| // Copyright (C) MongoDB, Inc. 2017-present. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| // not use this file except in compliance with the License. You may obtain |
| // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| |
| package wiremessage |
| |
| import ( |
| "bytes" |
| "errors" |
| |
| "github.com/mongodb/mongo-go-driver/bson" |
| ) |
| |
| func readInt32(b []byte, pos int32) int32 { |
| return (int32(b[pos+0])) | (int32(b[pos+1]) << 8) | (int32(b[pos+2]) << 16) | (int32(b[pos+3]) << 24) |
| } |
| |
| func readCString(b []byte, pos int32) (string, error) { |
| null := bytes.IndexByte(b[pos:], 0x00) |
| if null == -1 { |
| return "", errors.New("invalid cstring") |
| } |
| return string(b[pos : int(pos)+null]), nil |
| } |
| |
| func readInt64(b []byte, pos int32) int64 { |
| return (int64(b[pos+0])) | (int64(b[pos+1]) << 8) | (int64(b[pos+2]) << 16) | (int64(b[pos+3]) << 24) | (int64(b[pos+4]) << 32) | |
| (int64(b[pos+5]) << 40) | (int64(b[pos+6]) << 48) | (int64(b[pos+7]) << 56) |
| |
| } |
| |
| // readDocument will attempt to read a bson.Reader from the given slice of bytes |
| // from the given position. |
| func readDocument(b []byte, pos int32) (bson.Raw, int, Error) { |
| if int(pos)+4 > len(b) { |
| return nil, 0, Error{Message: "document too small to be valid"} |
| } |
| size := int(readInt32(b, int32(pos))) |
| if int(pos)+size > len(b) { |
| return nil, 0, Error{Message: "document size is larger than available bytes"} |
| } |
| if b[int(pos)+size-1] != 0x00 { |
| return nil, 0, Error{Message: "document invalid, last byte is not null"} |
| } |
| // TODO(GODRIVER-138): When we add 3.0 support, alter this so we either do one larger make or use a pool. |
| rdr := make(bson.Raw, size) |
| copy(rdr, b[pos:int(pos)+size]) |
| return rdr, size, Error{Type: ErrNil} |
| } |