223 lines
7.7 KiB
C++
223 lines
7.7 KiB
C++
/*
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* This code implements the MD5 message-digest algorithm.
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* The algorithm is due to Ron Rivest. This code was
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* written by Colin Plumb in 1993, no copyright is claimed.
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* This code is in the public domain; do with it what you wish.
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*
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* Equivalent code is available from RSA Data Security, Inc.
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* This code has been tested against that, and is equivalent,
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* except that you don't need to include two pages of legalese
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* with every copy.
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*
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* To compute the message digest of a chunk of bytes, declare an
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* MD5Context structure, pass it to MD5Init, call MD5Update as
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* needed on buffers full of bytes, and then call MD5Final, which
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* will fill a supplied 16-byte array with the digest.
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*/
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// Changes from original C code:
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// Ported to C++, type casting, Google code style.
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#include "webrtc/base/md5.h"
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// TODO: Avoid memcmpy - hash directly from memory.
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#include <string.h> // for memcpy().
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#include "webrtc/base/byteorder.h" // for RTC_ARCH_CPU_LITTLE_ENDIAN.
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namespace rtc {
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#ifdef RTC_ARCH_CPU_LITTLE_ENDIAN
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#define ByteReverse(buf, len) // Nothing.
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#else // RTC_ARCH_CPU_BIG_ENDIAN
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static void ByteReverse(uint32_t* buf, int len) {
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for (int i = 0; i < len; ++i) {
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buf[i] = rtc::GetLE32(&buf[i]);
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}
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}
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#endif
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// Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
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// initialization constants.
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void MD5Init(MD5Context* ctx) {
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ctx->buf[0] = 0x67452301;
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ctx->buf[1] = 0xefcdab89;
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ctx->buf[2] = 0x98badcfe;
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ctx->buf[3] = 0x10325476;
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ctx->bits[0] = 0;
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ctx->bits[1] = 0;
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}
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// Update context to reflect the concatenation of another buffer full of bytes.
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void MD5Update(MD5Context* ctx, const uint8_t* buf, size_t len) {
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// Update bitcount.
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uint32_t t = ctx->bits[0];
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if ((ctx->bits[0] = t + (static_cast<uint32_t>(len) << 3)) < t) {
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ctx->bits[1]++; // Carry from low to high.
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}
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ctx->bits[1] += static_cast<uint32_t>(len >> 29);
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t = (t >> 3) & 0x3f; // Bytes already in shsInfo->data.
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// Handle any leading odd-sized chunks.
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if (t) {
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uint8_t* p = reinterpret_cast<uint8_t*>(ctx->in) + t;
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t = 64-t;
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if (len < t) {
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memcpy(p, buf, len);
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return;
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}
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memcpy(p, buf, t);
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ByteReverse(ctx->in, 16);
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MD5Transform(ctx->buf, ctx->in);
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buf += t;
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len -= t;
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}
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// Process data in 64-byte chunks.
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while (len >= 64) {
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memcpy(ctx->in, buf, 64);
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ByteReverse(ctx->in, 16);
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MD5Transform(ctx->buf, ctx->in);
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buf += 64;
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len -= 64;
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}
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// Handle any remaining bytes of data.
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memcpy(ctx->in, buf, len);
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}
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// Final wrapup - pad to 64-byte boundary with the bit pattern.
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// 1 0* (64-bit count of bits processed, MSB-first)
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void MD5Final(MD5Context* ctx, uint8_t digest[16]) {
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// Compute number of bytes mod 64.
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uint32_t count = (ctx->bits[0] >> 3) & 0x3F;
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// Set the first char of padding to 0x80. This is safe since there is
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// always at least one byte free.
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uint8_t* p = reinterpret_cast<uint8_t*>(ctx->in) + count;
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*p++ = 0x80;
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// Bytes of padding needed to make 64 bytes.
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count = 64 - 1 - count;
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// Pad out to 56 mod 64.
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if (count < 8) {
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// Two lots of padding: Pad the first block to 64 bytes.
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memset(p, 0, count);
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ByteReverse(ctx->in, 16);
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MD5Transform(ctx->buf, ctx->in);
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// Now fill the next block with 56 bytes.
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memset(ctx->in, 0, 56);
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} else {
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// Pad block to 56 bytes.
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memset(p, 0, count - 8);
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}
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ByteReverse(ctx->in, 14);
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// Append length in bits and transform.
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ctx->in[14] = ctx->bits[0];
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ctx->in[15] = ctx->bits[1];
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MD5Transform(ctx->buf, ctx->in);
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ByteReverse(ctx->buf, 4);
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memcpy(digest, ctx->buf, 16);
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memset(ctx, 0, sizeof(*ctx)); // In case it's sensitive.
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}
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// The four core functions - F1 is optimized somewhat.
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// #define F1(x, y, z) (x & y | ~x & z)
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#define F1(x, y, z) (z ^ (x & (y ^ z)))
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#define F2(x, y, z) F1(z, x, y)
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#define F3(x, y, z) (x ^ y ^ z)
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#define F4(x, y, z) (y ^ (x | ~z))
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// This is the central step in the MD5 algorithm.
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#define MD5STEP(f, w, x, y, z, data, s) \
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(w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)
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// The core of the MD5 algorithm, this alters an existing MD5 hash to
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// reflect the addition of 16 longwords of new data. MD5Update blocks
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// the data and converts bytes into longwords for this routine.
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void MD5Transform(uint32_t buf[4], const uint32_t in[16]) {
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uint32_t a = buf[0];
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uint32_t b = buf[1];
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uint32_t c = buf[2];
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uint32_t d = buf[3];
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MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478, 7);
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MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);
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MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17);
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MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);
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MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf, 7);
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MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);
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MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17);
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MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22);
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MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8, 7);
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MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);
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MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
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MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
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MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
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MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
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MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
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MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
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MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562, 5);
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MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340, 9);
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MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
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MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);
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MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d, 5);
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MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
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MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
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MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);
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MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6, 5);
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MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
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MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);
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MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);
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MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
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MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8, 9);
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MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);
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MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
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MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942, 4);
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MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11);
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MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
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MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
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MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44, 4);
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MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);
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MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);
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MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
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MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
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MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);
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MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);
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MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23);
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MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039, 4);
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MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
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MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
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MD5STEP(F3, b, c, d, a, in[ 2] + 0xc4ac5665, 23);
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MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244, 6);
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MD5STEP(F4, d, a, b, c, in[ 7] + 0x432aff97, 10);
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MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
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MD5STEP(F4, b, c, d, a, in[ 5] + 0xfc93a039, 21);
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MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
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MD5STEP(F4, d, a, b, c, in[ 3] + 0x8f0ccc92, 10);
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MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
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MD5STEP(F4, b, c, d, a, in[ 1] + 0x85845dd1, 21);
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MD5STEP(F4, a, b, c, d, in[ 8] + 0x6fa87e4f, 6);
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MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
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MD5STEP(F4, c, d, a, b, in[ 6] + 0xa3014314, 15);
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MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
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MD5STEP(F4, a, b, c, d, in[ 4] + 0xf7537e82, 6);
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MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
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MD5STEP(F4, c, d, a, b, in[ 2] + 0x2ad7d2bb, 15);
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MD5STEP(F4, b, c, d, a, in[ 9] + 0xeb86d391, 21);
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buf[0] += a;
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buf[1] += b;
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buf[2] += c;
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buf[3] += d;
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}
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} // namespace rtc
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