/// <summary> Запись потока в LargeObject</summary>
public static bool WriteLargeObject(this PGSQLDataAccess pgda, int loid, System.IO.Stream io, int blockSize = 512 * 1024)
{
var result = false;
pgda.UseTransaction((dc) =>
{
var fd = Convert.ToInt32(new PGSQLCommand("SELECT lo_open(:p0,:p1)", loid, 0x20000).ExecuteScalar(dc));
try
{
var buff = new byte[blockSize];
int len;
try
{
new PGSQLCommand("SELECT lo_truncate(:p0, 0)", fd).ExecuteNonQuery(dc);
var cmd = new PGSQLCommand("SELECT lowrite(:p0, :p1)", fd, buff);
do
{
len = io.Read(buff, 0, blockSize);
if (len != blockSize)
{
var newbuff = new byte[len];
Array.Copy(buff, newbuff, len);
buff = newbuff;
cmd["p1"] = newbuff;
}
cmd.ExecuteScalar(dc);
}while (len == blockSize);
result = true;
}
catch//(Exception ex)
{
result = false;
}
}
finally
{
new PGSQLCommand("SELECT lo_close(:p0)", fd).ExecuteNonQuery(dc);
}
});
return(result);
}
/// <summary> Чтение LargeObject в поток</summary>
public static bool ReadLargeObject(this PGSQLDataAccess pgda, int loid, System.IO.Stream io, int blockSize = 512 * 1024)
{
var result = false;
pgda.UseTransaction((dc) =>
{
var fd = Convert.ToInt32(new PGSQLCommand("SELECT lo_open(:p0,:p1)", loid, 0x40000).ExecuteScalar(dc));
try
{
int len;
try
{
var cmd = new PGSQLCommand("SELECT loread(:p0, :p1)", fd, blockSize);
do
{
var buff = (byte[])cmd.ExecuteScalar(dc);
len = buff.Length;
if (len > 0)
{
io.Write(buff, 0, len);
}
}while (len == blockSize);
result = true;
}
catch//(Exception ex)
{
result = false;
}
}
finally
{
new PGSQLCommand("SELECT lo_close(:p0)", fd).ExecuteNonQuery(dc);
}
});
return(result);
}