text: /*
   * Based on the git SHA1 Implementation.
   *
   * Copyright (C) 2009-2015, Linus Torvalds and others.
   *
   * SHA1 routine optimized to do word accesses rather than byte accesses,
   * and to avoid unnecessary copies into the context array.
   *
   * This was initially based on the Mozilla SHA1 implementation, although
   * none of the original Mozilla code remains.
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation, version 2.1
   * exclusively.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  /* this is only to get definitions for memcpy(), ntohl() and htonl() */
  #include <string.h>
  #include <inttypes.h>
  #include <arpa/inet.h>
  
  #include <import/sha1.h>
  
  /*
   * Performance might be improved if the CPU architecture is OK with
   * unaligned 32-bit loads and a fast ntohl() is available.
   * Otherwise fall back to byte loads and shifts which is portable,
   * and is faster on architectures with memory alignment issues.
   */
  
  #if defined(__i386__) || defined(__x86_64__) || \
      defined(__ppc__) || defined(__ppc64__) || \
      defined(__powerpc__) || defined(__powerpc64__) || \
      defined(__s390__) || defined(__s390x__)
  
  #define get_be32(p)	ntohl(*(unsigned int *)(p))
  #define put_be32(p, v)	do { *(unsigned int *)(p) = htonl(v); } while (0)
  
  #else
  
  static inline uint32_t get_be32(const void *ptr)
  {
  	const unsigned char *p = ptr;
  	return	(uint32_t)p[0] << 24 |
  		(uint32_t)p[1] << 16 |
  		(uint32_t)p[2] <<  8 |
  		(uint32_t)p[3] <<  0;
  }
  
  static inline void put_be32(void *ptr, uint32_t value)
  {
  	unsigned char *p = ptr;
  	p[0] = value >> 24;
  	p[1] = value >> 16;
  	p[2] = value >>  8;
  	p[3] = value >>  0;
  }
  
  #endif
  
  #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
  
  /*
   * Force usage of rol or ror by selecting the one with the smaller constant.
   * It _can_ generate slightly smaller code (a constant of 1 is special), but
   * perhaps more importantly it's possibly faster on any uarch that does a
   * rotate with a loop.
   */
  
  #define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; })
  #define SHA_ROL(x,n)	SHA_ASM("rol", x, n)
  #define SHA_ROR(x,n)	SHA_ASM("ror", x, n)
  
  #else
  
  #define SHA_ROT(X,l,r)	(((X) << (l)) | ((X) >> (r)))
  #define SHA_ROL(X,n)	SHA_ROT(X,n,32-(n))
  #define SHA_ROR(X,n)	SHA_ROT(X,32-(n),n)
  
  #endif
  
  /*
   * If you have 32 registers or more, the compiler can (and should)
   * try to change the array[] accesses into registers. However, on
   * machines with less than ~25 registers, that won't really work,
   * and at least gcc will make an unholy mess of it.
   *
   * So to avoid that mess which just slows things down, we force
   * the stores to memory to actually happen (we might be better off
   * with a 'W(t)=(val);asm("":"+m" (W(t))' there instead, as
   * suggested by Artur Skawina - that will also make gcc unable to
   * try to do the silly "optimize away loads" part because it won't
   * see what the value will be).
   *
   * Ben Herrenschmidt reports that on PPC, the C version comes close
   * to the optimized asm with this (ie on PPC you don't want that
   * 'volatile', since there are lots of registers).
   *
   * On ARM we get the best code generation by forcing a full memory barrier
   * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
   * the stack frame size simply explode and performance goes down the drain.
   */
  
  #if defined(__i386__) || defined(__x86_64__)
    #define setW(x, val) (*(volatile unsigned int *)&W(x) = (val))
  #elif defined(__GNUC__) && defined(__arm__)
    #define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
  #else
    #define setW(x, val) (W(x) = (val))
  #endif
  
  /* This "rolls" over the 512-bit array */
  #define W(x) (array[(x)&15])
  
