Differences From:

File src/diff.c part of check-in [4db464a748] - Fix a bug in the unified diff generator. by drh on 2007-11-21 16:03:19. [view]

To:

File src/diff.c part of check-in [4c22ae52fd] - Changes to the diff algorithm to put bounds on run-time for very large files with many differences. (This came up on the previous check-in when you try to diff the two versions of sqlite3.c.) by drh on 2007-11-25 17:13:14. [view]

@@ -111,8 +111,18 @@
   return pA->h==pB->h && memcmp(pA->z,pB->z,pA->h & LENGTH_MASK)==0;
 }
 
 /*
+** Append a single line of "diff" output to pOut.
+*/
+static void appendDiffLine(Blob *pOut, char *zPrefix, DLine *pLine){
+  blob_append(pOut, zPrefix, 1);
+  blob_append(pOut, pLine->z, pLine->h & LENGTH_MASK);
+  blob_append(pOut, "\n", 1);
+}
+
+
+/*
 ** Generate a report of the differences between files pA and pB.
 ** If pOut is not NULL then a unified diff is appended there.  It
 ** is assumed that pOut has already been initialized.  If pOut is
 ** NULL, then a pointer to an array of integers is returned.
@@ -238,8 +248,9 @@
   }
 
   szM = 0;
   MAX = X>Y ? X : Y;
+  if( MAX>2000 ) MAX = 2000;
   for(d=0; go && d<=MAX; d++){
     if( szM<d+1 ){
       szM += szM + 10;
       M = realloc(M, sizeof(M[0])*szM);
@@ -415,9 +426,9 @@
       a += skip;
       b += skip;
       m = R[r] - skip;
       for(j=0; j<m; j++){
-        blob_appendf(pOut," %.*s\n", A[a+j].h & LENGTH_MASK, A[a+j].z);
+        appendDiffLine(pOut, " ", &A[a+j]);
       }
       a += m;
       b += m;
 
@@ -424,20 +435,20 @@
       /* Show the differences */
       for(i=0; i<nr; i++){
         m = R[r+i*3+1];
         for(j=0; j<m; j++){
-          blob_appendf(pOut,"-%.*s\n", A[a+j].h & LENGTH_MASK, A[a+j].z);
+          appendDiffLine(pOut, "-", &A[a+j]);
         }
         a += m;
         m = R[r+i*3+2];
         for(j=0; j<m; j++){
-          blob_appendf(pOut,"+%.*s\n", B[b+j].h & LENGTH_MASK, B[b+j].z);
+          appendDiffLine(pOut, "+", &B[b+j]);
         }
         b += m;
         if( i<nr-1 ){
           m = R[r+i*3+3];
           for(j=0; j<m; j++){
-            blob_appendf(pOut," %.*s\n", B[b+j].h & LENGTH_MASK, B[b+j].z);
+            appendDiffLine(pOut, " ", &B[b+j]);
           }
           b += m;
           a += m;
         }
@@ -447,9 +458,9 @@
       assert( nr==i );
       m = R[r+nr*3];
       if( m>nContext ) m = nContext;
       for(j=0; j<m; j++){
-        blob_appendf(pOut," %.*s\n", B[b+j].h & LENGTH_MASK, B[b+j].z);
+        appendDiffLine(pOut, " ", &B[b+j]);
       }
     }
     free(R);
     R = 0;