mirror of
https://github.com/fumiama/fumidb.git
synced 2026-06-06 17:20:33 +08:00
350 lines
12 KiB
C
350 lines
12 KiB
C
// page.c
|
||
// 管理文件中的空闲块
|
||
|
||
#include <stdint.h>
|
||
#include <unistd.h>
|
||
#include <fcntl.h>
|
||
#include <errno.h>
|
||
|
||
#include "../include/binary.h"
|
||
#include "../include/page.h"
|
||
|
||
static const uint8_t nullpage[PAGESZ];
|
||
|
||
void* alloc_page(int fd, void* page) {
|
||
uint64_t ptr = 8, prev_ptr = 0, prev_prev_ptr = 0;
|
||
uint8_t buf[8];
|
||
if(page == NULL) return NULL;
|
||
// 对于 page，只关心位于第一页 8~15 字节的 ptr of unused blk
|
||
while(ptr) {
|
||
if(unlikely(ptr == prev_ptr)) { // 文件损坏
|
||
errno = ESPIPE;
|
||
return NULL;
|
||
}
|
||
if(!(ptr%PAGESZ)) { // 找到符合要求的页
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
if(read(fd, buf, 8) != 8) return NULL;
|
||
putle64(page, ptr);
|
||
page += 8;
|
||
if(lseek(fd, prev_ptr, SEEK_SET) < 0) return NULL;
|
||
if(write(fd, buf, 8) != 8) return NULL; // 从空闲块链表移除本块
|
||
return page;
|
||
}
|
||
if(prev_prev_ptr && ptr < prev_ptr && ptr != 8) { // 不符合顺序，进行一次调整
|
||
lseek(fd, prev_prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return NULL; // 1->next = 3
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
prev_prev_ptr = ptr; // new1 = 3
|
||
readle64(fd, ptr); // ptr(new3) = 3->next
|
||
lseek(fd, -8, SEEK_SET);
|
||
putle64(buf, prev_ptr); // new2 = 2
|
||
if(write(fd, buf, 8) != 8) return NULL; // 3->next = 2
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return NULL; // 2->next = ptr
|
||
continue;
|
||
}
|
||
prev_prev_ptr = prev_ptr;
|
||
prev_ptr = ptr;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
readle64(fd, ptr);
|
||
}
|
||
ptr = lseek(fd, 0, SEEK_END);
|
||
if((int)ptr < 0) return NULL;
|
||
if(ptr%PAGESZ) { // 文件没有页对齐
|
||
errno = ESPIPE;
|
||
return NULL;
|
||
}
|
||
if(write(fd, nullpage, PAGESZ) != PAGESZ) return NULL;
|
||
putle64(page, ptr);
|
||
return page+8;
|
||
}
|
||
|
||
void* get_page(int fd, uint64_t ptr, void* page) {
|
||
if(page == NULL) return NULL;
|
||
if(ptr%PAGESZ) return NULL;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
putle64(page, ptr);
|
||
page += 8;
|
||
if(read(fd, page, PAGESZ) != PAGESZ) return NULL;
|
||
return page;
|
||
}
|
||
|
||
int sync_page(int fd, void* page) {
|
||
if(page == NULL) return EOF;
|
||
uint64_t ptr = le64(page-8);
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
return write(fd, page, PAGESZ) != PAGESZ;
|
||
}
|
||
|
||
int free_page(int fd, void* page) {
|
||
if(page == NULL) return EOF;
|
||
uint64_t ptr = 8, prev_ptr = 0, prev_prev_ptr = 0, page_ptr = le64(page-8);
|
||
uint8_t buf[8];
|
||
while(ptr && ptr < page_ptr) {
|
||
if(unlikely(ptr == prev_ptr)) { // 文件损坏
|
||
errno = ESPIPE;
|
||
return EOF;
|
||
}
|
||
if(prev_prev_ptr && ptr < prev_ptr && ptr != 8) { // 不符合顺序，进行一次调整
|
||
lseek(fd, prev_prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 1->next = 3
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
prev_prev_ptr = ptr; // new1 = 3
|
||
readle64(fd, ptr); // ptr(new3) = 3->next
|
||
lseek(fd, -8, SEEK_SET);
|
||
putle64(buf, prev_ptr); // new2 = 2
|
||
if(write(fd, buf, 8) != 8) return EOF; // 3->next = 2
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 2->next = ptr
|
||
continue;
|
||
}
|
||
prev_prev_ptr = prev_ptr;
|
||
prev_ptr = ptr;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
readle64(fd, ptr);
|
||
}
|
||
putle64(page, ptr);
|
||
putle16(page+8, PAGESZ);
