I have C# code as below:
private static string password = "Password";
private static string salt = "SALT";
private static string hashAlgorithm = "SHA1";
private static int iterations = 2;
var saltValueBytes = Encoding.UTF8.GetBytes(salt);
var passwordKey = new PasswordDeriveBytes(password, saltValueBytes, hashAlgorithm, iterations)
...
I need to implement the same in Mac, I came to know that Opnessl implements related methods(i.e. libcrypto). What is the equivalent method in Opnessl to above code?
This shows how to implement PBKDF1 with OpenSSL, which according to the documentation is the algorithm used by PasswordDeriveBytes.
#include <string.h>
#include <stdlib.h>
#include <openssl/sha.h>
void pbkdf1(const char *password, const char *salt, long iter, unsigned char dk[SHA_DIGEST_LENGTH])
{
size_t pwlen = strlen(password);
size_t dlen = pwlen + 8;
unsigned char *buf;
if (dlen > SHA_DIGEST_LENGTH)
buf = malloc(dlen);
else
buf = malloc(SHA_DIGEST_LENGTH);
memcpy(buf, password, pwlen);
strncpy((char *)buf + pwlen, salt, 8);
while (iter-- > 0)
{
SHA1(buf, dlen, buf);
dlen = SHA_DIGEST_LENGTH;
}
memcpy(dk, buf, SHA_DIGEST_LENGTH);
free(buf);
}
OpenSSL implements PBKDF2, which .NET exposes as Rfc2898DeriveBytes. PasswordDeriveBytes uses (according to the .NET 4 docs) "an extension of the PBKDF1 algorithm". PBKDF1 is not exposed by OpenSSL (and who knows what the 'extension' in question may be).
Using PBKDF2 (aka Rfc2898DeriveBytes) if possible will save you a lot of problems here.
This is a c++ quick and dirty translation of the mono source code to perform GetBytes(X) where X can be greater than the size of the hash. As you can see I'v implemented only the SHA1 version...
#include <iostream>
#include <string.h>
#include <openssl/sha.h>
#define SHA1_BYTES_LEN 20
using namespace std;
namespace DeriveKeys
{
class PasswordDeriveBytes
{
private:
unsigned char* password;
int pass_len;
unsigned char* salt;
int salt_len;
int IterationCount;
int state;
unsigned char* initial;
unsigned char* output;
unsigned int output_len;
unsigned int position;
int hashnumber;
public:
PasswordDeriveBytes(unsigned char* password, unsigned char* salt, int iterations)
{
Prepare(password, salt, iterations);
}
private:
string convertInt(int number)
{
if (number == 0)
return "0";
string temp="";
string returnvalue="";
while (number>0)
{
temp+=number%10+48;
number/=10;
}
for (unsigned int i=0; i<temp.length(); i++)
returnvalue+=temp[temp.length()-i-1];
return returnvalue;
}
void Prepare(unsigned char* password, unsigned char* salt, int iterations)
{
if (password == NULL)
return;
Prepare(password, strlen((const char*)password), salt, strlen((const char*)salt), iterations);
}
void Prepare(unsigned char* password, int pass_len, unsigned char* salt, int salt_len, int iterations)
{
if (password == NULL)
return;
this->password = new unsigned char[pass_len];
memcpy(this->password,password,pass_len);
//memcpy((char *)this->password, (const char*)password, pass_len);
this->pass_len = pass_len;
//(unsigned char*)password.Clone();
this->salt = new unsigned char[salt_len];
