sha2.c

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/*-------------------------------------------------------------------------
 *
 * sha2.c
 *     SHA functions for SHA-224, SHA-256, SHA-384 and SHA-512.
 *
 * This includes the fallback implementation for SHA2 cryptographic
 * hashes.
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/common/sha2.c
 *
 *-------------------------------------------------------------------------
 */
 
/*  $OpenBSD: sha2.c,v 1.6 2004/05/03 02:57:36 millert Exp $    */
/*
 * FILE:    sha2.c
 * AUTHOR:  Aaron D. Gifford <me@aarongifford.com>
 *
 * Copyright (c) 2000-2001, Aaron D. Gifford
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTOR(S) ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTOR(S) BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $From: sha2.c,v 1.1 2001/11/08 00:01:51 adg Exp adg $
 */
 
 
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
 
#include "sha2_int.h"
 
/*
 * In backend, use palloc/pfree to ease the error handling.  In frontend,
 * use malloc to be able to return a failure status back to the caller.
 */
#ifndef FRONTEND
#define ALLOC(size) palloc(size)
#define FREE(ptr) pfree(ptr)
#else
#define ALLOC(size) malloc(size)
#define FREE(ptr) free(ptr)
#endif
 
/*
 * UNROLLED TRANSFORM LOOP NOTE:
 * You can define SHA2_UNROLL_TRANSFORM to use the unrolled transform
 * loop version for the hash transform rounds (defined using macros
 * later in this file).  Either define on the command line, for example:
 *
 *   cc -DSHA2_UNROLL_TRANSFORM -o sha2 sha2.c sha2prog.c
 *
 * or define below:
 *
 *   #define SHA2_UNROLL_TRANSFORM
 *
 */
 
/*** SHA-256/384/512 Various Length Definitions ***********************/
#define PG_SHA256_SHORT_BLOCK_LENGTH    (PG_SHA256_BLOCK_LENGTH - 8)
#define PG_SHA384_SHORT_BLOCK_LENGTH    (PG_SHA384_BLOCK_LENGTH - 16)
#define PG_SHA512_SHORT_BLOCK_LENGTH    (PG_SHA512_BLOCK_LENGTH - 16)
 
/*** ENDIAN REVERSAL MACROS *******************************************/
#ifndef WORDS_BIGENDIAN
#define REVERSE32(w,x)  { \
    uint32 tmp = (w); \
    tmp = (tmp >> 16) | (tmp << 16); \
    (x) = ((tmp & 0xff00ff00UL) >> 8) | ((tmp & 0x00ff00ffUL) << 8); \
}
#define REVERSE64(w,x)  { \
    uint64 tmp = (w); \
    tmp = (tmp >> 32) | (tmp << 32); \
    tmp = ((tmp & 0xff00ff00ff00ff00ULL) >> 8) | \
          ((tmp & 0x00ff00ff00ff00ffULL) << 8); \
    (x) = ((tmp & 0xffff0000ffff0000ULL) >> 16) | \
          ((tmp & 0x0000ffff0000ffffULL) << 16); \
}
#endif                          /* not bigendian */
 
/*
 * Macro for incrementally adding the unsigned 64-bit integer n to the
 * unsigned 128-bit integer (represented using a two-element array of
 * 64-bit words):
 */
#define ADDINC128(w,n)  { \
    (w)[0] += (uint64)(n); \
    if ((w)[0] < (n)) { \
        (w)[1]++; \
    } \
}
 
/*** THE SIX LOGICAL FUNCTIONS ****************************************/
/*
 * Bit shifting and rotation (used by the six SHA-XYZ logical functions:
 *
 *   NOTE:  The naming of R and S appears backwards here (R is a SHIFT and
 *   S is a ROTATION) because the SHA-256/384/512 description document
 *   (see http://www.iwar.org.uk/comsec/resources/cipher/sha256-384-512.pdf)
 *   uses this same "backwards" definition.
 */
/* Shift-right (used in SHA-256, SHA-384, and SHA-512): */
#define R(b,x)      ((x) >> (b))
/* 32-bit Rotate-right (used in SHA-256): */
#define S32(b,x)    (((x) >> (b)) | ((x) << (32 - (b))))
/* 64-bit Rotate-right (used in SHA-384 and SHA-512): */
#define S64(b,x)    (((x) >> (b)) | ((x) << (64 - (b))))
 
