/* SHA module */

/* This module provides an interface to NIST's Secure Hash Algorithm */

/* See below for information about the original code this module was

   based upon. Additional work performed by:

   Andrew Kuchling (amk@amk.ca)

   Greg Stein (gstein@lyra.org)

   Copyright (C) 2005   Gregory P. Smith (greg@krypto.org)

   Licensed to PSF under a Contributor Agreement.

*/

/* SHA objects */

#include "Python.h"

#include "structmember.h"

/* Endianness testing and definitions */

#define TestEndianness(variable) {int i=1; variable=PCT_BIG_ENDIAN;\

	if (*((char*)&i)==1) variable=PCT_LITTLE_ENDIAN;}

#define PCT_LITTLE_ENDIAN 1

#define PCT_BIG_ENDIAN 0

/* Some useful types */

typedef unsigned char SHA_BYTE;

#if SIZEOF_INT == 4

typedef unsigned int SHA_INT32;	/* 32-bit integer */

#else

/* not defined. compilation will die. */

#endif

/* The SHA block size and message digest sizes, in bytes */

#define SHA_BLOCKSIZE    64

#define SHA_DIGESTSIZE  20

/* The structure for storing SHS info */

typedef struct {

    PyObject_HEAD

    SHA_INT32 digest[5];		/* Message digest */

    SHA_INT32 count_lo, count_hi;	/* 64-bit bit count */

    SHA_BYTE data[SHA_BLOCKSIZE];	/* SHA data buffer */

    int Endianness;

    int local;				/* unprocessed amount in data */

} SHAobject;

/* When run on a little-endian CPU we need to perform byte reversal on an

   array of longwords. */

static void longReverse(SHA_INT32 *buffer, int byteCount, int Endianness)

{

    SHA_INT32 value;

    if ( Endianness == PCT_BIG_ENDIAN )

	return;

    byteCount /= sizeof(*buffer);

    while (byteCount--) {

        value = *buffer;

        value = ( ( value & 0xFF00FF00L ) >> 8  ) | \

                ( ( value & 0x00FF00FFL ) << 8 );

        *buffer++ = ( value << 16 ) | ( value >> 16 );

    }

}

static void SHAcopy(SHAobject *src, SHAobject *dest)

{

    dest->Endianness = src->Endianness;

    dest->local = src->local;

    dest->count_lo = src->count_lo;

    dest->count_hi = src->count_hi;

    memcpy(dest->digest, src->digest, sizeof(src->digest));

    memcpy(dest->data, src->data, sizeof(src->data));

}

/* ------------------------------------------------------------------------

 *

 * This code for the SHA algorithm was noted as public domain. The original

 * headers are pasted below.

 *

 * Several changes have been made to make it more compatible with the

 * Python environment and desired interface.

 *

 */

/* NIST Secure Hash Algorithm */

/* heavily modified by Uwe Hollerbach <uh@alumni.caltech edu> */

/* from Peter C. Gutmann's implementation as found in */

/* Applied Cryptography by Bruce Schneier */

/* Further modifications to include the "UNRAVEL" stuff, below */

/* This code is in the public domain */

/* UNRAVEL should be fastest & biggest */

/* UNROLL_LOOPS should be just as big, but slightly slower */

/* both undefined should be smallest and slowest */

#define UNRAVEL

/* #define UNROLL_LOOPS */

/* The SHA f()-functions.  The f1 and f3 functions can be optimized to

   save one boolean operation each - thanks to Rich Schroeppel,

   rcs@cs.arizona.edu for discovering this */

/*#define f1(x,y,z)	((x & y) | (~x & z))		// Rounds  0-19 */

#define f1(x,y,z)	(z ^ (x & (y ^ z)))		/* Rounds  0-19 */

#define f2(x,y,z)	(x ^ y ^ z)			/* Rounds 20-39 */

/*#define f3(x,y,z)	((x & y) | (x & z) | (y & z))	// Rounds 40-59 */

#define f3(x,y,z)	((x & y) | (z & (x | y)))	/* Rounds 40-59 */

#define f4(x,y,z)	(x ^ y ^ z)			/* Rounds 60-79 */

/* SHA constants */

#define CONST1		0x5a827999L			/* Rounds  0-19 */

#define CONST2		0x6ed9eba1L			/* Rounds 20-39 */

#define CONST3		0x8f1bbcdcL			/* Rounds 40-59 */

#define CONST4		0xca62c1d6L			/* Rounds 60-79 */

/* 32-bit rotate */

#define R32(x,n)	((x << n) | (x >> (32 - n)))

/* the generic case, for when the overall rotation is not unraveled */

#define FG(n)	\

    T = R32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n;	\

    E = D; D = C; C = R32(B,30); B = A; A = T

/* specific cases, for when the overall rotation is unraveled */

#define FA(n)	\

    T = R32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; B = R32(B,30)

