cacheowanie

Makefile

@@ -2,10 +2,11 @@ CC=gcc
 CFLAGS=-Wall -O0 -g
 LDFLAGS=-lm -lreadline
 
-all: makeidx openidx
+all: makeidx openidx readidx
 
-makeidx: makeidx.o io.o common.o index.o bitmap.c
-openidx: openidx.o io.o common.o index.o bitmap.c
+makeidx: makeidx.o io.o common.o index.o bitmap.o tape.o
+readidx: readidx.o io.o common.o index.o bitmap.o tape.o
+openidx: openidx.o io.o common.o index.o bitmap.o tape.o
 
 -include $(wildcard *.d)
 

index.c

@@ -4,11 +4,16 @@
 #include "io.h"
 #include "common.h"
 #include "bitmap.h"
+#include <libgen.h>
+#include <linux/limits.h>
 
 #define BTREE_ERR_CANNOT_OPEN_FILE    -1
 #define BTREE_ERR_PAGE_SIZE_DIFFERENT -2
 
-#define SWAP(type, x, y) do { type tmp; tmp = y; y = x; x = tmp; } while (0)
+#define SWAP(type, x, y) do { type __tmp__; __tmp__ = y; y = x; x = __tmp__; } while (0)
+
+unsigned reads  = 0;
+unsigned writes = 0;
 
 /* private functions */
 void _btree_insert_into_node(btree_t *tree, btree_node_t *node, btree_entry_t *entry);
@@ -21,16 +26,24 @@ int _btree_save_header(btree_t *tree)
 
 page_t _btree_alloc(btree_t *tree)
 {
-    page_t page = 2;
+    page_t page = 1, bitmap_page = 1;
     long long bit;
     uint8_t bitmap[PAGE_SIZE];
 
-    file_read(tree->file, 1, bitmap, PAGE_SIZE);
-    bit = bitmap_find_first(bitmap, PAGE_SIZE);
-    bitmap_set(bitmap, bit);
-    file_write(tree->file, 1, bitmap, PAGE_SIZE);
+    do { 
+        file_read(tree->file, bitmap_page, bitmap, PAGE_SIZE);
+        bit = bitmap_find_first(bitmap, PAGE_SIZE);
 
-    page += bit;
+        if (bit == -1) {
+            bitmap_page += PAGE_SIZE * 8 + 1;
+            page        += PAGE_SIZE * 8 + 1;
+        }
+    } while (bit == -1);
+
+    bitmap_set(bitmap, bit);
+    file_write(tree->file, bitmap_page, bitmap, PAGE_SIZE);
+
+    page += bit + 1;
 
     printfv(VERBOSITY_DEBUG, "[alloc] allocated page %zu.\n", page);
 
@@ -42,7 +55,7 @@ void _btree_page_free(btree_t *tree, page_t page)
     printfv(VERBOSITY_DEBUG, "[alloc] freeing page %zu.\n", page);
 
     uint8_t bitmap[PAGE_SIZE];
-    file_read(tree->file, 1, bitmap, PAGE_SIZE);
+    file_read(tree->file, 1 + (page / (PAGE_SIZE * 8)) * PAGE_SIZE, bitmap, PAGE_SIZE);
     bitmap_unset(bitmap, page - 2);
     file_write(tree->file, 1, bitmap, PAGE_SIZE);
 }
@@ -145,15 +158,31 @@ void _btree_node_insert_entry(btree_node_t* node, btree_entry_t entry)
     node->header.entries++;
 }
 
