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Microsoft Windows NT Build 511 (SDK Final Release) 07-24-1993
/******************************************************************************\
* This is a part of the Microsoft Source Code Samples.
* Copyright (C) 1993 Microsoft Corporation.
* All rights reserved.
* This source code is only intended as a supplement to
* Microsoft Development Tools and/or WinHelp documentation.
* See these sources for detailed information regarding the
* Microsoft samples programs.
\******************************************************************************/
/****************************** Module Header *******************************
* Module Name: COMPITEM.C
*
* Module which does the comparison between two files.
*
* Functions:
*
* ci_copytext()
* ci_makecomposite()
* ci_compare()
* ci_onesection()
* compitem_new()
* compitem_delete()
* compitem_discardsections()
* compitem_getcomposite()
* compitem_getleftsections()
* compitem_getrightsections()
* compitem_getleftfile()
* compitem_getrightfile()
* compitem_getstate()
* compitem_gettext_tag()
* compitem_gettext_result()
* compitem_getfilename()
* compitem_frefilename()
*
* Comments:
*
* This module uses the structure compitem which is a data type that knows
* about two files, and can compare them. The result of the comparison
* is a list of sections for each file, and a composite list of sections
* representing the comparison of the two files.
*
* A compitem has a state (one of the integer values defined in state.h)
* representing the result of the comparison. It can also be
* queried for the text result (text equivalent of the state) as well
* as the tag - or title for this compitem (usually a text string containing
* the name(s) of the files being compared).
*
* A compitem will supply a composite section list even if the files are
* the same, or if there is only one file. The composite section list will
* only be built (and the files read in) when the compitem_getcomposite()
* call is made (and not at compitem_new time).
*
*
****************************************************************************/
#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include "gutils.h"
#include "state.h"
#include "windiff.h"
#include "wdiffrc.h"
#include "list.h"
#include "line.h"
#include "scandir.h"
#include "file.h"
#include "section.h"
#include "compitem.h"
struct compitem {
FILEDATA left; /* handle for left-hand file */
FILEDATA right; /* handle for right-hand file */
LIST secs_composite; /* list of sections (composite file)*/
LIST secs_left; /* list of sections (left file) */
LIST secs_right; /* list of sections (right file) */
int state; /* compitem state - result of compare */
BOOL bDiscard; /* true if not alloc-ed on list */
LPSTR tag; /* text for tag (title of compitem) */
LPSTR result; /* text equivalent of state */
};
LPSTR ci_copytext(LPSTR in);
void ci_makecomposite(COMPITEM ci);
void ci_compare(COMPITEM ci);
/***************************************************************************
* Function: compitem_new
*
* Purpose:
*
* Returns a handle to a new compitem - given the filenames for the
* left and right files to be compared. Either left or right or neither
* (but not both) may be null. In this case we set the state accordingly.
*
* The parameters are handles to DIRITEM objects: these allow us to get the
* the name of the file relative to the compare roots (needed for the tag)
* and the absolute name of the file (needed for opening the file).
*
* Comments:
*
* If the list parameter is not null, the List_New* functions are used to
* allocate memory for the compitem. We remember this (in the bDiscard flag)
* so we do not delete the compitem if it was allocated on the list.
*
* If the list parameter is null, the memory
* for the compitem is allocated from the gmem_* heap initialised by the app.
*
****************************************************************************/
COMPITEM
compitem_new(DIRITEM leftname, DIRITEM rightname, LIST list, BOOL fExact)
{
COMPITEM ci;
LPSTR str1, str2;
char buf[2*MAX_PATH+20];
/*
* Allocate the memory for the compitem, either at the end of the
* list or in the gmem_* heap.
*/
if (list == NULL) {
/* no list passed */
ci = (COMPITEM) gmem_get(hHeap, sizeof(struct compitem));
memset(ci, 0, sizeof(struct compitem));
ci->bDiscard = TRUE;
} else {
/* add to end of list */
ci = (COMPITEM) List_NewLast(list, sizeof(struct compitem));
ci->bDiscard = FALSE;
}
ci->secs_composite = NULL;
ci->secs_left = NULL;
ci->secs_right = NULL;
/*
* Make a filedata for each of the files that are non-null.
* Filedata objects are responsible for reading the file and
* accessing the lines in it. Don't read in the files until we need to.
