| // Copyright 2018 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package protoapi |
| |
| import ( |
| "encoding/binary" |
| "encoding/json" |
| "fmt" |
| "hash/crc32" |
| "math" |
| "strconv" |
| ) |
| |
| // TODO: Are these the final signatures that we want? |
| |
| // EnumName is a helper function to simplify printing protocol buffer enums |
| // by name. Given an enum map and a value, it returns a useful string. |
| func EnumName(m map[int32]string, v int32) string { |
| s, ok := m[v] |
| if ok { |
| return s |
| } |
| return strconv.Itoa(int(v)) |
| } |
| |
| // UnmarshalJSONEnum is a helper function to simplify recovering enum int values |
| // from their JSON-encoded representation. Given a map from the enum's symbolic |
| // names to its int values, and a byte buffer containing the JSON-encoded |
| // value, it returns an int32 that can be cast to the enum type by the caller. |
| // |
| // The function can deal with both JSON representations, numeric and symbolic. |
| func UnmarshalJSONEnum(m map[string]int32, data []byte, enumName string) (int32, error) { |
| if data[0] == '"' { |
| // New style: enums are strings. |
| var repr string |
| if err := json.Unmarshal(data, &repr); err != nil { |
| return -1, err |
| } |
| val, ok := m[repr] |
| if !ok { |
| return 0, fmt.Errorf("unrecognized enum %s value %q", enumName, repr) |
| } |
| return val, nil |
| } |
| // Old style: enums are ints. |
| var val int32 |
| if err := json.Unmarshal(data, &val); err != nil { |
| return 0, fmt.Errorf("cannot unmarshal %#q into enum %s", data, enumName) |
| } |
| return val, nil |
| } |
| |
| // CompressGZIP compresses the input as a GZIP-encoded file. |
| // The current implementation does no compression. |
| func CompressGZIP(in []byte) (out []byte) { |
| // RFC 1952, section 2.3.1. |
| var gzipHeader = [10]byte{0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff} |
| |
| // RFC 1951, section 3.2.4. |
| var blockHeader [5]byte |
| const maxBlockSize = math.MaxUint16 |
| numBlocks := 1 + len(in)/maxBlockSize |
| |
| // RFC 1952, section 2.3.1. |
| var gzipFooter [8]byte |
| binary.LittleEndian.PutUint32(gzipFooter[0:4], crc32.ChecksumIEEE(in)) |
| binary.LittleEndian.PutUint32(gzipFooter[4:8], uint32(len(in))) |
| |
| // Encode the input without compression using raw DEFLATE blocks. |
| out = make([]byte, 0, len(gzipHeader)+len(blockHeader)*numBlocks+len(in)+len(gzipFooter)) |
| out = append(out, gzipHeader[:]...) |
| for blockHeader[0] == 0 { |
| blockSize := maxBlockSize |
| if blockSize > len(in) { |
| blockHeader[0] = 0x01 // final bit per RFC 1951, section 3.2.3. |
| blockSize = len(in) |
| } |
| binary.LittleEndian.PutUint16(blockHeader[1:3], uint16(blockSize)^0x0000) |
| binary.LittleEndian.PutUint16(blockHeader[3:5], uint16(blockSize)^0xffff) |
| out = append(out, blockHeader[:]...) |
| out = append(out, in[:blockSize]...) |
| in = in[blockSize:] |
| } |
| out = append(out, gzipFooter[:]...) |
| return out |
| } |
| |
| // TODO: Remove this when v2 textpb is available. |
| var CompactTextString func(Message) string |