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rOACCT/node_modules/source-map-js/lib/base64-vlq.js
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base64-vlq.js
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			/* -- Mode: js; js-indent-level: 2; -- */
			/*
			* Copyright 2011 Mozilla Foundation and contributors
			* Licensed under the New BSD license. See LICENSE or:
			* http://opensource.org/licenses/BSD-3-Clause
			*
			* Based on the Base 64 VLQ implementation in Closure Compiler:
			* https://code.google.com/p/closure-compiler/source/browse/trunk/src/com/google/debugging/sourcemap/Base64VLQ.java
			*
			* Copyright 2011 The Closure Compiler Authors. All rights reserved.
			* Redistribution and use in source and binary forms, with or without
			* modification, are permitted provided that the following conditions are
			* met:
			*
			* * Redistributions of source code must retain the above copyright
			* notice, this list of conditions and the following disclaimer.
			* * Redistributions in binary form must reproduce the above
			* copyright notice, this list of conditions and the following
			* disclaimer in the documentation and/or other materials provided
			* with the distribution.
			* * Neither the name of Google Inc. nor the names of its
			* contributors may be used to endorse or promote products derived
			* from this software without specific prior written permission.
			*
			* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
			* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
			* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
			* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
			* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
			* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
			* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
			* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
			* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
			*/

			var base64 = require('./base64');

			// A single base 64 digit can contain 6 bits of data. For the base 64 variable
			// length quantities we use in the source map spec, the first bit is the sign,
			// the next four bits are the actual value, and the 6th bit is the
			// continuation bit. The continuation bit tells us whether there are more
			// digits in this value following this digit.
			//
			// Continuation
			// \| Sign
			// \| \|
			// V V
			// 101011

			var VLQ_BASE_SHIFT = 5;

			// binary: 100000
			var VLQ_BASE = 1 << VLQ_BASE_SHIFT;

			// binary: 011111
			var VLQ_BASE_MASK = VLQ_BASE - 1;

			// binary: 100000
			var VLQ_CONTINUATION_BIT = VLQ_BASE;

			/**
			* Converts from a two-complement value to a value where the sign bit is
			* placed in the least significant bit. For example, as decimals:
			* 1 becomes 2 (10 binary), -1 becomes 3 (11 binary)
			* 2 becomes 4 (100 binary), -2 becomes 5 (101 binary)
			*/
			function toVLQSigned(aValue) {
			return aValue < 0
			? ((-aValue) << 1) + 1
			: (aValue << 1) + 0;
			}

			/**
			* Converts to a two-complement value from a value where the sign bit is
			* placed in the least significant bit. For example, as decimals:
			* 2 (10 binary) becomes 1, 3 (11 binary) becomes -1
			* 4 (100 binary) becomes 2, 5 (101 binary) becomes -2
			*/
			function fromVLQSigned(aValue) {
			var isNegative = (aValue & 1) === 1;
			var shifted = aValue >> 1;
			return isNegative
			? -shifted
			: shifted;
			}

			/**
			* Returns the base 64 VLQ encoded value.
			*/
			exports.encode = function base64VLQ_encode(aValue) {
			var encoded = "";
			var digit;

			var vlq = toVLQSigned(aValue);

			do {
			digit = vlq & VLQ_BASE_MASK;
			vlq >>>= VLQ_BASE_SHIFT;
			if (vlq > 0) {
			// There are still more digits in this value, so we must make sure the
			// continuation bit is marked.
			digit \|= VLQ_CONTINUATION_BIT;
			}
			encoded += base64.encode(digit);
			} while (vlq > 0);

			return encoded;
			};

			/**
			* Decodes the next base 64 VLQ value from the given string and returns the
			* value and the rest of the string via the out parameter.
			*/
			exports.decode = function base64VLQ_decode(aStr, aIndex, aOutParam) {
			var strLen = aStr.length;
			var result = 0;
			var shift = 0;
			var continuation, digit;

			do {
			if (aIndex >= strLen) {
			throw new Error("Expected more digits in base 64 VLQ value.");
			}

			digit = base64.decode(aStr.charCodeAt(aIndex++));
			if (digit === -1) {
			throw new Error("Invalid base64 digit: " + aStr.charAt(aIndex - 1));
			}

			continuation = !!(digit & VLQ_CONTINUATION_BIT);
			digit &= VLQ_BASE_MASK;
			result = result + (digit << shift);
			shift += VLQ_BASE_SHIFT;
			} while (continuation);

			aOutParam.value = fromVLQSigned(result);
			aOutParam.rest = aIndex;
			};