//strncpy((char *)this->salt, (const char*)salt, salt_len);
memcpy(this->salt,salt,salt_len);
this->salt_len = salt_len;
this->IterationCount = iterations;
state = 0;
}
public:
unsigned char* GetBytes(int cb)
{
if (cb < 1)
return NULL;
if (state == 0)
{
// it's now impossible to change the HashName, Salt
// and IterationCount
Reset();
state = 1;
}
unsigned char* result = new unsigned char[cb];
int cpos = 0;
// the initial hash (in reset) + at least one iteration
int iter = IterationCount-1;
if (iter < 1)
{
iter = 1;
}
// start with the PKCS5 key
if (this->output == NULL)
{
// calculate the PKCS5 key
this->output = initial;
this->output_len = SHA1_BYTES_LEN;
// generate new key material
for (int i = 0; i < iter - 1; i++)
{
SHA1((const unsigned char*)this->output,this->output_len,this->output);
this->output_len = SHA1_BYTES_LEN;
}
}
while (cpos < cb)
{
unsigned char* output2 = new unsigned char[SHA1_BYTES_LEN];
unsigned int output2_len = SHA1_BYTES_LEN;
if (hashnumber == 0)
{
SHA1((const unsigned char*)this->output,this->output_len,output2);
output2_len = SHA1_BYTES_LEN;
}
else if (hashnumber < 1000)
{
string n = convertInt(hashnumber);
output2 = new unsigned char[this->output_len + n.length()];
output2_len = this->output_len + n.length();
for (unsigned int j = 0; j < n.length(); j++)
output2[j] = (unsigned char)(n[j]);
memcpy(output2 + n.length(),this->output,this->output_len);
SHA1((const unsigned char*)output2,output2_len,output2);
output2_len = SHA1_BYTES_LEN;
}
else
{
return NULL;
}
int rem = this->output_len - this->position;
int l = cb - cpos;
if (l > rem)
{
l = rem;
}
memcpy(result + cpos, output2 + this->position, l);
cpos += l;
this->position += l;
while (this->position >= output2_len)
{
this->position -= output2_len;
this->hashnumber++;
}
}
return result;
}
void Reset()
{
this->state = 0;
this->position = 0;
this->hashnumber = 0;
this->initial = new unsigned char[SHA1_BYTES_LEN];
this->output = NULL;
this->output_len = 0;
if (this->salt != NULL)
{
unsigned char* rv = new unsigned char[this->pass_len + this->salt_len];
memcpy(rv,this->password, this->pass_len);
memcpy(rv + this->pass_len, this->salt, this->salt_len);
SHA1((const unsigned char*)rv,this->pass_len + this->salt_len, initial);
}
else
{
SHA1((const unsigned char*)this->password,this->pass_len,initial);
}
}
};
}
Related
Hi im trying to repeat this wifi baby monitor project based on esp8266:
baby monitor project
But instead of receiving data on another esp8266, I want to receive data on pc.
I'm a c # programmer and I've encountered an problem of understanding c/c++ pointers how arrays works here and receive udp.
this is esp8266 receiver source code which works without any problems, but data that it receives, passes them to DAC. And i cant figure out where i can read just values one by one which was readed by esp8266 transmiter from ADC. Also readed data from ADC is 12 bit and author of original code use all 16 bit with some compression to transfer more data, and this compression part is what i have difficulty to uderstand it
#include <Wire.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <WiFiUdp.h>
