/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif

#include "prerr.h"
#include "secerr.h"

#include "prtypes.h"

#include "blapi.h"

#define MD2_DIGEST_LEN    16
#define MD2_BUFSIZE       16
#define MD2_X_SIZE        48  /* The X array, [CV | INPUT | TMP VARS] */
#define MD2_CV             0  /* index into X for chaining variables */
#define MD2_INPUT         16  /* index into X for input */
#define MD2_TMPVARS       32  /* index into X for temporary variables */
#define MD2_CHECKSUM_SIZE 16

struct MD2ContextStr {
	unsigned char checksum[MD2_BUFSIZE];
	unsigned char X[MD2_X_SIZE];
	PRUint8 unusedBuffer;
};

static const PRUint8 MD2S[256] = {
 0051, 0056, 0103, 0311, 0242, 0330, 0174, 0001,
 0075, 0066, 0124, 0241, 0354, 0360, 0006, 0023,
 0142, 0247, 0005, 0363, 0300, 0307, 0163, 0214,
 0230, 0223, 0053, 0331, 0274, 0114, 0202, 0312,
 0036, 0233, 0127, 0074, 0375, 0324, 0340, 0026,
 0147, 0102, 0157, 0030, 0212, 0027, 0345, 0022,
 0276, 0116, 0304, 0326, 0332, 0236, 0336, 0111,
 0240, 0373, 0365, 0216, 0273, 0057, 0356, 0172,
 0251, 0150, 0171, 0221, 0025, 0262, 0007, 0077,
 0224, 0302, 0020, 0211, 0013, 0042, 0137, 0041,
 0200, 0177, 0135, 0232, 0132, 0220, 0062, 0047,
 0065, 0076, 0314, 0347, 0277, 0367, 0227, 0003,
 0377, 0031, 0060, 0263, 0110, 0245, 0265, 0321,
 0327, 0136, 0222, 0052, 0254, 0126, 0252, 0306,
 0117, 0270, 0070, 0322, 0226, 0244, 0175, 0266,
 0166, 0374, 0153, 0342, 0234, 0164, 0004, 0361,
 0105, 0235, 0160, 0131, 0144, 0161, 0207, 0040,
 0206, 0133, 0317, 0145, 0346, 0055, 0250, 0002,
 0033, 0140, 0045, 0255, 0256, 0260, 0271, 0366,
 0034, 0106, 0141, 0151, 0064, 0100, 0176, 0017,
 0125, 0107, 0243, 0043, 0335, 0121, 0257, 0072,
 0303, 0134, 0371, 0316, 0272, 0305, 0352, 0046,
 0054, 0123, 0015, 0156, 0205, 0050, 0204, 0011,
 0323, 0337, 0315, 0364, 0101, 0201, 0115, 0122,
 0152, 0334, 0067, 0310, 0154, 0301, 0253, 0372,
 0044, 0341, 0173, 0010, 0014, 0275, 0261, 0112,
 0170, 0210, 0225, 0213, 0343, 0143, 0350, 0155,
 0351, 0313, 0325, 0376, 0073, 0000, 0035, 0071,
 0362, 0357, 0267, 0016, 0146, 0130, 0320, 0344,
 0246, 0167, 0162, 0370, 0353, 0165, 0113, 0012,
 0061, 0104, 0120, 0264, 0217, 0355, 0037, 0032,
 0333, 0231, 0215, 0063, 0237, 0021, 0203, 0024
};

SECStatus 
MD2_Hash(unsigned char *dest, const char *src)
{
	unsigned int len;
	MD2Context *cx = MD2_NewContext();
	if (!cx) {
		PORT_SetError(PR_OUT_OF_MEMORY_ERROR);
		return SECFailure;
	}
	MD2_Begin(cx);
	MD2_Update(cx, (const unsigned char *)src, PORT_Strlen(src));
	MD2_End(cx, dest, &len, MD2_DIGEST_LEN);
	MD2_DestroyContext(cx, PR_TRUE);
	return SECSuccess;
}

MD2Context *
MD2_NewContext(void)
{
	MD2Context *cx = (MD2Context *)PORT_ZAlloc(sizeof(MD2Context));
	if (cx == NULL) {
		PORT_SetError(PR_OUT_OF_MEMORY_ERROR);
		return NULL;
	}
	return cx;
}

void 
MD2_DestroyContext(MD2Context *cx, PRBool freeit)
{
	if (freeit)
		PORT_ZFree(cx, sizeof(*cx));
}

void 
MD2_Begin(MD2Context *cx)
{
	memset(cx, 0, sizeof(*cx));
	cx->unusedBuffer = MD2_BUFSIZE;
}