*/
if (leftname != NULL) {
ci->left = file_new(leftname, FALSE);
if (ci->left == NULL) {
return(NULL);
}
} else {
ci->left = NULL;
}
if ( rightname != NULL) {
ci->right = file_new(rightname, FALSE);
if (ci->right == NULL) {
return(NULL);
}
} else {
ci->right = NULL;
}
/*
* See if we have one or two files, and set the state accordingly
*/
if ( ! ci->left && !ci->right) {
/* two NULL files - this is wrong */
return(NULL);
}
/* Set the tag (title field) for this item. If the
* two files have names that match, we use just that name -
* otherwise we use both names separated by a colon 'left : right'.
*
* In both cases, use the names relative to compare root (the
* names will certainly be different if we compare the abs paths)
*/
str1 = dir_getrelname(leftname);
str2 = dir_getrelname(rightname);
/* If only one file - set name to that */
if (ci->left == NULL) {
ci->tag = ci_copytext(str2);
} else if (ci->right == NULL) {
ci->tag = ci_copytext(str1);
} else {
if (lstrcmpi(str1, str2) == 0) {
ci->tag = ci_copytext(str2);
} else {
wsprintf(buf, "%s : %s", str1, str2);
ci->tag = ci_copytext(buf);
}
}
dir_freerelname(leftname, str1);
dir_freerelname(leftname, str2);
if (ci->left == NULL) {
str1 = dir_getroot_item(rightname);
wsprintf(buf, "only in %s", str1);
dir_freeroot_item(rightname, str1);
ci->result = ci_copytext(buf);
ci->state = STATE_FILERIGHTONLY;
} else if (ci->right == NULL) {
str1 = dir_getroot_item(leftname);
wsprintf(buf, "only in %s", str1);
dir_freeroot_item(leftname, str1);
ci->result = ci_copytext(buf);
ci->state = STATE_FILELEFTONLY;
} else {
/* two files - are they the same ? compare
* the file sizes
*/
if (dir_getfilesize(leftname) != dir_getfilesize(rightname))
{
ci->state = STATE_DIFFER;
ci->result = ci_copytext("different sizes");
} else if (!fExact){
ci->result = ci_copytext("same size");
ci->state = STATE_SAME;
} else {
ci->result = ci_copytext("identical");
ci->state = STATE_SAME;
}
}
#if FALSE
if (dir_getfilesize(leftname) == dir_getfilesize(rightname)) {
if ( !fExact )
{
ci->result = ci_copytext("same size etc.");
ci->state = STATE_SAME;
} else {
ci->result = ci_copytext("files differ");
ci->state = STATE_DIFFER;
ci->result = ci_copytext("files differ");
}
} else {
ci->result = ci_copytext("files differ");
ci->state = STATE_DIFFER;
}
}
#endif
/*
* Building the section lists and composite lists can wait
* until needed.
*/
return(ci);
} /* compitem_new */
/***************************************************************************
* Function: compitem_delete
*
* Purpose:
*
* Deletes a compitem and free all associated data.
*
* Comments:
*
* If the ci->bDiscard flag is set, the compitem was alloc-ed on a list,
* and should not be discarded (the list itself will be deleted).
*
* The DIRDATA we were passed are not deleted. the filedata, lines
* and sections are.