#include "ESP8266mDNS.h"
#include <ArduinoOTA.h>
//#include "wifi_params.h"
const int mySDA = D7;
const int mySCL = D6;
const int AMPLI_MUTE_PIN = D2;
const int AMPLI_SHUTDOWN_PIN = D1;
const int RIGHT_BTN = D3;
const int LEFT_BTN = D4;
const int LED1 = D8;
const int udp_recv_port = 45990;
WiFiUDP udp;
TwoWire i2c;
#define NB_DATA_BUFS 5
uint16_t data_buf[NB_DATA_BUFS][700]; // data buffer, N buffered
unsigned int current_play_data_buf; // current data buf being played
unsigned int play_data_buf_pos; // position in the ADC data buffer
unsigned int current_recv_data_buf; // current data buf being received
bool play_waiting = true;
bool amplifier_stopped = false;
long play_waiting_at;
bool left_btn_pressed;
bool right_btn_pressed;
#define ICACHE_RAM_ATTR __attribute__((section(".iram.text")))
#define twi_sda mySDA
#define twi_scl mySCL
#define twi_dcount 0
#define twi_clockStretchLimit 10
#define SDA_LOW() (GPES = (1 << twi_sda)) //Enable SDA (becomes output and since GPO is 0 for the pin, it will pull the line low)
#define SDA_HIGH() (GPEC = (1 << twi_sda)) //Disable SDA (becomes input and since it has pullup it will go high)
#define SDA_READ() ((GPI & (1 << twi_sda)) != 0)
#define SCL_LOW() (GPES = (1 << twi_scl))
#define SCL_HIGH() (GPEC = (1 << twi_scl))
#define SCL_READ() ((GPI & (1 << twi_scl)) != 0)
static void twi_delay(unsigned char v) {
unsigned int i;
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
unsigned int reg;
for (i = 0; i<v; i++) reg = GPI;
#pragma GCC diagnostic pop
}
static inline ICACHE_RAM_ATTR bool twi_write_start(void) {
SCL_HIGH();
SDA_HIGH();
if (SDA_READ() == 0) return false;
SDA_LOW();
return true;
}
static inline ICACHE_RAM_ATTR bool twi_write_stop(void) {
uint32_t i = 0;
SCL_LOW();
SDA_LOW();
SCL_HIGH();
while (SCL_READ() == 0 && (i++) < twi_clockStretchLimit); // Clock stretching
SDA_HIGH();
return true;
}
static inline ICACHE_RAM_ATTR bool twi_write_bit(bool bit) {
uint32_t i = 0;
SCL_LOW();
if (bit) SDA_HIGH();
else SDA_LOW();
twi_delay(twi_dcount + 1);
SCL_HIGH();
while (SCL_READ() == 0 && (i++) < twi_clockStretchLimit);// Clock stretching
return true;
}
static inline ICACHE_RAM_ATTR bool twi_read_bit(void) {
uint32_t i = 0;
SCL_LOW();
SDA_HIGH();
twi_delay(twi_dcount + 2);
SCL_HIGH();
while (SCL_READ() == 0 && (i++) < twi_clockStretchLimit);// Clock stretching
bool bit = SDA_READ();
return bit;
}
static inline ICACHE_RAM_ATTR bool twi_write_byte(unsigned char byte) {
unsigned char bit;
for (bit = 0; bit < 8; bit++) {
twi_write_bit(byte & 0x80);
byte <<= 1;
}
return !twi_read_bit();//NACK/ACK
}
static inline ICACHE_RAM_ATTR unsigned char twi_read_byte(bool nack) {
unsigned char byte = 0;
unsigned char bit;
for (bit = 0; bit < 8; bit++) byte = (byte << 1) | twi_read_bit();
twi_write_bit(nack);
return byte;
}
unsigned char inline ICACHE_RAM_ATTR mytwi_writeTo(unsigned char address, unsigned char * buf, unsigned int len, unsigned char sendStop) {
unsigned int i;
if (!twi_write_start()) return 4;//line busy
if (!twi_write_byte(((address << 1) | 0) & 0xFF)) {
if (sendStop) twi_write_stop();