/* Two of six logical functions used in SHA-256, SHA-384, and SHA-512: */
#define Ch(x,y,z)   (((x) & (y)) ^ ((~(x)) & (z)))
#define Maj(x,y,z)  (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
 
/* Four of six logical functions used in SHA-256: */
#define Sigma0_256(x)   (S32(2,  (x)) ^ S32(13, (x)) ^ S32(22, (x)))
#define Sigma1_256(x)   (S32(6,  (x)) ^ S32(11, (x)) ^ S32(25, (x)))
#define sigma0_256(x)   (S32(7,  (x)) ^ S32(18, (x)) ^ R(3 ,   (x)))
#define sigma1_256(x)   (S32(17, (x)) ^ S32(19, (x)) ^ R(10,   (x)))
 
/* Four of six logical functions used in SHA-384 and SHA-512: */
#define Sigma0_512(x)   (S64(28, (x)) ^ S64(34, (x)) ^ S64(39, (x)))
#define Sigma1_512(x)   (S64(14, (x)) ^ S64(18, (x)) ^ S64(41, (x)))
#define sigma0_512(x)   (S64( 1, (x)) ^ S64( 8, (x)) ^ R( 7,   (x)))
#define sigma1_512(x)   (S64(19, (x)) ^ S64(61, (x)) ^ R( 6,   (x)))
 
/*** INTERNAL FUNCTION PROTOTYPES *************************************/
/* NOTE: These should not be accessed directly from outside this
 * library -- they are intended for private internal visibility/use
 * only.
 */
static void SHA512_Last(pg_sha512_ctx *context);
static void SHA256_Transform(pg_sha256_ctx *context, const uint8 *data);
static void SHA512_Transform(pg_sha512_ctx *context, const uint8 *data);
 
/*** SHA-XYZ INITIAL HASH VALUES AND CONSTANTS ************************/
/* Hash constant words K for SHA-256: */
static const uint32 K256[64] = {
    0x428a2f98UL, 0x71374491UL, 0xb5c0fbcfUL, 0xe9b5dba5UL,
    0x3956c25bUL, 0x59f111f1UL, 0x923f82a4UL, 0xab1c5ed5UL,
    0xd807aa98UL, 0x12835b01UL, 0x243185beUL, 0x550c7dc3UL,
    0x72be5d74UL, 0x80deb1feUL, 0x9bdc06a7UL, 0xc19bf174UL,
    0xe49b69c1UL, 0xefbe4786UL, 0x0fc19dc6UL, 0x240ca1ccUL,
    0x2de92c6fUL, 0x4a7484aaUL, 0x5cb0a9dcUL, 0x76f988daUL,
    0x983e5152UL, 0xa831c66dUL, 0xb00327c8UL, 0xbf597fc7UL,
    0xc6e00bf3UL, 0xd5a79147UL, 0x06ca6351UL, 0x14292967UL,
    0x27b70a85UL, 0x2e1b2138UL, 0x4d2c6dfcUL, 0x53380d13UL,
    0x650a7354UL, 0x766a0abbUL, 0x81c2c92eUL, 0x92722c85UL,
    0xa2bfe8a1UL, 0xa81a664bUL, 0xc24b8b70UL, 0xc76c51a3UL,
    0xd192e819UL, 0xd6990624UL, 0xf40e3585UL, 0x106aa070UL,
    0x19a4c116UL, 0x1e376c08UL, 0x2748774cUL, 0x34b0bcb5UL,
    0x391c0cb3UL, 0x4ed8aa4aUL, 0x5b9cca4fUL, 0x682e6ff3UL,
    0x748f82eeUL, 0x78a5636fUL, 0x84c87814UL, 0x8cc70208UL,
    0x90befffaUL, 0xa4506cebUL, 0xbef9a3f7UL, 0xc67178f2UL
};
 
/* Initial hash value H for SHA-224: */
static const uint32 sha224_initial_hash_value[8] = {
    0xc1059ed8UL,
    0x367cd507UL,
    0x3070dd17UL,
    0xf70e5939UL,
    0xffc00b31UL,
    0x68581511UL,
    0x64f98fa7UL,
    0xbefa4fa4UL
};
 
