1 // Copyright (C) 2017 The Android Open Source Project 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 // Protos for "memory images". 16 17 syntax = "proto2"; 18 option optimize_for = LITE_RUNTIME; 19 20 package libtextclassifier.nlp_core; 21 22 message MemoryImageDataBlobInfo { 23 // Size (in bytes) of this data blob. 24 optional uint64 num_bytes = 1; 25 26 // Indicates whether this data blob corresponds to an array. 27 optional bool is_array = 2 [default = true]; 28 29 // Size (in bytes) of each array element. Useful for little <-> big endian 30 // conversions. -1 means unknown: no endianness conversion in that case. 31 optional int32 element_size = 3 [default = -1]; 32 } 33 34 message MemoryImageHeader { 35 // Version of the algorithm used to produce the memory image. We should 36 // increase the value used here every time we perform an incompatible change. 37 // Algorithm version v should handle only memory images of the same version, 38 // and crash otherwise. 39 optional int32 version = 1 [default = -1]; 40 41 // True if the info stored in the data blobs uses the little endian 42 // convention. Almost all machines today are little-endian but we want to be 43 // able to crash with an informative message or perform a (costly) conversion 44 // in the rare cases when that's not true. 45 optional bool is_little_endian = 2 [default = true]; 46 47 // Alignment (in bytes) for all data blobs. E.g., if this field is 16, then 48 // each data blob starts at an offset that's a multiple of 16, where the 49 // offset is measured from the beginning of the memory image. On the client 50 // side, allocating the entire memory image at an aligned address (by same 51 // alignment) makes sure all data blobs are properly aligned. 52 // 53 // NOTE: I (salcianu) explored the idea of a different alignment for each data 54 // blob: e.g., float[] should be fine with 4-byte alignment (alignment = 4) 55 // but char[] are fine with no alignment (alignment = 1). As we expect only a 56 // few (but large) data blobs, the space benefit is not worth the extra code 57 // complexity. 58 optional int32 alignment = 3 [default = 8]; 59 60 // One MemoryImageDataBlobInfo for each data blob, in order. There is one 61 // data blob for each large field we handle specially. 62 repeated MemoryImageDataBlobInfo blob_info = 4; 63 } 64
