1 /* 2 * Copyright 2021 Google LLC 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 #include "varint.h" 17 18 #include <cstdint> 19 20 #include <gtest/gtest.h> 21 22 // A straightforward implementation of Length64 for testing 23 inline int Varint_Length64Old(uint64_t v) { 24 // Each byte of output stores 7 bits of "v" until "v" becomes zero 25 int nbytes = 0; 26 do { 27 nbytes++; 28 v >>= 7; 29 } while (v != 0); 30 return nbytes; 31 } 32 33 TEST(VarintTest, Length64) { 34 ASSERT_EQ(Varint::Length64(0), 1); 35 ASSERT_EQ(Varint::Length64(1), 1); 36 ASSERT_EQ(Varint::Length64(127), 1); 37 ASSERT_EQ(Varint::Length64(128), 2); 38 ASSERT_EQ(Varint::Length64(16383), 2); 39 ASSERT_EQ(Varint::Length64(16384), 3); 40 // Check around each power of two 41 for (int i = 0; i < 63; i++) { 42 uint64_t v = (1ull << i); 43 ASSERT_EQ(Varint::Length64(v - 1), Varint_Length64Old(v - 1)); 44 ASSERT_EQ(Varint::Length64(v), Varint_Length64Old(v)); 45 ASSERT_EQ(Varint::Length64(v + 1), Varint_Length64Old(v + 1)); 46 } 47 ASSERT_EQ(Varint::Length64(((uint64_t)1 << 21) - 1), 3); 48 ASSERT_EQ(Varint::Length64((uint64_t)1 << 21), 4); 49 ASSERT_EQ(Varint::Length64((uint64_t)1 << 63), Varint::kMax64); 50 ASSERT_EQ(Varint::Length64(~0ull), Varint::kMax64); 51 } 52 53 TEST(VarintTest, Encode32) { 54 // Encode32 the 28-bit number 1110 0100 1001 1001 1000 0110 0111 55 // aka hex E 49 98 67 56 // which can be split in groups of 7 bytes as 1110010 0100110 0110000 1100111 57 // which should encode to (reverse the bytes, set the MSB to 1): 58 // 11100111 10110000 10100110 01110010 aka hex E7 B0 A6 72 59 char s[20]; 60 uint32_t n = 0xe499867; 61 unsigned char n_encrypt[5] = {0xe7, 0xb0, 0xa6, 0x72, '\0'}; 62 char* end_s = Varint::Encode32(s, n); 63 // now end_s - s represents the encryption length 64 ASSERT_EQ(end_s - s, Varint::Length64(n)); 65 *end_s = '\0'; // terminate the string 66 ASSERT_EQ(std::string(s), std::string(reinterpret_cast<char*>(n_encrypt))); 67 } 68 69 TEST(VarintTest, Encode64) { 70 // Encode64 the 60-bit number 71 // 1110 0100 1001 1001 1000 0110 0111 1001 0100 0111 0000 1101 1001 1000 1101 72 // aka hex E 49 98 67 94 70 D9 8D 73 // which can be split in groups of 7 bytes as 74 // 1110 0100100 1100110 0001100 1111001 0100011 1000011 0110011 0001101 75 // which should encode to (reverse the bytes, set the MSB to 1): 76 // 10001101 10110011 11000011 10100011 11111001 10001100 11100110 10100100 77 // 00001110 aka hex 8D B3 C3 A3 F9 8C E6 A4 0E 78 char s[10]; 79 uint64_t n = 0xe4998679470d98dull; 80 unsigned char n_encrypt[10] = {0x8d, 0xb3, 0xc3, 0xa3, 0xf9, 0x8c, 0xe6, 0xa4, 0x0e, '\0'}; 81 char* end_s = Varint::Encode64(s, n); 82 // now end_s - s represents the encryption length 83 ASSERT_EQ(end_s - s, Varint::Length64(n)); 84 *end_s = '\0'; // terminate the string 85 ASSERT_EQ(std::string(s), std::string(reinterpret_cast<char*>(n_encrypt))); 86 } 87