base64_sse3_test.cpp

#include <stdio.h>
#include <intrin.h>
#include "smmintrin.h"

size_t hash(unsigned char* lut, size_t c){
	size_t a; 	
	size_t b;

	// psrld 
	// note: the 0xE0 simulates the shifting in of three bits from the next byte... 
	a = 0xE0 | (c >> 3);

	// pshufb
	b = lut[c & 0x0F];
	if(c & 0x80) b = 0x00;
	
	// pavg
	return ((a + b + 1) >> 1);
}


// I'm lazy... just use the real thing
unsigned char adds8(unsigned char a, unsigned char b){
	__m128i x = _mm_cvtsi32_si128(a);
	__m128i y = _mm_cvtsi32_si128(b);
	__m128i r = _mm_adds_epi8(x, y);
	return _mm_cvtsi128_si32(r);
}

unsigned char valid_chars[64] = {
	0x2B, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35,
	0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44,
	0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C,
	0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54,
	0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x61, 0x62,
	0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A,
	0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72,
	0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A
};

unsigned char decoded_chars[64] = {
	62, 63, 52, 53, 54, 55, 56, 57,
	58, 59, 60, 61,  0,  1,  2,  3,
	 4,  5,  6,  7,  8,  9, 10, 11,
	12, 13, 14, 15, 16, 17, 18, 19,
	20, 21, 22, 23, 24, 25, 26, 27,
	28, 29, 30, 31, 32, 33, 34, 35,
	36, 37, 38, 39, 40, 41, 42, 43,
	44, 45, 46, 47, 48, 49, 50, 51
};

//  all signed chars are also invalid
unsigned char invalid_chars[64] = {
	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
	0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
	0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
	0x28, 0x29, 0x2A, 0x2C, 0x2D, 0x2E, 0x3A, 0x3B,
	0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x5B, 0x5C, 0x5D,
	0x5E, 0x5F, 0x60, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F
};

unsigned char delta_asso[16] = {
		0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
		0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0x00, 0x0F
};
unsigned char delta_values[16] = {
		0x00, 0x00, 0x00, 0x13, 0x04, 0xBF, 0xBF, 0xB9,
		0xB9, 0x00, 0x10, 0xC3, 0xBF, 0xBF, 0xB9, 0xB9
};
unsigned char check_asso[16] = {
		0x0D, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
		0x01, 0x01, 0x03, 0x07, 0x0B, 0x0B, 0x0B, 0x0F
};
unsigned char check_values[16] = {
		0x80, 0x80, 0x80, 0x80, 0xCF, 0xBF, 0xD5, 0xA6,
		0xB5, 0x86, 0xD1, 0x80, 0xB1, 0x80, 0x91, 0x80
};

void check_decode(){
	for( size_t i = 0; i < 64; i++ ){
		unsigned char c = valid_chars[i];
		unsigned char h = hash(delta_asso, c);
		unsigned char v = adds8(delta_values[h & 0x0F],c);
		if( decoded_chars[i] != v ){
			printf("FAIL: %02X decoded to %02X \n",c,v);
		}
	}

	// set equal sign (0x3D) to zero in decode, because why not?
	unsigned char x = adds8(delta_values[hash(delta_asso, 0x3D) & 0x0F], 0x3D);
	if( x != 0 ) printf("FAIL: %02X decoded to %02X \n",0x3D,x);
}

void check_invalid_char_detection()
{
	for( size_t i = 0; i < 64; i++ ){
		unsigned char c = valid_chars[i];
		unsigned char h = hash(check_asso, c);
		unsigned char v = adds8(check_values[h & 0x0F],c);
		if(v >= 0x80){
			printf("FAIL: valid char 0x%02X not detected\n",c);
		}
	}

	for( size_t i = 0; i < 64; i++ ){
		unsigned char c = invalid_chars[i];
		unsigned char h = hash(check_asso, c);
		unsigned char v = adds8(check_values[h & 0x0F], c);
		if(v < 0x80){
			printf("FAIL: invalid char 0x%02X not detected\n",c);
			printf( "%02X %02X %02X\n", h, check_values[h & 0x0F], v );
		}
	}