-void _btree_init(btree_t *tree)
+void _btree_init(btree_t *tree, char* mode)
 {
+    char path[PATH_MAX];
+    strcpy(path, tree->header.main);
+
+    char *dir = dirname(path);
+    sprintf(path, "%s/%s", dir, tree->header.main);
+
     _btree_stack_clear(tree);
+    
+    tree->main = tape_open(path, mode);
 }
 
 int btree_init(btree_t *tree, char* filename, size_t d)
 {
-    printfv(VERBOSITY_DEBUG, "[btree] Initializing btree in file %s d=%zu.\n", filename, d);
-    tree->file = file_open(filename, "w+", PAGE_SIZE);
+    char path[PATH_MAX];
+    strcpy(path, filename);
+
+    char* ext = strrchr(path, '.');
+    if (ext) *ext = 0;
+
+    sprintf(tree->header.main, "%s.dat", path);
+
+    printfv(VERBOSITY_DEBUG, "[btree] Initializing btree in file %s d=%zu, main=%s.\n", filename, d, tree->header.main);
+    tree->file = file_open(filename, "w+");
 
     if (!tree->file) {
         fprintf(stderr, "Cannot open file %s.\n", filename);
@@ -171,7 +200,7 @@ int btree_init(btree_t *tree, char* filename, size_t d)
     root.header.entries = 0;
 
     _btree_write_node(&root, tree, tree->header.root);
-    _btree_init(tree);
+    _btree_init(tree, "w");
 
     return 0;
 }
@@ -180,7 +209,7 @@ int btree_open(btree_t *tree, char* filename)
 {
     printfv(VERBOSITY_DEBUG, "[btree] Trying to open btree index in file %s\n", filename);
 
-    tree->file = file_open(filename, "r+", PAGE_SIZE);
+    tree->file = file_open(filename, "r+");
 
     if (!tree->file) {
         fprintf(stderr, "Cannot open file %s.\n", filename);
@@ -189,7 +218,7 @@ int btree_open(btree_t *tree, char* filename)
     
     file_read(tree->file, 0, &tree->header, sizeof(btree_header_t));
 
-    printfv(VERBOSITY_DEBUG, "[btree] Found BTREE d=%zu, ps=%zu, root=%" PRIu64 "\n", tree->header.d, tree->header.page_size, tree->header.root);
+    printfv(VERBOSITY_DEBUG, "[btree] Found BTREE d=%zu, ps=%zu, root=%" PRIu64 ", mainfile=%s\n", tree->header.d, tree->header.page_size, tree->header.root, tree->header.main);
 
     if (tree->header.page_size != PAGE_SIZE) {
         fprintf(stderr, "BTree page size mismatch, expecting %d got %zu, closing.\n", PAGE_SIZE, tree->header.page_size);
@@ -197,7 +226,7 @@ int btree_open(btree_t *tree, char* filename)
         return BTREE_ERR_PAGE_SIZE_DIFFERENT;
     }
 
-    _btree_init(tree);
+    _btree_init(tree, "rb+");
 
     return 0;
 }
@@ -427,14 +456,16 @@ page_t btree_find(btree_t *tree, record_key_t key, btree_entry_t* dest, btree_no
 
 page_t btree_insert(btree_t *tree, record_t record)
 {
-    record_key_t key   = record.key; 
+    record_key_t key    = record.key; 
     btree_node_t node;
     
     if (btree_find(tree, key, NULL, &node, NULL) != PAGE_NONE) {
         printfv(VERBOSITY_DEBUG, "[btree] record with key %zu already exists.\n", key);
         return PAGE_NONE;
     }
-    btree_entry_t entry = { PAGE_NONE, key, 2137, PAGE_NONE };
+
+    offset_t     offset = tape_append(tree->main, &record, sizeof(record));
+    btree_entry_t entry = { PAGE_NONE, key, offset, PAGE_NONE };
 
     _btree_insert_into_node(tree, &node, &entry);
     return node.page;
@@ -591,6 +622,23 @@ page_t btree_remove(btree_t *tree, record_key_t key)
     return node.page;
 }
 
