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Diff.cpp
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Diff.cpp
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#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "gb-include.h"
#include "Titledb.h"
#include "Diff.h"
// local Debug stuff for diff
#define DPRINTF(format,args...) if ( opt->m_debug > 0 )\
printf("DEBUG: "/**/format, ## args)
#define DPRINTF2(format, args...) if ( opt->m_debug > 1 )\
printf("DEBUG2: "/**/format, ## args)
// element compare functions
int xmlTagCompare(void *elt1, void *elt2);
int xmlTagCompare2(void *elt1, void *elt2);
bool xmlWhitespaceNode(XmlNode *node);
//
long editPath(char *seq1, char *seq2,
const DiffOpt *opt,
const long start1, const long start2,
const long n1, const long n2,
long *midX, long *midY, long *midLen);
long xmlEditPath(Xml *xml1, Xml* xml2,
const DiffOpt *opt,
const long start1, const long start2,
const long n1, const long n2,
long *midX, long *midY, long *midLen);
// Load 2 files into Xml classes and print the output from
// printXmlDiff on them
void diffXmlFiles(char *file1, char *file2, DiffOpt *opt){
int fd = open(file1, O_RDONLY);
if (fd < 0 ) {
fprintf(stderr, "error opening %s\n", file1);
return;
}
long contentLen1 = lseek(fd, 0, SEEK_END);
if (contentLen1 < 0){
fprintf(stderr, "error seeking %s\n", file1);
close(fd);
return;
}
char *content1 = (char*)mmalloc(contentLen1+1, "xmldiff");
if (!content1){
fprintf(stderr, "can't alloc %ld bytes for %s\n",
contentLen1+1, file1);
close(fd);
return;
}
content1[contentLen1] = '\0';
lseek(fd, 0, SEEK_SET);
long n = read(fd, content1, contentLen1);
if (n && n != contentLen1){
fprintf(stderr, "error reading %s: "
"expected %ld bytes got %ld.\n"
"(errno=%s)\n",
file1, contentLen1, n, strerror(errno));
return;
}
close(fd);
fd = open(file2, O_RDONLY);
if (fd < 0 ) {
fprintf(stderr, "error opening %s\n", file2);
return;
}
long contentLen2 = lseek(fd, 0, SEEK_END);
if (contentLen2 < 0){
fprintf(stderr, "error seeking %s\n", file2);
close(fd);
return;
}
char *content2 = (char*)mmalloc(contentLen2+1, "xmldiff");
if (!content2){
fprintf(stderr, "can't alloc %ld bytes for %s\n",
contentLen2+1, file2);
close(fd);
return;
}
content2[contentLen2] = '\0';
lseek(fd, 0, SEEK_SET);
n = read(fd, content2, contentLen2);
if (n && n != contentLen2){
fprintf(stderr, "error reading %s: "
"expected %ld bytes got %ld.\n"
"(errno=%s)\n",
file2, contentLen2, n, strerror(errno));
return;
}
close(fd);
Xml xml1;
xml1.set(csISOLatin1,
content1,
contentLen1,
false, 0, false,
TITLEREC_CURRENT_VERSION);
Xml xml2;
xml2.set(csISOLatin1,
content2,
contentLen2,
false, 0, false,
TITLEREC_CURRENT_VERSION);
//printf("%s: len=%ld, nodes=%ld\n",
// file1, contentLen1, xml1.getNumNodes());
//printf("%s: len=%ld, nodes=%ld\n",
// file2, contentLen2, xml2.getNumNodes());
