32 lines
884 B
JavaScript
32 lines
884 B
JavaScript
export const decodeB64StringToArrayBuffer = (input) => {
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const bytes = Math.floor((input.length / 4) * 3)
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const ab = new ArrayBuffer(bytes)
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const uarray = new Uint8Array(ab)
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const keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
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let chr1, chr2, chr3
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let enc1, enc2, enc3, enc4
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let j = 0
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input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "")
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for (let i = 0; i < bytes; i += 3) {
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//get the 3 octets in 4 ASCII chars
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enc1 = keyStr.indexOf(input.charAt(j++))
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enc2 = keyStr.indexOf(input.charAt(j++))
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enc3 = keyStr.indexOf(input.charAt(j++))
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enc4 = keyStr.indexOf(input.charAt(j++))
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chr1 = (enc1 << 2) | (enc2 >> 4)
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chr2 = ((enc2 & 15) << 4) | (enc3 >> 2)
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chr3 = ((enc3 & 3) << 6) | enc4
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uarray[i] = chr1
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if (enc3 != 64) uarray[i + 1] = chr2
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if (enc4 != 64) uarray[i + 2] = chr3
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}
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return ab
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}
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