Tables
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#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <assert.h>
typedef enum {
QUERY_UNKNOWN,
QUERY_SELECT,
QUERY_WHERE,
QUERY_ANY,
QUERY_COUNT,
} Query_Tag;
typedef struct {
size_t col_count;
size_t *col_strides;
size_t row_count;
size_t row_stride;
void *data;
} Table_Header;
typedef Table_Header *Table;
typedef struct {
Query_Tag tag;
union {
void *(*select)(void *);
void *(*where)(void *);
bool (*any)(void *);
intptr_t (*count)();
};
} Query_Cond;
typedef struct {
size_t count;
Query_Cond *e;
} Query_Header;
typedef Query_Header *Query;
Table table_init(size_t row_count, size_t col_count)
{
void *data = calloc(row_count * col_count * 8, 1);
assert(data);
size_t *col_strides = (size_t *)calloc(col_count * 8, 1);
assert(col_strides);
for(size_t i = 0; i < col_count; ++i) {
col_strides[i] = i * 8;
}
Table table = (Table)calloc(sizeof(Table_Header), 1);
*table = (Table_Header){
.col_count = col_count,
.col_strides = col_strides,
.row_count = row_count,
.row_stride = col_count * 8,
.data = data,
};
return table;
}
void *get_cell(Table table, size_t r, size_t c) {
assert(r < table->row_count);
assert(c < table->col_count);
size_t row_i = r * table->row_stride;
size_t col_i = table->col_strides[c];
uint8_t *cell = (uint8_t *)table->data + row_i + col_i;
return cell;
}
void *query(Table table, Query query) {
if (table == 0 || query == 0) {
return 0;
}
for(size_t i = 0; i < query->count; ++i) {
switch(query->e[i].tag) {
case QUERY_UNKNOWN:break;
case QUERY_SELECT:break;
case QUERY_WHERE:break;
case QUERY_ANY:break;
case QUERY_COUNT:break;
default:break;
}
}
return 0;
}
int main(int argc, char **argv) {
Table table = table_init(4, 20);
size_t *cell0 = (size_t *)get_cell(table, 0, 0);
assert(table->data == cell0);
size_t *cell1 = (size_t *)get_cell(table, 3, 15);
*cell1 = 15;
size_t *cell2 = (size_t *)get_cell(table, 3, 15);
printf("%zu\n", *cell2);
void *row = query(table, 0);
return 0;
}
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