static void
md2_compress(MD2Context *cx)
{
	int j;
	unsigned char P;
	P = cx->checksum[MD2_CHECKSUM_SIZE-1];
	/* Compute the running checksum, and set the tmp variables to be 
	 * CV[i] XOR input[i] 
	 */
#define CKSUMFN(n) \
	P = cx->checksum[n] ^ MD2S[cx->X[MD2_INPUT+n] ^ P]; \
	cx->checksum[n] = P; \
	cx->X[MD2_TMPVARS+n] = cx->X[n] ^ cx->X[MD2_INPUT+n];
	CKSUMFN(0);
	CKSUMFN(1);
	CKSUMFN(2);
	CKSUMFN(3);
	CKSUMFN(4);
	CKSUMFN(5);
	CKSUMFN(6);
	CKSUMFN(7);
	CKSUMFN(8);
	CKSUMFN(9);
	CKSUMFN(10);
	CKSUMFN(11);
	CKSUMFN(12);
	CKSUMFN(13);
	CKSUMFN(14);
	CKSUMFN(15);
	/* The compression function. */
#define COMPRESS(n) \
	P = cx->X[n] ^ MD2S[P]; \
	cx->X[n] = P;
	P = 0x00;
	for (j=0; j<18; j++) {
		COMPRESS(0);
		COMPRESS(1);
		COMPRESS(2);
		COMPRESS(3);
		COMPRESS(4);
		COMPRESS(5);
		COMPRESS(6);
		COMPRESS(7);
		COMPRESS(8);
		COMPRESS(9);
		COMPRESS(10);
		COMPRESS(11);
		COMPRESS(12);
		COMPRESS(13);
		COMPRESS(14);
		COMPRESS(15);
		COMPRESS(16);
		COMPRESS(17);
		COMPRESS(18);
		COMPRESS(19);
		COMPRESS(20);
		COMPRESS(21);
		COMPRESS(22);
		COMPRESS(23);
		COMPRESS(24);
		COMPRESS(25);
		COMPRESS(26);
		COMPRESS(27);
		COMPRESS(28);
		COMPRESS(29);
		COMPRESS(30);
		COMPRESS(31);
		COMPRESS(32);
		COMPRESS(33);
		COMPRESS(34);
		COMPRESS(35);
		COMPRESS(36);
		COMPRESS(37);
		COMPRESS(38);
		COMPRESS(39);
		COMPRESS(40);
		COMPRESS(41);
		COMPRESS(42);
		COMPRESS(43);
		COMPRESS(44);
		COMPRESS(45);
		COMPRESS(46);
		COMPRESS(47);
		P = (P + j) % 256;
	}
	cx->unusedBuffer = MD2_BUFSIZE;
}

void 
MD2_Update(MD2Context *cx, const unsigned char *input, unsigned int inputLen)
{
	PRUint32 bytesToConsume;
	
	/* Fill the remaining input buffer. */
	if (cx->unusedBuffer != MD2_BUFSIZE) {
		bytesToConsume = PR_MIN(inputLen, cx->unusedBuffer);
		memcpy(&cx->X[MD2_INPUT + (MD2_BUFSIZE - cx->unusedBuffer)],
		            input, bytesToConsume);
		if (cx->unusedBuffer + bytesToConsume >= MD2_BUFSIZE)
			md2_compress(cx);
		inputLen -= bytesToConsume;
		input += bytesToConsume;
	}

	/* Iterate over 16-byte chunks of the input. */
	while (inputLen >= MD2_BUFSIZE) {
		memcpy(&cx->X[MD2_INPUT], input, MD2_BUFSIZE);
		md2_compress(cx);
		inputLen -= MD2_BUFSIZE;
		input += MD2_BUFSIZE;
	}

	/* Copy any input that remains into the buffer. */
	if (inputLen)
		memcpy(&cx->X[MD2_INPUT], input, inputLen);
	cx->unusedBuffer = MD2_BUFSIZE - inputLen;
}

void 
MD2_End(MD2Context *cx, unsigned char *digest,
        unsigned int *digestLen, unsigned int maxDigestLen)
{
	PRUint8 padStart;
	if (maxDigestLen < MD2_BUFSIZE) {
		PORT_SetError(SEC_ERROR_INVALID_ARGS);
		return;
	}
	padStart = MD2_BUFSIZE - cx->unusedBuffer;
	memset(&cx->X[MD2_INPUT + padStart], cx->unusedBuffer, 
	            cx->unusedBuffer);
	md2_compress(cx);
	memcpy(&cx->X[MD2_INPUT], cx->checksum, MD2_BUFSIZE);
	md2_compress(cx);
	*digestLen = MD2_DIGEST_LEN;
	memcpy(digest, &cx->X[MD2_CV], MD2_DIGEST_LEN);
}

unsigned int 
MD2_FlattenSize(MD2Context *cx)
{
	return sizeof(*cx);
}

SECStatus 
MD2_Flatten(MD2Context *cx, unsigned char *space)
{
	memcpy(space, cx, sizeof(*cx));
	return SECSuccess;
}

MD2Context * 
MD2_Resurrect(unsigned char *space, void *arg)
{
	MD2Context *cx = MD2_NewContext();
	if (cx)
		memcpy(cx, space, sizeof(*cx));
	return cx;
}

void MD2_Clone(MD2Context *dest, MD2Context *src) 
{
	memcpy(dest, src, sizeof *dest);
}