finish page & file

src/file.c

@@ -0,0 +1,49 @@
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include "../include/binary.h"
+#include "../include/page.h"
+#include "../include/file.h"
+
+uint8_t header[PAGESZ] = {'F', 'U', 'M', 'I', 'D', 'B', 1, 0};
+
+int init_file_header_page(int fd) {
+    lseek(fd, 0, SEEK_SET);
+    return write(fd, header, PAGESZ) != PAGESZ;
+}
+
+uint16_t get_db_version(int fd) {
+    uint16_t v;
+    if(lseek(fd, 6, SEEK_SET) < 0) return EOF;
+    readle16(fd, v);
+    return v;
+}
+
+int set_first_unused_block(int fd, uint64_t ptr) {
+    uint8_t buf[8];
+    if(lseek(fd, 8, SEEK_SET) < 0) return EOF;
+    putle64(buf, ptr);
+    return write(fd, buf, 8) != 8;
+}
+
+uint64_t get_first_unused_block(int fd) {
+    uint64_t ptr;
+    if(lseek(fd, 8, SEEK_SET) < 0) return EOF;
+    readle64(fd, ptr);
+    return ptr;
+}
+
+int set_first_table(int fd, uint64_t ptr) {
+    uint8_t buf[8];
+    if(lseek(fd, 16, SEEK_SET) < 0) return EOF;
+    putle64(buf, ptr);
+    return write(fd, buf, 8) != 8;
+}
+
+uint64_t get_first_table(int fd) {
+    uint64_t ptr;
+    if(lseek(fd, 16, SEEK_SET) < 0) return EOF;
+    readle64(fd, ptr);
+    return ptr;
+}