return 2; //received NACK on transmit of address
}
for (i = 0; i<len; i++) {
if (!twi_write_byte(buf[i])) {
if (sendStop) twi_write_stop();
return 3;//received NACK on transmit of data
}
}
if (sendStop) twi_write_stop();
i = 0;
while (SDA_READ() == 0 && (i++) < 10) {
SCL_LOW();
SCL_HIGH();
}
return 0;
}
static inline ICACHE_RAM_ATTR uint8_t DAC(uint16_t value)
{
/* value is 76543210 XXXXBA98
per the datasheet for fast write:
1 1 0 0 A2 A1 A0 0 <ACK> 0 0 PD1 PD0 D11 D10 D9 D8 <ACK> D7 D6 D5 D4 D3 D2 D1 D0 <ACK>
*/
uint8_t buf[2] = { (value >> 8) & 0x0F, (value & 0xFF) };
int ret = mytwi_writeTo(0x60, buf, 2, true);
Serial.println(value);
return ret;
}
void ICACHE_RAM_ATTR playsample_isr(void)
{
if (play_waiting) {
return;
}
DAC(data_buf[current_play_data_buf][play_data_buf_pos]);
play_data_buf_pos++;
if (play_data_buf_pos >= sizeof(data_buf[0]) / sizeof(data_buf[0][0])) {
play_data_buf_pos = 0;
current_play_data_buf++;
if (current_play_data_buf == NB_DATA_BUFS) {
current_play_data_buf = 0;
}
if (current_play_data_buf == current_recv_data_buf) {
play_waiting = true;
play_waiting_at = micros();
}
}
}
void ota_onstart(void)
{
// Disable timer when an OTA happens
timer1_detachInterrupt();
timer1_disable();
}
void ota_onprogress(unsigned int sz, unsigned int total)
{
Serial.print("OTA: "); Serial.print(sz); Serial.print("/"); Serial.print(total);
Serial.print("="); Serial.print(100 * sz / total); Serial.println("%");
}
void ota_onerror(ota_error_t err)
{
Serial.print("OTA ERROR:"); Serial.println((int)err);
}
void left_btn_intr()
{
left_btn_pressed = 1;
}
void right_btn_intr()
{
right_btn_pressed = 1;
}
void setup(void)
{
Serial.begin(115200);
Serial.println("I was built on " __DATE__ " at " __TIME__ "");
i2c.begin(mySDA, mySCL);
i2c.setClock(400000);
WiFi.mode(WIFI_STA);
WiFi.begin("valik 2", "299745buhlo");
WiFi.setSleepMode(WIFI_MODEM_SLEEP);
Serial.print("Connecting to wifi");
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.print("Cnnectd to ");
Serial.println("valik 2");
Serial.print("IP ");
Serial.println(WiFi.localIP());
ArduinoOTA.onStart(ota_onstart);
ArduinoOTA.onError(ota_onerror);
ArduinoOTA.onProgress(ota_onprogress);
ArduinoOTA.setHostname("bb-recv");
ArduinoOTA.begin();
timer1_isr_init();
timer1_attachInterrupt(playsample_isr);
timer1_enable(TIM_DIV16, TIM_EDGE, TIM_LOOP);
timer1_write(clockCyclesPerMicrosecond() / 16 * 50); //50us = 20 kHz sampling freq
udp.begin(udp_recv_port);
pinMode(AMPLI_MUTE_PIN, OUTPUT);
pinMode(AMPLI_SHUTDOWN_PIN, OUTPUT);
digitalWrite(AMPLI_SHUTDOWN_PIN, 0);
digitalWrite(AMPLI_MUTE_PIN, 0);
pinMode(LEFT_BTN, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(LEFT_BTN), left_btn_intr, FALLING);
pinMode(RIGHT_BTN, INPUT_PULLUP);
attachInterrupt(digitalPinToInterrupt(RIGHT_BTN), right_btn_intr, FALLING);
pinMode(LED1, OUTPUT);
digitalWrite(LED1, 0);
}
int do_undelta7(const uint8_t *val, int sz, uint16_t *out)
{
// Implement delta 7 decompression.
// First bit = 0 <=> uncompressed 15 bits following
// First bit = 1 <=> 7 bits follow representing delta
// must switch to big endian...
