scmdiff.cpp@ 106061

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1	/* $Id: scmdiff.cpp 106061 2024-09-16 14:03:52Z vboxsync $ */
2	/** @file
3	* IPRT Testcase / Tool - Source Code Massager.
4	*/
5
6	/*
7	* Copyright (C) 2010-2024 Oracle and/or its affiliates.
8	*
9	* This file is part of VirtualBox base platform packages, as
10	* available from https://www.virtualbox.org.
11	*
12	* This program is free software; you can redistribute it and/or
13	* modify it under the terms of the GNU General Public License
14	* as published by the Free Software Foundation, in version 3 of the
15	* License.
16	*
17	* This program is distributed in the hope that it will be useful, but
18	* WITHOUT ANY WARRANTY; without even the implied warranty of
19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20	* General Public License for more details.
21	*
22	* You should have received a copy of the GNU General Public License
23	* along with this program; if not, see <https://www.gnu.org/licenses>.
24	*
25	* SPDX-License-Identifier: GPL-3.0-only
26	*/
27
28
29	/*********************************************************************************************************************************
30	* Header Files *
31	*********************************************************************************************************************************/
32	#include <iprt/assert.h>
33	#include <iprt/ctype.h>
34	#include <iprt/message.h>
35	#include <iprt/stream.h>
36	#include <iprt/string.h>
37
38	#include "scmdiff.h"
39
40
41	/*********************************************************************************************************************************
42	* Global Variables *
43	*********************************************************************************************************************************/
44	static const char g_szTabSpaces[16+1] = " ";
45
46
47
48	/**
49	* Prints a range of lines with a prefix.
50	*
51	* @param pState The diff state.
52	* @param chPrefix The prefix.
53	* @param pStream The stream to get the lines from.
54	* @param iLine The first line.
55	* @param cLines The number of lines.
56	*/
57	static void scmDiffPrintLines(PSCMDIFFSTATE pState, char chPrefix, PSCMSTREAM pStream, size_t iLine, size_t cLines)
58	{
59	while (cLines-- > 0)
60	{
61	SCMEOL enmEol;
62	size_t cchLine;
63	const char *pchLine = ScmStreamGetLineByNo(pStream, iLine, &cchLine, &enmEol);
64
65	RTStrmPutCh(pState->pDiff, chPrefix);
66	if (pchLine && cchLine)
67	{
68	if (!pState->fSpecialChars)
69	RTStrmWrite(pState->pDiff, pchLine, cchLine);
70	else
71	{
72	size_t offVir = 0;
73	const char *pchStart = pchLine;
74	const char pchTab = (const char )memchr(pchLine, '\t', cchLine);
75	while (pchTab)
76	{
77	RTStrmWrite(pState->pDiff, pchStart, pchTab - pchStart);
78	offVir += pchTab - pchStart;
79
80	size_t cchTab = pState->cchTab - offVir % pState->cchTab;
81	switch (cchTab)
82	{
83	case 1: RTStrmPutStr(pState->pDiff, "."); break;
84	case 2: RTStrmPutStr(pState->pDiff, ".."); break;
85	case 3: RTStrmPutStr(pState->pDiff, "[T]"); break;
86	case 4: RTStrmPutStr(pState->pDiff, "[TA]"); break;
87	case 5: RTStrmPutStr(pState->pDiff, "[TAB]"); break;
88	default: RTStrmPrintf(pState->pDiff, "[TAB%.*s]", cchTab - 5, g_szTabSpaces); break;
89	}
90	offVir += cchTab;
91
92	/* next */
93	pchStart = pchTab + 1;
94	pchTab = (const char *)memchr(pchStart, '\t', cchLine - (pchStart - pchLine));
95	}
96	size_t cchLeft = cchLine - (pchStart - pchLine);
97	if (cchLeft)
98	RTStrmWrite(pState->pDiff, pchStart, cchLeft);
99	}
100	}
101
102	if (!pState->fSpecialChars)
103	RTStrmPutCh(pState->pDiff, '\n');
104	else if (enmEol == SCMEOL_LF)
105	RTStrmPutStr(pState->pDiff, "[LF]\n");
106	else if (enmEol == SCMEOL_CRLF)
107	RTStrmPutStr(pState->pDiff, "[CRLF]\n");
108	else
109	RTStrmPutStr(pState->pDiff, "[NONE]\n");
110
111	iLine++;
112	}
113	}
114
115
116	/**
117	* Reports a difference and propels the streams to the lines following the
118	* resync.
119	*
120	*
121	* @returns New pState->cDiff value (just to return something).