/* Initial hash value H for SHA-256: */
static const uint32 sha256_initial_hash_value[8] = {
    0x6a09e667UL,
    0xbb67ae85UL,
    0x3c6ef372UL,
    0xa54ff53aUL,
    0x510e527fUL,
    0x9b05688cUL,
    0x1f83d9abUL,
    0x5be0cd19UL
};
 
/* Hash constant words K for SHA-384 and SHA-512: */
static const uint64 K512[80] = {
    0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL,
    0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
    0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
    0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
    0xd807aa98a3030242ULL, 0x12835b0145706fbeULL,
    0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
    0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL,
    0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
    0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
    0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
    0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL,
    0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
    0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL,
    0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
    0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
    0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
    0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL,
    0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
    0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL,
    0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
    0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
    0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
    0xd192e819d6ef5218ULL, 0xd69906245565a910ULL,
    0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
    0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL,
    0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
    0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
    0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
    0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL,
    0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
    0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL,
    0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
    0xca273eceea26619cULL, 0xd186b8c721c0c207ULL,
    0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
    0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL,
    0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
    0x28db77f523047d84ULL, 0x32caab7b40c72493ULL,
    0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
    0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
    0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
};
 
/* Initial hash value H for SHA-384 */
static const uint64 sha384_initial_hash_value[8] = {
    0xcbbb9d5dc1059ed8ULL,
    0x629a292a367cd507ULL,
    0x9159015a3070dd17ULL,
    0x152fecd8f70e5939ULL,
    0x67332667ffc00b31ULL,
    0x8eb44a8768581511ULL,
    0xdb0c2e0d64f98fa7ULL,
    0x47b5481dbefa4fa4ULL
};
 
/* Initial hash value H for SHA-512 */
static const uint64 sha512_initial_hash_value[8] = {
    0x6a09e667f3bcc908ULL,
    0xbb67ae8584caa73bULL,
    0x3c6ef372fe94f82bULL,
    0xa54ff53a5f1d36f1ULL,
    0x510e527fade682d1ULL,
    0x9b05688c2b3e6c1fULL,
    0x1f83d9abfb41bd6bULL,
    0x5be0cd19137e2179ULL
};
 
 
/*** SHA-256: *********************************************************/
void
pg_sha256_init(pg_sha256_ctx *context)
{
    if (context == NULL)
        return;
    memcpy(context->state, sha256_initial_hash_value, PG_SHA256_DIGEST_LENGTH);
    memset(context->buffer, 0, PG_SHA256_BLOCK_LENGTH);
    context->bitcount = 0;
}
 
#ifdef SHA2_UNROLL_TRANSFORM
 
/* Unrolled SHA-256 round macros: */
 
#define ROUND256_0_TO_15(a,b,c,d,e,f,g,h) do {                  \
    W256[j] = (uint32)data[3] | ((uint32)data[2] << 8) |        \
        ((uint32)data[1] << 16) | ((uint32)data[0] << 24);      \
    data += 4;                              \
    T1 = (h) + Sigma1_256((e)) + Ch((e), (f), (g)) + K256[j] + W256[j]; \
    (d) += T1;                              \
    (h) = T1 + Sigma0_256((a)) + Maj((a), (b), (c));            \
    j++;                                    \
} while(0)
 
#define ROUND256(a,b,c,d,e,f,g,h) do {                      \
    s0 = W256[(j+1)&0x0f];                          \
    s0 = sigma0_256(s0);                            \
    s1 = W256[(j+14)&0x0f];                         \
    s1 = sigma1_256(s1);                            \
    T1 = (h) + Sigma1_256((e)) + Ch((e), (f), (g)) + K256[j] +      \
         (W256[j&0x0f] += s1 + W256[(j+9)&0x0f] + s0);          \
    (d) += T1;                              \
    (h) = T1 + Sigma0_256((a)) + Maj((a), (b), (c));            \
    j++;                                    \
} while(0)
 
static void
SHA256_Transform(pg_sha256_ctx *context, const uint8 *data)
{
    uint32      a,
                b,
                c,
                d,
                e,
                f,
                g,
                h,
                s0,
                s1;
    uint32      T1,
               *W256;
    int         j;
 
    W256 = (uint32 *) context->buffer;
 