uint16_t last = 0;
uint8_t *ptr = (uint8_t *)&out[0];
const uint8_t *start = ptr;
for (int i = 0; i < sz; i++) {
uint16_t *ptr16 = (uint16_t *)ptr;
const int8_t firstbyte = val[i];
if (firstbyte & 0x80) {
// Delta7 compressed
// byte is CSMMMMMM
int8_t delta = firstbyte & 0x3F;
if (firstbyte & 0x40) {
delta = -delta;
}
const uint16_t value = last + delta;
*ptr16 = value;
ptr += 2;
last = value;
}
else {
// uncompressed -- switch bytes back to LE
*ptr++ = val[i + 1];
*ptr++ = val[i];
last = val[i + 1] | val[i] << 8;
i++;
}
}
return ptr - start;
}
void loop(void)
{
ArduinoOTA.handle();
int sz = udp.parsePacket();
//Serial.println(current_play_data_buf);
if (sz) {
uint8_t buf[sz];
udp.read(&buf[0], sz);
current_recv_data_buf++;
if (current_recv_data_buf == NB_DATA_BUFS) {
current_recv_data_buf = 0;
if (current_recv_data_buf == current_play_data_buf && !play_waiting) {
Serial.println("buffer overflow when receiving");
}
}
do_undelta7(buf, sz, &data_buf[current_recv_data_buf][0]);
if (play_waiting) {
Serial.print("Restarting play, was waiting (us)"); Serial.println(micros() - play_waiting_at);
// Re-enable *then* unmute in that order to avoid pops
digitalWrite(AMPLI_SHUTDOWN_PIN, 1);
digitalWrite(AMPLI_MUTE_PIN, 1);
play_waiting = false;
amplifier_stopped = false;
digitalWrite(LED1, 1);
}
Serial.println("");
}
// If not playing anything, but amplifier is still up
if (!amplifier_stopped && play_waiting) {
if ((micros() - play_waiting_at) > 2000 * 1000) {
// If nothing has been played for two seconds, shut down the amplifier
Serial.println("Shutting down amplifier!");
digitalWrite(AMPLI_SHUTDOWN_PIN, 0);
digitalWrite(AMPLI_MUTE_PIN, 0);
amplifier_stopped = true;
digitalWrite(LED1, 0);
}
}
if (left_btn_pressed) {
left_btn_pressed = 0;
digitalWrite(AMPLI_MUTE_PIN, 0);
digitalWrite(AMPLI_SHUTDOWN_PIN, 0);
}
if (right_btn_pressed) {
digitalWrite(AMPLI_SHUTDOWN_PIN, 1);
digitalWrite(AMPLI_MUTE_PIN, 1);
udp.beginPacket(udp.remoteIP(), 45990);
udp.write("sendnow");
udp.endPacket();
right_btn_pressed = 0;
}
// If the amplifier is stopped, add a delay for power saving
if (amplifier_stopped) {
delay(10);
}
}
This is my attempt to translate code to c++ for windows. But i encountered problem where programm just freeze without any errors and without closing.
#include "stdafx.h"
#include <winsock2.h>
#include <stdio.h>
#include <cstdint>
#include <ctime>
#pragma comment (lib, "ws2_32.lib")
#define NB_DATA_BUFS 5
uint16_t data_buf[NB_DATA_BUFS][700]; // data buffer, N buffered
unsigned int current_play_data_buf; // current data buf being played
unsigned int play_data_buf_pos; // position in the ADC data buffer
unsigned int current_recv_data_buf; // current data buf being received
bool play_waiting = true;
bool amplifier_stopped = false;
long play_waiting_at;
bool left_btn_pressed;
bool right_btn_pressed;
void InitWinsock()
{
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);
}
int do_undelta7(const uint8_t *val, int sz, uint16_t *out)
{
// Implement delta 7 decompression.
// First bit = 0 <=> uncompressed 15 bits following
// First bit = 1 <=> 7 bits follow representing delta
// must switch to big endian...
