js-cfb/bits/80_deflate.js

var _deflateRaw = (function() {
	var DST_LN_RE = use_typed_arrays ? new Uint8Array(0x8000) : [];
	for(var j = 0, k = 0; j < DST_LN.length; ++j) {
		for(; k < DST_LN[j+1]; ++k) DST_LN_RE[k] = j;
	}
	for(;k < 32768; ++k) DST_LN_RE[k] = 29;

	var LEN_LN_RE = use_typed_arrays ? new Uint8Array(0x102) : [];
	for(j = 0, k = 0; j < LEN_LN.length; ++j) {
		for(; k < LEN_LN[j+1]; ++k) LEN_LN_RE[k] = j;
	}

	function write_stored(data, out) {
		var boff = 0;
		while(boff < data.length) {
			var L = Math.min(0xFFFF, data.length - boff);
			var h = boff + L == data.length;
			out.write_shift(1, +h);
			out.write_shift(2, L);
			out.write_shift(2, (~L) & 0xFFFF);
			while(L-- > 0) out[out.l++] = data[boff++];
		}
		return out.l;
	}

	/* Fixed Huffman */
	function write_huff_fixed(data, out) {
		var bl = 0;
		var boff = 0;
		var addrs = use_typed_arrays ? new Uint16Array(0x8000) : [];
		while(boff < data.length) {
			var L = /* data.length - boff; */ Math.min(0xFFFF, data.length - boff);

			/* write a stored block for short data */
			if(L < 10) {
				bl = write_bits_3(out, bl, +!!(boff + L == data.length)); // jshint ignore:line
				if(bl & 7) bl += 8 - (bl & 7);
				out.l = (bl / 8) | 0;
				out.write_shift(2, L);
				out.write_shift(2, (~L) & 0xFFFF);
				while(L-- > 0) out[out.l++] = data[boff++];
				bl = out.l * 8;
				continue;
			}

			bl = write_bits_3(out, bl, +!!(boff + L == data.length) + 2); // jshint ignore:line
			var hash = 0;
			while(L-- > 0) {
				var d = data[boff];
				hash = ((hash << 5) ^ d) & 0x7FFF;

				var match = -1, mlen = 0;

				if((match = addrs[hash])) {
					match |= boff & ~0x7FFF;
					if(match > boff) match -= 0x8000;
					if(match < boff) while(data[match + mlen] == data[boff + mlen] && mlen < 250) ++mlen;
				}

				if(mlen > 2) {
					/* Copy Token  */
					d = LEN_LN_RE[mlen];
					if(d <= 22) bl = write_bits_8(out, bl, bitswap8[d+1]>>1) - 1;
					else {
						write_bits_8(out, bl, 3);
						bl += 5;
						write_bits_8(out, bl, bitswap8[d-23]>>5);
						bl += 3;
					}
					var len_eb = (d < 8) ? 0 : ((d - 4)>>2);
					if(len_eb > 0) {
						write_bits_16(out, bl, mlen - LEN_LN[d]);
						bl += len_eb;
					}

					d = DST_LN_RE[boff - match];
					bl = write_bits_8(out, bl, bitswap8[d]>>3);
					bl -= 3;

					var dst_eb = d < 4 ? 0 : (d-2)>>1;
					if(dst_eb > 0) {
						write_bits_16(out, bl, boff - match - DST_LN[d]);
						bl += dst_eb;
					}
					for(var q = 0; q < mlen; ++q) {
						addrs[hash] = boff & 0x7FFF;
						hash = ((hash << 5) ^ data[boff]) & 0x7FFF;
						++boff;
					}
					L-= mlen - 1;
				} else {
					/* Literal Token */
					if(d <= 143) d = d + 48;
					else bl = write_bits_1(out, bl, 1);
					bl = write_bits_8(out, bl, bitswap8[d]);
					addrs[hash] = boff & 0x7FFF;
					++boff;
				}
			}

			bl = write_bits_8(out, bl, 0) - 1;
		}
		out.l = ((bl + 7)/8)|0;
		return out.l;
	}
	return function _deflateRaw(data, out) {
		if(data.length < 8) return write_stored(data, out);
		return write_huff_fixed(data, out);
	};
})();

function _deflate(data) {
	var buf = new_buf(50+Math.floor(data.length*1.1));
	var off = _deflateRaw(data, buf);
	return buf.slice(0, off);
}