encoding.c revision 1.2
1/* 2 * Copyright (c) 2014-2019 Pavel Kalvoda <me@pavelkalvoda.com> 3 * 4 * libcbor is free software; you can redistribute it and/or modify 5 * it under the terms of the MIT license. See LICENSE for details. 6 */ 7 8#include "encoding.h" 9#include "internal/encoders.h" 10 11size_t cbor_encode_uint8(uint8_t value, unsigned char *buffer, 12 size_t buffer_size) { 13 return _cbor_encode_uint8(value, buffer, buffer_size, 0x00); 14} 15 16size_t cbor_encode_uint16(uint16_t value, unsigned char *buffer, 17 size_t buffer_size) { 18 return _cbor_encode_uint16(value, buffer, buffer_size, 0x00); 19} 20 21size_t cbor_encode_uint32(uint32_t value, unsigned char *buffer, 22 size_t buffer_size) { 23 return _cbor_encode_uint32(value, buffer, buffer_size, 0x00); 24} 25 26size_t cbor_encode_uint64(uint64_t value, unsigned char *buffer, 27 size_t buffer_size) { 28 return _cbor_encode_uint64(value, buffer, buffer_size, 0x00); 29} 30 31size_t cbor_encode_uint(uint64_t value, unsigned char *buffer, 32 size_t buffer_size) { 33 return _cbor_encode_uint(value, buffer, buffer_size, 0x00); 34} 35 36size_t cbor_encode_negint8(uint8_t value, unsigned char *buffer, 37 size_t buffer_size) { 38 return _cbor_encode_uint8(value, buffer, buffer_size, 0x20); 39} 40 41size_t cbor_encode_negint16(uint16_t value, unsigned char *buffer, 42 size_t buffer_size) { 43 return _cbor_encode_uint16(value, buffer, buffer_size, 0x20); 44} 45 46size_t cbor_encode_negint32(uint32_t value, unsigned char *buffer, 47 size_t buffer_size) { 48 return _cbor_encode_uint32(value, buffer, buffer_size, 0x20); 49} 50 51size_t cbor_encode_negint64(uint64_t value, unsigned char *buffer, 52 size_t buffer_size) { 53 return _cbor_encode_uint64(value, buffer, buffer_size, 0x20); 54} 55 56size_t cbor_encode_negint(uint64_t value, unsigned char *buffer, 57 size_t buffer_size) { 58 return _cbor_encode_uint(value, buffer, buffer_size, 0x20); 59} 60 61size_t cbor_encode_bytestring_start(size_t length, unsigned char *buffer, 62 size_t buffer_size) { 63 return _cbor_encode_uint((size_t)length, buffer, buffer_size, 0x40); 64} 65 66size_t _cbor_encode_byte(uint8_t value, unsigned char *buffer, 67 size_t buffer_size) { 68 if (buffer_size >= 1) { 69 buffer[0] = value; 70 return 1; 71 } else 72 return 0; 73} 74 75size_t cbor_encode_indef_bytestring_start(unsigned char *buffer, 76 size_t buffer_size) { 77 return _cbor_encode_byte(0x5F, buffer, buffer_size); 78} 79 80size_t cbor_encode_string_start(size_t length, unsigned char *buffer, 81 size_t buffer_size) { 82 return _cbor_encode_uint((size_t)length, buffer, buffer_size, 0x60); 83} 84 85size_t cbor_encode_indef_string_start(unsigned char *buffer, 86 size_t buffer_size) { 87 return _cbor_encode_byte(0x7F, buffer, buffer_size); 88} 89 90size_t cbor_encode_array_start(size_t length, unsigned char *buffer, 91 size_t buffer_size) { 92 return _cbor_encode_uint((size_t)length, buffer, buffer_size, 0x80); 93} 94 95size_t cbor_encode_indef_array_start(unsigned char *buffer, 96 size_t buffer_size) { 97 return _cbor_encode_byte(0x9F, buffer, buffer_size); 98} 99 100size_t cbor_encode_map_start(size_t length, unsigned char *buffer, 101 size_t buffer_size) { 102 return _cbor_encode_uint((size_t)length, buffer, buffer_size, 0xA0); 103} 104 105size_t