+bool btree_update(btree_t *tree, record_key_t key, record_t record) 
+{
+    if (record.key != key) {
+        printfv(VERBOSITY_DEBUG, "[btree] update key mismatch, removing %zu and adding %zu.\n", key, record.key);
+        btree_remove(tree, key);
+        return btree_insert(tree, record) != PAGE_NONE;
+    }
+
+    btree_entry_t entry;
+    if (btree_find(tree, key, &entry, NULL, NULL) == PAGE_NONE) {
+        printfv(VERBOSITY_DEBUG, "[btree] Record with key %zu not found.\n", key, record.key);
+        return false;
+    }
+
+    return true;
+}
+
 btree_entry_t *btree_get_entry(btree_node_t* node, unsigned n) 
 {
     if (n > node->header.entries) {
@@ -604,4 +652,5 @@ void btree_close(btree_t* tree)
 {
     printfv(VERBOSITY_DEBUG, "[btree] Closing index %s.\n", tree->file->filename);
     file_close(tree->file);
+    tape_close(tree->main);
 }

index.h

@@ -3,6 +3,7 @@
 
 #include "io.h"
 #include "record.h"
+#include "tape.h"
 #include <inttypes.h>
 
 #define SIZEOF_ENTRIES(n) (sizeof(btree_node_header_t) + (sizeof(btree_entry_t) - sizeof(page_t))*(n) + ((n) > 0 ? 1 : 0) * sizeof(page_t))
@@ -16,11 +17,15 @@
 #define NODE_IS_ROOT 1
 #define NODE_IS_LEAF 2
 
+extern unsigned reads;
+extern unsigned writes;
+
 typedef struct {
     size_t d;         /* 8 bytes long */
     size_t page_size; /* 8 bytes long */
     page_t root;      /* 8 bytes long */
-} btree_header_t;     /* 24 bytes long */
+    char   main[256]; /* 256 bytes long */
+} btree_header_t;     /* 280 bytes long */
 
 typedef struct {
     uint16_t flags;
@@ -48,6 +53,7 @@ typedef struct {
 
 typedef struct {
     file_t         *file;
+    tape_t         *main;
     btree_header_t header;
     struct {
         btree_stack_elem_t *current;

io.c

@@ -5,22 +5,23 @@
 #include <stdlib.h>
 #include <string.h>
 
-file_t* file_open(const char* filename, const char* mode, size_t page_size)
+page_cache_entry_t *_file_load_page(file_t* file, page_t page);
+void _file_flush_page(file_t *file, page_cache_entry_t *entry);
+
+file_t* file_open(const char* filename, const char* mode)
 {
     FILE* handle = fopen(filename, mode);
 
     if (!handle) {
-        printfv(VERBOSITY_NORMAL, "Can't open file %s.\n", filename);
+        printfv(VERBOSITY_NORMAL, "[io] Can't open file %s.\n", filename);
         return NULL;
     }
 
-    printfv(VERBOSITY_DEBUG, "File %s opened in %s with page size %zu.\n", filename, mode, page_size);
+    printfv(VERBOSITY_DEBUG, "[io] File %s opened in %s with page size %zu.\n", filename, mode, PAGE_SIZE);
     file_t* result = malloc(sizeof(file_t));
 
-    result->page_size = page_size;
-    result->file      = handle;
-    result->filename  = malloc(strlen(filename) + 1); 
-    result->buffer    = malloc(page_size);
+    result->file     = handle;
+    result->filename = malloc(strlen(filename) + 1); 
 
     strcpy(result->filename, filename);
 
@@ -29,32 +30,80 @@ file_t* file_open(const char* filename, const char* mode, size_t page_size)
 
 void file_close(file_t* file)
 {
-    printfv(VERBOSITY_DEBUG, "Closing file %s.\n", file->filename);
+    file_flush(file);
+
+    printfv(VERBOSITY_DEBUG, "[io] Closing file %s.\n", file->filename);
     fclose(file->file);
 
     free(file->filename);
-    free(file->buffer);
     free(file);
 }
 
-size_t file_read(file_t* file, unsigned block, void* buffer, size_t length)
+size_t file_read(file_t* file, page_t page, void* buffer, size_t length)
 {
-    memset(file->buffer, 0, file->page_size);
+    page_cache_entry_t *entry = _file_load_page(file, page);
+    memcpy(buffer, entry->data, length);
 
-    printfv(VERBOSITY_DEBUG, "Reading page %u of %s.\n", block, file->filename);
-
-    fseek(file->file, block * file->page_size, SEEK_SET);
-    int read = fread(file->buffer, 1, file->page_size, file->file); 
-    memcpy(buffer, file->buffer, length);
-    return read;
+    return entry->size;
 }
 