122	* @param pState The diff state. The cDiffs member will be
123	* incremented.
124	* @param cMatches The resync length.
125	* @param iLeft Where the difference starts on the left side.
126	* @param cLeft How long it is on this side. ~(size_t)0 is used
127	* to indicate that it goes all the way to the end.
128	* @param iRight Where the difference starts on the right side.
129	* @param cRight How long it is.
130	*/
131	static size_t scmDiffReport(PSCMDIFFSTATE pState, size_t cMatches,
132	size_t iLeft, size_t cLeft,
133	size_t iRight, size_t cRight)
134	{
135	/*
136	* Adjust the input.
137	*/
138	if (cLeft == ~(size_t)0)
139	{
140	size_t c = ScmStreamCountLines(pState->pLeft);
141	if (c >= iLeft)
142	cLeft = c - iLeft;
143	else
144	{
145	iLeft = c;
146	cLeft = 0;
147	}
148	}
149
150	if (cRight == ~(size_t)0)
151	{
152	size_t c = ScmStreamCountLines(pState->pRight);
153	if (c >= iRight)
154	cRight = c - iRight;
155	else
156	{
157	iRight = c;
158	cRight = 0;
159	}
160	}
161
162	/*
163	* Print header if it's the first difference
164	*/
165	if (!pState->cDiffs)
166	RTStrmPrintf(pState->pDiff, "diff %s %s\n", pState->pszFilename, pState->pszFilename);
167
168	/*
169	* Emit the change description.
170	*/
171	char ch = cLeft == 0
172	? 'a'
173	: cRight == 0
174	? 'd'
175	: 'c';
176	if (cLeft > 1 && cRight > 1)
177	RTStrmPrintf(pState->pDiff, "%zu,%zu%c%zu,%zu\n", iLeft + 1, iLeft + cLeft, ch, iRight + 1, iRight + cRight);
178	else if (cLeft > 1)
179	RTStrmPrintf(pState->pDiff, "%zu,%zu%c%zu\n", iLeft + 1, iLeft + cLeft, ch, iRight + 1);
180	else if (cRight > 1)
181	RTStrmPrintf(pState->pDiff, "%zu%c%zu,%zu\n", iLeft + 1, ch, iRight + 1, iRight + cRight);
182	else
183	RTStrmPrintf(pState->pDiff, "%zu%c%zu\n", iLeft + 1, ch, iRight + 1);
184
185	/*
186	* And the lines.
187	*/
188	if (cLeft)
189	scmDiffPrintLines(pState, '<', pState->pLeft, iLeft, cLeft);
190	if (cLeft && cRight)
191	RTStrmPrintf(pState->pDiff, "---\n");
192	if (cRight)
193	scmDiffPrintLines(pState, '>', pState->pRight, iRight, cRight);
194
195	/*
196	* Reposition the streams (safely ignores return value).
197	*/
198	ScmStreamSeekByLine(pState->pLeft, iLeft + cLeft + cMatches);
199	ScmStreamSeekByLine(pState->pRight, iRight + cRight + cMatches);
200
201	pState->cDiffs++;
202	return pState->cDiffs;
203	}
204
205	/**
206	* Helper for scmDiffCompare that takes care of trailing spaces and stuff
207	* like that.
208	*/
209	static bool scmDiffCompareSlow(PSCMDIFFSTATE pState,
210	const char *pchLeft, size_t cchLeft, SCMEOL enmEolLeft,
211	const char *pchRight, size_t cchRight, SCMEOL enmEolRight)
212	{
213	if (pState->fIgnoreTrailingWhite)
214	{
215	while (cchLeft > 0 && RT_C_IS_SPACE(pchLeft[cchLeft - 1]))
216	cchLeft--;
217	while (cchRight > 0 && RT_C_IS_SPACE(pchRight[cchRight - 1]))
218	cchRight--;
219	}
220
221	if (pState->fIgnoreLeadingWhite)
222	{
223	while (cchLeft > 0 && RT_C_IS_SPACE(*pchLeft))
224	pchLeft++, cchLeft--;
225	while (cchRight > 0 && RT_C_IS_SPACE(*pchRight))
226	pchRight++, cchRight--;
227	}
228
229	if ( cchLeft != cchRight
230	\|\| (enmEolLeft != enmEolRight && !pState->fIgnoreEol)
231	\|\| memcmp(pchLeft, pchRight, cchLeft))
232	return false;
233	return true;
234	}
235
236	/**
237	* Compare two lines.
238	*
239	* @returns true if the are equal, false if not.