    /* Initialize registers with the prev. intermediate value */
    a = context->state[0];
    b = context->state[1];
    c = context->state[2];
    d = context->state[3];
    e = context->state[4];
    f = context->state[5];
    g = context->state[6];
    h = context->state[7];
 
    j = 0;
    do
    {
        /* Rounds 0 to 15 (unrolled): */
        ROUND256_0_TO_15(a, b, c, d, e, f, g, h);
        ROUND256_0_TO_15(h, a, b, c, d, e, f, g);
        ROUND256_0_TO_15(g, h, a, b, c, d, e, f);
        ROUND256_0_TO_15(f, g, h, a, b, c, d, e);
        ROUND256_0_TO_15(e, f, g, h, a, b, c, d);
        ROUND256_0_TO_15(d, e, f, g, h, a, b, c);
        ROUND256_0_TO_15(c, d, e, f, g, h, a, b);
        ROUND256_0_TO_15(b, c, d, e, f, g, h, a);
    } while (j < 16);
 
    /* Now for the remaining rounds to 64: */
    do
    {
        ROUND256(a, b, c, d, e, f, g, h);
        ROUND256(h, a, b, c, d, e, f, g);
        ROUND256(g, h, a, b, c, d, e, f);
        ROUND256(f, g, h, a, b, c, d, e);
        ROUND256(e, f, g, h, a, b, c, d);
        ROUND256(d, e, f, g, h, a, b, c);
        ROUND256(c, d, e, f, g, h, a, b);
        ROUND256(b, c, d, e, f, g, h, a);
    } while (j < 64);
 
    /* Compute the current intermediate hash value */
    context->state[0] += a;
    context->state[1] += b;
    context->state[2] += c;
    context->state[3] += d;
    context->state[4] += e;
    context->state[5] += f;
    context->state[6] += g;
    context->state[7] += h;
 
    /* Clean up */
    a = b = c = d = e = f = g = h = T1 = 0;
}
#else                           /* SHA2_UNROLL_TRANSFORM */
 
static void
SHA256_Transform(pg_sha256_ctx *context, const uint8 *data)
{
    uint32      a,
                b,
                c,
                d,
                e,
                f,
                g,
                h,
                s0,
                s1;
    uint32      T1,
                T2,
               *W256;
    int         j;
 
    W256 = (uint32 *) context->buffer;
 
    /* Initialize registers with the prev. intermediate value */
    a = context->state[0];
    b = context->state[1];
    c = context->state[2];
    d = context->state[3];
    e = context->state[4];
    f = context->state[5];
    g = context->state[6];
    h = context->state[7];
 
    j = 0;
    do
    {
        W256[j] = (uint32) data[3] | ((uint32) data[2] << 8) |
            ((uint32) data[1] << 16) | ((uint32) data[0] << 24);
        data += 4;
        /* Apply the SHA-256 compression function to update a..h */
        T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] + W256[j];
        T2 = Sigma0_256(a) + Maj(a, b, c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;
 
        j++;
    } while (j < 16);
 
    do
    {
        /* Part of the message block expansion: */
        s0 = W256[(j + 1) & 0x0f];
        s0 = sigma0_256(s0);
        s1 = W256[(j + 14) & 0x0f];
        s1 = sigma1_256(s1);
 
        /* Apply the SHA-256 compression function to update a..h */
        T1 = h + Sigma1_256(e) + Ch(e, f, g) + K256[j] +
            (W256[j & 0x0f] += s1 + W256[(j + 9) & 0x0f] + s0);
        T2 = Sigma0_256(a) + Maj(a, b, c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;
 
        j++;
    } while (j < 64);
 
    /* Compute the current intermediate hash value */
    context->state[0] += a;
    context->state[1] += b;
    context->state[2] += c;
    context->state[3] += d;
    context->state[4] += e;
    context->state[5] += f;
    context->state[6] += g;
    context->state[7] += h;
 
    /* Clean up */
    a = b = c = d = e = f = g = h = T1 = T2 = 0;
}
#endif                          /* SHA2_UNROLL_TRANSFORM */
 
void
pg_sha256_update(pg_sha256_ctx *context, const uint8 *data, size_t len)
{
    size_t      freespace,
                usedspace;
 