printXmlDiff(&xml1,&xml2, opt);
}
// Run our Xml Diff algorithm on 2 Xmls
void printXmlDiff(Xml *xml1, Xml *xml2, DiffOpt *argOpt){
// Supply default args if necessary
DiffOpt defaultOpt;
DiffOpt *opt = &defaultOpt;
if (argOpt) opt = argOpt;
// set default compare function if necessary
if (!opt->m_compare)
opt->m_compare = xmlTagCompare2;
opt->m_eltSize = sizeof(XmlNode);
long seq1 [4096];
long seq2 [4096];
long seqLen[4096];
SafeBuf buf;
//long numSeq = longestCommonSubsequence(seq1, seq2, seqLen,4096,
// &xml1-> &xml2->;
//printf("lcs length: %ld\n", numSeq);
long numSeq = lcsXml(seq1, seq2, seqLen,4096, xml1, xml2, opt);
//buf.safePrintf("LCS:\nlength: %ld\n", numSeq);
// long start = -1;
// for (long i=0;i<numSeq;i++){
// long i1 = seq1[i];
// long i2 = seq2[i];
// long iLen = seqLen[i];
//buf.safePrintf("node=(%ld, %ld) len=%ld\n", i1, i2, iLen);
// if (xml1->isUnicode())
// buf.utf16Encode(xml1->getNode(i1),
// xml1->getNodeLen(i1));
// else
// buf.latin1Encode(xml1->getNode(i1),
// xml1->getNodeLen(i1));
// buf.safePrintf("-");
// if (xml1->isUnicode())
// buf.utf16Encode(xml1->getNode(i1+iLen-1),
// xml1->getNodeLen(i1+iLen-1));
// else
// buf.latin1Encode(xml1->getNode(i1+iLen-1),
// xml1->getNodeLen(i1+iLen-1));
// buf.safePrintf("\n");
//if (i < numSeq-1) buf.safePrintf("\n");
// continue;
// }
//buf.safePrintf("\n");
//buf.safePrintf("DIFF:\n");
// Print Diff
long n1 = xml1->getNumNodes();
long n2 = xml2->getNumNodes();
long i = 0;
long j = 0;
long lastC = 0;
for (long seqi=0; i<n1 || j<n2 || seqi<numSeq ; seqi++){
// safe values
long a = n1;
long b = n2;
long len = 0;
long d = 0;
long numEdits = 0;
// node before this common sequence
if (seqi<numSeq){
// stop at next common sequence
a =seq1[seqi];
b = seq2[seqi];
len = seqLen[seqi];
d = b-a;
}
//buf.safePrintf("***** COMMON SEQ %li: (%li-%li), (%li-%li) "
// "a=%li b=%li i=%li j=%li "
// "len=%li\n",
// seqi,
// a, a+len-1, b, b+len-1,
// a, b, i, j, len);
//buf.safePrintf("***** COMMON SEQ %li: "
// "(%li-%li), (%li-%li) *****\n",
// seqi,
// a, a+len-1, b, b+len-1);
if (i<a || j<b){
long editLoc = i;
// print location, in first file,
// of the following edits
// but only if context tags have not caught up
if (editLoc > lastC){
char name[1024];
name[0] = '\0';
long namelen;
//namelen = xml1->getCompoundName
// (editLoc,name,1024);
buf.safePrintf("@@@ node %li: ",
editLoc);
if(xml1->isUnicode())
buf.utf16Encode(name,namelen);
else
buf.latin1Encode(name,namelen);
buf.safePrintf("\n");
}
// leading context
long c = i;
// go back opt->m_context nodes, skipping empty tags,
// go back as far as the first node, or
// the last node that was output as trailing context
for (long x=i-1, numTags = 0;
x >= 0 && numTags < opt->m_context && x > lastC;
x--){
if (xmlWhitespaceNode(xml1->getNodePtr(x)))
continue;
numTags++;
c = x;
}