240	*/
241	DECLINLINE(bool) scmDiffCompare(PSCMDIFFSTATE pState,
242	const char *pchLeft, size_t cchLeft, SCMEOL enmEolLeft,
243	const char *pchRight, size_t cchRight, SCMEOL enmEolRight)
244	{
245	if ( cchLeft != cchRight
246	\|\| (enmEolLeft != enmEolRight && !pState->fIgnoreEol)
247	\|\| memcmp(pchLeft, pchRight, cchLeft))
248	{
249	if ( pState->fIgnoreTrailingWhite
250	\|\| pState->fIgnoreLeadingWhite)
251	return scmDiffCompareSlow(pState,
252	pchLeft, cchLeft, enmEolLeft,
253	pchRight, cchRight, enmEolRight);
254	return false;
255	}
256	return true;
257	}
258
259	/**
260	* Compares two sets of lines from the two files.
261	*
262	* @returns true if they matches, false if they don't.
263	* @param pState The diff state.
264	* @param iLeft Where to start in the left stream.
265	* @param iRight Where to start in the right stream.
266	* @param cLines How many lines to compare.
267	*/
268	static bool scmDiffCompareLines(PSCMDIFFSTATE pState, size_t iLeft, size_t iRight, size_t cLines)
269	{
270	for (size_t iLine = 0; iLine < cLines; iLine++)
271	{
272	SCMEOL enmEolLeft;
273	size_t cchLeft;
274	const char *pchLeft = ScmStreamGetLineByNo(pState->pLeft, iLeft + iLine, &cchLeft, &enmEolLeft);
275
276	SCMEOL enmEolRight;
277	size_t cchRight;
278	const char *pchRight = ScmStreamGetLineByNo(pState->pRight, iRight + iLine, &cchRight, &enmEolRight);
279
280	if (!scmDiffCompare(pState, pchLeft, cchLeft, enmEolLeft, pchRight, cchRight, enmEolRight))
281	return false;
282	}
283	return true;
284	}
285
286
287	/**
288	* Resynchronize the two streams and reports the difference.
289	*
290	* Upon return, the streams will be positioned after the block of @a cMatches
291	* lines where it resynchronized them.
292	*
293	* @returns pState->cDiffs (just so we can use it in a return statement).
294	* @param pState The state.
295	* @param cMatches The number of lines that needs to match for the
296	* stream to be considered synchronized again.
297	*/
298	static size_t scmDiffSynchronize(PSCMDIFFSTATE pState, size_t cMatches)
299	{
300	size_t const iStartLeft = ScmStreamTellLine(pState->pLeft) - 1;
301	size_t const iStartRight = ScmStreamTellLine(pState->pRight) - 1;
302	Assert(cMatches > 0);
303
304	/*
305	* Compare each new line from each of the streams will all the preceding
306	* ones, including iStartLeft/Right.
307	*/
308	for (size_t iRange = 1; ; iRange++)
309	{
310	/*
311	* Get the next line in the left stream and compare it against all the
312	* preceding lines on the right side.
313	*/
314	SCMEOL enmEol;
315	size_t cchLine;
316	const char *pchLine = ScmStreamGetLineByNo(pState->pLeft, iStartLeft + iRange, &cchLine, &enmEol);
317	if (!pchLine)
318	return scmDiffReport(pState, 0, iStartLeft, ~(size_t)0, iStartRight, ~(size_t)0);
319
320	for (size_t iRight = cMatches - 1; iRight < iRange; iRight++)
321	{
322	SCMEOL enmEolRight;
323	size_t cchRight;
324	const char *pchRight = ScmStreamGetLineByNo(pState->pRight, iStartRight + iRight,
325	&cchRight, &enmEolRight);
326	if ( scmDiffCompare(pState, pchLine, cchLine, enmEol, pchRight, cchRight, enmEolRight)
327	&& scmDiffCompareLines(pState,
328	iStartLeft + iRange + 1 - cMatches,
329	iStartRight + iRight + 1 - cMatches,
330	cMatches - 1)
331	)
332	return scmDiffReport(pState, cMatches,
333	iStartLeft, iRange + 1 - cMatches,
334	iStartRight, iRight + 1 - cMatches);
335	}
336
337	/*
338	* Get the next line in the right stream and compare it against all the
339	* lines on the right side.