  /*
   * Where do we get the source from? The first 16 iterations get it from
   * the input data, the next mix it from the 512-bit array.
   */
  #define SHA_SRC(t) get_be32((unsigned char *) block + (t)*4)
  #define SHA_MIX(t) SHA_ROL(W((t)+13) ^ W((t)+8) ^ W((t)+2) ^ W(t), 1);
  
  #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
  	unsigned int TEMP = input(t); setW(t, TEMP); \
  	E += TEMP + SHA_ROL(A,5) + (fn) + (constant); \
  	B = SHA_ROR(B, 2); } while (0)
  
  #define T_0_15(t, A, B, C, D, E)  SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
  #define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
  #define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
  #define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
  #define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) ,  0xca62c1d6, A, B, C, D, E )
  
  static void blk_SHA1_Block(blk_SHA_CTX *ctx, const void *block)
  {
  	unsigned int A,B,C,D,E;
  	unsigned int array[16];
  
  	A = ctx->H[0];
  	B = ctx->H[1];
  	C = ctx->H[2];
  	D = ctx->H[3];
  	E = ctx->H[4];
  
  	/* Round 1 - iterations 0-16 take their input from 'block' */
  	T_0_15( 0, A, B, C, D, E);
  	T_0_15( 1, E, A, B, C, D);
  	T_0_15( 2, D, E, A, B, C);
  	T_0_15( 3, C, D, E, A, B);
  	T_0_15( 4, B, C, D, E, A);
  	T_0_15( 5, A, B, C, D, E);
  	T_0_15( 6, E, A, B, C, D);
  	T_0_15( 7, D, E, A, B, C);
  	T_0_15( 8, C, D, E, A, B);
  	T_0_15( 9, B, C, D, E, A);
  	T_0_15(10, A, B, C, D, E);
  	T_0_15(11, E, A, B, C, D);
  	T_0_15(12, D, E, A, B, C);
  	T_0_15(13, C, D, E, A, B);
  	T_0_15(14, B, C, D, E, A);
  	T_0_15(15, A, B, C, D, E);
  
  	/* Round 1 - tail. Input from 512-bit mixing array */
  	T_16_19(16, E, A, B, C, D);
  	T_16_19(17, D, E, A, B, C);
  	T_16_19(18, C, D, E, A, B);
  	T_16_19(19, B, C, D, E, A);
  
  	/* Round 2 */
  	T_20_39(20, A, B, C, D, E);
  	T_20_39(21, E, A, B, C, D);
  	T_20_39(22, D, E, A, B, C);
  	T_20_39(23, C, D, E, A, B);
  	T_20_39(24, B, C, D, E, A);
  	T_20_39(25, A, B, C, D, E);
  	T_20_39(26, E, A, B, C, D);
  	T_20_39(27, D, E, A, B, C);
  	T_20_39(28, C, D, E, A, B);
  	T_20_39(29, B, C, D, E, A);
  	T_20_39(30, A, B, C, D, E);
  	T_20_39(31, E, A, B, C, D);
  	T_20_39(32, D, E, A, B, C);
  	T_20_39(33, C, D, E, A, B);
  	T_20_39(34, B, C, D, E, A);
  	T_20_39(35, A, B, C, D, E);
  	T_20_39(36, E, A, B, C, D);
  	T_20_39(37, D, E, A, B, C);
  	T_20_39(38, C, D, E, A, B);
  	T_20_39(39, B, C, D, E, A);
  