-size_t file_write(file_t* file, unsigned block, const void* buffer, size_t length)
+size_t file_write(file_t* file, page_t page, const void* buffer, size_t length)
 {
-    memset(file->buffer, 0, file->page_size);
-    memcpy(file->buffer, buffer, length);
+    page_cache_entry_t *entry = _file_load_page(file, page);
 
-    printfv(VERBOSITY_DEBUG, "Writing page %u to %s. (%zu bytes)\n", block, file->filename, length);
-    fseek(file->file, block * file->page_size, SEEK_SET);
-    return fwrite(file->buffer, 1, file->page_size, file->file); 
+    memset(entry->data, 0, PAGE_SIZE);
+    memcpy(entry->data, buffer, length);
+
+    entry->flags |= PAGE_DIRTY;
+    entry->size   = length;
+
+    return entry->size;
+}
+
+void file_flush(file_t* file)
+{
+    for (unsigned i = 0; i < CACHE_ENTRIES; i++) {
+        _file_flush_page(file, file->cache + i);
+    }
+}
+
+page_cache_entry_t *_file_load_page(file_t* file, page_t page)
+{
+    page_cache_entry_t *entry = file->cache + (page % CACHE_ENTRIES);
+
+    if (entry->page == page && entry->flags & PAGE_PRESENT) {
+        // already in cache
+        return entry;
+    }
+
+    _file_flush_page(file, entry);
+    
+    int result = fseek(file->file, page * PAGE_SIZE, SEEK_SET);
+
+    memset(entry->data, 0, PAGE_SIZE); 
+    entry->size = fread(entry->data, 1, PAGE_SIZE, file->file);
+    if (entry->size) {
+        printfv(VERBOSITY_DEBUG, "[io] Loading page %u of %s (%zu bytes).\n", page, file->filename, entry->size);
+        reads++;
+    }
+
+    entry->page = page;
+    entry->flags |= PAGE_PRESENT;
+
+    return entry;
+}
+
+void _file_flush_page(file_t *file, page_cache_entry_t *entry) 
+{
+    if (entry->flags & PAGE_PRESENT && entry->flags & PAGE_DIRTY) {
+        printfv(VERBOSITY_DEBUG, "[io] Flushing page %u to %s (%zu bytes).\n", entry->page, file->filename, entry->size);
+
+        fseek(file->file, entry->page * PAGE_SIZE, SEEK_SET);
+        fwrite(entry->data, 1, entry->size, file->file); 
+
+        // disable dirty flag
+        entry->flags &= ~PAGE_DIRTY;
+
+        writes++;
+    }
 }

io.h

@@ -1,28 +1,43 @@
 #ifndef IO_H
 #define IO_H
 
-#define PAGE_SIZE 512
-#define PAGE_NONE 0 
+#define PAGE_SIZE  512
+#define PAGE_NONE  0 
+
+#define PAGE_PRESENT 1
+#define PAGE_DIRTY   2
+
+#define CACHE_ENTRIES 16
 
 #include <stdio.h>
 #include <inttypes.h>
 
-typedef struct {
-    FILE* file;
-
-    char*  filename;
-    size_t page_size;
-
-    void*  buffer;
-} file_t;
+extern unsigned reads;
+extern unsigned writes;
 
 typedef uint64_t page_t;
 typedef uint64_t offset_t;
 
-file_t* file_open(const char* filename, const char* mode, size_t page_size);
+typedef struct {
+    page_t  page;
+    size_t  size;
+    char    data[PAGE_SIZE];
+    uint8_t flags;
+} page_cache_entry_t;
+
+typedef struct {
+    FILE* file;
+    char* filename;
+
+    page_cache_entry_t cache[CACHE_ENTRIES];
+} file_t;
+
+file_t* file_open(const char* filename, const char* mode);
 void file_close(file_t* file);
 