#define FB(n)	\

    E = R32(T,5) + f##n(A,B,C) + D + *WP++ + CONST##n; A = R32(A,30)

#define FC(n)	\

    D = R32(E,5) + f##n(T,A,B) + C + *WP++ + CONST##n; T = R32(T,30)

#define FD(n)	\

    C = R32(D,5) + f##n(E,T,A) + B + *WP++ + CONST##n; E = R32(E,30)

#define FE(n)	\

    B = R32(C,5) + f##n(D,E,T) + A + *WP++ + CONST##n; D = R32(D,30)

#define FT(n)	\

    A = R32(B,5) + f##n(C,D,E) + T + *WP++ + CONST##n; C = R32(C,30)

/* do SHA transformation */

static void

sha_transform(SHAobject *sha_info)

{

    int i;

    SHA_INT32 T, A, B, C, D, E, W[80], *WP;

    memcpy(W, sha_info->data, sizeof(sha_info->data));

    longReverse(W, (int)sizeof(sha_info->data), sha_info->Endianness);

    for (i = 16; i < 80; ++i) {

	W[i] = W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16];

	/* extra rotation fix */

	W[i] = R32(W[i], 1);

    }

    A = sha_info->digest[0];

    B = sha_info->digest[1];

    C = sha_info->digest[2];

    D = sha_info->digest[3];

    E = sha_info->digest[4];

    WP = W;

#ifdef UNRAVEL

    FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1); FC(1); FD(1);

    FE(1); FT(1); FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1);

    FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2); FE(2); FT(2);

    FA(2); FB(2); FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2);

    FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3); FA(3); FB(3);

    FC(3); FD(3); FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3);

    FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4); FC(4); FD(4);

    FE(4); FT(4); FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4);

    sha_info->digest[0] += E;

    sha_info->digest[1] += T;

    sha_info->digest[2] += A;

    sha_info->digest[3] += B;

    sha_info->digest[4] += C;

#else /* !UNRAVEL */

#ifdef UNROLL_LOOPS

    FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);

    FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);

    FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);

    FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);

    FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);

    FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);

    FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);

    FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);

#else /* !UNROLL_LOOPS */

    for (i =  0; i < 20; ++i) { FG(1); }

    for (i = 20; i < 40; ++i) { FG(2); }

    for (i = 40; i < 60; ++i) { FG(3); }

    for (i = 60; i < 80; ++i) { FG(4); }

#endif /* !UNROLL_LOOPS */

    sha_info->digest[0] += A;

    sha_info->digest[1] += B;

    sha_info->digest[2] += C;

    sha_info->digest[3] += D;

    sha_info->digest[4] += E;

#endif /* !UNRAVEL */

}

/* initialize the SHA digest */

static void

sha_init(SHAobject *sha_info)

{

    TestEndianness(sha_info->Endianness)

    sha_info->digest[0] = 0x67452301L;

    sha_info->digest[1] = 0xefcdab89L;

    sha_info->digest[2] = 0x98badcfeL;

    sha_info->digest[3] = 0x10325476L;

    sha_info->digest[4] = 0xc3d2e1f0L;

    sha_info->count_lo = 0L;

    sha_info->count_hi = 0L;

    sha_info->local = 0;

}

/* update the SHA digest */

static void

sha_update(SHAobject *sha_info, SHA_BYTE *buffer, int count)

{

    int i;

    SHA_INT32 clo;

    clo = sha_info->count_lo + ((SHA_INT32) count << 3);

    if (clo < sha_info->count_lo) {

        ++sha_info->count_hi;

    }

    sha_info->count_lo = clo;

    sha_info->count_hi += (SHA_INT32) count >> 29;

    if (sha_info->local) {

        i = SHA_BLOCKSIZE - sha_info->local;

        if (i > count) {

            i = count;

        }

        memcpy(((SHA_BYTE *) sha_info->data) + sha_info->local, buffer, i);

        count -= i;

        buffer += i;

        sha_info->local += i;

        if (sha_info->local == SHA_BLOCKSIZE) {

            sha_transform(sha_info);

        }

        else {

            return;

        }

    }

    while (count >= SHA_BLOCKSIZE) {

        memcpy(sha_info->data, buffer, SHA_BLOCKSIZE);

        buffer += SHA_BLOCKSIZE;

        count -= SHA_BLOCKSIZE;

        sha_transform(sha_info);

    }

    memcpy(sha_info->data, buffer, count);

    sha_info->local = count;

}

/* finish computing the SHA digest */

static void

sha_final(unsigned char digest[20], SHAobject *sha_info)

{

    int count;