cbor_encode_indef_map_start(unsigned char *buffer, size_t buffer_size) { 106 return _cbor_encode_byte(0xBF, buffer, buffer_size); 107} 108 109size_t cbor_encode_tag(uint64_t value, unsigned char *buffer, 110 size_t buffer_size) { 111 return _cbor_encode_uint(value, buffer, buffer_size, 0xC0); 112} 113 114size_t cbor_encode_bool(bool value, unsigned char *buffer, size_t buffer_size) { 115 return value ? _cbor_encode_byte(0xF5, buffer, buffer_size) 116 : _cbor_encode_byte(0xF4, buffer, buffer_size); 117} 118 119size_t cbor_encode_null(unsigned char *buffer, size_t buffer_size) { 120 return _cbor_encode_byte(0xF6, buffer, buffer_size); 121} 122 123size_t cbor_encode_undef(unsigned char *buffer, size_t buffer_size) { 124 return _cbor_encode_byte(0xF7, buffer, buffer_size); 125} 126 127size_t cbor_encode_half(float value, unsigned char *buffer, 128 size_t buffer_size) { 129 /* Assuming value is normalized */ 130 uint32_t val = ((union _cbor_float_helper){.as_float = value}).as_uint; 131 uint16_t res; 132 uint8_t exp = (uint8_t)((val & 0x7F800000) >> 133 23); /* 0b0111_1111_1000_0000_0000_0000_0000_0000 */ 134 uint32_t mant = 135 val & 0x7FFFFF; /* 0b0000_0000_0111_1111_1111_1111_1111_1111 */ 136 if (exp == 0xFF) { /* Infinity or NaNs */ 137 if (value != value) { 138 res = (uint16_t)0x00e700; /* Not IEEE semantics - required by CBOR 139 [s. 3.9] */ 140 } else { 141 res = 142 (uint16_t)((val & 0x80000000) >> 16 | 0x7C00 | (mant ? 1 : 0) << 15); 143 } 144 } else if (exp == 0x00) { /* Zeroes or subnorms */ 145 res = (uint16_t)((val & 0x80000000) >> 16 | mant >> 13); 146 } else { /* Normal numbers */ 147 int8_t logical_exp = (int8_t)(exp - 127); 148 assert(logical_exp == exp - 127); 149 150 // Now we know that 2^exp <= 0 logically 151 if (logical_exp < -24) { 152 /* No unambiguous representation exists, this float is not a half float 153 and is too small to be represented using a half, round off to zero. 154 Consistent with the reference implementation. */ 155 res = 0; 156 } else if (logical_exp < -14) { 157 /* Offset the remaining decimal places by shifting the significand, the 158 value is lost. This is an implementation decision that works around the 159 absence of standard half-float in the language. */ 160 res = (uint16_t)(val & 0x80000000) >> 16 | 161 (uint16_t)(1 << (24 + logical_exp)); 162 } else { 163 res = (uint16_t)((val & 0x80000000) >> 16 | 164 ((((uint8_t)logical_exp) + 15) << 10) | 165 (uint16_t)(mant >> 13)); 166 } 167 } 168 return _cbor_encode_uint16(res, buffer, buffer_size, 0xE0); 169} 170 171size_t cbor_encode_single(float value, unsigned char *buffer, 172 size_t buffer_size) { 173 return _cbor_encode_uint32( 174 ((union _cbor_float_helper){.as_float = value}).as_uint, buffer, 175 buffer_size, 0xE0); 176} 177 178size_t cbor_encode_double(double value, unsigned char *buffer, 179 size_t buffer_size) { 180 return _cbor_encode_uint64( 181 ((union _cbor_double_helper){.as_double = value}).as_uint, buffer, 182 buffer_size, 0xE0); 183} 184 185size_t cbor_encode_break(unsigned char *buffer, size_t buffer_size) { 186 return _cbor_encode_byte(0xFF, buffer, buffer_size); 187} 188 189size_t cbor_encode_ctrl(uint8_t value, unsigned char *buffer, 190 size_t buffer_size) { 191 return _cbor_encode_uint8(value, buffer, buffer_size, 0xE0); 192} 193