text: // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
  /*
   * The above copyright notice applies to changes made to code derived from
   * (original license follows):
   *
   * This is an OpenSSL-compatible implementation of the RSA Data Security, Inc.
   * MD5 Message-Digest Algorithm (RFC 1321).
   *
   * Homepage:
   * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5
   *
   * Author:
   * Alexander Peslyak, better known as Solar Designer <solar at openwall.com>
   *
   * This software was written by Alexander Peslyak in 2001.  No copyright is
   * claimed, and the software is hereby placed in the public domain.
   * In case this attempt to disclaim copyright and place the software in the
   * public domain is deemed null and void, then the software is
   * Copyright (c) 2001 Alexander Peslyak and it is hereby released to the
   * general public under the following terms:
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted.
   *
   * There's ABSOLUTELY NO WARRANTY, express or implied.
   *
   * (This is a heavily cut-down "BSD license".)
   *
   * This differs from Colin Plumb's older public domain implementation in that
   * no exactly 32-bit integer data type is required (any 32-bit or wider
   * unsigned integer data type will do), there's no compile-time endianness
   * configuration, and the function prototypes match OpenSSL's.  No code from
   * Colin Plumb's implementation has been reused; this comment merely compares
   * the properties of the two independent implementations.
   *
   * The primary goals of this implementation are portability and ease of use.
   * It is meant to be fast, but not as fast as possible.  Some known
   * optimizations are not included to reduce source code size and avoid
   * compile-time configuration.
   */
  
  // Vespalib integration notice: we use static linkage on the digest processing
  // functions, as their signatures intentionally alias those of OpenSSL. Once we
  // start linking with OpenSSL itself, consider using its digest functions instead.
  
  #include <string.h>
  #include "md5.h"
  
  /* Any 32-bit or wider unsigned integer data type will do */
  typedef unsigned int MD5_u32plus;
  
  typedef struct {
      MD5_u32plus lo, hi;
      MD5_u32plus a, b, c, d;
      unsigned char buffer[64];
      MD5_u32plus block[16];
  } MD5_CTX;
  
  /*
   * The basic MD5 functions.
   *
   * F and G are optimized compared to their RFC 1321 definitions for
   * architectures that lack an AND-NOT instruction, just like in Colin Plumb's
   * implementation.
   */
  #define F(x, y, z)  ((z) ^ ((x) & ((y) ^ (z))))
  #define G(x, y, z)  ((y) ^ ((z) & ((x) ^ (y))))
  #define H(x, y, z)  (((x) ^ (y)) ^ (z))
  #define H2(x, y, z) ((x) ^ ((y) ^ (z)))
  #define I(x, y, z)  ((y) ^ ((x) | ~(z)))
  
  /*
   * The MD5 transformation for all four rounds.
   */
  #define STEP(f, a, b, c, d, x, t, s) \
      (a) += f((b), (c), (d)) + (x) + (t); \
      (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s)))); \
      (a) += (b);
  
  /*
   * SET reads 4 input bytes in little-endian byte order and stores them in a
   * properly aligned word in host byte order.
   */
  #define SET(n) \
      (ctx->block[(n)] = \
      (MD5_u32plus)ptr[(n) * 4] | \
      ((MD5_u32plus)ptr[(n) * 4 + 1] << 8) | \
      ((MD5_u32plus)ptr[(n) * 4 + 2] << 16) | \
      ((MD5_u32plus)ptr[(n) * 4 + 3] << 24))
  #define GET(n) \
      (ctx->block[(n)])
  
  /*
   * This processes one or more 64-byte data blocks, but does NOT update the bit
   * counters.  There are no alignment requirements.
   */
  static const void *body(MD5_CTX *ctx, const void *data, unsigned long size) {
      const unsigned char *ptr;
      MD5_u32plus a, b, c, d;
      MD5_u32plus saved_a, saved_b, saved_c, saved_d;
  
      ptr = (const unsigned char *) data;
  
      a = ctx->a;
      b = ctx->b;
      c = ctx->c;
      d = ctx->d;
  
      do {
          saved_a = a;
          saved_b = b;
          saved_c = c;
          saved_d = d;
  
  /* Round 1 */
          STEP(F, a, b, c, d, SET(0), 0xd76aa478, 7)
          STEP(F, d, a, b, c, SET(1), 0xe8c7b756, 12)
          STEP(F, c, d, a, b, SET(2), 0x242070db, 17)
          STEP(F, b, c, d, a, SET(3), 0xc1bdceee, 22)
          STEP(F, a, b, c, d, SET(4), 0xf57c0faf, 7)
          STEP(F, d, a, b, c, SET(5), 0x4787c62a, 12)
          STEP(F, c, d, a, b, SET(6), 0xa8304613, 17)
          STEP(F, b, c, d, a, SET(7), 0xfd469501, 22)
          STEP(F, a, b, c, d, SET(8), 0x698098d8, 7)
          STEP(F, d, a, b, c, SET(9), 0x8b44f7af, 12)
          STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17)
          STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22)
          STEP(F, a, b, c, d, SET(12), 0x6b901122, 7)
          STEP(F, d, a, b, c, SET(13), 0xfd987193, 12)
          STEP(F, c, d, a, b, SET(14), 0xa679438e, 17)
          STEP(F, b, c, d, a, SET(15), 0x49b40821, 22)
  