uint16_t last = 0;
uint8_t *ptr = (uint8_t *)&out[0];
const uint8_t *start = ptr;
for (int i = 0; i < sz; i++) {
uint16_t *ptr16 = (uint16_t *)ptr;
const int8_t firstbyte = val[i];
if (firstbyte & 0x80) {
// Delta7 compressed
// byte is CSMMMMMM
int8_t delta = firstbyte & 0x3F;
if (firstbyte & 0x40) {
delta = -delta;
}
const uint16_t value = last + delta;
*ptr16 = value;
ptr += 2;
last = value;
}
else {
// uncompressed -- switch bytes back to LE
*ptr++ = val[i + 1];
*ptr++ = val[i];
last = val[i + 1] | val[i] << 8;
i++;
}
}
return ptr - start;
}
void DAC(uint16_t value)
{
/* value is 76543210 XXXXBA98
per the datasheet for fast write:
1 1 0 0 A2 A1 A0 0 <ACK> 0 0 PD1 PD0 D11 D10 D9 D8 <ACK> D7 D6 D5 D4 D3 D2 D1 D0 <ACK>
*/
uint8_t buf[2] = { (value >> 8) & 0x0F, (value & 0xFF) };
printf("%u\n", value & 0xFFF);
}
int _tmain(int argc, _TCHAR* argv[])
{
SOCKET socketC;
InitWinsock();
struct sockaddr_in serverInfo;
int len = 2000;
serverInfo.sin_family = AF_INET;
serverInfo.sin_port = htons(45990);
serverInfo.sin_addr.s_addr = inet_addr("192.168.1.105");
socketC = socket(AF_INET, SOCK_DGRAM, 0);
char buffers[16];
ZeroMemory(buffers, sizeof(buffers));
sendto(socketC, buffers, sizeof(IReleaseMarshalBuffers), 0, (sockaddr*)&serverInfo, len);
while (1)
{
sockaddr_in from;
const int paketSize = sizeof(from);
int r = paketSize;
char buffer[paketSize];
sprintf(buffer, "%.7s", "sendnow");
if (strcmp(buffer, "exit") == 0)
break;
recvfrom(socketC, buffer, sizeof(buffer), 0, (sockaddr*)&serverInfo, &len);
uint8_t buf[sizeof(buffer)];
uint8_t * bufeerPntr = (uint8_t*)buffer;
uint8_t * bufPntr = (uint8_t*)buffer;
for(int i=0;i<sizeof(buffer);i++)
{
buf[i] = buffer[i];
}
//udp.read(&buf[0], sizeof(buffer));
current_recv_data_buf++;
if (current_recv_data_buf == NB_DATA_BUFS) {
current_recv_data_buf = 0;
if (current_recv_data_buf == current_play_data_buf && !play_waiting) {
printf("buffer overflow when receiving\n");
}
}
do_undelta7(buf, sizeof(buffer), &data_buf[current_recv_data_buf][0]);
}
closesocket(socketC);
return 0;
}
This is my attempt to translate decoding part to c# (c# is much easier for me to understand) but i forced to use pointers and strange * and & things which i have difficulty to understand:
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
public class UDPListener
{
private const int listenPort = 45990;
public static int Main()
{
bool done = false;
UdpClient listener = new UdpClient(listenPort);
IPEndPoint groupEP = new IPEndPoint(IPAddress.Parse("192.168.1.3"), listenPort);
string received_data;
int BUFSIZE = 700;
byte[] receive_byte_array;
uint current_recv_data_buf = 1;
while (!done)
{
Console.WriteLine("Waiting for broadcast");
receive_byte_array = listener.Receive(ref groupEP);
Console.WriteLine("Received a broadcast from {0}", groupEP.ToString());
received_data = Encoding.ASCII.GetString(receive_byte_array, 0, receive_byte_array.Length);
unsafe
{
UInt16*[,] data_buf = new UInt16*[5, 700];
int sz = receive_byte_array.Length;
if (sz > 0)
{
byte[] buf = new byte[receive_byte_array.Length];
UInt16* f = stackalloc UInt16[2000];
//udp.read(&buf[0], sz);
buf = receive_byte_array;
current_recv_data_buf++;
UInt16 last = 0;
UInt16* #out1 = stackalloc UInt16[800];
for (int i = 0; i < 800; i++)
{
#out1[i] = (char)i;
}
//UIntPtr* ptr = (UIntPtr*)&#out[0];
UIntPtr* ptr = (UIntPtr*)&#out1[0];
UIntPtr* start = ptr;
for (int i = 0; i < sz; i++)
{
UIntPtr* ptr16 = ptr;
byte firstbyte = buf[i];
if ((firstbyte & 0x80) != 0)
{
// Delta7 compressed
// byte is CSMMMMMM
byte delta = (byte)(firstbyte & 0x3F);
if ((firstbyte & 0x40) != 0)
{
delta = (byte)(0 - delta);
}
UInt16 value = (UInt16)(last + delta);
*ptr16 = (UIntPtr)value;
ptr += 2;
last = value;
}
else
{
*ptr++ = (UIntPtr)buf[i + 1];
*ptr++ = (UIntPtr)buf[i];
last = (UInt16)(buf[i + 1] | buf[i] << 8);
i++;
}
}
for (int i = 0; i < 91; i++)
{
System.Console.WriteLine(#out1[i]);
}
string b = "";
}
}
}
listener.Close();
return 0;
}
} // end of class UDPListener
udp.read(&buf[0], sz); copies the received UDP packet into buffer buf. The function do_undelta7 then makes a decompression of the data in the input buffer to output buffer data_buf[current_recv_data_buf]. data_buf is array of buffers. The interrupt playsample_isr plays the content of the buffers in data_buf.