    SHA_INT32 lo_bit_count, hi_bit_count;

    lo_bit_count = sha_info->count_lo;

    hi_bit_count = sha_info->count_hi;

    count = (int) ((lo_bit_count >> 3) & 0x3f);

    ((SHA_BYTE *) sha_info->data)[count++] = 0x80;

    if (count > SHA_BLOCKSIZE - 8) {

	memset(((SHA_BYTE *) sha_info->data) + count, 0,

	       SHA_BLOCKSIZE - count);

	sha_transform(sha_info);

	memset((SHA_BYTE *) sha_info->data, 0, SHA_BLOCKSIZE - 8);

    }

    else {

	memset(((SHA_BYTE *) sha_info->data) + count, 0,

	       SHA_BLOCKSIZE - 8 - count);

    }

    /* GJS: note that we add the hi/lo in big-endian. sha_transform will

       swap these values into host-order. */

    sha_info->data[56] = (hi_bit_count >> 24) & 0xff;

    sha_info->data[57] = (hi_bit_count >> 16) & 0xff;

    sha_info->data[58] = (hi_bit_count >>  8) & 0xff;

    sha_info->data[59] = (hi_bit_count >>  0) & 0xff;

    sha_info->data[60] = (lo_bit_count >> 24) & 0xff;

    sha_info->data[61] = (lo_bit_count >> 16) & 0xff;

    sha_info->data[62] = (lo_bit_count >>  8) & 0xff;

    sha_info->data[63] = (lo_bit_count >>  0) & 0xff;

    sha_transform(sha_info);

    digest[ 0] = (unsigned char) ((sha_info->digest[0] >> 24) & 0xff);

    digest[ 1] = (unsigned char) ((sha_info->digest[0] >> 16) & 0xff);

    digest[ 2] = (unsigned char) ((sha_info->digest[0] >>  8) & 0xff);

    digest[ 3] = (unsigned char) ((sha_info->digest[0]      ) & 0xff);

    digest[ 4] = (unsigned char) ((sha_info->digest[1] >> 24) & 0xff);

    digest[ 5] = (unsigned char) ((sha_info->digest[1] >> 16) & 0xff);

    digest[ 6] = (unsigned char) ((sha_info->digest[1] >>  8) & 0xff);

    digest[ 7] = (unsigned char) ((sha_info->digest[1]      ) & 0xff);

    digest[ 8] = (unsigned char) ((sha_info->digest[2] >> 24) & 0xff);

    digest[ 9] = (unsigned char) ((sha_info->digest[2] >> 16) & 0xff);

    digest[10] = (unsigned char) ((sha_info->digest[2] >>  8) & 0xff);

    digest[11] = (unsigned char) ((sha_info->digest[2]      ) & 0xff);

    digest[12] = (unsigned char) ((sha_info->digest[3] >> 24) & 0xff);

    digest[13] = (unsigned char) ((sha_info->digest[3] >> 16) & 0xff);

    digest[14] = (unsigned char) ((sha_info->digest[3] >>  8) & 0xff);

    digest[15] = (unsigned char) ((sha_info->digest[3]      ) & 0xff);

    digest[16] = (unsigned char) ((sha_info->digest[4] >> 24) & 0xff);

    digest[17] = (unsigned char) ((sha_info->digest[4] >> 16) & 0xff);

    digest[18] = (unsigned char) ((sha_info->digest[4] >>  8) & 0xff);

    digest[19] = (unsigned char) ((sha_info->digest[4]      ) & 0xff);

}

/*

 * End of copied SHA code.

 *

 * ------------------------------------------------------------------------

 */

static PyTypeObject SHAtype;

static SHAobject *

newSHAobject(void)

{

    return (SHAobject *)PyObject_New(SHAobject, &SHAtype);

}

/* Internal methods for a hashing object */

static void

SHA_dealloc(PyObject *ptr)

{

    PyObject_Del(ptr);

}

/* External methods for a hashing object */

PyDoc_STRVAR(SHA_copy__doc__, "Return a copy of the hashing object.");

static PyObject *

SHA_copy(SHAobject *self, PyObject *unused)

{

    SHAobject *newobj;

    if ( (newobj = newSHAobject())==NULL)

        return NULL;

    SHAcopy(self, newobj);

    return (PyObject *)newobj;

}

PyDoc_STRVAR(SHA_digest__doc__,

"Return the digest value as a string of binary data.");

static PyObject *

SHA_digest(SHAobject *self, PyObject *unused)

{

    unsigned char digest[SHA_DIGESTSIZE];

    SHAobject temp;

    SHAcopy(self, &temp);

    sha_final(digest, &temp);

    return PyString_FromStringAndSize((const char *)digest, sizeof(digest));

