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/** | |
* bcd2number -> takes a nodejs buffer with a BCD and returns the corresponding number. | |
* @param buffer The node.js Buffer object | |
* @param offset The byte offset in the buffer where the BCD starts | |
* @param length The number of bytes to read (a single byte represents 2 digits) | |
* @return number | |
*/ | |
var bcd2number = function(buffer, offset, length) | |
{ | |
var n = 0; | |
var m = 1; | |
for(var i = 0; i<length; i+=1) { | |
n += (buffer[length-1-i+offset] & 0x0F) * m; | |
n += ((buffer[length-1-i+offset]>>4) & 0x0F) * m * 10; | |
m *= 100; | |
} | |
return n; | |
} | |
/** | |
* number2bcd -> takes a number and returns the corresponding BCD in a nodejs buffer object. | |
* @param number 32 bit positive number | |
* @param size nodejs buffer size | |
* @return nodejs buffer | |
*/ | |
var number2bcd = function(number, size) { | |
var s = size || 4; //default value: 4 | |
var bcd = new Buffer(s); | |
bcd.fill(0); | |
while(number !== 0 && s !== 0) { | |
s-=1; | |
bcd[s] = (number % 10); | |
number = (number / 10)|0; | |
bcd[s] += (number % 10) << 4; | |
number = (number / 10)|0; | |
} | |
return bcd; | |
} |
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