Working on B+ tree implementation.

CMakeLists.txt

@@ -3,4 +3,5 @@ project(SDB C)
 
 set(CMAKE_C_STANDARD 11)
 
-add_executable(SDB src/main.c src/InputBuffer.c src/InputBuffer.h src/SQL.c src/SQL.h src/scanner.c src/scanner.h src/parser.c src/parser.h)
+include_directories(${CMAKE_SOURCE_DIR}/lib)
+add_executable(SDB src/main.c src/InputBuffer.c src/InputBuffer.h src/SQL.c src/SQL.h src/scanner.c src/scanner.h src/parser.c src/parser.h src/bplus_tree.c src/bplus_tree.h)

src/SQL.c

@@ -428,7 +428,7 @@ void print_column_spec_list(ColumnSpecList *list) {
     for (size_t i = 0; i < list->length; i++) {
         ColumnSpec *spec = list->columns[i];
         if (spec->type == COLTYPE_STRING) {
-            printf("%s STRING(%d)", spec->identifier, spec->size);
+            printf("%s STRING(%ld)", spec->identifier, spec->size);
         } else if (spec->type == COLTYPE_INT) {
             printf("%s INTEGER", spec->identifier);
         }
@@ -470,6 +470,6 @@ void print_value(Value *value) {
         }
         printf("'");
     } else if (value->type == VALUE_NUMBER) {
-        printf("%lld", value->number);
+        printf("%ld", value->number);
     }
 }