***************************************************************************/
void
compitem_delete(COMPITEM ci)
{
if (ci == NULL) {
return;
}
compitem_discardsections(ci);
/* Delete the two filedatas (and associated line lists) */
file_delete(ci->left);
file_delete(ci->right);
/* text we allocated */
gmem_free(hHeap, ci->tag, lstrlen(ci->tag) + 1);
gmem_free(hHeap, ci->result, lstrlen(ci->result) + 1);
/* Free the compitem struct itself if not alloced on a list */
if (ci->bDiscard) {
gmem_free(hHeap, (LPSTR) ci, sizeof(struct compitem));
}
}
/*
/***************************************************************************
* Function: compitem_discardsections
*
* Purpose:
*
* To discard sections - throw away cached information relating to the
* comparison (but not the files if they are read into memory). This
* is used to force a re-compare if changes in the comparison options
* are made
*
***************************************************************************/
void
compitem_discardsections(COMPITEM ci)
{
/* delete the lists of sections we built */
if (ci == NULL) {
return;
}
if (ci->secs_composite) {
section_deletelist(ci->secs_composite);
ci->secs_composite = NULL;
}
if (ci->secs_left) {
section_deletelist(ci->secs_left);
ci->secs_left = NULL;
}
if (ci->secs_right) {
section_deletelist(ci->secs_right);
ci->secs_right = NULL;
}
/* reset the line lists to throw away cached hash codes and links */
if (ci->left != NULL) {
file_reset(ci->left);
}
if (ci->right != NULL) {
file_reset(ci->right);
}
}
/***************************************************************************
* Function: compitem_getcomposite
*
* Purpose:
*
* To get the handle for the composite section list
*
***************************************************************************/
LIST
compitem_getcomposite(COMPITEM ci)
{
if (ci == NULL) {
return NULL;
}
/*
* do the comparison if we haven't already done it
*/
if (ci->secs_composite == NULL) {
ci_makecomposite(ci);
}
return(ci->secs_composite);
}
/***************************************************************************
* Function: compitem_getleftsections
*
* Purpose:
*
* To get the handle for the list of sections in the left file
*
***************************************************************************/
LIST
compitem_getleftsections(COMPITEM ci)
{
if (ci == NULL) {
return NULL;
}
/*
* do the comparison if we haven't already done it
*/
if (ci->secs_composite == NULL) {
ci_makecomposite(ci);
}
return(ci->secs_left);
}
/***************************************************************************
* Function: compitem_getrightsections
*
* Purpose:
*
* To get the handle for the list of sections in the right file
*
***************************************************************************/
LIST
compitem_getrightsections(COMPITEM ci)
{
if (ci == NULL) {
return NULL;
}
/*
* do the comparison if we haven't already done it
*/
if (ci->secs_composite == NULL) {
ci_makecomposite(ci);
}
return(ci->secs_right);
}
/***************************************************************************
* Function: compitem_getleftfile
*
* Purpose:
*
* To get the handle to the left file itself
*
***************************************************************************/
FILEDATA
compitem_getleftfile(COMPITEM ci)
{
if (ci == NULL) {
return(NULL);
}
return(ci->left);
}
/***************************************************************************
* Function: compitem_getrightfile
*
* Purpose:
*
* To get the handle to the right file itself
*
***************************************************************************/
FILEDATA
compitem_getrightfile(COMPITEM ci)
{
if (ci == NULL) {
return(NULL);
}
return(ci->right);
}
/***************************************************************************
* Function: compitem_getstate
*
* Purpose:
*
* To get the state (compare result) of this compitem
*
***************************************************************************/
int
compitem_getstate(COMPITEM ci)
{
if (ci == NULL) {
return(0);
}
return(ci->state);
}
/***************************************************************************
* Function: compitem_gettext_tag
*
* Purpose:
*
* To get the tag (text for the compitem title)
*
***************************************************************************/
LPSTR
compitem_gettext_tag(COMPITEM ci)
{
if (ci == NULL) {
return(NULL);
}
return(ci->tag);
}
/***************************************************************************
* Function: compitem_gettext_result
*
* Purpose:
*
* To get the result text (text equiv of state)
*
***************************************************************************/
LPSTR
compitem_gettext_result(COMPITEM ci)
{
if (ci == NULL) {
return(NULL);
}
return(ci->result);
}
/***************************************************************************
* Function: compitem_getfilename
*
* Purpose:
*
* To return the name of the file associated with this compitem. The option
* argument (one of CI_LEFT, CI_RIGHT, CI_COMP) indicates which file
* is required.
*
* Comments:
*
* CI_LEFT and CI_RIGHT just result in calls to dir_getopenname to get
* an open-able filename.
*
* For CI_COMP, we create a temporary file, write out all the text in the
* composite section list to this file, and then pass the name of the
* temporary file to the caller. This file will be deleted on
* the call to compitem_freefilename().
*
***************************************************************************/
LPSTR
compitem_getfilename(COMPITEM item, int option)
{
LPSTR fname;
LINE line;
LPSTR tag, text;
SECTION sec;
OFSTRUCT os;
int fh;
if (item == NULL) {
return(NULL);
}
switch(option) {
case CI_LEFT:
if (item->left != NULL) {
return(dir_getopenname(file_getdiritem(item->left)));
} else {
return(NULL);
}
case CI_RIGHT:
if (item->right != NULL) {
return(dir_getopenname(file_getdiritem(item->right)));
} else {
return(NULL);
}
case CI_COMP:
/* caller has asked for the filename of the composite file.
