void HiveSerializedRowSet::extractField(size_t column_idx) {
assert(column_idx < getColumnCount());
assert(m_row_weak_ptr != NULL);
/* The field buffer should always be large enough to hold the field */
assert(getFieldLen(column_idx) < sizeof(m_field_buffer));
/* Just safety precaution to prevent buffer overflow */
/* Reduce buffer size by one to save space for null terminator */
size_t extract_len = min(getFieldLen(column_idx), sizeof(m_field_buffer) - 1);
size_t copied = m_row_weak_ptr->copy(m_field_buffer, extract_len, m_field_offsets[column_idx]);
assert(copied == extract_len);
/* Make sure the buffer is null terminated */
m_field_buffer[extract_len] = '\0';
}
inline size_t getTupleLen(const MetaRelation& relation){
size_t len = 0;
for(auto field_map: relation.fields){
len += getFieldLen(field_map.second);
}
return len;
}
HiveReturn HiveRowSet::getFieldAsCString(size_t column_idx, char* buffer, size_t buffer_len,
size_t* data_byte_size, int* is_null_value, char* err_buf,
size_t err_buf_len) {
RETURN_ON_ASSERT(buffer == NULL, __FUNCTION__,
"Column data output buffer cannot be NULL.", err_buf, err_buf_len, HIVE_ERROR);
RETURN_ON_ASSERT(is_null_value == NULL, __FUNCTION__,
"Column data is_null_value (output) cannot be NULL.", err_buf, err_buf_len,
HIVE_ERROR);
RETURN_ON_ASSERT(getColumnCount() == 0, __FUNCTION__,
"Rowset contains zero columns.", err_buf, err_buf_len, HIVE_ERROR);
RETURN_ON_ASSERT(column_idx >= getColumnCount(), __FUNCTION__,
"Column index out of bounds.", err_buf, err_buf_len, HIVE_ERROR);
RETURN_ON_ASSERT(buffer_len == 0, __FUNCTION__,
"Output buffer cannot have a size of zero.", err_buf, err_buf_len, HIVE_ERROR);
if (m_last_column_fetched != column_idx) {
extractField(column_idx);
m_bytes_read = 0; /* Reset the read offset if different from the last column fetched */
m_last_column_fetched = column_idx;
m_is_completely_read = false;
}
if (m_is_completely_read) {
return HIVE_NO_MORE_DATA; /* This field has already been completely fetched by a previous call*/
}
/* If the column data is the same as the null format spec... */
if (strcmp(getNullFormat(), m_field_buffer) == 0) {
/* This value must be NULL */
*is_null_value = 1;
if (data_byte_size != NULL) {
*data_byte_size = 0;
}
buffer[0] = '\0';
} else {
/* This value has been determined not to be NULL */
*is_null_value = 0;
size_t data_total_len = getFieldLen(column_idx);
/* Cannot read more data then the total number of bytes available */
assert(data_total_len >= m_bytes_read);
size_t bytes_remaining = data_total_len - m_bytes_read; // Excludes null char
if (data_byte_size != NULL) {
/* Save the number of remaining characters to return before this fetch */
*data_byte_size = bytes_remaining;
}
/* Move pointer to the read location */
const char* src_str_ptr = m_field_buffer + m_bytes_read;
/* The total number of bytes to read (+1 null terminator) should be no more than the
* size of the field buffer */
assert(m_bytes_read + bytes_remaining + 1 <= sizeof(m_field_buffer));
/* Copy as many characters as possible from the read location */
size_t bytes_copied = safe_strncpy(buffer, src_str_ptr, min(buffer_len, bytes_remaining + 1)); // +1 for null terminator
/* bytes_copied does not count the null terminator */
m_bytes_read += bytes_copied;
if (m_bytes_read < data_total_len) {
return HIVE_SUCCESS_WITH_MORE_DATA; /* Data truncated; more data to return */
}
}
m_is_completely_read = true;
return HIVE_SUCCESS; /* All data successfully read */
}
HiveReturn HiveRowSet::getFieldDataLen(size_t column_idx, size_t* col_len, char* err_buf,
size_t err_buf_len) {
RETURN_ON_ASSERT(col_len == NULL, __FUNCTION__,
"Pointer to col_len (output) cannot be NULL.", err_buf, err_buf_len, HIVE_ERROR);
RETURN_ON_ASSERT(getColumnCount() == 0, __FUNCTION__,
"Rowset contains zero columns.", err_buf, err_buf_len, HIVE_ERROR);
RETURN_ON_ASSERT(column_idx >= getColumnCount(), __FUNCTION__,
"Column index out of bounds.", err_buf, err_buf_len, HIVE_ERROR);
*col_len = getFieldLen(column_idx);
return HIVE_SUCCESS;
}
