
return cchLine == 0;
}
/**
* Get a line from the stream.
*
* A line is always delimited by a LF character or the end of the stream. The
* delimiter is not included in returned line length, but instead returned via
* the @a penmEol indicator.
*
* @returns Pointer to the first character in the line, not NULL terminated.
* NULL if the end of the stream has been reached or some problem
* occurred.
*
* @param pStream The stream. Must be in read mode.
* @param pcchLine The length.
* @param penmEol Where to return the end of line type indicator.
*/
const char *ScmStreamGetLine(PSCMSTREAM pStream, size_t *pcchLine, PSCMEOL penmEol)
{
if (!pStream->fFullyLineated)
return scmStreamGetLineInternal(pStream, pcchLine, penmEol);
size_t offCur = pStream->off;
size_t iCurLine = pStream->iLine;
const char *pszLine = ScmStreamGetLineByNo(pStream, iCurLine, pcchLine, penmEol);
if ( pszLine
&& offCur > pStream->paLines[iCurLine].off)
{
offCur -= pStream->paLines[iCurLine].off;
Assert(offCur <= pStream->paLines[iCurLine].cch + pStream->paLines[iCurLine].enmEol);
if (offCur < pStream->paLines[iCurLine].cch)
*pcchLine -= offCur;
else
*pcchLine = 0;
pszLine += offCur;
}
return pszLine;
}
/**
* Resynchronize the two streams and reports the difference.
*
* Upon return, the streams will be positioned after the block of @a cMatches
* lines where it resynchronized them.
*
* @returns pState->cDiffs (just so we can use it in a return statement).
* @param pState The state.
* @param cMatches The number of lines that needs to match for the
* stream to be considered synchronized again.
*/
static size_t scmDiffSynchronize(PSCMDIFFSTATE pState, size_t cMatches)
{
size_t const iStartLeft = ScmStreamTellLine(pState->pLeft) - 1;
size_t const iStartRight = ScmStreamTellLine(pState->pRight) - 1;
Assert(cMatches > 0);
/*
* Compare each new line from each of the streams will all the preceding
* ones, including iStartLeft/Right.
*/
for (size_t iRange = 1; ; iRange++)
{
/*
* Get the next line in the left stream and compare it against all the
* preceding lines on the right side.
*/
SCMEOL enmEol;
size_t cchLine;
const char *pchLine = ScmStreamGetLineByNo(pState->pLeft, iStartLeft + iRange, &cchLine, &enmEol);
if (!pchLine)
return scmDiffReport(pState, 0, iStartLeft, ~(size_t)0, iStartRight, ~(size_t)0);
for (size_t iRight = cMatches - 1; iRight < iRange; iRight++)
{
SCMEOL enmEolRight;
size_t cchRight;
const char *pchRight = ScmStreamGetLineByNo(pState->pRight, iStartRight + iRight,
&cchRight, &enmEolRight);
if ( scmDiffCompare(pState, pchLine, cchLine, enmEol, pchRight, cchRight, enmEolRight)
&& scmDiffCompareLines(pState,
iStartLeft + iRange + 1 - cMatches,
iStartRight + iRight + 1 - cMatches,
cMatches - 1)
)
return scmDiffReport(pState, cMatches,
iStartLeft, iRange + 1 - cMatches,
iStartRight, iRight + 1 - cMatches);
}
/*
* Get the next line in the right stream and compare it against all the
* lines on the right side.
*/
pchLine = ScmStreamGetLineByNo(pState->pRight, iStartRight + iRange, &cchLine, &enmEol);
if (!pchLine)
return scmDiffReport(pState, 0, iStartLeft, ~(size_t)0, iStartRight, ~(size_t)0);
for (size_t iLeft = cMatches - 1; iLeft <= iRange; iLeft++)
{
SCMEOL enmEolLeft;
size_t cchLeft;
const char *pchLeft = ScmStreamGetLineByNo(pState->pLeft, iStartLeft + iLeft,
&cchLeft, &enmEolLeft);
if ( scmDiffCompare(pState, pchLeft, cchLeft, enmEolLeft, pchLine, cchLine, enmEol)
&& scmDiffCompareLines(pState,
iStartLeft + iLeft + 1 - cMatches,
iStartRight + iRange + 1 - cMatches,
cMatches - 1)
)
return scmDiffReport(pState, cMatches,
iStartLeft, iLeft + 1 - cMatches,
iStartRight, iRange + 1 - cMatches);
}
}
}