+
+/*
+ * Diff related functions
+ */
+static xbt_matrix_t diff_build_LCS(xbt_dynar_t da, xbt_dynar_t db) {
+ xbt_matrix_t C = xbt_matrix_new(xbt_dynar_length(da),xbt_dynar_length(db),
+ sizeof(int),NULL);
+ int i,j;
+ /* Compute the LCS */
+ /*
+ C = array(0..m, 0..n)
+ for i := 0..m
+ C[i,0] = 0
+ for j := 1..n
+ C[0,j] = 0
+ for i := 1..m
+ for j := 1..n
+ if X[i] = Y[j]
+ C[i,j] := C[i-1,j-1] + 1
+ else:
+ C[i,j] := max(C[i,j-1], C[i-1,j])
+ return C[m,n]
+ */
+ for (i=0; i<xbt_dynar_length(da); i++)
+ *((int*) xbt_matrix_get_ptr(C,i,0) ) = 0;
+
+ for (j=0; j<xbt_dynar_length(db); j++)
+ *((int*) xbt_matrix_get_ptr(C,0,j) ) = 0;
+
+ for (i=1; i<xbt_dynar_length(da); i++)
+ for (j=1; j<xbt_dynar_length(db); j++) {
+
+ if (!strcmp(xbt_dynar_get_as(da,i,char*), xbt_dynar_get_as(db,j,char*)))
+ *((int*) xbt_matrix_get_ptr(C,i,j) ) = xbt_matrix_get_as(C,i-1,j-1,int) + 1;
+ else
+ *((int*) xbt_matrix_get_ptr(C,i,j) ) = max(xbt_matrix_get_as(C,i ,j-1,int),
+ xbt_matrix_get_as(C,i-1,j,int));
+ }
+ return C;
+}
+
+static void diff_build_diff(xbt_dynar_t res,
+ xbt_matrix_t C,
+ xbt_dynar_t da, xbt_dynar_t db,
+ int i,int j) {
+ char *topush;
+ /* Construct the diff
+ function printDiff(C[0..m,0..n], X[1..m], Y[1..n], i, j)
+ if i > 0 and j > 0 and X[i] = Y[j]
+ printDiff(C, X, Y, i-1, j-1)
+ print " " + X[i]
+ else
+ if j > 0 and (i = 0 or C[i,j-1] >= C[i-1,j])
+ printDiff(C, X, Y, i, j-1)
+ print "+ " + Y[j]
+ else if i > 0 and (j = 0 or C[i,j-1] < C[i-1,j])
+ printDiff(C, X, Y, i-1, j)
+ print "- " + X[i]
+ */
+
+ if (i>=0 && j >= 0 && !strcmp(xbt_dynar_get_as(da,i,char*),
+ xbt_dynar_get_as(db,j,char*))) {
+ diff_build_diff(res,C,da,db,i-1,j-1);
+ topush = bprintf(" %s",xbt_dynar_get_as(da,i,char*));
+ xbt_dynar_push(res, &topush);
+ } else if (j>=0 &&
+ (i<0 || xbt_matrix_get_as(C,i,j-1,int) >= xbt_matrix_get_as(C,i-1,j,int))) {
+ diff_build_diff(res,C,da,db,i,j-1);
+ topush = bprintf("+ %s",xbt_dynar_get_as(db,j,char*));
+ xbt_dynar_push(res,&topush);
+ } else if (i>=0 &&
+ (j<0 || xbt_matrix_get_as(C,i,j-1,int) < xbt_matrix_get_as(C,i-1,j,int))) {
+ diff_build_diff(res,C,da,db,i-1,j);
+ topush = bprintf("- %s",xbt_dynar_get_as(da,i,char*));
+ xbt_dynar_push(res,&topush);
+ } else if (i<0 && j<0) {
+ return;
+ } else {
+ THROW_IMPOSSIBLE;
+ }
+}
+
+/** @brief Compute the unified diff of two strings */
+char *xbt_str_diff(char *a, char *b) {
+ xbt_dynar_t da = xbt_str_split(a, "\n");
+ xbt_dynar_t db = xbt_str_split(b, "\n");
+
+ xbt_matrix_t C = diff_build_LCS(da,db);
+ xbt_dynar_t diff = xbt_dynar_new(sizeof(char*),free_string);
+ char *res=NULL;
+
+ diff_build_diff(diff, C, da,db, xbt_dynar_length(da)-1, xbt_dynar_length(db)-1);
+ res = xbt_str_join(diff, "\n");
+
+ xbt_dynar_free(&da);
+ xbt_dynar_free(&db);
+ xbt_dynar_free(&diff);
+ xbt_matrix_free(C);
+
+ return res;
+}