/*

 * Trivial amendments by James Bonfield <jkb@sanger.ac.uk> to provide an

 * HTSlib interface. 2015.

 *

 * Externally our API uses an opaque hts_md5_context structure.

 *

 * Internally either this gets defined and used with the routines here

 * or it remains incomplete and is cast to the OpenSSL MD5_CTX structure

 * and used by routines from OpenSSL.

 */

/*

 * 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.

 */

#define HTS_BUILDING_LIBRARY // Enables HTSLIB_EXPORT, see htslib/hts_defs.h

#include <config.h>

#include <stdlib.h>

#include "htslib/hts.h"

#include "htslib/hts_endian.h"

#ifndef HAVE_OPENSSL

#include <string.h>

/* Any 32-bit or wider unsigned integer data type will do */

typedef unsigned int hts_md5_u32plus;

struct hts_md5_context {

  hts_md5_u32plus lo, hi;

  hts_md5_u32plus a, b, c, d;

  unsigned char buffer[64];

  hts_md5_u32plus block[16];

};

/*

 * 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.

 *

 * The check for little-endian architectures that tolerate unaligned

 * memory accesses is just an optimization.  Nothing will break if it

 * doesn't work.

 */

#if defined(HTS_LITTLE_ENDIAN) && HTS_ALLOW_UNALIGNED != 0

#define SET(n) \

  (*(hts_md5_u32plus *)&ptr[(n) * 4])

#define GET(n) \

  SET(n)

#else

#define SET(n) \

  (ctx->block[(n)] = \

  (hts_md5_u32plus)ptr[(n) * 4] | \

  ((hts_md5_u32plus)ptr[(n) * 4 + 1] << 8) | \

  ((hts_md5_u32plus)ptr[(n) * 4 + 2] << 16) | \

  ((hts_md5_u32plus)ptr[(n) * 4 + 3] << 24))

#define GET(n) \

  (ctx->block[(n)])

#endif

/*

 * 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(hts_md5_context *ctx, const void *data, unsigned long size)

{

  const unsigned char *ptr;

  hts_md5_u32plus a, b, c, d;

  hts_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;

}

void hts_md5_reset(hts_md5_context *ctx)

{

  ctx->a = 0x67452301;

  ctx->b = 0xefcdab89;

  ctx->c = 0x98badcfe;

  ctx->d = 0x10325476;

  ctx->lo = 0;

  ctx->hi = 0;

}

void hts_md5_update(hts_md5_context *ctx, const void *data, unsigned long size)

{

  hts_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);

}

void hts_md5_final(unsigned char *result, hts_md5_context *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;

  ctx->buffer[56] = ctx->lo;

  ctx->buffer[57] = ctx->lo >> 8;

  ctx->buffer[58] = ctx->lo >> 16;

  ctx->buffer[59] = ctx->lo >> 24;

  ctx->buffer[60] = ctx->hi;

  ctx->buffer[61] = ctx->hi >> 8;

  ctx->buffer[62] = ctx->hi >> 16;

  ctx->buffer[63] = ctx->hi >> 24;

  body(ctx, ctx->buffer, 64);

  result[0] = ctx->a;

  result[1] = ctx->a >> 8;

  result[2] = ctx->a >> 16;

  result[3] = ctx->a >> 24;

  result[4] = ctx->b;

  result[5] = ctx->b >> 8;

  result[6] = ctx->b >> 16;

  result[7] = ctx->b >> 24;

  result[8] = ctx->c;

  result[9] = ctx->c >> 8;

  result[10] = ctx->c >> 16;

  result[11] = ctx->c >> 24;

  result[12] = ctx->d;

  result[13] = ctx->d >> 8;

  result[14] = ctx->d >> 16;

  result[15] = ctx->d >> 24;

  memset(ctx, 0, sizeof(*ctx));

}

hts_md5_context *hts_md5_init(void)

{

    hts_md5_context *ctx = malloc(sizeof(*ctx));

    if (!ctx)

        return NULL;

    hts_md5_reset(ctx);

    return ctx;

}

#else

#include <openssl/md5.h>

#include <assert.h>

/*

 * Wrappers around the OpenSSL libcrypto.so MD5 implementation.

 *

 * These are here to ensure they end up in the symbol table of the

 * library regardless of the static inline in the headers.

 */

hts_md5_context *hts_md5_init(void)

{

    MD5_CTX *ctx = malloc(sizeof(*ctx));

    if (!ctx)

        return NULL;

    MD5_Init(ctx);

    return (hts_md5_context *)ctx;

}

void hts_md5_reset(hts_md5_context *ctx)

{

    MD5_Init((MD5_CTX *)ctx);

}

void hts_md5_update(hts_md5_context *ctx, const void *data, unsigned long size)

{

    MD5_Update((MD5_CTX *)ctx, data, size);

}

void hts_md5_final(unsigned char *result, hts_md5_context *ctx)

{

    MD5_Final(result, (MD5_CTX *)ctx);

}

#endif

void hts_md5_destroy(hts_md5_context *ctx)

{

    if (!ctx)

        return;

    free(ctx);

}

void hts_md5_hex(char *hex, const unsigned char *digest)

{

    int i;

    for (i = 0; i < 16; i++) {

        hex[i*2+0] = "0123456789abcdef"[(digest[i]>>4)&0xf];

        hex[i*2+1] = "0123456789abcdef"[digest[i]&0xf];

    }

    hex[32] = 0;

}