    /* Calling with no data is valid (we do nothing) */
    if (len == 0)
        return;
 
    usedspace = (context->bitcount >> 3) % PG_SHA256_BLOCK_LENGTH;
    if (usedspace > 0)
    {
        /* Calculate how much free space is available in the buffer */
        freespace = PG_SHA256_BLOCK_LENGTH - usedspace;
 
        if (len >= freespace)
        {
            /* Fill the buffer completely and process it */
            memcpy(&context->buffer[usedspace], data, freespace);
            context->bitcount += freespace << 3;
            len -= freespace;
            data += freespace;
            SHA256_Transform(context, context->buffer);
        }
        else
        {
            /* The buffer is not yet full */
            memcpy(&context->buffer[usedspace], data, len);
            context->bitcount += len << 3;
            /* Clean up: */
            usedspace = freespace = 0;
            return;
        }
    }
    while (len >= PG_SHA256_BLOCK_LENGTH)
    {
        /* Process as many complete blocks as we can */
        SHA256_Transform(context, data);
        context->bitcount += PG_SHA256_BLOCK_LENGTH << 3;
        len -= PG_SHA256_BLOCK_LENGTH;
        data += PG_SHA256_BLOCK_LENGTH;
    }
    if (len > 0)
    {
        /* There's left-overs, so save 'em */
        memcpy(context->buffer, data, len);
        context->bitcount += len << 3;
    }
    /* Clean up: */
    usedspace = freespace = 0;
}
 
static void
SHA256_Last(pg_sha256_ctx *context)
{
    unsigned int usedspace;
 
    usedspace = (context->bitcount >> 3) % PG_SHA256_BLOCK_LENGTH;
#ifndef WORDS_BIGENDIAN
    /* Convert FROM host byte order */
    REVERSE64(context->bitcount, context->bitcount);
#endif
    if (usedspace > 0)
    {
        /* Begin padding with a 1 bit: */
        context->buffer[usedspace++] = 0x80;
 
        if (usedspace <= PG_SHA256_SHORT_BLOCK_LENGTH)
        {
            /* Set-up for the last transform: */
            memset(&context->buffer[usedspace], 0, PG_SHA256_SHORT_BLOCK_LENGTH - usedspace);
        }
        else
        {
            if (usedspace < PG_SHA256_BLOCK_LENGTH)
            {
                memset(&context->buffer[usedspace], 0, PG_SHA256_BLOCK_LENGTH - usedspace);
            }
            /* Do second-to-last transform: */
            SHA256_Transform(context, context->buffer);
 
            /* And set-up for the last transform: */
            memset(context->buffer, 0, PG_SHA256_SHORT_BLOCK_LENGTH);
        }
    }
    else
    {
        /* Set-up for the last transform: */
        memset(context->buffer, 0, PG_SHA256_SHORT_BLOCK_LENGTH);
 
        /* Begin padding with a 1 bit: */
        *context->buffer = 0x80;
    }
    /* Set the bit count: */
    *(uint64 *) &context->buffer[PG_SHA256_SHORT_BLOCK_LENGTH] = context->bitcount;
 
    /* Final transform: */
    SHA256_Transform(context, context->buffer);
}
 
void
pg_sha256_final(pg_sha256_ctx *context, uint8 *digest)
{
    /* If no digest buffer is passed, we don't bother doing this: */
    if (digest != NULL)
    {
        SHA256_Last(context);
 
#ifndef WORDS_BIGENDIAN
        {
            /* Convert TO host byte order */
            int         j;
 
            for (j = 0; j < 8; j++)
            {
                REVERSE32(context->state[j], context->state[j]);
            }
        }
#endif
        memcpy(digest, context->state, PG_SHA256_DIGEST_LENGTH);
    }
 
    /* Clean up state data: */
    memset(context, 0, sizeof(pg_sha256_ctx));
}
 
 
/*** SHA-512: *********************************************************/
void
pg_sha512_init(pg_sha512_ctx *context)
{
    if (context == NULL)
        return;
    memcpy(context->state, sha512_initial_hash_value, PG_SHA512_DIGEST_LENGTH);
    memset(context->buffer, 0, PG_SHA512_BLOCK_LENGTH);
    context->bitcount[0] = context->bitcount[1] = 0;
}
 