-size_t file_read(file_t* file, unsigned block, void* buffer, size_t size);
-size_t file_write(file_t* file, unsigned block, const void* buffer, size_t size);
+size_t file_read(file_t* file, page_t page, void* buffer, size_t size);
+size_t file_write(file_t* file, page_t page, const void* buffer, size_t size);
+
+void file_flush(file_t* file);
 
 #endif

openidx.c

@@ -62,6 +62,7 @@ result_t dump_command(const char* command, char* args);
 result_t print_command(const char* command, char* args);
 result_t records_command(const char* command, char* args);
 result_t find_command(const char* command, char* args);
+result_t read_command(const char* command, char* args);
 result_t delete_command(const char* command, char* args);
 result_t verbosity_command(const char* command, char* args);
 
@@ -73,6 +74,7 @@ static command_t commands[] = {
     { "print", "Prints tree", print_command },
     { "records", "Prints records of given page", records_command },
     { "find", "Finds record", find_command },
+    { "read", "Reads record", read_command },
     { "delete", "Deletes record", delete_command },
     { "verbosity", "Changes the verbosity", verbosity_command },
 };
@@ -144,6 +146,29 @@ result_t find_command(const char* command, char* args)
     return RESULT_OK;
 }
 
+result_t read_command(const char* command, char* args)
+{
+    record_key_t key;
+
+    if (sscanf(args, "%u", &key) == 1) {
+        btree_entry_t entry;
+        page_t        page;
+        record_t      record;
+
+        if ((page = btree_find(&tree, key, &entry, NULL, NULL))) {
+            printf("Record %u found on page %zu, offset: %lu\n", key, page, entry.location);
+            tape_read(tree.main, entry.location, &record, sizeof(record_t));
+            printf("PK: %u, x: %lf, y: %lf\n", record.key, record.x, record.y);
+        } else {
+            printf("404 Not found\n");
+        }
+    } else {
+        printf("Usage: read key\n");
+    }
+
+    return RESULT_OK;
+}
+
 result_t delete_command(const char* command, char* args)
 {
     record_key_t key;
@@ -217,7 +242,7 @@ void print_page(page_t page, unsigned depth, unsigned current)
     for (int i = 0; i < node.header.entries; i++) {
         entry = btree_get_entry(&node, i);
         print_page(entry->left, depth - 1, current + 1);
-        printf("%s%zu < %u [0x%zx] > %zu\n", prefix, entry->left, entry->key, entry->location, entry->right);
+        printf("%s%zu < %u [0x%08zx] > %zu\n", prefix, entry->left, entry->key, entry->location, entry->right);
     }
     print_page(entry->right, depth - 1, current + 1);
 }

readidx.c

@@ -0,0 +1,83 @@
+#include <stdlib.h>
+#include <memory.h>
+
+#define OPTPARSE_IMPLEMENTATION
+#define OPTPARSE_API static
+#include "common.h"
+#include "index.h"
+
+typedef struct {
+    char* index;
+} opts_t;
+
+opts_t options;
+btree_t tree;
+
+void init_args(int args, char* argv[])
+{
+    optparse_t opts;
+    optparse_init(&opts, argv);
+
+    for (char opt; opt != -1; opt = optparse(&opts, "qv")) {
+        switch (opt) {
+            case 'q':
+                verbosity--;
+                break;
+            case 'v':
+                verbosity++;
+                break;
+        }
+    }
+
+    options.index = optparse_arg(&opts);
+}
+
+void help(const char* name) {
+    printf(
+        "%s - some help"
+        ,
+        name
+    );
+}
+
+void print_page(page_t page)
+{
+    if (!page) return;
+
+    char buffer[PAGE_SIZE];
+    char prefix[1024] = {};
+
+    file_read(tree.file, page, buffer, PAGE_SIZE);
+
+    btree_node_t node;
+    memcpy(&node.header,  buffer, sizeof(node.header));
+    memcpy(&node.entries, buffer + sizeof(node.header), NODE_SIZE_MAX);
+
+    btree_entry_t *entry;
+    for (int i = 0; i < node.header.entries; i++) {
+        entry = btree_get_entry(&node, i);
+        print_page(entry->left);
+        printf("%u\n", entry->key);
+    }
+    print_page(entry->right);
+}
+
+int main(int argc, char* argv[])
+{
+    if (argc < 2) {
+        help(argv[0]);
+        return 0;
+    }
+
+    init_args(argc, argv);
+    
+    if (btree_open(&tree, options.index) != 0) {
+        fprintf(stderr, "Cannot open indes %s for reading.", options.index);
+        return 1;
+    }
+
+    print_page(tree.header.root);
+
+    return EXIT_SUCCESS;
+}
+

