| 1 | import { hexAddPrefix } from './addPrefix.js';
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| 2 | import { hexStripPrefix } from './stripPrefix.js';
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| 3 | /**
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| 4 | * @name hexFixLength
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| 5 | * @summary Shifts a hex string to a specific bitLength
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| 6 | * @description
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| 7 | * Returns a `0x` prefixed string with the specified number of bits contained in the return value. (If bitLength is -1, length checking is not done). Values with more bits are trimmed to the specified length. Input values with less bits are returned as-is by default. When `withPadding` is set, shorter values are padded with `0`.
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| 8 | * @example
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| 9 | * <BR>
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| 10 | *
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| 11 | * ```javascript
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| 12 | * import { hexFixLength } from '@polkadot/util';
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| 13 | *
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| 14 | * console.log('fixed', hexFixLength('0x12', 16)); // => 0x12
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| 15 | * console.log('fixed', hexFixLength('0x12', 16, true)); // => 0x0012
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| 16 | * console.log('fixed', hexFixLength('0x0012', 8)); // => 0x12
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| 17 | * ```
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| 18 | */
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| 19 | export function hexFixLength(value, bitLength = -1, withPadding = false) {
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| 20 | const strLength = Math.ceil(bitLength / 4);
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| 21 | const hexLength = strLength + 2;
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| 22 | return hexAddPrefix((bitLength === -1 || value.length === hexLength || (!withPadding && value.length < hexLength))
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| 23 | ? hexStripPrefix(value)
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| 24 | : (value.length > hexLength)
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| 25 | ? hexStripPrefix(value).slice(-1 * strLength)
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| 26 | : `${'0'.repeat(strLength)}${hexStripPrefix(value)}`.slice(-1 * strLength));
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| 27 | } |
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