130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <YeltsinDB/constants.h>
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#include <YeltsinDB/table_page.h>
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#include <YeltsinDB/error_code.h>
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#include <YeltsinDB/macro.h>
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/**
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* @struct __YDB_TablePage
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* @brief A struct that defines a page of a table.
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*/
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struct __YDB_TablePage {
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char* data; /**< Raw page data. */
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YDB_PageSize size; /**< The amount of memory in a page. */
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YDB_PageSize pos; /**< The current position of page data I/O stream. TODO: rewrite it */
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YDB_PageSize row_count; /**< Row count in a page. */
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YDB_Flags flags; /**< The flags of a page. */
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};
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YDB_TablePage* ydb_page_alloc(YDB_PageSize size) {
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YDB_TablePage* new_page = malloc(sizeof(YDB_TablePage));
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new_page->pos = 0;
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new_page->flags = 0; // No flags set
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new_page->size = size;
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new_page->data = calloc(1, new_page->size);
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return new_page;
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}
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void ydb_page_free(YDB_TablePage* page) {
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free(page->data);
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free(page);
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}
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YDB_Error ydb_page_data_seek(YDB_TablePage *page, YDB_PageSize pos) {
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THROW_IF_NULL(page, YDB_ERR_PAGE_NOT_INITIALIZED);
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if ((pos < 0) || (pos >= page->size)) {
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return YDB_ERR_PAGE_INDEX_OUT_OF_RANGE;
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}
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page->pos = pos;
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return YDB_ERR_SUCCESS;
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}
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YDB_PageSize ydb_page_data_tell(YDB_TablePage *page) {
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THROW_IF_NULL(page, YDB_ERR_PAGE_NOT_INITIALIZED);
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return page->pos;
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}
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YDB_Error ydb_page_data_read(YDB_TablePage *src, void *dst, YDB_PageSize n) {
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THROW_IF_NULL(src, YDB_ERR_PAGE_NOT_INITIALIZED);
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THROW_IF_NULL(dst, YDB_ERR_WRITE_TO_NULLPTR);
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THROW_IF_NULL(n, YDB_ERR_ZERO_SIZE_RW);
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if (src->pos == src->size) {
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return YDB_ERR_PAGE_INDEX_OUT_OF_RANGE;
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}
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// Trait as int64_t to prevent overflow.
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int64_t new_pos = src->pos + n;
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if (new_pos > (int64_t) src->size) {
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return YDB_ERR_PAGE_INDEX_OUT_OF_RANGE;
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}
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void* data_start = src->data + src->pos;
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memcpy(dst, data_start, n);
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src->pos += n;
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return YDB_ERR_SUCCESS;
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}
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YDB_Error ydb_page_data_write(YDB_TablePage *dst, const void *src, YDB_PageSize n) {
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THROW_IF_NULL(src, YDB_ERR_WRITE_TO_NULLPTR);
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THROW_IF_NULL(dst, YDB_ERR_PAGE_NOT_INITIALIZED);
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THROW_IF_NULL(n, YDB_ERR_ZERO_SIZE_RW);
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if (dst->pos == dst->size) {
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return YDB_ERR_PAGE_NO_MORE_MEM;
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}
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// Trait as int64_t to prevent overflow.
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int64_t new_pos = dst->pos + n;
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if (new_pos > (int64_t) dst->size) {
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return YDB_ERR_PAGE_INDEX_OUT_OF_RANGE;
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}
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void* data_start = dst->data + dst->pos;
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memcpy(data_start, src, n);
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dst->pos += n;
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return YDB_ERR_SUCCESS;
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}
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YDB_Flags ydb_page_flags_get(YDB_TablePage *page) {
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THROW_IF_NULL(page, 0);
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return page->flags;
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}
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void ydb_page_flags_set(YDB_TablePage *page, YDB_Flags flags) {
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if (!page) return;
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page->flags = flags;
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}
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YDB_PageSize ydb_page_row_count_get(YDB_TablePage *page) {
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THROW_IF_NULL(page, 0);
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return page->row_count;
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}
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void ydb_page_row_count_set(YDB_TablePage *page, YDB_PageSize row_count) {
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if (!page) return;
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page->row_count = row_count;
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}
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YDB_TablePage *ydb_page_clone(const YDB_TablePage *page) {
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YDB_TablePage* result = malloc(sizeof(YDB_TablePage));
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memcpy(result, page, sizeof(YDB_TablePage));
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result->data = malloc(result->size);
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memcpy(result->data, page->data, result->size);
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return result;
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}
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#ifdef __cplusplus
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}
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#endif
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