  /* Round 2 */
          STEP(G, a, b, c, d, GET(1), 0xf61e2562, 5)
          STEP(G, d, a, b, c, GET(6), 0xc040b340, 9)
          STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14)
          STEP(G, b, c, d, a, GET(0), 0xe9b6c7aa, 20)
          STEP(G, a, b, c, d, GET(5), 0xd62f105d, 5)
          STEP(G, d, a, b, c, GET(10), 0x02441453, 9)
          STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14)
          STEP(G, b, c, d, a, GET(4), 0xe7d3fbc8, 20)
          STEP(G, a, b, c, d, GET(9), 0x21e1cde6, 5)
          STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9)
          STEP(G, c, d, a, b, GET(3), 0xf4d50d87, 14)
          STEP(G, b, c, d, a, GET(8), 0x455a14ed, 20)
          STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5)
          STEP(G, d, a, b, c, GET(2), 0xfcefa3f8, 9)
          STEP(G, c, d, a, b, GET(7), 0x676f02d9, 14)
          STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20)
  
  /* Round 3 */
          STEP(H, a, b, c, d, GET(5), 0xfffa3942, 4)
          STEP(H2, d, a, b, c, GET(8), 0x8771f681, 11)
          STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16)
          STEP(H2, b, c, d, a, GET(14), 0xfde5380c, 23)
          STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4)
          STEP(H2, d, a, b, c, GET(4), 0x4bdecfa9, 11)
          STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16)
          STEP(H2, b, c, d, a, GET(10), 0xbebfbc70, 23)
          STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4)
          STEP(H2, d, a, b, c, GET(0), 0xeaa127fa, 11)
          STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16)
          STEP(H2, b, c, d, a, GET(6), 0x04881d05, 23)
          STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4)
          STEP(H2, d, a, b, c, GET(12), 0xe6db99e5, 11)
          STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16)
          STEP(H2, b, c, d, a, GET(2), 0xc4ac5665, 23)
  
  /* Round 4 */
          STEP(I, a, b, c, d, GET(0), 0xf4292244, 6)
          STEP(I, d, a, b, c, GET(7), 0x432aff97, 10)
          STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15)
          STEP(I, b, c, d, a, GET(5), 0xfc93a039, 21)
          STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6)
          STEP(I, d, a, b, c, GET(3), 0x8f0ccc92, 10)
          STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15)
          STEP(I, b, c, d, a, GET(1), 0x85845dd1, 21)
          STEP(I, a, b, c, d, GET(8), 0x6fa87e4f, 6)
          STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10)
          STEP(I, c, d, a, b, GET(6), 0xa3014314, 15)
          STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21)
          STEP(I, a, b, c, d, GET(4), 0xf7537e82, 6)
          STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10)
          STEP(I, c, d, a, b, GET(2), 0x2ad7d2bb, 15)
          STEP(I, b, c, d, a, GET(9), 0xeb86d391, 21)
  
          a += saved_a;
          b += saved_b;
          c += saved_c;
          d += saved_d;
  
          ptr += 64;
      } while (size -= 64);
  
      ctx->a = a;
      ctx->b = b;
      ctx->c = c;
      ctx->d = d;
  
      return ptr;
  }
  
  static void MD5_Init(MD5_CTX *ctx) {
      ctx->a = 0x67452301;
      ctx->b = 0xefcdab89;
      ctx->c = 0x98badcfe;
      ctx->d = 0x10325476;
  
      ctx->lo = 0;
      ctx->hi = 0;
  }
  
  static void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size) {
      MD5_u32plus saved_lo;
      unsigned long used, available;
  
      saved_lo = ctx->lo;
      if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
          ctx->hi++;
      ctx->hi += size >> 29;
  
      used = saved_lo & 0x3f;
  
      if (used) {
          available = 64 - used;
  
          if (size < available) {
              memcpy(&ctx->buffer[used], data, size);
              return;
          }
  
          memcpy(&ctx->buffer[used], data, available);
          data = (const unsigned char *) data + available;
          size -= available;
          body(ctx, ctx->buffer, 64);
      }
  
      if (size >= 64) {
          data = body(ctx, data, size & ~(unsigned long) 0x3f);
          size &= 0x3f;
      }
  
      memcpy(ctx->buffer, data, size);
  }
  
  #define OUT(dst, src) \
      (dst)[0] = (unsigned char)(src); \
      (dst)[1] = (unsigned char)((src) >> 8); \
      (dst)[2] = (unsigned char)((src) >> 16); \
      (dst)[3] = (unsigned char)((src) >> 24);
  
  static void MD5_Final(unsigned char *result, MD5_CTX *ctx) {
      unsigned long used, available;
  
      used = ctx->lo & 0x3f;
  
      ctx->buffer[used++] = 0x80;
  
      available = 64 - used;
  
      if (available < 8) {
          memset(&ctx->buffer[used], 0, available);
          body(ctx, ctx->buffer, 64);
          used = 0;
          available = 64;
      }
  
      memset(&ctx->buffer[used], 0, available - 8);
  
      ctx->lo <<= 3;
      OUT(&ctx->buffer[56], ctx->lo)
      OUT(&ctx->buffer[60], ctx->hi)
  
      body(ctx, ctx->buffer, 64);
  
      OUT(&result[0], ctx->a)
      OUT(&result[4], ctx->b)
      OUT(&result[8], ctx->c)
      OUT(&result[12], ctx->d)
  
      memset(ctx, 0, sizeof(*ctx));
  }
  
  void fastc_md5sum(const void *s, size_t len, unsigned char *key) {
      MD5_CTX m5;
      MD5_Init(&m5);
      MD5_Update(&m5, (const unsigned char *)s, len);
      MD5_Final(key, &m5);
  }
  
  