for ( ; c < i ; c++) {
// char name[1024];
// long namelen = xml1->getCompoundName
// (c,name,1024);
// if (namelen)
// buf.safePrintf("- %li: %s\n",c,name);
//buf.safePrintf(" (node %6li) \t| ", c);
if (xmlWhitespaceNode(xml1->getNodePtr(c)))
continue;
char *s = xml1->getNode(c);
long slen = xml1->getNodeLen(c);
if (xml1->isUnicode())
buf.utf16Encode(s,slen);
else buf.latin1Encode(s,slen);
//lastC = c;
}
if (c>lastC) buf.safePrintf("\n");
//buf.safePrintf("-------------------------\n");
}
// Deletes
if (i<a){
buf.safePrintf("-------------------------\n");
//buf.safePrintf("<<<<<<<<<<<<<<<<<<<<<<<<<\n");
//buf.safePrintf("- (node %6li-%li) \t| ", i,a-1);
buf.safePrintf("--- (node %li-%li)\n", i,a-1);
while (i < a){
char *s = xml1->getNode(i);
long slen = xml1->getNodeLen(i);
if (xml1->isUnicode())
buf.utf16Encode(s,slen);
else buf.latin1Encode(s,slen);
i++;
numEdits++;
}
buf.safePrintf("\n");
//buf.safePrintf("\n");
buf.safePrintf("-------------------------\n");
}
// Adds
if (j<b){
buf.safePrintf("+++++++++++++++++++++++++\n");
//buf.safePrintf("-------------------------\n");
//buf.safePrintf(">>>>>>>>>>>>>>>>>>>>>>>>>\n");
//buf.safePrintf("+ (node %6li-%li) \t| ", j,b-1);
buf.safePrintf("+++ (node %li-%li)\n", j,b-1);
while (j < b){
char *s = xml2->getNode(j);
long slen = xml2->getNodeLen(j);
if (xml2->isUnicode())
buf.utf16Encode(s,slen);
else buf.latin1Encode(s,slen);
j++;
numEdits++;
}
buf.safePrintf("\n");
buf.safePrintf("+++++++++++++++++++++++++\n");
}
long c = a;
// skip if there were no diffs...sometimes we get
// 2 consecutive sequences of common nodes, dunno why
if (numEdits == 0) goto skipTrail;
//buf.safePrintf("-------------------------\n");
if (lastC < a) lastC = a;
// trailing context
for ( long numTags = 0;
numTags < opt->m_context && c < a+len ; c++) {
lastC = c;
if (xmlWhitespaceNode(xml1->getNodePtr(c)))
continue;
numTags++;
char *s = xml1->getNode(c);
long slen = xml1->getNodeLen(c);
if (xml1->isUnicode())
buf.utf16Encode(s,slen);
else buf.latin1Encode(s,slen);
}
buf.safePrintf("\n");
skipTrail:
if (opt->m_context <= 0)
buf.safePrintf(" (node %li-%li, %li-%li)\n",
a, a+len-1, b, b+len-1);
// skip past common nodes
if (i == a) i+=len;
if (j == b) j+=len;
}
//buf.safePrintf("\n");
buf.print();
}
// a linear space version of LCS/diff algorithm described at
// http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.6927
// The algorithm works by imagining the elements of the 2 sequences
// as X and Y nodes on a graph. A vertical or horizontal edge between nodes
// corresponds to adding or deleting an element, while a diagonal edge
// is a common element between the two.
// The shortest path from (0,0) to (n1, n2) corresponds to the (an)
// optimal diff (shortest edit script) between the sequences, and the
// diagonal edges on that path represent a Longest Common Subsequence.