|
||
putle64(buf, page_ptr);
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 将本页附加到链表
|
||
sync_page(fd, page);
|
||
return 0;
|
||
}
|
||
|
||
void* alloc_block(int fd, uint16_t size, void* blk) {
|
||
uint64_t ptr = 8, prev_ptr = 0, prev_prev_ptr = 0;
|
||
uint8_t buf[8];
|
||
uint16_t blksz;
|
||
|
||
if(unlikely(blk == NULL)) {
|
||
errno = EINVAL;
|
||
return NULL;
|
||
}
|
||
if(unlikely(size > PAGESZ)) {
|
||
errno = EFBIG;
|
||
return NULL;
|
||
}
|
||
// 对于 page，只关心位于第一页 8~15 字节的 ptr of unused blk
|
||
while(ptr) {
|
||
if(unlikely(lseek(fd, ptr, SEEK_SET) < 0)) return NULL;
|
||
if(unlikely(read(fd, buf, 8) != 8)) {
|
||
errno = ENOSR;
|
||
return NULL;
|
||
}
|
||
if(unlikely(ptr == prev_ptr)) { // 文件损坏
|
||
errno = ESPIPE;
|
||
return NULL;
|
||
}
|
||
if(ptr == 8) blksz = 0;
|
||
else readle16(fd, blksz);
|
||
#ifdef DEBUG
|
||
printf("ptr: %016llx, blksize: %d\n", ptr, blksz);
|
||
#endif
|
||
if(blksz >= size) { // 找到符合要求的块
|
||
if(blksz - size > 10) { // 分裂块
|
||
lseek(fd, ptr+size, SEEK_SET);
|
||
write(fd, buf, 8);
|
||
blksz -= size;
|
||
putle16(buf, blksz);
|
||
write(fd, buf, 2);
|
||
putle64(buf, ptr+size);
|
||
}
|
||
putle64(blk, ptr);
|
||
putle16(blk+8, size);
|
||
#ifdef DEBUG
|
||
printf("find match: ptr: %016llx, size: %d\n", ptr, size);
|
||
#endif
|
||
blk += 10;
|
||
if(lseek(fd, prev_ptr, SEEK_SET) < 0) return NULL;
|
||
if(write(fd, buf, 8) != 8) { // 从空闲块链表移除本块
|
||
errno = ENOSR;
|
||
return NULL;
|
||
}
|
||
return blk;
|
||
}
|
||
if(prev_prev_ptr && ptr < prev_ptr && ptr != 8) { // 不符合顺序，进行一次调整
|
||
lseek(fd, prev_prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return NULL; // 1->next = 3
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
prev_prev_ptr = ptr; // new1 = 3
|
||
readle64(fd, ptr); // ptr(new3) = 3->next
|
||
lseek(fd, -8, SEEK_SET);
|
||
putle64(buf, prev_ptr); // new2 = 2
|
||
if(write(fd, buf, 8) != 8) return NULL; // 3->next = 2
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return NULL; // 2->next = ptr
|
||
continue;
|
||
}
|
||
prev_prev_ptr = prev_ptr;
|
||
prev_ptr = ptr;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
readle64(fd, ptr);
|
||
}
|
||
ptr = lseek(fd, 0, SEEK_END);
|
||
if((int)ptr < 0) return NULL;
|
||
if(ptr%PAGESZ) { // 文件没有页对齐
|
||
errno = ESPIPE;
|
||
return NULL;
|
||
}
|
||
if(write(fd, nullpage, PAGESZ) != PAGESZ) {
|
||
errno = ENOSR;
|
||
return NULL;
|
||
}
|
||
if(PAGESZ-size > 10) { // 回收冗余
|
||
if(lseek(fd, prev_ptr, SEEK_SET) < 0) return NULL;
|
||
putle64(buf, ptr+size);
|
||
if(write(fd, buf, 8) != 8) return NULL;
|
||
if(lseek(fd, ptr+size+8, SEEK_SET) < 0) return NULL;
|
||
putle16(buf, PAGESZ - size);
|
||
if(write(fd, buf, 2) != 2) return NULL;
|
||
}
|
||
putle64(blk, ptr);
|
||
putle16(blk+8, size);
|
||
return blk+10;
|
||
}
|
||
|
||
void* get_block(int fd, uint16_t size, uint64_t ptr, void* blk) {
|
||
if(blk == NULL) return NULL;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return NULL;
|
||
putle64(blk, ptr);
|
||
putle16(blk+8, size);
|
||
blk += 10;
|
||
if(read(fd, blk, size) != size) return NULL;
|
||
return blk;
|
||
}
|
||
|
||
int sync_block(int fd, void* blk) {
|
||
if(blk == NULL) return EOF;
|
||
uint64_t off = le64(blk-10);
|
||
uint16_t size = le16(blk-2);
|
||
if(size > PAGESZ) {
|
||
errno = EFBIG;
|
||
return EOF;
|
||
}
|
||
#ifdef DEBUG
|
||
printf("off: %016llx, size: %d\n", off, size);
|
||
#endif
|
||
if(lseek(fd, off, SEEK_SET) < 0) return EOF;
