Optimize data file constants
parent
ab4ea22cc1
commit
3704f944e7
GPG Key ID:
B133F3167ABF94D8
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@ -1,6 +1,7 @@
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#pragma once
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#include <stdint.h>
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#include <YeltsinDB/types.h>
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/**
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* @file constants.h
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@ -9,6 +10,56 @@
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*/
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#define YDB_TABLE_FILE_SIGN "TBL!"
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#define YDB_TABLE_PAGE_SIZE 65536
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#define YDB_TABLE_FILE_SIGN_SIZE (sizeof(YDB_TABLE_FILE_SIGN))
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#define YDB_TABLE_FILE_VER_MAJOR_SIZE (1)
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#define YDB_TABLE_FILE_VER_MINOR_SIZE (1)
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#define YDB_TABLE_FILE_DATA_START_OFFSET (YDB_TABLE_FILE_SIGN_SIZE + YDB_TABLE_FILE_VER_MAJOR_SIZE + \
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YDB_TABLE_FILE_VER_MINOR_SIZE)
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#define YDB_TABLE_PAGE_SIZE (65536)
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#define YDB_TABLE_PAGE_FLAG_DELETED (1)
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// TODO static_assert for sizes
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// v0
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enum YDB_v0_sizes {
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YDB_v0_first_page_size = 8,
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YDB_v0_last_page_size = 8,
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YDB_v0_last_free_page_size = 8,
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YDB_v0_page_flags_size = 1,
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YDB_v0_page_next_size = 8,
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YDB_v0_page_row_count_size = 2,
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};
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enum YDB_v0_offsets {
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YDB_v0_first_page_offset = YDB_TABLE_FILE_DATA_START_OFFSET,
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YDB_v0_last_page_offset = YDB_v0_first_page_offset + YDB_v0_first_page_size,
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YDB_v0_last_free_page_offset = YDB_v0_last_page_offset + YDB_v0_last_page_size,
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YDB_v0_data_offset = YDB_v0_last_free_page_offset + YDB_v0_last_free_page_size,
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};
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enum YDB_v0_page_offsets {
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YDB_v0_page_flags_offset = 0,
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YDB_v0_page_next_offset = YDB_v0_page_flags_offset + YDB_v0_page_flags_size,
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YDB_v0_page_row_count_offset = YDB_v0_page_next_offset + YDB_v0_page_next_size,
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YDB_v0_page_data_offset = YDB_v0_page_row_count_offset + YDB_v0_page_row_count_size,
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};
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// v1
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enum YDB_v1_sizes {
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YDB_v1_first_page_size = 8,
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YDB_v1_last_page_size = 8,
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YDB_v1_last_free_page_size = 8,
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YDB_v1_page_flags_size = 1,
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YDB_v1_page_next_size = 8,
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YDB_v1_page_prev_size = 8,
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YDB_v1_page_row_count_size = 2,
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};
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enum YDB_v1_page_offsets {
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YDB_v1_page_flags_offset = 0,
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YDB_v1_page_next_offset = YDB_v1_page_flags_offset + YDB_v1_page_flags_size,
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YDB_v1_page_prev_offset = YDB_v1_page_next_offset + YDB_v1_page_next_size,
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YDB_v1_page_row_count_offset = YDB_v1_page_prev_offset + YDB_v1_page_prev_size,
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YDB_v1_page_data_offset = YDB_v1_page_row_count_offset + YDB_v1_page_row_count_size,
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};
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53
src/ydb.c
53
src/ydb.c
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@ -33,38 +33,6 @@ struct __YDB_Engine {
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FILE *fd; /**< Current table data file descriptor. */
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};
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struct __data_offsets {
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YDB_Offset signature,
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ver_major,
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ver_minor,
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first_page_offset,
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last_page_offset,
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last_free_page_offset,
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meta_end;
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};
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struct __page_offsets {
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YDB_Offset flags,
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next_page_offset,
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row_count,
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meta_end;
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};
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static const struct __data_offsets v0_offsets = {
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.signature = 0,
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.ver_major = 4,
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.ver_minor = 5,
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.first_page_offset = 6,
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.last_page_offset = 14,
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.last_free_page_offset = 22,
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.meta_end = 30
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};
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static const struct __page_offsets v0_page_offsets = {
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.flags = 0,
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.next_page_offset = 1,
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.row_count = 9,
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.meta_end = 11
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};
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YDB_Engine *ydb_init_instance() {