// This recursive version finds a path forward from the start and backward
// from the end. When they overlap in the middle, we've found the middlemost
// match (or edit)
// Max number of edits/diffs
#define MAXD 10000
#if 0
long lcsXml(long *lcsBuf1, // xml1 indexes of nodes in lcs
long *lcsBuf2, // xml2 indexes of nodes in lcs
long *lcsLenBuf, // number of consecutive nodes in each lcsBuf
long lcsBufLen, // max number of sequence matches we can fit
Xml *xml1, Xml *xml2,
const DiffOpt *opt,
const long argStart1, const long argStart2, // index of start nodes
const long argN1, const long argN2, // limit on number of nodes
const long rlevel){
// return value...length of overall lcs
long len = 0;
long start1 = argStart1;
long start2 = argStart2;
long n1 = argN1;
long n2 = argN2;
if (n1 < 0) n1 = xml1->getNumNodes() - start1;
if (n2 < 0) n2 = xml2->getNumNodes() - start2;
XmlNode *nodes1 = xml1->getNodes();
XmlNode *nodes2 = xml2->getNodes();
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("lcsXml(%ld): [%ld - %ld] (%ld), [%ld - %ld] (%ld) \n",
rlevel,
start1, start1+n1-1, n1,
start2, start2+n2-1, n2);
}
if (lcsBufLen <= 0) return 0;
if (n1 <= 0 || n2 <= 0) return 0;
long *p1 = lcsBuf1;
long *p2 = lcsBuf2;
long *pLen = lcsLenBuf;
// First, find any common prefix
long prefixLen = 0;
for ( long i=0 ; i < n1 && i < n2 ; i++){
//if (xmlNodeCompare(xml1, start1 + i,
// xml2, start2 + i, opt) != 0)
if (xmlTagCompare(&nodes1[start1 + i],
&nodes2[start2 + i]) != 0)
break;
prefixLen++;
}
if (prefixLen > 0){
// store it in result
*p1++ = start1;
*p2++ = start2;
*pLen++ = prefixLen;
len++;
// remove from input
start1 += prefixLen;
start2 += prefixLen;
n1 -= prefixLen;
n2 -= prefixLen;
}
// optimization no further match possible
if (n1 <= 0 || n2 <= 0) {
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("len=%ld\n",len);
}
return len;
}
// find any common suffix too
long suffixLen = 0;
for ( long i=0 ; i < n1 && i < n2 ; i++){
//if (xmlNodeCompare(xml1, start1+n1-1 - i,
// xml2, start2+n2-1 - i, opt) != 0)
if (xmlTagCompare(&nodes1[start1+n1-1 - i],
&nodes2[start2+n2-1 - i]) != 0)
break;
suffixLen++;
}
if (suffixLen > 0){
// remove from input
n1 -= suffixLen;
n2 -= suffixLen;
}
long mid1=0, mid2=0, midLen=0;
long pathLen = 0;
// optimization: no possible matches
if (n1+n2 <= 3)
pathLen = n1+n2;
else {
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
DPRINTF("editPath: [%ld - %ld] (%ld), "
"[%ld - %ld] (%ld)\n",
start1, start1+n1, n1,
start2, start2+n2, n2);
}
pathLen = xmlEditPath(xml1, xml2, opt,
start1, start2, n1, n2,
&mid1, &mid2, &midLen);
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
DPRINTF("editPath -> [%ld - %ld] (%ld), "
"[%ld - %ld] (%ld)\n",
mid1, mid1+midLen-1, midLen,
mid2, mid2+midLen-1, midLen);
}
}
If (pathLen < 0) {
log(LOG_WARN, "Diff: Error finding shortest diff");
return -1;
}
// All nodes different
if ( pathLen >= n1 + n2 ){
// Add the suffix
if (suffixLen > 0 && len < lcsBufLen){
*p1++ = start1+n1;
*p2++ = start2+n2;
*pLen++ = suffixLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("suffix lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("len=%ld\n",len);
}
return len;
}
if (pathLen > 1){
// Recurse on the first half
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("Recurse left:\n");
}
long n = lcsXml(p1, p2,pLen,lcsBufLen-len,
xml1, xml2, opt,
start1, start2,
mid1-start1, mid2-start2,
rlevel+1);
if (n<0) return -1;
p1 += n;
p2 += n;