	// note:
	// all check_values are signed...
	// because using sat_adds8: signed + signed = signed
	// with signed input it is possible hash overflows 
	// in which case, 0 + signed = signed
	for( int i = 0; i < 16; i++ ){
		unsigned char c = check_values[i];
		if((c & 0x80) == 0){
			printf("FAIL: check_value %02X is unsigned\n", c);
		}
	}
	for( size_t i = 128; i < 256; i++ ){
		unsigned char c = i;
		unsigned char h = hash(check_asso, c);
		unsigned char v = adds8(check_values[h & 0x0F], c);
		if(v < 0x80){
			printf("FAIL: invalid char 0x%02X not detected\n",c);
		}
	}
}

// hash must produce unsigned results for unsigned input
void check_unsigned_hash(){
	for( size_t i = 0; i < 128; i++ ){
		unsigned char h_c = hash(check_asso, i);
		if(h_c >= 0x80){
			printf("FAIL: %02X hashes to %02X\n",i,h_c);
		}
		unsigned char h_d = hash(delta_asso, i);
		if(h_d >= 0x80){
			printf("FAIL: %02X hashes to %02X\n",i,h_d);
		}
	}
}

void print_hash( unsigned char* lut ){
	for( size_t i = 0; i < 128; i++ ){
		unsigned char c = i;
		unsigned char h = hash(lut, c);
		if((i & 0x0F) == 0)printf("\n");
		printf( "%01X ", h & 0x0F);
	}
	printf("\n");
}

static const char moby_dick_base64[] =
	"Q2FsbCBtZSBJc2htYWVsLiBTb21lIHllYXJzIGFnby0tbmV2ZXIgbWluZCBob3cgbG9uZ"
	"yBwcmVjaXNlbHktLWhhdmluZwpsaXR0bGUgb3Igbm8gbW9uZXkgaW4gbXkgcHVyc2UsIG"
	"FuZCBub3RoaW5nIHBhcnRpY3VsYXIgdG8gaW50ZXJlc3QgbWUgb24Kc2hvcmUsIEkgdGh"
	"vdWdodCBJIHdvdWxkIHNhaWwgYWJvdXQgYSBsaXR0bGUgYW5kIHNlZSB0aGUgd2F0ZXJ5"
	"IHBhcnQgb2YKdGhlIHdvcmxkLiBJdCBpcyBhIHdheSBJIGhhdmUgb2YgZHJpdmluZyBvZ"
	"mYgdGhlIHNwbGVlbiBhbmQgcmVndWxhdGluZwp0aGUgY2lyY3VsYXRpb24uIFdoZW5ldm"
	"VyIEkgZmluZCBteXNlbGYgZ3Jvd2luZyBncmltIGFib3V0IHRoZSBtb3V0aDsKd2hlbmV"
	"2ZXIgaXQgaXMgYSBkYW1wLCBkcml6emx5IE5vdmVtYmVyIGluIG15IHNvdWw7IHdoZW5l"
	"dmVyIEkgZmluZApteXNlbGYgaW52b2x1bnRhcmlseSBwYXVzaW5nIGJlZm9yZSBjb2Zma"
	"W4gd2FyZWhvdXNlcywgYW5kIGJyaW5naW5nIHVwCnRoZSByZWFyIG9mIGV2ZXJ5IGZ1bm"
	"VyYWwgSSBtZWV0OyBhbmQgZXNwZWNpYWxseSB3aGVuZXZlciBteSBoeXBvcyBnZXQKc3V"
	"jaCBhbiB1cHBlciBoYW5kIG9mIG1lLCB0aGF0IGl0IHJlcXVpcmVzIGEgc3Ryb25nIG1v"
	"cmFsIHByaW5jaXBsZSB0bwpwcmV2ZW50IG1lIGZyb20gZGVsaWJlcmF0ZWx5IHN0ZXBwa"
	"W5nIGludG8gdGhlIHN0cmVldCwgYW5kIG1ldGhvZGljYWxseQprbm9ja2luZyBwZW9wbG"
	"UncyBoYXRzIG9mZi0tdGhlbiwgSSBhY2NvdW50IGl0IGhpZ2ggdGltZSB0byBnZXQgdG8"
	"gc2VhCmFzIHNvb24gYXMgSSBjYW4uIFRoaXMgaXMgbXkgc3Vic3RpdHV0ZSBmb3IgcGlz"
	"dG9sIGFuZCBiYWxsLiBXaXRoIGEKcGhpbG9zb3BoaWNhbCBmbG91cmlzaCBDYXRvIHRoc"
	"m93cyBoaW1zZWxmIHVwb24gaGlzIHN3b3JkOyBJIHF1aWV0bHkKdGFrZSB0byB0aGUgc2"
	"hpcC4gVGhlcmUgaXMgbm90aGluZyBzdXJwcmlzaW5nIGluIHRoaXMuIElmIHRoZXkgYnV"
	"0IGtuZXcKaXQsIGFsbW9zdCBhbGwgbWVuIGluIHRoZWlyIGRlZ3JlZSwgc29tZSB0aW1l"
	"IG9yIG90aGVyLCBjaGVyaXNoIHZlcnkKbmVhcmx5IHRoZSBzYW1lIGZlZWxpbmdzIHRvd"
	"2FyZHMgdGhlIG9jZWFuIHdpdGggbWUuCg==";