}

PyDoc_STRVAR(SHA_hexdigest__doc__,

"Return the digest value as a string of hexadecimal digits.");

static PyObject *

SHA_hexdigest(SHAobject *self, PyObject *unused)

{

    unsigned char digest[SHA_DIGESTSIZE];

    SHAobject temp;

    PyObject *retval;

    char *hex_digest;

    int i, j;

    /* Get the raw (binary) digest value */

    SHAcopy(self, &temp);

    sha_final(digest, &temp);

    /* Create a new string */

    retval = PyString_FromStringAndSize(NULL, sizeof(digest) * 2);

    if (!retval)

	    return NULL;

    hex_digest = PyString_AsString(retval);

    if (!hex_digest) {

	    Py_DECREF(retval);

	    return NULL;

    }

    /* Make hex version of the digest */

    for(i=j=0; i<sizeof(digest); i++) {

        char c;

        c = (digest[i] >> 4) & 0xf;

	c = (c>9) ? c+'a'-10 : c + '0';

        hex_digest[j++] = c;

        c = (digest[i] & 0xf);

	c = (c>9) ? c+'a'-10 : c + '0';

        hex_digest[j++] = c;

    }

    return retval;

}

PyDoc_STRVAR(SHA_update__doc__,

"Update this hashing object's state with the provided string.");

static PyObject *

SHA_update(SHAobject *self, PyObject *args)

{

    unsigned char *cp;

    int len;

    if (!PyArg_ParseTuple(args, "s#:update", &cp, &len))

        return NULL;

    sha_update(self, cp, len);

    Py_INCREF(Py_None);

    return Py_None;

}

static PyMethodDef SHA_methods[] = {

    {"copy",	  (PyCFunction)SHA_copy,      METH_NOARGS,  SHA_copy__doc__},

    {"digest",	  (PyCFunction)SHA_digest,    METH_NOARGS,  SHA_digest__doc__},

    {"hexdigest", (PyCFunction)SHA_hexdigest, METH_NOARGS,  SHA_hexdigest__doc__},

    {"update",	  (PyCFunction)SHA_update,    METH_VARARGS, SHA_update__doc__},

    {NULL,	  NULL}		/* sentinel */

};

static PyObject *

SHA_get_block_size(PyObject *self, void *closure)

{

    return PyInt_FromLong(SHA_BLOCKSIZE);

}

static PyObject *

SHA_get_digest_size(PyObject *self, void *closure)

{

    return PyInt_FromLong(SHA_DIGESTSIZE);

}

static PyObject *

SHA_get_name(PyObject *self, void *closure)

{

    return PyString_FromStringAndSize("SHA1", 4);

}

static PyGetSetDef SHA_getseters[] = {

    {"digest_size",

     (getter)SHA_get_digest_size, NULL,

     NULL,

     NULL},

    {"block_size",

     (getter)SHA_get_block_size, NULL,

     NULL,

     NULL},

    {"name",

     (getter)SHA_get_name, NULL,

     NULL,

     NULL},

    /* the old md5 and sha modules support 'digest_size' as in PEP 247.

     * the old sha module also supported 'digestsize'.  ugh. */

    {"digestsize",

     (getter)SHA_get_digest_size, NULL,

     NULL,

     NULL},

    {NULL}  /* Sentinel */

};

static PyTypeObject SHAtype = {

    PyVarObject_HEAD_INIT(NULL, 0)

    "_sha.sha",		/*tp_name*/

    sizeof(SHAobject),	/*tp_size*/

    0,			/*tp_itemsize*/

    /* methods */

    SHA_dealloc,	/*tp_dealloc*/

    0,			/*tp_print*/

    0,                  /*tp_getattr*/

    0,                  /*tp_setattr*/

    0,                  /*tp_compare*/

    0,                  /*tp_repr*/

    0,                  /*tp_as_number*/

    0,                  /*tp_as_sequence*/

    0,                  /*tp_as_mapping*/

    0,                  /*tp_hash*/

    0,                  /*tp_call*/

    0,                  /*tp_str*/

    0,                  /*tp_getattro*/

    0,                  /*tp_setattro*/

    0,                  /*tp_as_buffer*/

    Py_TPFLAGS_DEFAULT, /*tp_flags*/

    0,                  /*tp_doc*/

    0,                  /*tp_traverse*/

    0,			/*tp_clear*/

    0,			/*tp_richcompare*/

    0,			/*tp_weaklistoffset*/

    0,			/*tp_iter*/

    0,			/*tp_iternext*/

    SHA_methods,	/* tp_methods */

    0,                  /* tp_members */

    SHA_getseters,      /* tp_getset */

};

/* The single module-level function: new() */

PyDoc_STRVAR(SHA_new__doc__,