pLen += n;
len += n;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("left len=%ld\n", n);
}
// add middle common sequence
if ( len < lcsBufLen && midLen > 0){
*p1++ = mid1;
*p2++ = mid2;
*pLen++ = midLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("middle lcs += (%ld-%ld),(%ld-%ld)\n",
mid1, mid1+midLen-1,
mid2, mid2+midLen-1);
}
len++;
}
// Recurse on the second half
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("Recurse right:\n");
}
n = lcsXml(p1, p2,pLen,lcsBufLen-len,
xml1, xml2, opt,
mid1+midLen, mid2+midLen,
start1+n1 - (mid1+midLen),
start2+n2 - (mid2+midLen),
rlevel+1);
if (n<0) return -1;
p1 += n;
p2 += n;
pLen += n;
len += n;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("right len=%ld\n", n);
}
}
// edit path length of 1 or less means at most 1 node was
// added or deleted...since we've already removed the common prefix,
// the extra node should be at the beginning of one of the sequences
else {
if (n1 > n2){
// remove extra node from xml1
//if (xmlNodeCompare(xml1, start1 , xml2, start2,
// opt ))
start1++;
n1--;
}
else if (n2 > n1){
// remove extra node from xml2
//if (xmlNodeCompare(xml1, start1 , xml2, start2,
//opt ))
start2++;
n2--;
}
// sanity check
if ( n1 != n2) {
log(LOG_WARN, "Diff: PANIC! Sequences do not match! "
"n1=%ld n2=%ld", n1, n2);
char *xx = NULL; *xx=0;
}
if ( len < lcsBufLen && n1 > 0 && n2 > 0) {
*p1++ = start1;
*p2++ = start2;
*pLen++ = n1;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("end lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
}
// Add the suffix
if (suffixLen > 0 && len < lcsBufLen){
*p1++ = start1+n1;
*p2++ = start2+n2;
*pLen++ = suffixLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("suffix lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("len=%ld\n",len);
}
return len;
// compact the sequences
long newLen = len;
for (long i=1, j=0;i<len;i++){
if ( i <= j ) continue;
if ( lcsBuf1[i] != lcsBuf1[j] + lcsLenBuf[j] ||
lcsBuf2[i] != lcsBuf2[j] + lcsLenBuf[j] ) {
j++;
if ( i <= j ) continue;
//fill hole
lcsBuf1[j]=lcsBuf1[i];
lcsBuf2[j]=lcsBuf2[i];
lcsLenBuf[j]=lcsLenBuf[i];
}
// merge consecutive sequences
lcsLenBuf[j] += lcsLenBuf[i];
newLen--;
}
return newLen;
}
#else
long lcsXml(long *lcsBuf1, // xml1 indexes of nodes in lcs
long *lcsBuf2, // xml2 indexes of nodes in lcs
long *lcsLenBuf, // number of consecutive nodes in each lcsBuf
long lcsBufLen, // max number of sequence matches we can fit
Xml *xml1, Xml *xml2,
DiffOpt *opt,
const long argStart1,
const long argStart2, // index of start nodes
const long argN1,
const long argN2, // limit on number of nodes
const long rlevel){
XmlNode *nodes1 = xml1->getNodes();
XmlNode *nodes2 = xml2->getNodes();
long start1 = argStart1;
long start2 = argStart2;
long n1 = argN1;
long n2 = argN2;
if (n1<0) n1 = xml1->getNumNodes();
if (n2<0) n2 = xml2->getNumNodes();
return longestCommonSubseq(lcsBuf1, lcsBuf2, lcsLenBuf,lcsBufLen,
(char*)nodes1, (char*)nodes2, opt,
start1, start2, n1, n2,rlevel);
}
#endif
long longestCommonSubseq(long *outbuf1, // out1 indexes of nodes in lcs
long *outbuf2, // xml2 indexes of nodes in lcs
long *outlens, // number of consecutive nodes lcsBuf
long outbuflen, // Size of output bufs (elts not bytes)
char *seq1,
char *seq2,
const DiffOpt *opt,
const long argStart1, // index of first elements
const long argStart2,
const long argN1, // element count in seq 1 and seq2
const long argN2,
const long rlevel){
// return value...length of overall lcs