i missed an unsigned byte in do_undelta7
so now it's decoding well
c#
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Media;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using NAudio.Wave;
public class UDPListener
{
uint current_recv_data_buf;
static int NB_DATA_BUFS = 5;
static UInt16[] data_buf = new UInt16[700];
uint current_play_data_buf; // current data buf being played
uint play_data_buf_pos; // position in the ADC data buffer
private const int listenPort = 45990;
public static unsafe int Main()
{
bool done = false;
UdpClient listener = new UdpClient(listenPort);
IPEndPoint groupEP = new IPEndPoint(IPAddress.Parse("192.168.1.3"), listenPort);
int BUFSIZE = 700;
byte[] receive_byte_array;
uint current_recv_data_buf = 1;
List<byte> tenBuffsToPlay = new List<byte>();
int iterBuffsToPLay = 0;
byte[] byteArrToPlay = new byte[data_buf.Length * 2];
byte[] byte10ArrToPlay;
int pktcount = 0;
var sampleRate = 20000;
var frequency = 500;
var amplitude = 0.2;
var seconds = 5;
while (!done)
{
receive_byte_array = listener.Receive(ref groupEP);
if (receive_byte_array.Length > 0)
{
Console.WriteLine("received !"+pktcount++);
int sz = receive_byte_array.Length;
unsafe
{
byte[] buf = new byte[sz];
buf = receive_byte_array;
fixed (UInt16* data_bufPtr = &data_buf[0])
fixed (byte* ptrbuf = buf)
do_undelta7(ptrbuf, sz, data_bufPtr);
//string firstPart = "";
//string secondPart = "";
for (int i =0;i<data_buf.Length;i++)
{
//Console.WriteLine("Hex: {0:X}", data_buf[i]);
byteArrToPlay[i*2] = (byte)((data_buf[i] >> 8)&0x0f);
byteArrToPlay[(i*2)+1] = (byte)(data_buf[i] & 0xff);
//firstPart = Convert.ToString(byteArrToPlay[i], 2).PadLeft(4, '0');
//Console.Write(firstPart);
//secondPart = Convert.ToString(byteArrToPlay[i+1], 2).PadLeft(4, '0');
//Console.Write(secondPart+"\n");
}
//byteArrToPlay = data_buf.SelectMany(BitConverter.GetBytes).ToArray();
//foreach (var Arr in byteArrToPlay)
// {
// Console.WriteLine("Hex: {0:X}", Arr);
// }
tenBuffsToPlay.AddRange(byteArrToPlay);
iterBuffsToPLay++;
if (iterBuffsToPLay == 3)
{
byte10ArrToPlay = tenBuffsToPlay.ToArray();
/*var raw = new byte[sampleRate * seconds * 2];
var multiple = 2.0 * frequency / sampleRate;
for (int n = 0; n < sampleRate * seconds; n++)
{
var sampleSaw = ((n * multiple) % 2) - 1;
var sampleValue = sampleSaw > 0 ? amplitude : -amplitude;
var sample = (short)(sampleValue * Int16.MaxValue);
var bytes = BitConverter.GetBytes(sample);
raw[n * 2] = bytes[0];
raw[n * 2 + 1] = bytes[1];
}*/
var ms = new MemoryStream(byte10ArrToPlay);
var rs = new RawSourceWaveStream(ms, new WaveFormat(sampleRate, 16, 1));
var wo = new WaveOutEvent();
wo.Init(rs);
wo.Play();
/*while (wo.PlaybackState == PlaybackState.Playing)
{
Thread.Sleep(1);
}*/
//wo.Dispose();
/*using (MemoryStream ms = new MemoryStream())
{
WriteWavHeader(ms, false, 1, 16, 20000, (byte10ArrToPlay.Length / 2 - 45));
// Construct the sound player
ms.Write(byte10ArrToPlay, 0, byte10ArrToPlay.Length);
ms.Position = 0;
SoundPlayer player = new SoundPlayer(ms);
player.Play();
}*/
tenBuffsToPlay.Clear();
iterBuffsToPLay = 0;
}
}
}
}
listener.Close();
return 0;
}
static unsafe long do_undelta7(byte* val, int sz, UInt16* outArray)
{
// Implement delta 7 decompression.
