1 /* 2 * 3 * Copyright 2015 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 #include <grpc/support/port_platform.h> 20 21 #include "src/core/ext/transport/chttp2/transport/varint.h" 22 23 uint32_t grpc_chttp2_hpack_varint_length(uint32_t tail_value) { 24 if (tail_value < (1 << 7)) { 25 return 2; 26 } else if (tail_value < (1 << 14)) { 27 return 3; 28 } else if (tail_value < (1 << 21)) { 29 return 4; 30 } else if (tail_value < (1 << 28)) { 31 return 5; 32 } else { 33 return 6; 34 } 35 } 36 37 void grpc_chttp2_hpack_write_varint_tail(uint32_t tail_value, uint8_t* target, 38 uint32_t tail_length) { 39 switch (tail_length) { 40 case 5: 41 target[4] = static_cast<uint8_t>((tail_value >> 28) | 0x80); 42 /* fallthrough */ 43 case 4: 44 target[3] = static_cast<uint8_t>((tail_value >> 21) | 0x80); 45 /* fallthrough */ 46 case 3: 47 target[2] = static_cast<uint8_t>((tail_value >> 14) | 0x80); 48 /* fallthrough */ 49 case 2: 50 target[1] = static_cast<uint8_t>((tail_value >> 7) | 0x80); 51 /* fallthrough */ 52 case 1: 53 target[0] = static_cast<uint8_t>((tail_value) | 0x80); 54 } 55 target[tail_length - 1] &= 0x7f; 56 } 57