long len = 0;
long start1 = argStart1;
long start2 = argStart2;
long n1 = argN1;
long n2 = argN2;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("longestCommonSubseq(%ld): [%ld , %ld] [%ld , %ld] \n",
rlevel,start1, start1+n1-1, start2, start2+n2-1);
}
// no space
if (outbuflen <= 0) return -1;
// no input
if (n1 <= 0 || n2 <= 0) return 0;
long *p1 = outbuf1;
long *p2 = outbuf2;
long *pLen = outlens;
// First, find any common prefix
long prefixLen = 0;
for ( long i=0 ; i < n1 && i < n2 ; i++){
char *e1 = seq1+(start1+i)*opt->m_eltSize;
char *e2 = seq2+(start2+i)*opt->m_eltSize;
if (opt->m_compare(e1, e2) != 0)
break;
prefixLen++;
}
if (prefixLen > 0){
// store it in result
*p1++ = start1;
*p2++ = start2;
*pLen++ = prefixLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("prefix lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
// remove from input
start1 += prefixLen;
start2 += prefixLen;
n1 -= prefixLen;
n2 -= prefixLen;
}
// no further match possible
if (n1 <= 0 || n2 <= 0) return len;
// find any common suffix too
long suffixLen = 0;
for ( long i=0 ; i < n1 && i < n2 ; i++){
char *e1 = seq1+(start1+n1-1-i)*opt->m_eltSize;
char *e2 = seq2+(start2+n2-1-i)*opt->m_eltSize;
if (opt->m_compare(e1, e2) != 0)
break;
suffixLen++;
}
if (suffixLen > 0){
// remove from input
n1 -= suffixLen;
n2 -= suffixLen;
}
long mid1=0, mid2=0, midLen=0;
long pathLen = 0;
if (n1+n2 <= 3)
// No matches possible
pathLen = n1+n2;
else
pathLen = editPath(seq1, seq2, opt,
start1, start2, n1, n2,
&mid1, &mid2, &midLen);
if (pathLen < 0) {
log(LOG_WARN, "Diff: Error finding shortest diff");
return -1;
}
// All nodes different
if ( pathLen >= n1 + n2 ){
// Add the suffix
if (suffixLen > 0 && len < outbuflen){
*p1++ = start1+n1;
*p2++ = start2+n2;
*pLen++ = suffixLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("suffix lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
return len;
}
if (pathLen > 1){
// Recurse on the first half
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("Recurse left:\n");
}
long n = longestCommonSubseq(p1, p2,pLen,outbuflen-len,
seq1, seq2, opt,
start1, start2,
mid1-start1, mid2-start2,
rlevel+1);
if (n<0) return -1;
p1 += n;
p2 += n;
pLen += n;
len += n;
// add middle common sequence
if ( len < outbuflen && midLen > 0){
*p1++ = mid1;
*p2++ = mid2;
*pLen++ = midLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("middle lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
// Recurse on the second half
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("Recurse right:\n");
}
n = longestCommonSubseq(p1, p2,pLen,outbuflen-len,
seq1, seq2, opt,
mid1+midLen, mid2+midLen,
start1+n1 - (mid1+midLen),
start2+n2 - (mid2+midLen),
rlevel+1);
if (n<0) return -1;
p1 += n;
p2 += n;
pLen += n;
len += n;
}
// edit path length of 1 or less means at most 1 node was
// added or deleted...since we've already removed the common prefix,
// the extra node should be at the beginning of one of the sequences
else {
if (n1 > n2){
start1++;
n1--;
}
if (n2 > n1){
start2++;
n2--;
}
// sanity check
if ( n1 != n2) {
log(LOG_WARN, "Diff: PANIC! Sequences do not match! "
"n1=%ld n2=%ld", n1, n2);
char *xx = NULL; *xx=0;
}
if ( len < outbuflen && n1 > 0 && n2 > 0) {
*p1++ = start1;
*p2++ = start2;
*pLen++ = n1;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("end lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
}
// Add the suffix
if (suffixLen > 0 && len < outbuflen){