  	/* Round 3 */
  	T_40_59(40, A, B, C, D, E);
  	T_40_59(41, E, A, B, C, D);
  	T_40_59(42, D, E, A, B, C);
  	T_40_59(43, C, D, E, A, B);
  	T_40_59(44, B, C, D, E, A);
  	T_40_59(45, A, B, C, D, E);
  	T_40_59(46, E, A, B, C, D);
  	T_40_59(47, D, E, A, B, C);
  	T_40_59(48, C, D, E, A, B);
  	T_40_59(49, B, C, D, E, A);
  	T_40_59(50, A, B, C, D, E);
  	T_40_59(51, E, A, B, C, D);
  	T_40_59(52, D, E, A, B, C);
  	T_40_59(53, C, D, E, A, B);
  	T_40_59(54, B, C, D, E, A);
  	T_40_59(55, A, B, C, D, E);
  	T_40_59(56, E, A, B, C, D);
  	T_40_59(57, D, E, A, B, C);
  	T_40_59(58, C, D, E, A, B);
  	T_40_59(59, B, C, D, E, A);
  
  	/* Round 4 */
  	T_60_79(60, A, B, C, D, E);
  	T_60_79(61, E, A, B, C, D);
  	T_60_79(62, D, E, A, B, C);
  	T_60_79(63, C, D, E, A, B);
  	T_60_79(64, B, C, D, E, A);
  	T_60_79(65, A, B, C, D, E);
  	T_60_79(66, E, A, B, C, D);
  	T_60_79(67, D, E, A, B, C);
  	T_60_79(68, C, D, E, A, B);
  	T_60_79(69, B, C, D, E, A);
  	T_60_79(70, A, B, C, D, E);
  	T_60_79(71, E, A, B, C, D);
  	T_60_79(72, D, E, A, B, C);
  	T_60_79(73, C, D, E, A, B);
  	T_60_79(74, B, C, D, E, A);
  	T_60_79(75, A, B, C, D, E);
  	T_60_79(76, E, A, B, C, D);
  	T_60_79(77, D, E, A, B, C);
  	T_60_79(78, C, D, E, A, B);
  	T_60_79(79, B, C, D, E, A);
  
  	ctx->H[0] += A;
  	ctx->H[1] += B;
  	ctx->H[2] += C;
  	ctx->H[3] += D;
  	ctx->H[4] += E;
  }
  
  void blk_SHA1_Init(blk_SHA_CTX *ctx)
  {
  	ctx->size = 0;
  
  	/* Initialize H with the magic constants (see FIPS180 for constants) */
  	ctx->H[0] = 0x67452301;
  	ctx->H[1] = 0xefcdab89;
  	ctx->H[2] = 0x98badcfe;
  	ctx->H[3] = 0x10325476;
  	ctx->H[4] = 0xc3d2e1f0;
  }
  
  void blk_SHA1_Update(blk_SHA_CTX *ctx, const void *data, unsigned long len)
  {
  	unsigned int lenW = ctx->size & 63;
  
  	ctx->size += len;
  
  	/* Read the data into W and process blocks as they get full */
  	if (lenW) {
  		unsigned int left = 64 - lenW;
  		if (len < left)
  			left = len;
  		memcpy(lenW + (char *)ctx->W, data, left);
  		lenW = (lenW + left) & 63;
  		len -= left;
  		data = ((const char *)data + left);
  		if (lenW)
  			return;
  		blk_SHA1_Block(ctx, ctx->W);
  	}
  	while (len >= 64) {
  		blk_SHA1_Block(ctx, data);
  		data = ((const char *)data + 64);
  		len -= 64;
  	}
  	if (len)
  		memcpy(ctx->W, data, len);
  }
  
  void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
  {
  	static const unsigned char pad[64] = { 0x80 };
  	unsigned int padlen[2];
  	int i;
  
  	/* Pad with a binary 1 (ie 0x80), then zeroes, then length */
  	padlen[0] = htonl((uint32_t)(ctx->size >> 29));
  	padlen[1] = htonl((uint32_t)(ctx->size << 3));
  
  	i = ctx->size & 63;
  	blk_SHA1_Update(ctx, pad, 1 + (63 & (55 - i)));
  	blk_SHA1_Update(ctx, padlen, 8);
  
  	/* Output hash */
  	for (i = 0; i < 5; i++)
  		put_be32(hashout + i * 4, ctx->H[i]);
  }
  