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YDB_Engine *new_instance = calloc(1, sizeof(YDB_Engine));
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return new_instance;
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@ -98,12 +66,12 @@ static YDB_Error __ydb_read_page(YDB_Engine *inst) {
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YDB_Flags page_flags = p_data[0];
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YDB_Offset next;
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YDB_PageSize row_count;
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memcpy(&next, p_data + v0_page_offsets.next_page_offset, sizeof(next));
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memcpy(&next, p_data + YDB_v0_page_next_offset, sizeof(next));
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REASSIGN_FROM_LE(next);
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memcpy(&row_count, p_data + v0_page_offsets.row_count, sizeof(row_count));
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memcpy(&row_count, p_data + YDB_v0_page_row_count_offset, sizeof(row_count));
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REASSIGN_FROM_LE(row_count);
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const YDB_PageSize meta_size = v0_page_offsets.meta_end;
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const YDB_PageSize meta_size = YDB_v0_page_data_offset;
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const YDB_PageSize data_size = YDB_TABLE_PAGE_SIZE - meta_size;
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YDB_TablePage *p = ydb_page_alloc(data_size);
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@ -138,12 +106,12 @@ static YDB_Offset __ydb_allocate_page_and_seek(YDB_Engine *inst) {
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// TODO throw error on fail
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// Write next page offset in the previous page
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fseek(inst->fd, inst->last_page_offset + v0_page_offsets.next_page_offset, SEEK_SET); // Skip page flag
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fseek(inst->fd, inst->last_page_offset + YDB_v0_page_next_offset, SEEK_SET); // Skip page flag
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fwrite(&allocated_page_offset_le, sizeof(YDB_Offset), 1, inst->fd);
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// Write last page offset
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inst->last_page_offset = result;
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fseek(inst->fd, v0_offsets.last_page_offset, SEEK_SET);
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fseek(inst->fd, YDB_v0_last_page_offset, SEEK_SET);
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fwrite(&allocated_page_offset_le, sizeof(YDB_Offset), 1, inst->fd);
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fflush(inst->fd);
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} else {
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@ -151,10 +119,10 @@ static YDB_Offset __ydb_allocate_page_and_seek(YDB_Engine *inst) {
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result = inst->last_free_page_offset;
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// Read last free page offset after allocation
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fseek(inst->fd, result + v0_page_offsets.next_page_offset, SEEK_SET); // Skip flag
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fseek(inst->fd, result + YDB_v0_page_next_offset, SEEK_SET); // Skip flag
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fread(&inst->last_free_page_offset, sizeof(YDB_Offset), 1, inst->fd);
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REASSIGN_FROM_LE(inst->last_free_page_offset);
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fseek(inst->fd, -(long)(sizeof(YDB_Offset) + 1), SEEK_CUR);
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fseek(inst->fd, -(long)(sizeof(YDB_Offset) + 1), SEEK_CUR); //FIXME magic
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// Rewrite page header
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char page_header[] = "\x00" // No flags
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@ -163,7 +131,7 @@ static YDB_Offset __ydb_allocate_page_and_seek(YDB_Engine *inst) {
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fwrite(page_header, sizeof(page_header)-1, 1, inst->fd);
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// Write last free page offset after allocation in file
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fseek(inst->fd, v0_offsets.last_free_page_offset, SEEK_SET);
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fseek(inst->fd, YDB_v0_last_free_page_offset, SEEK_SET);
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YDB_Offset lfp_offset_le = TO_LE(inst->last_free_page_offset);
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fwrite(&lfp_offset_le, sizeof(YDB_Offset), 1, inst->fd);
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}
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@ -184,6 +152,7 @@ YDB_Error ydb_load_table(YDB_Engine *instance, const char *path) {
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instance->fd = fopen(path, "rb+");
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THROW_IF_NULL(instance->fd, YDB_ERR_UNKNOWN); // TODO file open error
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// FIXME magic
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char signature[4];
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fread(signature, 1, 4, instance->fd);
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int signature_match = memcmp(signature, YDB_TABLE_FILE_SIGN, 3) == 0;
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@ -350,7 +319,7 @@ YDB_Error ydb_append_page(YDB_Engine* instance, YDB_TablePage* page) {
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YDB_PageSize rc = ydb_page_row_count_get(page);
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YDB_Flags f = ydb_page_flags_get(page);
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YDB_Offset next = 0;
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char d[YDB_TABLE_PAGE_SIZE - v0_page_offsets.meta_end];
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char d[YDB_TABLE_PAGE_SIZE - YDB_v0_page_data_offset];
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ydb_page_data_seek(page, 0);
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if (ydb_page_data_read(page, d, sizeof(d))) {
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return YDB_ERR_UNKNOWN; // FIXME
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@ -395,7 +364,7 @@ YDB_Error ydb_replace_current_page(YDB_Engine *instance, YDB_TablePage *page) {
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fwrite(&row_cnt_le, sizeof(row_cnt), 1, instance->fd);
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// Write data
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char page_data[YDB_TABLE_PAGE_SIZE - v0_page_offsets.meta_end];
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char page_data[YDB_TABLE_PAGE_SIZE - YDB_v0_page_data_offset];
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ydb_page_data_seek(page, 0);
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if (ydb_page_data_read(page, page_data, sizeof(page_data))) {
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return YDB_ERR_UNKNOWN; // FIXME
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