340	*/
341	pchLine = ScmStreamGetLineByNo(pState->pRight, iStartRight + iRange, &cchLine, &enmEol);
342	if (!pchLine)
343	return scmDiffReport(pState, 0, iStartLeft, ~(size_t)0, iStartRight, ~(size_t)0);
344
345	for (size_t iLeft = cMatches - 1; iLeft <= iRange; iLeft++)
346	{
347	SCMEOL enmEolLeft;
348	size_t cchLeft;
349	const char *pchLeft = ScmStreamGetLineByNo(pState->pLeft, iStartLeft + iLeft,
350	&cchLeft, &enmEolLeft);
351	if ( scmDiffCompare(pState, pchLeft, cchLeft, enmEolLeft, pchLine, cchLine, enmEol)
352	&& scmDiffCompareLines(pState,
353	iStartLeft + iLeft + 1 - cMatches,
354	iStartRight + iRange + 1 - cMatches,
355	cMatches - 1)
356	)
357	return scmDiffReport(pState, cMatches,
358	iStartLeft, iLeft + 1 - cMatches,
359	iStartRight, iRange + 1 - cMatches);
360	}
361	}
362	}
363
364	/**
365	* Creates a diff of the changes between the streams @a pLeft and @a pRight.
366	*
367	* This currently only implements the simplest diff format, so no contexts.
368	*
369	* Also, note that we won't detect differences in the final newline of the
370	* streams.
371	*
372	* @returns The number of differences.
373	* @param pszFilename The filename.
374	* @param pLeft The left side stream.
375	* @param pRight The right side stream.
376	* @param fIgnoreEol Whether to ignore end of line markers.
377	* @param fIgnoreLeadingWhite Set if leading white space should be ignored.
378	* @param fIgnoreTrailingWhite Set if trailing white space should be ignored.
379	* @param fSpecialChars Whether to print special chars in a human
380	* readable form or not.
381	* @param cchTab The tab size.
382	* @param pDiff Where to write the diff.
383	*/
384	size_t ScmDiffStreams(const char *pszFilename, PSCMSTREAM pLeft, PSCMSTREAM pRight, bool fIgnoreEol,
385	bool fIgnoreLeadingWhite, bool fIgnoreTrailingWhite, bool fSpecialChars,
386	size_t cchTab, PRTSTREAM pDiff)
387	{
388	#ifdef RT_STRICT
389	ScmStreamCheckItegrity(pLeft);
390	ScmStreamCheckItegrity(pRight);
391	#endif
392
393	/*
394	* Set up the diff state.
395	*/
396	SCMDIFFSTATE State;
397	State.cDiffs = 0;
398	State.pszFilename = pszFilename;
399	State.pLeft = pLeft;
400	State.pRight = pRight;
401	State.fIgnoreEol = fIgnoreEol;
402	State.fIgnoreLeadingWhite = fIgnoreLeadingWhite;
403	State.fIgnoreTrailingWhite = fIgnoreTrailingWhite;
404	State.fSpecialChars = fSpecialChars;
405	State.cchTab = cchTab;
406	State.pDiff = pDiff;
407
408	/*
409	* Compare them line by line.
410	*/
411	ScmStreamRewindForReading(pLeft);
412	ScmStreamRewindForReading(pRight);
413	const char *pchLeft;
414	const char *pchRight;
415
416	for (;;)
417	{
418	SCMEOL enmEolLeft;
419	size_t cchLeft;
420	pchLeft = ScmStreamGetLine(pLeft, &cchLeft, &enmEolLeft);
421
422	SCMEOL enmEolRight;
423	size_t cchRight;
424	pchRight = ScmStreamGetLine(pRight, &cchRight, &enmEolRight);
425	if (!pchLeft \|\| !pchRight)
426	break;
427
428	if (!scmDiffCompare(&State, pchLeft, cchLeft, enmEolLeft, pchRight, cchRight, enmEolRight))
429	scmDiffSynchronize(&State, 3);
430	}
431
432	/*
433	* Deal with any remaining differences.
434	*/
435	if (pchLeft)
436	scmDiffReport(&State, 0, ScmStreamTellLine(pLeft) - 1, ~(size_t)0, ScmStreamTellLine(pRight), 0);
437	else if (pchRight)
438	scmDiffReport(&State, 0, ScmStreamTellLine(pLeft), 0, ScmStreamTellLine(pRight) - 1, ~(size_t)0);
439
440	/*
441	* Report any errors.
442	*/
443	if (RT_FAILURE(ScmStreamGetStatus(pLeft)))
444	RTMsgError("Left diff stream error: %Rrc\n", ScmStreamGetStatus(pLeft));
445	if (RT_FAILURE(ScmStreamGetStatus(pRight)))
446	RTMsgError("Right diff stream error: %Rrc\n", ScmStreamGetStatus(pRight));
447
448	return State.cDiffs;
449	}
450

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source: vbox/trunk/src/bldprogs/scmdiff.cpp@ 106061

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