src/bplus_tree.c

@@ -0,0 +1,251 @@
+//
+// Created by sam on 14/06/18.
+//
+
+#include <malloc.h>
+#include <string.h>
+#include <assert.h>
+#include "bplus_tree.h"
+
+BPlusKV *new_bplus_kv(uint64_t key, void *value, BPlusNode *leftPointer) {
+    BPlusKV *kv = malloc(sizeof(BPlusKV));
+    kv->key = key;
+    kv->value = value;
+    kv->rightPointer = leftPointer;
+    return kv;
+}
+
+void free_bplus_kv(BPlusKV *kv) {
+    if (kv->rightPointer != NULL) {
+        free_bplus_node(kv->rightPointer);
+    }
+    if (kv->value != NULL) {
+        free(kv->value);
+    }
+    free(kv);
+}
+
+BPlusNode *new_bplus_node(uint64_t id, bool isInternal, size_t order) {
+    BPlusNode *node = malloc(sizeof(BPlusNode));
+    node->id = id;
+    node->isInternal = isInternal;
+    node->order = order;
+    node->parent = NULL;
+    node->keys = calloc(order, sizeof(BPlusKV *));
+    node->keyCount = 0;
+    node->leftPointer = NULL;
+    node->leftLeaf = NULL;
+    node->rightLeaf = NULL;
+    return node;
+}
+
+void free_bplus_node(BPlusNode *node) {
+    for (size_t i = 0; i < node->keyCount; i++) {
+        free_bplus_kv(node->keys[i]);
+    }
+    free(node->keys);
+    if (node->leftPointer != NULL) {
+        free_bplus_node(node->leftPointer);
+    }
+    free(node);
+}
+
+bool bplus_node_insert_kv(BPlusNode *node, BPlusKV *kv) {
+    if (node->keyCount == node->order) {
+        return false;
+    }
+    //Insert if empty
+    if (node->keyCount == 0) {
+        node->keys[0] = kv;
+        node->keyCount = 1;
+        return true;
+    }
+    //Check if can add to end
+    if (kv->key > node->keys[node->keyCount - 1]->key) {
+        node->keys[node->keyCount++] = kv;
+        return true;
+    }
+
+    //Find an index where we should insert
+    size_t i;
+    for (i = 0; i < node->keyCount; i++) {
+        if (kv->key < node->keys[i]->key) {
+            break;
+        }
+    }
+    //Make hole for new value
+    for (size_t k = node->order - 1; k > i; k--) {
+        node->keys[k] = node->keys[k - 1];
+    }
+    node->keys[i] = kv;
+    node->keyCount++;
+    return true;
+}
+
+void print_bplus_node(BPlusNode *node, size_t indent) {
+    char *indentStr = calloc(indent + 1, sizeof(char));
+    memset(indentStr, ' ', sizeof(char) * indent);
+
+    if (node->parent == NULL) {
+        printf("%sROOT #%ld (%ld/%ld)\n", indentStr, node->id, node->keyCount, node->order);
+    } else if (node->isInternal) {
+        printf("%sINTERNAL #%ld (%ld/%ld)\n", indentStr, node->id, node->keyCount, node->order);
+    } else {
+        printf("%sLEAF #%ld (%ld/%ld)\n", indentStr, node->id, node->keyCount, node->order);
+    }
+
+    if (node->leftPointer != NULL) {
+        print_bplus_node(node->leftPointer, indent + 4);
+    }
+    for (size_t i = 0; i < node->keyCount; i++) {
+        printf("%s  Key: %ld\t", indentStr, node->keys[i]->key);
+        if (!node->isInternal) {
+            if (node->keys[i]->value != NULL) {
+                printf("Value: %p", node->keys[i]->value);
+            } else {
+                printf("Value: NULL");
+            }
+        }
+        printf("\n");
+        if (node->keys[i]->rightPointer != NULL) {
+            print_bplus_node(node->keys[i]->rightPointer, indent + 4);
+        }
+    }
+
+    free(indentStr);
+}
+
+BPlusTree *new_bplus_tree(size_t order) {
+    BPlusTree *tree = malloc(sizeof(BPlusTree));
+    tree->order = order;
+    tree->minFill = order / 2;
+    tree->nextID = 0;
+    tree->root = new_bplus_node(tree->nextID++, false, order);
+    return tree;
+}
+
+void free_bplus_tree(BPlusTree *tree) {
+    if (tree->root != NULL) {
+        free_bplus_node(tree->root);
+    }
+    free(tree);
+}
+
+void print_bplus_tree(BPlusTree *tree) {
+    printf("B+ Tree\n");
+    printf("- Order: %ld\n", tree->order);
+    printf("- Min Fill: %ld\n", tree->minFill);
+
+    if (tree->root != NULL) {
+        print_bplus_node(tree->root, 2);
+    } else {
+        printf("  EMPTY TREE\n");
+    }
+}
+
+BPlusNode *bplus_tree_find_leaf(BPlusTree *tree, uint64_t key) {
+    BPlusNode *node = tree->root;
+
+    //Descend to correct leaf node
+    while (node != NULL) {
+        //Found our way to a leaf node
+        if (!node->isInternal) {
+            break;
+        }
+        //We are assuming at least one key
+        if (key < node->keys[0]->key) {
+            //Follow left pointer if less than first key
+            node = node->leftPointer;
+            continue;
+        }
+        size_t i;
+        for (i = 1; i < node->keyCount; i++) {
+            if (key < node->keys[i]->key) {
+                break;
+            }
+        }
+        node = node->keys[i - 1]->rightPointer;
+    }
+    return node;
+}
+
+bool bplus_tree_insert(BPlusTree *tree, uint64_t newKey, void *newValue) {
+    BPlusNode *node = bplus_tree_find_leaf(tree, newKey);
+    assert(node != NULL);
+
+    if (node->keyCount < node->order - 1) {
+        //Can insert at this node
+        BPlusKV *kv = new_bplus_kv(newKey, newValue, NULL);
+        bool insertKV = bplus_node_insert_kv(node, kv);
+        assert(insertKV == true);
+    } else {
+        //Note: as this is a leaf node, we are not updating/maintaining any pointers
+        //Insert and split
+        BPlusKV *kv = new_bplus_kv(newKey, newValue, NULL);
+        bool insertKV = bplus_node_insert_kv(node, kv);
+        assert(insertKV == true);
+
+        //Decide on new midpoint
+        size_t midpointIndex = node->order / 2;
+
+        //Create new node and update leaf links
+        BPlusNode *newNode = new_bplus_node(tree->nextID++, false, node->order);
+        newNode->parent = node->parent;
+        newNode->rightLeaf = node->rightLeaf;
+        newNode->leftLeaf = node;
+        node->rightLeaf = newNode;
+
+        //Move keys >= midpoint to a new node
+        size_t k = 0;
+        for (size_t i = midpointIndex; i < node->order; i++) {
+            newNode->keys[k++] = node->keys[i];
+            node->keys[i] = NULL;
+            newNode->keyCount++;
+            node->keyCount--;
+        }
+
+        //Send midpoint key to parent
+        BPlusKV *ascendingKV = new_bplus_kv(newNode->keys[0]->key, NULL, NULL);
+        ascendingKV->rightPointer = newNode;
+
+        do {
+            if (node->parent == NULL) {
+                //Split root, create a new node with the ascending kv and replace it
+                BPlusNode *newRoot = new_bplus_node(tree->nextID++, true, tree->order);
+                newRoot->leftPointer = node;
+                bplus_node_insert_kv(newRoot, ascendingKV);
+                tree->root = newRoot;
+                newNode->parent = tree->root;
+                node->parent = tree->root;
+                break;
+            } else {
+                node = node->parent;
+                bplus_node_insert_kv(node, ascendingKV);
+                if (node->keyCount < node->order) {
+                    break;
+                } else {
+                    //Parent needs splitting
+                    midpointIndex = node->order / 2;
+                    //Create new node
+                    newNode = new_bplus_node(tree->nextID++, true, node->order);
+                    newNode->parent = node->parent;
+                    //Move midpoint up and move keys > midpoint to new node
+                    k = 0;
+                    for (size_t i = midpointIndex + 1; i < node->order; i++) {
+                        newNode->keys[k++] = node->keys[i];
+                        node->keys[i] = NULL;
+                        newNode->keyCount++;
+                        node->keyCount--;
+                    }
+                    ascendingKV = node->keys[midpointIndex];
+                    node->keys[midpointIndex] = NULL;
+                    node->keyCount--;
+                    newNode->leftPointer = ascendingKV->rightPointer;
+                    ascendingKV->rightPointer = newNode;
+                }
+            }
+        } while (node != NULL);
+
+    }
+
+}