* we need to create a temporary file and write the
* lines in the composite section list out to it.
*/
fname = gmem_get(hHeap, MAX_PATH);
GetTempPath(MAX_PATH, fname);
GetTempFileName(fname, "wdf", 0, fname);
fh = OpenFile(fname, &os, OF_READWRITE|OF_SHARE_DENY_NONE);
if (fh < 0) {
MessageBox(NULL, "Cannot open temp file", "Error", MB_OK | MB_ICONSTOP);
return(NULL);
}
/* make sure the composite list has been built */
if (item->secs_composite == NULL) {
ci_makecomposite(item);
}
/* write out every line in every section on the composite
* list to the temp file.
*/
List_TRAVERSE(item->secs_composite, sec) {
/* get the tag field based on the section state*/
switch(section_getstate(sec)) {
case STATE_SAME:
tag = " ";
break;
case STATE_LEFTONLY:
tag = " <! ";
break;
case STATE_RIGHTONLY:
tag = " !> ";
break;
case STATE_MOVEDLEFT:
tag = " <- ";
break;
case STATE_MOVEDRIGHT:
tag = " -> ";
break;
}
/* write out each line in this section.
* non-standard traverse of list as we only
* want to go from section first to section last
* inclusive.
*/
for (line = section_getfirstline(sec);
line != NULL;
line = List_Next(line) ) {
text = line_gettext(line);
/* write out to file */
_lwrite(fh, tag, lstrlen(tag));
_lwrite(fh, text, lstrlen(text));
if (line == section_getlastline(sec)) {
break;
}
}
}
/* now close the file and return its name */
_lclose(fh);
return(fname);
default:
MessageBox(NULL, "Bad argument", "Error", MB_OK | MB_ICONSTOP);
return(NULL);
}
}
/***************************************************************************
* Function: compitem_freefilename
*
* Purpose:
*
* Free memory created by a call to compitem_getfilename. If a temporary
* file was created, this may cause it to be deleted. The option argument must
* be the same as passed to the original compitem_getfilename call.
*
* If we created a temporary file for CI_COMP, then delete it; otherwise,
* just pass the name to dir_freeopenname.
*
***************************************************************************/
void
compitem_freefilename(COMPITEM item, int option, LPSTR filename)
{
OFSTRUCT os;
if ((item == NULL) || (filename == NULL)) {
return;
}
switch(option) {
case CI_LEFT:
dir_freeopenname(file_getdiritem(item->left), filename);
break;
case CI_RIGHT:
dir_freeopenname(file_getdiritem(item->right), filename);
break;
case CI_COMP:
/* this is a temporary file we created. Delete it. */
OpenFile(filename, &os, OF_DELETE);
gmem_free(hHeap, filename, MAX_PATH);
break;
}
}
/***************************************************************************
* Function: ci_copytext
*
* Purpose:
*
* To alloc a buffer large enough for the text string and copy the text into
* it and return a pointer to the string.
*
***************************************************************************/
LPSTR
ci_copytext(LPSTR in)
{
LPSTR out;
if (in == NULL) {
out = gmem_get(hHeap, 1);
out[0] = '\0';
} else {
out = gmem_get(hHeap, lstrlen(in) + 1);
lstrcpy(out, in);
}
return(out);
}
/***************************************************************************
* Function: ci_onesection
*
* Purpose:
*
* To make a list containing a single section from the whole list of lines
*
***************************************************************************/
LIST
ci_onesection(FILEDATA file)
{
LIST lines;
LIST sections;
SECTION section;
lines = file_getlinelist(file);
/* create a null list */
sections = List_Create();
/* tell the section to create itself on the end of this list. */
section = section_new(List_First(lines), List_Last(lines), sections);
section_setstate(section, STATE_SAME);
return(sections);
}
/***************************************************************************
* Function: ci_makecomposite
*
* Purpose:
*
* Compare the two files and build the composite list. This function is
* called whenever we need one of the section lists and only does the
* comparison if the composite list does not already exist.