#ifdef SHA2_UNROLL_TRANSFORM
 
/* Unrolled SHA-512 round macros: */
 
#define ROUND512_0_TO_15(a,b,c,d,e,f,g,h) do {                  \
    W512[j] = (uint64)data[7] | ((uint64)data[6] << 8) |        \
        ((uint64)data[5] << 16) | ((uint64)data[4] << 24) |     \
        ((uint64)data[3] << 32) | ((uint64)data[2] << 40) |     \
        ((uint64)data[1] << 48) | ((uint64)data[0] << 56);      \
    data += 8;                              \
    T1 = (h) + Sigma1_512((e)) + Ch((e), (f), (g)) + K512[j] + W512[j]; \
    (d) += T1;                              \
    (h) = T1 + Sigma0_512((a)) + Maj((a), (b), (c));            \
    j++;                                    \
} while(0)
 
 
#define ROUND512(a,b,c,d,e,f,g,h) do {                      \
    s0 = W512[(j+1)&0x0f];                          \
    s0 = sigma0_512(s0);                            \
    s1 = W512[(j+14)&0x0f];                         \
    s1 = sigma1_512(s1);                            \
    T1 = (h) + Sigma1_512((e)) + Ch((e), (f), (g)) + K512[j] +      \
             (W512[j&0x0f] += s1 + W512[(j+9)&0x0f] + s0);          \
    (d) += T1;                              \
    (h) = T1 + Sigma0_512((a)) + Maj((a), (b), (c));            \
    j++;                                    \
} while(0)
 
static void
SHA512_Transform(pg_sha512_ctx *context, const uint8 *data)
{
    uint64      a,
                b,
                c,
                d,
                e,
                f,
                g,
                h,
                s0,
                s1;
    uint64      T1,
               *W512 = (uint64 *) context->buffer;
    int         j;
 
    /* Initialize registers with the prev. intermediate value */
    a = context->state[0];
    b = context->state[1];
    c = context->state[2];
    d = context->state[3];
    e = context->state[4];
    f = context->state[5];
    g = context->state[6];
    h = context->state[7];
 
    j = 0;
    do
    {
        ROUND512_0_TO_15(a, b, c, d, e, f, g, h);
        ROUND512_0_TO_15(h, a, b, c, d, e, f, g);
        ROUND512_0_TO_15(g, h, a, b, c, d, e, f);
        ROUND512_0_TO_15(f, g, h, a, b, c, d, e);
        ROUND512_0_TO_15(e, f, g, h, a, b, c, d);
        ROUND512_0_TO_15(d, e, f, g, h, a, b, c);
        ROUND512_0_TO_15(c, d, e, f, g, h, a, b);
        ROUND512_0_TO_15(b, c, d, e, f, g, h, a);
    } while (j < 16);
 
    /* Now for the remaining rounds up to 79: */
    do
    {
        ROUND512(a, b, c, d, e, f, g, h);
        ROUND512(h, a, b, c, d, e, f, g);
        ROUND512(g, h, a, b, c, d, e, f);
        ROUND512(f, g, h, a, b, c, d, e);
        ROUND512(e, f, g, h, a, b, c, d);
        ROUND512(d, e, f, g, h, a, b, c);
        ROUND512(c, d, e, f, g, h, a, b);
        ROUND512(b, c, d, e, f, g, h, a);
    } while (j < 80);
 
    /* Compute the current intermediate hash value */
    context->state[0] += a;
    context->state[1] += b;
    context->state[2] += c;
    context->state[3] += d;
    context->state[4] += e;
    context->state[5] += f;
    context->state[6] += g;
    context->state[7] += h;
 
    /* Clean up */
    a = b = c = d = e = f = g = h = T1 = 0;
}
#else                           /* SHA2_UNROLL_TRANSFORM */
 
static void
SHA512_Transform(pg_sha512_ctx *context, const uint8 *data)
{
    uint64      a,
                b,
                c,
                d,
                e,
                f,
                g,
                h,
                s0,
                s1;
    uint64      T1,
                T2,
               *W512 = (uint64 *) context->buffer;
    int         j;
 