src/bplus_tree.h

@@ -0,0 +1,65 @@
+//
+// Created by sam on 14/06/18.
+//
+
+#ifndef SDB_BPLUS_TREE_H
+#define SDB_BPLUS_TREE_H
+
+#include <inttypes.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+struct BPlusNode_t;
+typedef struct BPlusNode_t BPlusNode;
+
+struct BPlusKV_t {
+    uint64_t key;
+    void *value;
+    BPlusNode *rightPointer;
+};
+typedef struct BPlusKV_t BPlusKV;
+
+BPlusKV *new_bplus_kv(uint64_t key, void *value, BPlusNode *leftPointer);
+
+void free_bplus_kv(BPlusKV *kv);
+
+struct BPlusNode_t {
+    uint64_t id;
+    bool isInternal;
+    size_t order;
+    BPlusNode *parent;
+    BPlusKV **keys;
+    size_t keyCount;
+    BPlusNode *leftPointer;
+    BPlusNode *leftLeaf;
+    BPlusNode *rightLeaf;
+};
+
+BPlusNode *new_bplus_node(uint64_t id, bool isInternal, size_t order);
+
+void free_bplus_node(BPlusNode *node);
+
+bool bplus_node_insert_kv(BPlusNode *node, BPlusKV *kv);
+
+void print_bplus_node(BPlusNode *node, size_t indent);
+
+struct BPlusTree_t {
+    size_t order;
+    size_t minFill;
+    BPlusNode *root;
+    uint64_t nextID;
+};
+typedef struct BPlusTree_t BPlusTree;
+
+BPlusTree *new_bplus_tree(size_t order);
+
+void free_bplus_tree(BPlusTree *tree);
+
+void print_bplus_tree(BPlusTree *tree);
+
+BPlusNode * bplus_tree_find_leaf(BPlusTree *tree, uint64_t key);
+
+bool bplus_tree_insert(BPlusTree *tree, uint64_t key, void *value);
+
+
+#endif //SDB_BPLUS_TREE_H