|
||
return write(fd, blk, size) != size;
|
||
}
|
||
|
||
int free_block(int fd, void* blk) {
|
||
if(blk == NULL) return EOF;
|
||
uint64_t ptr = 8, prev_ptr = 0, prev_prev_ptr = 0, off = le64(blk-10);
|
||
uint8_t buf[8];
|
||
uint16_t size = le16(blk-2), sz;
|
||
while(ptr && ptr < off) {
|
||
if(unlikely(ptr == prev_ptr)) { // 文件损坏
|
||
errno = ESPIPE;
|
||
return EOF;
|
||
}
|
||
if(prev_prev_ptr && ptr < prev_ptr && ptr != 8) { // 不符合顺序，进行一次调整
|
||
lseek(fd, prev_prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 1->next = 3
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
prev_prev_ptr = ptr; // new1 = 3
|
||
readle64(fd, ptr); // ptr(new3) = 3->next
|
||
lseek(fd, -8, SEEK_SET);
|
||
putle64(buf, prev_ptr); // new2 = 2
|
||
if(write(fd, buf, 8) != 8) return EOF; // 3->next = 2
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 2->next = ptr
|
||
continue;
|
||
}
|
||
prev_prev_ptr = prev_ptr;
|
||
prev_ptr = ptr;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
readle64(fd, ptr);
|
||
}
|
||
putle64(blk, ptr);
|
||
putle16(blk+8, size);
|
||
putle64(buf, off);
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 将本页附加到链表
|
||
readle16(fd, sz);
|
||
if(prev_ptr+sz == off && prev_ptr%PAGESZ < off%PAGESZ) { // 可以和前一块合并
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
write(fd, blk, 8);
|
||
putle16(buf, size+sz);
|
||
write(fd, buf, 2);
|
||
return 0;
|
||
}
|
||
if(off+size == ptr && off%PAGESZ < ptr%PAGESZ) { // 可以和后一块合并
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
readle64(fd, prev_ptr);
|
||
readle16(fd, sz);
|
||
putle64(blk, prev_ptr);
|
||
putle16(blk, size+sz);
|
||
}
|
||
sync_block(fd, blk);
|
||
return 0;
|
||
}
|
||
|
||
int add_block(int fd, uint16_t size, uint64_t off) {
|
||
uint64_t ptr = 8, prev_ptr = 0, prev_prev_ptr = 0;
|
||
uint8_t buf[8];
|
||
uint16_t sz;
|
||
while(ptr && ptr < off) {
|
||
if(unlikely(ptr == prev_ptr)) { // 文件损坏
|
||
errno = ESPIPE;
|
||
return EOF;
|
||
}
|
||
if(prev_prev_ptr && ptr < prev_ptr && ptr != 8) { // 不符合顺序，进行一次调整
|
||
lseek(fd, prev_prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 1->next = 3
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
prev_prev_ptr = ptr; // new1 = 3
|
||
readle64(fd, ptr); // ptr(new3) = 3->next
|
||
lseek(fd, -8, SEEK_SET);
|
||
putle64(buf, prev_ptr); // new2 = 2
|
||
if(write(fd, buf, 8) != 8) return EOF; // 3->next = 2
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 2->next = ptr
|
||
continue;
|
||
}
|
||
prev_prev_ptr = prev_ptr;
|
||
prev_ptr = ptr;
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
readle64(fd, ptr);
|
||
}
|
||
if(lseek(fd, off, SEEK_SET) < 0) return EOF;
|
||
putle64(buf, ptr);
|
||
write(fd, buf, 8);
|
||
putle16(buf, size);
|
||
write(fd, buf, 2);
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, off);
|
||
if(write(fd, buf, 8) != 8) return EOF; // 将本页附加到链表
|
||
readle16(fd, sz);
|
||
if(prev_ptr+sz == off && prev_ptr%PAGESZ < off%PAGESZ) { // 可以和前一块合并
|
||
lseek(fd, prev_ptr, SEEK_SET);
|
||
putle64(buf, ptr);
|
||
write(fd, buf, 8);
|
||
putle16(buf, size+sz);
|
||
write(fd, buf, 2);
|
||
return 0;
|
||
}
|
||
if(off+size == ptr && off%PAGESZ < ptr%PAGESZ) { // 可以和后一块合并
|
||
if(lseek(fd, ptr, SEEK_SET) < 0) return EOF;
|
||
readle64(fd, prev_ptr);
|
||
readle16(fd, sz);
|
||
lseek(fd, off, SEEK_SET);
|
||
putle64(buf, prev_ptr);
|
||
write(fd, buf, 8);
|
||
putle16(buf, size+sz);
|
||
write(fd, buf, 2);
|
||
}
|
||
return 0;
|
||
}
|