    /* Initialize registers with the prev. intermediate value */
    a = context->state[0];
    b = context->state[1];
    c = context->state[2];
    d = context->state[3];
    e = context->state[4];
    f = context->state[5];
    g = context->state[6];
    h = context->state[7];
 
    j = 0;
    do
    {
        W512[j] = (uint64) data[7] | ((uint64) data[6] << 8) |
            ((uint64) data[5] << 16) | ((uint64) data[4] << 24) |
            ((uint64) data[3] << 32) | ((uint64) data[2] << 40) |
            ((uint64) data[1] << 48) | ((uint64) data[0] << 56);
        data += 8;
        /* Apply the SHA-512 compression function to update a..h */
        T1 = h + Sigma1_512(e) + Ch(e, f, g) + K512[j] + W512[j];
        T2 = Sigma0_512(a) + Maj(a, b, c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;
 
        j++;
    } while (j < 16);
 
    do
    {
        /* Part of the message block expansion: */
        s0 = W512[(j + 1) & 0x0f];
        s0 = sigma0_512(s0);
        s1 = W512[(j + 14) & 0x0f];
        s1 = sigma1_512(s1);
 
        /* Apply the SHA-512 compression function to update a..h */
        T1 = h + Sigma1_512(e) + Ch(e, f, g) + K512[j] +
            (W512[j & 0x0f] += s1 + W512[(j + 9) & 0x0f] + s0);
        T2 = Sigma0_512(a) + Maj(a, b, c);
        h = g;
        g = f;
        f = e;
        e = d + T1;
        d = c;
        c = b;
        b = a;
        a = T1 + T2;
 
        j++;
    } while (j < 80);
 
    /* Compute the current intermediate hash value */
    context->state[0] += a;
    context->state[1] += b;
    context->state[2] += c;
    context->state[3] += d;
    context->state[4] += e;
    context->state[5] += f;
    context->state[6] += g;
    context->state[7] += h;
 
    /* Clean up */
    a = b = c = d = e = f = g = h = T1 = T2 = 0;
}
#endif                          /* SHA2_UNROLL_TRANSFORM */
 
void
pg_sha512_update(pg_sha512_ctx *context, const uint8 *data, size_t len)
{
    size_t      freespace,
                usedspace;
 
    /* Calling with no data is valid (we do nothing) */
    if (len == 0)
        return;
 
    usedspace = (context->bitcount[0] >> 3) % PG_SHA512_BLOCK_LENGTH;
    if (usedspace > 0)
    {
        /* Calculate how much free space is available in the buffer */
        freespace = PG_SHA512_BLOCK_LENGTH - usedspace;
 
        if (len >= freespace)
        {
            /* Fill the buffer completely and process it */
            memcpy(&context->buffer[usedspace], data, freespace);
            ADDINC128(context->bitcount, freespace << 3);
            len -= freespace;
            data += freespace;
            SHA512_Transform(context, context->buffer);
        }
        else
        {
            /* The buffer is not yet full */
            memcpy(&context->buffer[usedspace], data, len);
            ADDINC128(context->bitcount, len << 3);
            /* Clean up: */
            usedspace = freespace = 0;
            return;
        }
    }
    while (len >= PG_SHA512_BLOCK_LENGTH)
    {
        /* Process as many complete blocks as we can */
        SHA512_Transform(context, data);
        ADDINC128(context->bitcount, PG_SHA512_BLOCK_LENGTH << 3);
        len -= PG_SHA512_BLOCK_LENGTH;
        data += PG_SHA512_BLOCK_LENGTH;
    }
    if (len > 0)
    {
        /* There's left-overs, so save 'em */
        memcpy(context->buffer, data, len);
        ADDINC128(context->bitcount, len << 3);
    }
    /* Clean up: */
    usedspace = freespace = 0;
}
 
static void
SHA512_Last(pg_sha512_ctx *context)
{
    unsigned int usedspace;
 
    usedspace = (context->bitcount[0] >> 3) % PG_SHA512_BLOCK_LENGTH;
#ifndef WORDS_BIGENDIAN
    /* Convert FROM host byte order */
    REVERSE64(context->bitcount[0], context->bitcount[0]);
    REVERSE64(context->bitcount[1], context->bitcount[1]);
#endif
    if (usedspace > 0)
    {
        /* Begin padding with a 1 bit: */
        context->buffer[usedspace++] = 0x80;
 
        if (usedspace <= PG_SHA512_SHORT_BLOCK_LENGTH)
        {
            /* Set-up for the last transform: */
            memset(&context->buffer[usedspace], 0, PG_SHA512_SHORT_BLOCK_LENGTH - usedspace);
        }
        else
        {
            if (usedspace < PG_SHA512_BLOCK_LENGTH)
            {
                memset(&context->buffer[usedspace], 0, PG_SHA512_BLOCK_LENGTH - usedspace);
            }
            /* Do second-to-last transform: */
            SHA512_Transform(context, context->buffer);
 