bool base64_decode_ssse3( void* dst_void, void* src_void, size_t length )
{
	unsigned char* src = (unsigned char*)src_void;
	unsigned char* dst = (unsigned char*)dst_void;

	const __m128i delta_asso = _mm_setr_epi8(
			0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 
			0x00, 0x00, 0x00, 0x00, 0x00, 0x0F, 0x00, 0x0F
	);
	const __m128i delta_values = _mm_setr_epi8(
			0x00, 0x00, 0x00, 0x13, 0x04, 0xBF, 0xBF, 0xB9,
			0xB9, 0x00, 0x10, 0xC3, 0xBF, 0xBF, 0xB9, 0xB9
	);
	const __m128i check_asso = _mm_setr_epi8(
			0x0D, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
			0x01, 0x01, 0x03, 0x07, 0x0B, 0x0B, 0x0B, 0x0F
	);
	const __m128i check_values = _mm_setr_epi8(
			0x80, 0x80, 0x80, 0x80, 0xCF, 0xBF, 0xD5, 0xA6,
			0xB5, 0x86, 0xD1, 0x80, 0xB1, 0x80, 0x91, 0x80
	);

	for( unsigned char* end = &src[(length & ~15)]; src != end; src += 16){
		
		
		__m128i asrc, shifted, delta_hash, check_hash, out, chk;
		int mask;

		asrc = _mm_loadu_si128((__m128i *)src);

		shifted = _mm_srli_epi32(asrc, 3);
		
		delta_hash = _mm_avg_epu8(_mm_shuffle_epi8(delta_asso, asrc), shifted);
		check_hash = _mm_avg_epu8(_mm_shuffle_epi8(check_asso, asrc), shifted);
		
		out = _mm_adds_epi8(_mm_shuffle_epi8(delta_values, delta_hash), asrc);
		chk = _mm_adds_epi8(_mm_shuffle_epi8(check_values, check_hash), asrc);
		
		mask = _mm_movemask_epi8(chk);
		if(mask != 0){
			break;
		}

		const __m128i pack_shuffle = _mm_setr_epi8(
			2,  1,  0,  6,  5,  4, 10,  9,
			8, 14, 13, 12, -1, -1, -1, -1);
		out = _mm_maddubs_epi16(out, _mm_set1_epi32(0x01400140));
		out = _mm_madd_epi16(out, _mm_set1_epi32(0x00011000));
		out = _mm_shuffle_epi8(out, pack_shuffle);

		_mm_storeu_si128((__m128i *)dst, out);
		dst += 12;
	}
	return true;
}


int main ()
{
	print_hash( check_asso );
	print_hash( delta_asso );

	check_unsigned_hash();
	check_decode();
	check_invalid_char_detection();

	static unsigned char out[0x4000];
	memset(out,0,sizeof(out));
	base64_decode_ssse3(out, (void*)moby_dick_base64, -1);
	printf( "\n\n%s", out);

	printf("\npress enter to exit\n");
	getchar();
	return 0;
}