/**
* read_string - Retrieve a string from the buffer
*
* This reads a string from the buffer. It reads the length of the string
* as the first byte.
*
* offset[in] offset from start of buffer
*
* Returns string - String from the buffer
*/
char *Connector::read_string(int *offset) {
int len_bytes = get_lcb_len(buffer[*offset]);
int len = read_int(*offset, len_bytes);
char *str = (char *)malloc(len+1);
strncpy(str, (char *)&buffer[*offset+len_bytes], len);
str[len] = 0x00;
*offset += len_bytes+len;
return str;
}
/*
read_int - Retrieve an integer from the buffer in size bytes.
This reads an integer from the buffer at offset position indicated for
the number of bytes specified (size).
offset[in] offset from start of buffer
size[in] number of bytes to use to store the integer
Returns integer - integer from the buffer
*/
int MySQL_Packet::read_int(int offset, int size) {
int value = 0;
int new_size = 0;
if (size == 0)
new_size = get_lcb_len(offset);
if (size == 1)
return buffer[offset];
new_size = size;
int shifter = (new_size - 1) * 8;
for (int i = new_size; i > 0; i--) {
value += (byte)(buffer[i-1] << shifter);
shifter -= 8;
}
return value;
}
/**
* get_field - Read a field from the server
*
* This method reads a field packet from the server. Field packets are
* defined as:
*
* Bytes Name
* ----- ----
* n (Length Coded String) catalog
* n (Length Coded String) db
* n (Length Coded String) table
* n (Length Coded String) org_table
* n (Length Coded String) name
* n (Length Coded String) org_name
* 1 (filler)
* 2 charsetnr
* 4 length
* 1 type
* 2 flags
* 1 decimals
* 2 (filler), always 0x00
* n (Length Coded Binary) default
*
* Note: the sum of all db, column, and field names must be < 255 in length
*
*/
int Connector::get_field(field_struct *fs) {
int len_bytes;
int len;
int offset;
// Read field packets until EOF
read_packet();
if (buffer[4] != EOF_PACKET) {
// calculate location of db
len_bytes = get_lcb_len(4);
len = read_int(4, len_bytes);
offset = 4+len_bytes+len;
fs->db = read_string(&offset);
// get table
fs->table = read_string(&offset);
// calculate location of name
len_bytes = get_lcb_len(offset);
len = read_int(offset, len_bytes);
offset += len_bytes+len;
fs->name = read_string(&offset);
return 0;
}
return EOF_PACKET;
}