*p1++ = start1+n1;
*p2++ = start2+n2;
*pLen++ = suffixLen;
if (opt->m_debug){
for (long i=0;i<rlevel;i++) printf("\t");
printf("suffix lcs += (%ld-%ld),(%ld-%ld)\n",
start1, start1+n1-1,
start2, start2+n2-1);
}
len++;
}
return len;
// compact the sequences
//long newLen = len;
//for (long i=1, j=0;i<len;i++){
// if ( i <= j ) continue;
// if ( lcsBuf1[i] != lcsBuf1[j] + lcsLenBuf[j] ||
// lcsBuf2[i] != lcsBuf2[j] + lcsLenBuf[j] ) {
// j++;
// if ( i <= j ) continue;
//fill hole
// lcsBuf1[j]=lcsBuf1[i];
// lcsBuf2[j]=lcsBuf2[i];
// lcsLenBuf[j]=lcsLenBuf[i];
// }
// // merge consecutive sequences
// lcsLenBuf[j] += lcsLenBuf[i];
// newLen--;
//}
//return newLen;
}
// access negative array index
#define IDX(asize, idx) ( ((idx)<0) ? ((asize)+(idx)) : (idx) )
#define VSIZE (2*MAXD+1)
// This will return the length of the shortest edit path between
// xml1(start1, n1 nodes) and xml2(start2, n2 nodes),
// return the middle "snake" (matching nodes) in mid[XYUV] if one exists
long xmlEditPath(Xml *xml1, Xml* xml2,
const DiffOpt *opt,
const long start1, const long start2,
const long n1, const long n2,
long *midX, long *midY, long *midLen){
XmlNode *nodes1 = xml1->getNodes();
XmlNode *nodes2 = xml2->getNodes();
long v1[VSIZE];
long v2[VSIZE];
long delta = n1-n2;
// the algorithm terminates on a reverse iteration if the difference
// in length is even
bool reverseFinish = (delta % 2 == 0);
long maxD = n1+n2;
// round up
if (maxD % 2) maxD++;
maxD /= 2;
if (maxD>MAXD) maxD = MAXD;
v1[1] = 0;
v2[1] = n1;
*midLen = 0;
//DPRINTF("xmlEditPath: maxD:%ld delta:%ld "
//"s1:%ld s2:%ld n1:%ld n2:%ld\n",
DPRINTF2("xmlEditPath: maxD:%ld delta:%ld "
"[%ld - %ld] (%ld), "
"[%ld - %ld] (%ld)\n",
maxD, delta,
start1, start1+n1-1, n1,
start2, start2+n2-1, n2);
for (long d=0 ; d <= maxD ; d++ ){
DPRINTF2("D: %ld forward\n", d);
//find forward path
for (long k = -d ; k <= d ; k += 2) {
DPRINTF2("\tK: %ld\n", k);
// get best endpoints of last iteration
long a = v1[IDX(VSIZE, k-1)];
long b = v1[IDX(VSIZE, k+1)];
long x;
// select best path along diagonal k
if (k == -d || k != d && a < b) x = b;
else x = a+1;
long y = x-k;
// DPRINTF2("\t\tx=%ld y=%ld\n",x,y);
long startX = x;
long startY = y;
// follow any matched nodes
while (x >=0 && x < n1 &&
y >= 0 && y < n2 &&
//!xmlNodeCompare(xml1, x + start1 ,
// xml2, y + start2, opt )){
!xmlTagCompare(&nodes1[ x + start1 ],
&nodes2[ y + start2 ] )){
x++;
y++;
// DPRINTF2("\t\tx=%ld y=%ld\n",x,y);
}
// store best endpoint for this iteration
v1[IDX(VSIZE,k)] = x;
// store last match
if (startX != x){
*midX = startX + start1;
*midY = startY + start2;
*midLen = x - startX;
}
// check if odd
//if (delta % 2 == 0) continue;
if (reverseFinish) continue;
// out of range for overlap
if (k < delta-(d-1) || k > delta+(d-1)) continue;
// check for overlap with reverse path
long j = -k+delta;
long u = v2[IDX(VSIZE,j)];
long v = u + j - delta;
if (x-y != u-v || x < u) continue;
// found middle match...add the start offsets
DPRINTF2("FORWARD MATCH: x=%ld y=%ld u=%ld v=%ld\n",
x, y, u, v);
DPRINTF2("pathlen=%ld midX=%ld midY=%ld midLen=%ld\n",
2*d-1,*midX, *midY, *midLen);
// return length of SES
return 2*d-1;
}
DPRINTF2("D: %ld reverse\n",d);
// find reverse path
for (long k = -d ; k <= d ; k += 2) {
DPRINTF2("\tK: %ld\n", k);
long a = v2[IDX(VSIZE, k-1)];
long b = v2[IDX(VSIZE, k+1)];
long u;
// select best path along diagonal k
if (k == -d || k != d && a > b) u = b;
else u = a-1;