            /* And set-up for the last transform: */
            memset(context->buffer, 0, PG_SHA512_BLOCK_LENGTH - 2);
        }
    }
    else
    {
        /* Prepare for final transform: */
        memset(context->buffer, 0, PG_SHA512_SHORT_BLOCK_LENGTH);
 
        /* Begin padding with a 1 bit: */
        *context->buffer = 0x80;
    }
    /* Store the length of input data (in bits): */
    *(uint64 *) &context->buffer[PG_SHA512_SHORT_BLOCK_LENGTH] = context->bitcount[1];
    *(uint64 *) &context->buffer[PG_SHA512_SHORT_BLOCK_LENGTH + 8] = context->bitcount[0];
 
    /* Final transform: */
    SHA512_Transform(context, context->buffer);
}
 
void
pg_sha512_final(pg_sha512_ctx *context, uint8 *digest)
{
    /* If no digest buffer is passed, we don't bother doing this: */
    if (digest != NULL)
    {
        SHA512_Last(context);
 
        /* Save the hash data for output: */
#ifndef WORDS_BIGENDIAN
        {
            /* Convert TO host byte order */
            int         j;
 
            for (j = 0; j < 8; j++)
            {
                REVERSE64(context->state[j], context->state[j]);
            }
        }
#endif
        memcpy(digest, context->state, PG_SHA512_DIGEST_LENGTH);
    }
 
    /* Zero out state data */
    memset(context, 0, sizeof(pg_sha512_ctx));
}
 
 
/*** SHA-384: *********************************************************/
void
pg_sha384_init(pg_sha384_ctx *context)
{
    if (context == NULL)
        return;
    memcpy(context->state, sha384_initial_hash_value, PG_SHA512_DIGEST_LENGTH);
    memset(context->buffer, 0, PG_SHA384_BLOCK_LENGTH);
    context->bitcount[0] = context->bitcount[1] = 0;
}
 
void
pg_sha384_update(pg_sha384_ctx *context, const uint8 *data, size_t len)
{
    pg_sha512_update((pg_sha512_ctx *) context, data, len);
}
 
void
pg_sha384_final(pg_sha384_ctx *context, uint8 *digest)
{
    /* If no digest buffer is passed, we don't bother doing this: */
    if (digest != NULL)
    {
        SHA512_Last((pg_sha512_ctx *) context);
 
        /* Save the hash data for output: */
#ifndef WORDS_BIGENDIAN
        {
            /* Convert TO host byte order */
            int         j;
 
            for (j = 0; j < 6; j++)
            {
                REVERSE64(context->state[j], context->state[j]);
            }
        }
#endif
        memcpy(digest, context->state, PG_SHA384_DIGEST_LENGTH);
    }
 
    /* Zero out state data */
    memset(context, 0, sizeof(pg_sha384_ctx));
}
 
/*** SHA-224: *********************************************************/
void
pg_sha224_init(pg_sha224_ctx *context)
{
    if (context == NULL)
        return;
    memcpy(context->state, sha224_initial_hash_value, PG_SHA256_DIGEST_LENGTH);
    memset(context->buffer, 0, PG_SHA256_BLOCK_LENGTH);
    context->bitcount = 0;
}
 
void
pg_sha224_update(pg_sha224_ctx *context, const uint8 *data, size_t len)
{
    pg_sha256_update((pg_sha256_ctx *) context, data, len);
}
 
void
pg_sha224_final(pg_sha224_ctx *context, uint8 *digest)
{
    /* If no digest buffer is passed, we don't bother doing this: */
    if (digest != NULL)
    {
        SHA256_Last(context);
 
#ifndef WORDS_BIGENDIAN
        {
            /* Convert TO host byte order */
            int         j;
 
            for (j = 0; j < 8; j++)
            {
                REVERSE32(context->state[j], context->state[j]);
            }
        }
#endif
        memcpy(digest, context->state, PG_SHA224_DIGEST_LENGTH);
    }
 
    /* Clean up state data: */
    memset(context, 0, sizeof(pg_sha224_ctx));
}