add string diff via LCS

Utils/StringUtils.h

@@ -13,6 +13,9 @@
 #include <stdio.h>
 #include <ctype.h>
 
+#include "MathUtils.h"
+#include "ArraySort.h"
+
 namespace Utils {
     class StringUtils {
         private:
@@ -31,6 +34,112 @@ namespace Utils {
 
                 return true;
             }
+
+            typedef struct {
+                char **values;
+                int *masks;
+                int size;
+            } text_diff;
+
+            static
+            text_diff computeLCSDiff (char **from, int fromSize, char **to, int toSize)
+            {
+                char **diffValues = malloc(fromSize * toSize * sizeof(char *));
+                int *diffMasks    = calloc(fromSize * toSize,  sizeof(int));
+
+                int *dm = calloc((fromSize + 1) * (toSize + 1), sizeof(int));
+
+                if (!diffValues || !diffMasks || !dm) {
+                    fprintf(stderr, "CRITICAL: malloc failed");
+                }
+
+                int i = 0;
+                int j = 0;
+
+                /* Handled with calloc
+                for (j = 0; j <= toSize; ++j) {
+                    dm[0 + j] = 0;
+                }
+
+                for (i = 1; i <= fromSize; ++i) {
+                    dm[i * fromSize + 0] = 0;
+                }
+                */
+
+                for (i = 1; i <= fromSize; ++i) {
+                    for (j = 1; j <= toSize; ++j) {
+                        dm[i * fromSize + j] = strcmp(from[i - 1], to[j - 1]) == 0
+                            ? dm[(i - 1) * fromSize + (j - 1)] + 1
+                            : oms_max(dm[(i - 1) * fromSize + j], dm[i * fromSize + (j - 1)]);
+                    }
+                }
+
+                int diffIndex = 0;
+
+                i = fromSize;
+                j = toSize;
+
+                while (i > 0 || j > 0) {
+                    if (j > 0 && dm[i * fromSize + (j - 1)] == dm[i * fromSize + j]) {
+                        diffValues[diffIndex] = malloc((strlen(to[j - 1]) + 1) * sizeof(char));
+                        if (!diffValues[diffIndex]) {
+                            fprintf(stderr, "CRITICAL: malloc failed");
+                        }
+
+                        strcpy(diffValues[diffIndex], to[j - 1]);
+                        diffMasks[diffIndex] = 1;
+
+                        --j;
+                        ++diffIndex;
+
+                        continue;
+                    }
+
+                    if (i > 0 && dm[(i - 1) * fromSize + j] == dm[i * fromSize + j]) {
+                        diffValues[diffIndex] = malloc((strlen(from[i - 1]) + 1) * sizeof(char));
+                        if (!diffValues[diffIndex]) {
+                            fprintf(stderr, "CRITICAL: malloc failed");
+                        }
+
+                        strcpy(diffValues[diffIndex], from[i - 1]);
+                        diffMasks[diffIndex] = -1;
+
+                        --i;
+                        ++diffIndex;
+
+                        continue
+                    }
+
+                    diffValues[diffIndex] = malloc((strlen(from[i - 1]) + 1) * sizeof(char));
+                    if (!diffValues[diffIndex]) {
+                        fprintf(stderr, "CRITICAL: malloc failed");
+                    }
+
+                    strcpy(diffValues[diffIndex], from[i - 1]);
+
+                    /* Handled with calloc
+                    diffMasks[diffIndex] = 0;
+                    */
+
+                    --i;
+                    --j;
+                    ++diffIndex;
+                }
+
+                free(dm);
+
+                diffValues = realloc(diffValues, diffIndex * sizeof(char *));
+                diffMasks  = realloc(diffMasks, diffIndex * sizeof(int));
+
+                if (!diffValues || !diffMasks) {
+                    fprintf(stderr, "CRITICAL: malloc failed");
+                }
+
+                ArraySort::reverse_char(diffValues, diffIndex);
+                ArraySort::reverse_int(diffMasks, diffIndex);
+
+                return text_diff { diffValues, diffMasks, diffIndex  };
+            }
     };
 }