kopia lustrzana https://github.com/mobilinkd/tnc3-firmware
58 wiersze
1.4 KiB
C++
58 wiersze
1.4 KiB
C++
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// Copyright 2018 Rob Riggs <rob@mobilinkd.com>
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// All rights reserved.
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#include "base64.h"
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#include "assert.h"
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namespace {
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const char alphabet[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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}
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uint32_t base64encode(const uint8_t* src, uint32_t src_len, char* dest,
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uint32_t* dest_len)
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{
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uint32_t expected = ((src_len * 4) + 2) / 3;
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uint32_t dpos = 0;
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uint8_t b1, b2, b3, b4;
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for (uint32_t i = 0; i < src_len; i += 3)
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{
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if (dpos == *dest_len) return expected;
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b1 = src[i] >> 2;
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b2 = ((src[i] & 0x3) << 4);
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dest[dpos++] = alphabet[b1];
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if (dpos == *dest_len) return expected;
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if (i + 1 == src_len)
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{
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dest[dpos++] = alphabet[b2];
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break;
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}
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else
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{
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b2 |= (src[i + 1] >> 4);
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dest[dpos++] = alphabet[b2];
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b3 = (src[i + 1] & 0x0F) << 2;
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}
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if (dpos == *dest_len) return expected;
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if (i + 2 == src_len)
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{
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dest[dpos++] = alphabet[b3];
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break;
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}
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else
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{
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b3 |= src[i + 2] >> 6;
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dest[dpos++] = alphabet[b3];
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b4 = src[i + 2] & 0x3F;
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}
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if (dpos == *dest_len) return expected;
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dest[dpos++] = alphabet[b4];
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}
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*dest_len = dpos;
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assert(*dest_len == expected);
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return expected;
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}
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