/usr/lib/nodejs/pg/writer.js is in node-pg 0.13.3-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | //binary data writer tuned for creating
//postgres message packets as effeciently as possible by reusing the
//same buffer to avoid memcpy and limit memory allocations
var Writer = function(size) {
this.size = size || 1024;
this.buffer = Buffer(this.size + 5);
this.offset = 5;
this.headerPosition = 0;
};
//resizes internal buffer if not enough size left
Writer.prototype._ensure = function(size) {
var remaining = this.buffer.length - this.offset;
if(remaining < size) {
var oldBuffer = this.buffer;
this.buffer = new Buffer(oldBuffer.length + size);
oldBuffer.copy(this.buffer);
}
};
Writer.prototype.addInt32 = function(num) {
this._ensure(4);
this.buffer[this.offset++] = (num >>> 24 & 0xFF);
this.buffer[this.offset++] = (num >>> 16 & 0xFF);
this.buffer[this.offset++] = (num >>> 8 & 0xFF);
this.buffer[this.offset++] = (num >>> 0 & 0xFF);
return this;
};
Writer.prototype.addInt16 = function(num) {
this._ensure(2);
this.buffer[this.offset++] = (num >>> 8 & 0xFF);
this.buffer[this.offset++] = (num >>> 0 & 0xFF);
return this;
};
//for versions of node requiring 'length' as 3rd argument to buffer.write
var writeString = function(buffer, string, offset, len) {
buffer.write(string, offset, len);
};
//overwrite function for older versions of node
if(Buffer.prototype.write.length === 3) {
writeString = function(buffer, string, offset, len) {
buffer.write(string, offset);
};
}
Writer.prototype.addCString = function(string) {
//just write a 0 for empty or null strings
if(!string) {
this._ensure(1);
} else {
var len = Buffer.byteLength(string);
this._ensure(len + 1); //+1 for null terminator
writeString(this.buffer, string, this.offset, len);
this.offset += len;
}
this.buffer[this.offset++] = 0; // null terminator
return this;
};
Writer.prototype.addChar = function(c) {
this._ensure(1);
writeString(this.buffer, c, this.offset, 1);
this.offset++;
return this;
};
Writer.prototype.addString = function(string) {
string = string || "";
var len = Buffer.byteLength(string);
this._ensure(len);
this.buffer.write(string, this.offset);
this.offset += len;
return this;
};
Writer.prototype.getByteLength = function() {
return this.offset - 5;
};
Writer.prototype.add = function(otherBuffer) {
this._ensure(otherBuffer.length);
otherBuffer.copy(this.buffer, this.offset);
this.offset += otherBuffer.length;
return this;
};
Writer.prototype.clear = function() {
this.offset = 5;
this.headerPosition = 0;
this.lastEnd = 0;
};
//appends a header block to all the written data since the last
//subsequent header or to the beginning if there is only one data block
Writer.prototype.addHeader = function(code, last) {
var origOffset = this.offset;
this.offset = this.headerPosition;
this.buffer[this.offset++] = code;
//length is everything in this packet minus the code
this.addInt32(origOffset - (this.headerPosition+1));
//set next header position
this.headerPosition = origOffset;
//make space for next header
this.offset = origOffset;
if(!last) {
this._ensure(5);
this.offset += 5;
}
};
Writer.prototype.join = function(code) {
if(code) {
this.addHeader(code, true);
}
return this.buffer.slice(code ? 0 : 5, this.offset);
};
Writer.prototype.flush = function(code) {
var result = this.join(code);
this.clear();
return result;
};
module.exports = Writer;
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