/* sqlite3_mem — in-memory SQLite operations (Tier 5 test fixture) * * Creates an in-memory database, creates a table, inserts rows, * queries them, and prints the results. Validates the full libc surface * (malloc, string formatting, math) exercised by SQLite. */#include <stdio.h>#include <stdlib.h>#include <string.h>#include "sqlite3.h" #ifdef SQLITE_OS_OTHER/* SQLite still requires a default VFS for :memory: databases. */typedef struct MemFile {    sqlite3_file base;} MemFile; static int memClose(sqlite3_file *pFile) { (void)pFile; return SQLITE_OK; }static int memRead(sqlite3_file *pFile, void *zBuf, int iAmt, sqlite3_int64 iOfst) {    (void)pFile; (void)zBuf; (void)iAmt; (void)iOfst; return SQLITE_IOERR_READ;}static int memWrite(sqlite3_file *pFile, const void *zBuf, int iAmt, sqlite3_int64 iOfst) {    (void)pFile; (void)zBuf; (void)iAmt; (void)iOfst; return SQLITE_IOERR_WRITE;}static int memTruncate(sqlite3_file *pFile, sqlite3_int64 size) {    (void)pFile; (void)size; return SQLITE_IOERR_TRUNCATE;}static int memSync(sqlite3_file *pFile, int flags) {    (void)pFile; (void)flags; return SQLITE_OK;}static int memFileSize(sqlite3_file *pFile, sqlite3_int64 *pSize) {    (void)pFile; *pSize = 0; return SQLITE_OK;}static int memLock(sqlite3_file *pFile, int lock) {    (void)pFile; (void)lock; return SQLITE_OK;}static int memUnlock(sqlite3_file *pFile, int lock) {    (void)pFile; (void)lock; return SQLITE_OK;}static int memCheckReservedLock(sqlite3_file *pFile, int *pResOut) {    (void)pFile; *pResOut = 0; return SQLITE_OK;}static int memFileControl(sqlite3_file *pFile, int op, void *pArg) {    (void)pFile; (void)op; (void)pArg; return SQLITE_NOTFOUND;}static int memSectorSize(sqlite3_file *pFile) { (void)pFile; return 512; }static int memDeviceCharacteristics(sqlite3_file *pFile) { (void)pFile; return 0; } static const sqlite3_io_methods memIoMethods __attribute__((used)) = {    1,    memClose,    memRead,    memWrite,    memTruncate,    memSync,    memFileSize,    memLock,    memUnlock,    memCheckReservedLock,    memFileControl,    memSectorSize,    memDeviceCharacteristics,    0, 0, 0, 0}; static int memOpen(sqlite3_vfs *pVfs, sqlite3_filename zName, sqlite3_file *pFile,                   int flags, int *pOutFlags) {    (void)pVfs; (void)zName; (void)flags;    pFile->pMethods = 0;    if (pOutFlags) *pOutFlags = flags;    return SQLITE_CANTOPEN;}static int memDelete(sqlite3_vfs *pVfs, const char *zName, int syncDir) {    (void)pVfs; (void)zName; (void)syncDir; return SQLITE_OK;}static int memAccess(sqlite3_vfs *pVfs, const char *zName, int flags, int *pResOut) {    (void)pVfs; (void)zName; (void)flags; *pResOut = 0; return SQLITE_OK;}static int memFullPathname(sqlite3_vfs *pVfs, const char *zName, int nOut, char *zOut) {    (void)pVfs;    snprintf(zOut, (size_t)nOut, "%s", zName ? zName : ":memory:");    return SQLITE_OK;}static int memRandomness(sqlite3_vfs *pVfs, int nByte, char *zOut) {    (void)pVfs;    for (int i = 0; i < nByte; i++) zOut[i] = (char)(i * 37 + 17);    return nByte;}static int memSleep(sqlite3_vfs *pVfs, int microseconds) {    (void)pVfs; (void)microseconds; return 0;}static int memCurrentTime(sqlite3_vfs *pVfs, double *pTime) {    (void)pVfs; *pTime = 2440587.5; return SQLITE_OK;}static int memGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf) {    (void)pVfs;    if (nBuf > 0) zBuf[0] = 0;    return 0;} static sqlite3_vfs memVfs __attribute__((used)) = {    1,    sizeof(MemFile),    512,    0,    "secure-exec-mem",    0,    memOpen,    memDelete,    memAccess,    memFullPathname,    0, 0, 0, 0,    memRandomness,    memSleep,    memCurrentTime,    memGetLastError,    0, 0, 0, 0}; int sqlite3_os_init(void) { return sqlite3_vfs_register(&memVfs, 1); }int sqlite3_os_end(void)  { return SQLITE_OK; }#endif static int print_row(void *unused, int ncols, char **values, char **names) {    (void)unused;    for (int i = 0; i < ncols; i++) {        if (i > 0) printf("|");        printf("%s=%s", names[i], values[i] ? values[i] : "NULL");    }    printf("\n");    return 0;} static void exec_sql(sqlite3 *db, const char *sql, const char *label) {    char *err = NULL;    int rc = sqlite3_exec(db, sql, print_row, NULL, &err);    if (rc != SQLITE_OK) {        fprintf(stderr, "%s error: %s\n", label, err);        sqlite3_free(err);        sqlite3_close(db);        exit(1);    }} int main(void) {    sqlite3 *db;    int rc;     rc = sqlite3_open(":memory:", &db);    if (rc != SQLITE_OK) {        fprintf(stderr, "open error: %s\n", sqlite3_errmsg(db));        return 1;    }    printf("db: open\n");     exec_sql(db,        "CREATE TABLE users ("        "  id INTEGER PRIMARY KEY,"        "  name TEXT NOT NULL,"        "  score REAL"        ");",        "create");    printf("table: created\n");     exec_sql(db,        "INSERT INTO users VALUES (1, 'Alice', 95.5);"        "INSERT INTO users VALUES (2, 'Bob', 87.3);"        "INSERT INTO users VALUES (3, 'Charlie', NULL);"        "INSERT INTO users VALUES (4, 'Diana', 92.1);",        "insert");    printf("rows: 4\n");     printf("--- query: all ---\n");    exec_sql(db, "SELECT id, name, score FROM users ORDER BY id;", "select");     printf("--- query: avg ---\n");    exec_sql(db, "SELECT COUNT(*) as total, AVG(score) as avg_score FROM users WHERE score IS NOT NULL;", "avg");     printf("--- query: top ---\n");    exec_sql(db, "SELECT name, score FROM users WHERE score IS NOT NULL ORDER BY score DESC LIMIT 2;", "top");     printf("version: %s\n", sqlite3_libversion());     sqlite3_close(db);    printf("db: closed\n");     return 0;}