4. Adding a single file to a SQLar archive

4.1. Adding a file in C

4.1.1. sqlar_add_file

static int sqlar_add_file(const char *sqlar,
                          const char *file,
                          const char *name);

<<compress_function>>
static int sqlar_add_file(const char *sqlar,
                          const char *file,
                          const char *name)
{
    sqlite3 *db;
    int rc;
    sqlite3_stmt *stmt;
    struct stat x;
    char *zc;
    int sz_orig;
    int sz_compr;

    sz_orig = 0;
    sz_compr = 0;

    rc = stat(file, &x);
    if(rc) return SQLITE_CANTOPEN;
    rc = sqlite3_open(sqlar, &db);
    if(rc) return rc;
    rc = sqlite3_exec(db,
                      "CREATE TABLE IF NOT EXISTS sqlar(\n"
                      "  name TEXT PRIMARY KEY,\n"
                      "  mode INT,\n"
                      "  mtime INT,\n"
                      "  sz INT,\n"
                      "  data BLOB\n"
                      ");", 0, 0, 0);
    rc = sqlite3_exec(db, "SELECT 1 FROM sqlar LIMIT 1", 0, 0, 0);
    if(rc) {
        fprintf(stderr, "File %s is not a SQLar archive\n", sqlar);
        sqlite3_close(db);
        return rc;
    }
    sqlite3_prepare(db,
                    "REPLACE INTO sqlar(name,mode,mtime,sz,data)"
                    " VALUES(?1,?2,?3,?4,?5)",
                    -1,
                    &stmt,
                    NULL);

    sqlite3_bind_text(stmt, 1, name, -1, SQLITE_STATIC);
    sqlite3_bind_int(stmt, 2, x.st_mode);
    sqlite3_bind_int64(stmt, 3, x.st_mtime);

    zc = read_file(file, &sz_orig, &sz_compr);
    sqlite3_bind_int(stmt, 4, sz_orig);
    sqlite3_bind_blob(stmt, 5, zc, sz_compr, sqlite3_free);

    sqlite3_step(stmt);

    sqlite3_finalize(stmt);
    sqlite3_close(db);
    return SQLITE_OK;
}

4.1.2. Compress Function

static char *read_file(const char *filename, int *size_orig, int *size_compr)
{
    FILE *in;
    char *zin;
    long int nin;
    char *zcompr;
    unsigned long int ncompr;
    int rc;

    in = fopen(filename, "rb");

    if(in==0) {
        fprintf(stderr, "cannot open \"%s\" for reading\n", filename);
        return NULL;
    }

    fseek(in, 0, SEEK_END);
    nin = ftell(in);
    rewind(in);
    zin = sqlite3_malloc( nin+1 );

    if(zin==0) {
        fprintf(stderr, "cannot malloc for %ld bytes\n", nin+1);
        return NULL;
    }

    if( nin>0 && fread(zin, nin, 1, in)!=1 ){
        fprintf(stderr, "unable to read %ld bytes of file %s\n", nin, filename);
        return NULL;
    }

    fclose(in);
    ncompr = 13 + nin + (nin+999)/1000;
    zcompr = sqlite3_malloc(ncompr+1);

    if(zcompr==0) {
        fprintf(stderr, "cannot malloc for %ld bytes\n", ncompr+1);
        return NULL;
    }

    rc = compress((Bytef*)zcompr, &ncompr, (const Bytef*)zin, nin);

    if( rc!=Z_OK ) {
        fprintf(stderr, "Cannot compress %s\n", filename);
        return NULL;
    }

    if(nin>ncompr){
        sqlite3_free(zin);
        *size_orig = nin;
        *size_compr = (int)ncompr;
        return zcompr;
    }else{
        sqlite3_free(zcompr);
        *size_orig = *size_compr = nin;
        return zin;
    }
}

4.2. Adding a file in Scheme

{"sqlar:add-file", pp_add_file, 3, 3, {STR,STR,STR}},

static cell pp_add_file(cell x)
{
    const char *db;
    const char *file;
    const char *name;
    int rc;
    cell cstr;

    cstr = car(x);
    db = string(car(x));
    x = cdr(x);
    file = string(car(x));
    x = cdr(x);
    name = string(car(x));
    rc = sqlar_add_file(db, file, name);

    if(rc != SQLITE_OK) {
        error("Could not add file to sqlar archive", cstr);
    }
    return UNSPECIFIC;
}

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