garray

garray.c

#include <sqlite3ext.h>
SQLITE_EXTENSION_INIT1

#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

static int g_arr_size;
static int* g_arr;

static void gaSizeOfIntFunc(sqlite3_context *context, int argc, sqlite3_value **argv) {
  sqlite3_result_int64(context, sizeof(int));
}

static void gaInitFunc(sqlite3_context *context, int argc, sqlite3_value **argv) {
  assert(argc == 1);
  if (sqlite3_value_type(argv[0]) != SQLITE_INTEGER) {
    sqlite3_result_error(context, "len must be an integer ", -1);
    return;
  }
  int64_t len = sqlite3_value_int64(argv[0]);
  if (len <= 0 || len > 0x1000000) {
    sqlite3_result_error(context, "len must be in range [1 .. 2^24]", -1);
    return;
  }
  free(g_arr);
  g_arr = calloc((size_t)len, sizeof(int));
  if (!g_arr) {
    sqlite3_result_error_nomem(context);
    g_arr_size = 0;
  } else {
    sqlite3_result_int64(context, len);
    g_arr_size = len;
  }
}

static void gaRefFunc(sqlite3_context *context, int argc, sqlite3_value **argv) {
  assert(argc == 1);

  if (g_arr_size == 0) {
    sqlite3_result_error(context, "garray is not initialized", -1);
    return;
  }
  if (sqlite3_value_type(argv[0]) != SQLITE_INTEGER) {
    sqlite3_result_error(context, "index must be an integer", -1);
    return;
  }

  int64_t idx = sqlite3_value_int64(argv[0]);
  if (idx < 0 || idx >= g_arr_size) {
    sqlite3_result_error(context, "range error", -1);
  } else {
    sqlite3_result_int64(context, g_arr[idx]);
  }
}

static void gaSetFunc(sqlite3_context *context, int argc, sqlite3_value **argv) {
  assert(argc == 2);
  if (g_arr_size == 0) {
    sqlite3_result_error(context, "garray is not initialized", -1);
    return;
  }
  if (sqlite3_value_type(argv[0]) != SQLITE_INTEGER) {
    sqlite3_result_error(context, "idx must be an integer", -1);
    return;
  }
  if (sqlite3_value_type(argv[1]) != SQLITE_INTEGER) {
    sqlite3_result_error(context, "value must be an integer", -1);    
  }
  int64_t idx = sqlite3_value_int64(argv[0]);
  int64_t set_value = sqlite3_value_int64(argv[1]);
  if (idx < 0 || idx >= g_arr_size) {
    sqlite3_result_error(context, "range error", -1);
  } else {
    g_arr[idx] = (int)set_value;
    sqlite3_result_int64(context, g_arr[idx]);
  }
}

static void gaReleaseFunc(sqlite3_context *context, int argc, sqlite3_value **argv) {
  free(g_arr);
  g_arr = NULL;
  g_arr_size = 0;
  sqlite3_result_int64(context, 0);
}

#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_extension_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
  g_arr = NULL;
  g_arr_size = 0;
  sqlite3_create_function_v2(db, "gainit", 1, SQLITE_UTF8, 0, gaInitFunc, 0, 0, NULL);
  sqlite3_create_function_v2(db, "garef", 1, SQLITE_UTF8, 0, gaRefFunc, 0, 0, NULL);
  sqlite3_create_function_v2(db, "gaset", 2, SQLITE_UTF8, 0, gaSetFunc, 0, 0, NULL);
  sqlite3_create_function_v2(db, "garelease", 0, SQLITE_UTF8, 0, gaReleaseFunc, 0, 0, NULL);
  sqlite3_create_function_v2(db, "gasizeofint", 0, SQLITE_UTF8, 0, gaSizeOfIntFunc, 0, 0, NULL);
  return rc;
}