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1fa8efd | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 | const FLOAT = new Float64Array(1);
const FLOAT_BYTES = new Uint8Array(FLOAT.buffer, 0, 8);
FLOAT[0] = -1;
// Little endian [0, 0, 0, 0, 0, 0, 240, 191]
// Big endian [191, 240, 0, 0, 0, 0, 0, 0]
const isBigEndian = FLOAT_BYTES[7] === 0;
/**
* @experimental
* @public
*
* A collection of functions that get or set various numeric types and bit widths from a Uint8Array.
*/
export type NumberUtils = {
/** Is true if the current system is big endian. */
isBigEndian: boolean;
/**
* Parses a signed int32 at offset. Throws a `RangeError` if value is negative.
*/
getNonnegativeInt32LE: (source: Uint8Array, offset: number) => number;
getInt32LE: (source: Uint8Array, offset: number) => number;
getUint32LE: (source: Uint8Array, offset: number) => number;
getUint32BE: (source: Uint8Array, offset: number) => number;
getBigInt64LE: (source: Uint8Array, offset: number) => bigint;
getFloat64LE: (source: Uint8Array, offset: number) => number;
setInt32BE: (destination: Uint8Array, offset: number, value: number) => 4;
setInt32LE: (destination: Uint8Array, offset: number, value: number) => 4;
setBigInt64LE: (destination: Uint8Array, offset: number, value: bigint) => 8;
setFloat64LE: (destination: Uint8Array, offset: number, value: number) => 8;
};
/**
* Number parsing and serializing utilities.
*
* @experimental
* @public
*/
export const NumberUtils: NumberUtils = {
isBigEndian,
getNonnegativeInt32LE(source: Uint8Array, offset: number): number {
if (source[offset + 3] > 127) {
throw new RangeError(`Size cannot be negative at offset: ${offset}`);
}
return (
source[offset] |
(source[offset + 1] << 8) |
(source[offset + 2] << 16) |
(source[offset + 3] << 24)
);
},
/** Reads a little-endian 32-bit integer from source */
getInt32LE(source: Uint8Array, offset: number): number {
return (
source[offset] |
(source[offset + 1] << 8) |
(source[offset + 2] << 16) |
(source[offset + 3] << 24)
);
},
/** Reads a little-endian 32-bit unsigned integer from source */
getUint32LE(source: Uint8Array, offset: number): number {
return (
source[offset] +
source[offset + 1] * 256 +
source[offset + 2] * 65536 +
source[offset + 3] * 16777216
);
},
/** Reads a big-endian 32-bit integer from source */
getUint32BE(source: Uint8Array, offset: number): number {
return (
source[offset + 3] +
source[offset + 2] * 256 +
source[offset + 1] * 65536 +
source[offset] * 16777216
);
},
/** Reads a little-endian 64-bit integer from source */
getBigInt64LE(source: Uint8Array, offset: number): bigint {
const hi = BigInt(
source[offset + 4] +
source[offset + 5] * 256 +
source[offset + 6] * 65536 +
(source[offset + 7] << 24)
); // Overflow
const lo = BigInt(
source[offset] +
source[offset + 1] * 256 +
source[offset + 2] * 65536 +
source[offset + 3] * 16777216
);
return (hi << 32n) + lo;
},
/** Reads a little-endian 64-bit float from source */
getFloat64LE: isBigEndian
? (source: Uint8Array, offset: number) => {
FLOAT_BYTES[7] = source[offset];
FLOAT_BYTES[6] = source[offset + 1];
FLOAT_BYTES[5] = source[offset + 2];
FLOAT_BYTES[4] = source[offset + 3];
FLOAT_BYTES[3] = source[offset + 4];
FLOAT_BYTES[2] = source[offset + 5];
FLOAT_BYTES[1] = source[offset + 6];
FLOAT_BYTES[0] = source[offset + 7];
return FLOAT[0];
}
: (source: Uint8Array, offset: number) => {
FLOAT_BYTES[0] = source[offset];
FLOAT_BYTES[1] = source[offset + 1];
FLOAT_BYTES[2] = source[offset + 2];
FLOAT_BYTES[3] = source[offset + 3];
FLOAT_BYTES[4] = source[offset + 4];
FLOAT_BYTES[5] = source[offset + 5];
FLOAT_BYTES[6] = source[offset + 6];
FLOAT_BYTES[7] = source[offset + 7];
return FLOAT[0];
},
/** Writes a big-endian 32-bit integer to destination, can be signed or unsigned */
setInt32BE(destination: Uint8Array, offset: number, value: number): 4 {
destination[offset + 3] = value;
value >>>= 8;
destination[offset + 2] = value;
value >>>= 8;
destination[offset + 1] = value;
value >>>= 8;
destination[offset] = value;
return 4;
},
/** Writes a little-endian 32-bit integer to destination, can be signed or unsigned */
setInt32LE(destination: Uint8Array, offset: number, value: number): 4 {
destination[offset] = value;
value >>>= 8;
destination[offset + 1] = value;
value >>>= 8;
destination[offset + 2] = value;
value >>>= 8;
destination[offset + 3] = value;
return 4;
},
/** Write a little-endian 64-bit integer to source */
setBigInt64LE(destination: Uint8Array, offset: number, value: bigint): 8 {
const mask32bits = 0xffff_ffffn;
/** lower 32 bits */
let lo = Number(value & mask32bits);
destination[offset] = lo;
lo >>= 8;
destination[offset + 1] = lo;
lo >>= 8;
destination[offset + 2] = lo;
lo >>= 8;
destination[offset + 3] = lo;
let hi = Number((value >> 32n) & mask32bits);
destination[offset + 4] = hi;
hi >>= 8;
destination[offset + 5] = hi;
hi >>= 8;
destination[offset + 6] = hi;
hi >>= 8;
destination[offset + 7] = hi;
return 8;
},
/** Writes a little-endian 64-bit float to destination */
setFloat64LE: isBigEndian
? (destination: Uint8Array, offset: number, value: number) => {
FLOAT[0] = value;
destination[offset] = FLOAT_BYTES[7];
destination[offset + 1] = FLOAT_BYTES[6];
destination[offset + 2] = FLOAT_BYTES[5];
destination[offset + 3] = FLOAT_BYTES[4];
destination[offset + 4] = FLOAT_BYTES[3];
destination[offset + 5] = FLOAT_BYTES[2];
destination[offset + 6] = FLOAT_BYTES[1];
destination[offset + 7] = FLOAT_BYTES[0];
return 8;
}
: (destination: Uint8Array, offset: number, value: number) => {
FLOAT[0] = value;
destination[offset] = FLOAT_BYTES[0];
destination[offset + 1] = FLOAT_BYTES[1];
destination[offset + 2] = FLOAT_BYTES[2];
destination[offset + 3] = FLOAT_BYTES[3];
destination[offset + 4] = FLOAT_BYTES[4];
destination[offset + 5] = FLOAT_BYTES[5];
destination[offset + 6] = FLOAT_BYTES[6];
destination[offset + 7] = FLOAT_BYTES[7];
return 8;
}
};
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