intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 58 insertions, 0 deletions

diff --git a/contrib/libs/base64/ssse3/dec_ssse3.c b/contrib/libs/base64/ssse3/dec_ssse3.c
new file mode 100644
index 0000000000..ce11b3cb1b
--- /dev/null
+++ b/contrib/libs/base64/ssse3/dec_ssse3.c
@@ -0,0 +1,58 @@
+// If we have SSSE3 support, pick off 16 bytes at a time for as long as we can,
+// but make sure that we quit before seeing any == markers at the end of the
+// string. Also, because we write four zeroes at the end of the output, ensure
+// that there are at least 6 valid bytes of input data remaining to close the
+// gap. 16 + 2 + 6 = 24 bytes:
+while (srclen >= 24)
+{
+	// Load string:
+	__m128i str = _mm_loadu_si128((__m128i *)c);
+
+	// The input consists of six character sets in the Base64 alphabet,
+	// which we need to map back to the 6-bit values they represent.
+	// There are three ranges, two singles, and then there's the rest.
+	//
+	//  #  From       To        Add  Characters
+	//  1  [43]       [62]      +19  +
+	//  2  [47]       [63]      +16  /
+	//  3  [48..57]   [52..61]   +4  0..9
+	//  4  [65..90]   [0..25]   -65  A..Z
+	//  5  [97..122]  [26..51]  -71  a..z
+	// (6) Everything else => invalid input
+
+	const __m128i set1 = CMPEQ(str, '+');
+	const __m128i set2 = CMPEQ(str, '/');
+	const __m128i set3 = RANGE(str, '0', '9');
+	const __m128i set4 = RANGE(str, 'A', 'Z');
+	const __m128i set5 = RANGE(str, 'a', 'z');
+	const __m128i set6 = CMPEQ(str, '-');
+	const __m128i set7 = CMPEQ(str, '_');
+
+	__m128i delta = REPLACE(set1, 19);
+	delta = _mm_or_si128(delta, REPLACE(set2,  16));
+	delta = _mm_or_si128(delta, REPLACE(set3,   4));
+	delta = _mm_or_si128(delta, REPLACE(set4, -65));
+	delta = _mm_or_si128(delta, REPLACE(set5, -71));
+	delta = _mm_or_si128(delta, REPLACE(set6, 17));
+	delta = _mm_or_si128(delta, REPLACE(set7, -32));
+
+	// Check for invalid input: if any of the delta values are zero,
+	// fall back on bytewise code to do error checking and reporting:
+	if (_mm_movemask_epi8(CMPEQ(delta, 0))) {
+		break;
+	}
+
+	// Now simply add the delta values to the input:
+	str = _mm_add_epi8(str, delta);
+
+	// Reshuffle the input to packed 12-byte output format:
+	str = dec_reshuffle(str);
+
+	// Store back:
+	_mm_storeu_si128((__m128i *)o, str);
+
+	c += 16;
+	o += 12;
+	outl += 12;
+	srclen -= 16;
+}