tape.c

@@ -0,0 +1,96 @@
+#include "tape.h"
+#include "common.h"
+#include <stdlib.h>
+#include <memory.h>
+#include <string.h>
+
+tape_t* tape_open(const char* filename, const char* mode)
+{
+    file_t *file = file_open(filename, mode);
+    printfv(VERBOSITY_VERBOSE, "Opening file %s in mode %s.\n", filename, mode);
+   
+    if (!file) {
+        fprintf(stderr, "Cannot open %s in %s mode.", filename, mode);
+        return NULL;
+    }
+
+    tape_t* tape = malloc(sizeof(tape_t));
+
+    fseek(file->file, 0, SEEK_END);
+
+    tape->file = file;
+    tape->end  = ftell(file->file);
+
+    return tape;
+}
+
+void tape_close(tape_t* tape)
+{
+    file_close(tape->file);
+}
+
+void* tape_read(tape_t* tape, offset_t offset, void* record, size_t size)
+{
+    char buffer[PAGE_SIZE];
+
+    page_t page = offset / PAGE_SIZE;
+    offset      = offset % PAGE_SIZE;
+
+    offset_t written = 0;
+    file_read(tape->file, page, buffer, PAGE_SIZE);
+
+    while (size > PAGE_SIZE - offset) {
+        memcpy(record + written, buffer + offset, PAGE_SIZE - offset);
+
+        size    -= PAGE_SIZE - offset;
+        written += PAGE_SIZE - offset;
+
+        page++;
+        offset = 0;
+
+        file_read(tape->file, page, buffer, PAGE_SIZE);
+    }
+
+    memcpy(record + written, buffer + offset, size);
+
+    return record;
+}
+
+offset_t tape_write(tape_t* tape, offset_t location, void* record, size_t size)
+{
+    char buffer[PAGE_SIZE];
+
+    page_t   page   = location / PAGE_SIZE;
+    offset_t offset = location % PAGE_SIZE;
+
+    offset_t written = 0;
+    size_t original = file_read(tape->file, page, buffer, PAGE_SIZE);
+    while (size > PAGE_SIZE - offset) {
+        memcpy(buffer + offset, record + written, PAGE_SIZE - offset);
+
+        size    -= PAGE_SIZE - offset;
+        written += PAGE_SIZE - offset;
+
+        file_write(tape->file, page, buffer, PAGE_SIZE);
+
+        page++;
+        offset = 0;
+        
+        file_read(tape->file, page, buffer, PAGE_SIZE);
+    }
+
+    memcpy(buffer + offset, record + written, size);
+    file_write(tape->file, page, buffer, offset + size > original ? offset + size : original);
+
+    written += size;
+    if (location + written > tape->end) {
+        tape->end = location + written; 
+    }
+
+    return location;
+}
+
+offset_t tape_append(tape_t* tape, void* record, size_t size)
+{
+    return tape_write(tape, tape->end, record, size);
+}

tape.h

@@ -0,0 +1,20 @@
+#ifndef TAPE_H_
+#define TAPE_H_
+
+#include <stdio.h>
+#include "record.h"
+#include "io.h"
+
+typedef struct {
+    file_t   *file;
+    offset_t end;
+} tape_t;
+
+tape_t* tape_open(const char* filename, const char* mode);
+void    tape_close(tape_t* tape);
+
+void*    tape_read(tape_t* tape, offset_t offset, void* record, size_t size);
+offset_t tape_write(tape_t* tape, offset_t offet, void* record, size_t size);
+offset_t tape_append(tape_t* tape, void* record, size_t size);
+
+#endif