*
***************************************************************************/
void
ci_makecomposite(COMPITEM ci)
{
if (ci->secs_composite != NULL) {
return;
}
/* if there is only one file, make a single item list
* of sections
*/
if (ci->left == NULL) {
ci->secs_left = NULL;
ci->secs_right = ci_onesection(ci->right);
/* make a second list, not a pointer to the first
* or we will get confused when deleting
*/
ci->secs_composite = ci_onesection(ci->right);
return;
} else if (ci->right == NULL) {
ci->secs_right = NULL;
ci->secs_left = ci_onesection(ci->left);
/* make a second list, not a pointer to the first
* or we will get confused when deleting
*/
ci->secs_composite = ci_onesection(ci->left);
return;
}
/* we have two files - we need to compare them fully */
ci_compare(ci);
}
/***************************************************************************
* Function: ci_compare
*
* Purpose:
*
* Compare files and build a composite list.
*
* Comments:
*
* Comparison method:
*
* 0 Break each file into lines and hash each line. Lines which
* don't match can be rapidly eliminated by comparing the hash code.
*
* Store the hash codes in a binary search tree that
* will give for each hash code the number of times that it
* occurred in each file and one of the lines where it occurred
* in each file. The tree is used to rapidly find the partner
* of a line which occurs exactly once in each file.
*
* 1 Make a section covering the whole file (for both)
* and link unique lines between these sections (i.e. link lines
* which occur exactly once in each file as they must match each other).
* These are referred to as anchor points.
*
* 2 Build section lists for both files by traversing line lists and
* making a section for each set of adjacent lines that are unmatched
* and for each set of adjacent lines that match a set of adjacent
* lines in the other file. In making a section we start from a
* known matching line and work both forwards and backwards through
* the file including lines which match, whether they are unique or not.
*
* 3 Establish links between sections that match
* and also between sections that don't match but do
* correspond (by position in file between matching sections)
*
* 4 For each section pair that don't match but do correspond,
* link up matching lines unique within that section. (i.e. do
* the whole algorithm again on just this section).
*
* There may be some lines which occur many times over in each file.
* As these occurrences are matched up, so the number left to match
* reduces, and may reach one in each file. At this point these two
* can be matched. Therefore we...
*
* Repeat steps 0-4 until no more new links are added, but (especially
* in step 0) we only bother with lines which have not yet been matched.
* This means that a line which has only one unmatched instance in each
* file gets a count of one and so is a new anchor point.
*
* Finally build a composite list from the two lists of sections.
*
***************************************************************************/
void
ci_compare(COMPITEM ci)
{
LIST lines_left, lines_right;
SECTION whole_left, whole_right;
BOOL bChanges;
/* get the list of lines for each file */
lines_left = file_getlinelist(ci->left);
lines_right = file_getlinelist(ci->right);
if ((lines_left == NULL) || (lines_right == NULL)) {
ci->secs_left = NULL;
ci->secs_right = NULL;
ci->secs_composite = NULL;
return;
}
do {
/* we have made no changes so far this time round the
* loop
*/
bChanges = FALSE;
/* make a section covering the whole file */
whole_left = section_new(List_First(lines_left),
List_Last(lines_left), NULL);
whole_right = section_new(List_First(lines_right),
List_Last(lines_right), NULL);
/* link up matching unique lines between these sections */
if (section_match(whole_left, whole_right)) {
bChanges = TRUE;
}
/* delete the two temp sections */
section_delete(whole_left);
section_delete(whole_right);
/* discard previous section lists if made */
if (ci->secs_left) {
section_deletelist(ci->secs_left);
ci->secs_left = NULL;
}
if (ci->secs_right) {
section_deletelist(ci->secs_right);
ci->secs_right = NULL;
}
/* build new section lists for both files */
ci->secs_left = section_makelist(lines_left, TRUE);
ci->secs_right = section_makelist(lines_right, FALSE);
/* match up sections - make links and corresponds between
* sections. Attempts to section_match corresponding
* sections that are not matched. returns true if any
* further links were made
*/
if (section_matchlists(ci->secs_left, ci->secs_right)) {
bChanges = TRUE;
}
/* repeat as long as we keep adding new links */
} while (bChanges);
/* all possible lines linked, and section lists made .
* combine the two section lists to get a view of the
* whole comparison - the composite section list. This also
* sets the state of each section in the composite list.
*/
ci->secs_composite = section_makecomposite(ci->secs_left, ci->secs_right);
}
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