// First bit = 0 <=> uncompressed 15 bits following
// First bit = 1 <=> 7 bits follow representing delta
// must switch to big endian...
UInt16 last = 0;
byte* ptr = (byte*)&outArray[0];
byte* start = ptr;
for (int i = 0; i < sz; i++)
{
UInt16* ptr16 = (UInt16*)ptr;
byte firstbyte = val[i];
var bit = (firstbyte & (1 << 8 - 1)) != 0;
if (bit == true)
{
// Delta7 compressed
// byte is CSMMMMMM
sbyte delta = (sbyte)(firstbyte & 0x3f);
bit = (firstbyte & (1 << 7 - 1)) != 0;
if (bit == true)
{
delta = (sbyte)(0x0 - delta);
}
UInt16 value = (UInt16)(last + delta);
*ptr16 = value;
ptr += 2;
last = value;
}
else
{
// uncompressed -- switch bytes back to LE
*ptr++ = val[i + 1];
*ptr++ = val[i];
last = (UInt16)(val[i + 1] | val[i] << 8);
i++;
}
}
return ptr - start;
}
private static void WriteWavHeader(MemoryStream stream, bool isFloatingPoint, ushort channelCount, ushort bitDepth, int sampleRate, int totalSampleCount)
{
stream.Position = 0;
stream.Write(Encoding.ASCII.GetBytes("RIFF"), 0, 4);
stream.Write(BitConverter.GetBytes((2* totalSampleCount) + 36), 0, 4);
stream.Write(Encoding.ASCII.GetBytes("WAVE"), 0, 4);
stream.Write(Encoding.ASCII.GetBytes("fmt "), 0, 4);
stream.Write(BitConverter.GetBytes(16), 0, 4);
stream.Write(BitConverter.GetBytes((ushort)(isFloatingPoint ? 3 : 1)), 0, 2);
stream.Write(BitConverter.GetBytes(channelCount), 0, 2);
stream.Write(BitConverter.GetBytes(sampleRate), 0, 4);
stream.Write(BitConverter.GetBytes(sampleRate * 2), 0, 4);
stream.Write(BitConverter.GetBytes((ushort)2), 0, 2);
stream.Write(BitConverter.GetBytes(16), 0, 2);
stream.Write(Encoding.ASCII.GetBytes("data"), 0, 4);
stream.Write(BitConverter.GetBytes(2 * totalSampleCount), 0, 4);
}
} // end of class UDPListener
I am using C# and C++ with OpenSSL to compute HMACSHA256 has with a key and both produce different results. What am I doing wrong?
C# code:
public static string CreateSignature(string signingString, string sharedKey)
{
var key = Encoding.ASCII.GetBytes(sharedKey);
var hmac = new HMACSHA256(key);
var data = Encoding.ASCII.GetBytes(signingString);
var hash = hmac.ComputeHash(data);
return Convert.ToBase64String(hash);
}
C++ code:
std::string SignatureProvider::getSignature(std::string stringToSign, std::string key)
{
const char* pKey = key.c_str();
const char* pData = stringToSign.c_str();
unsigned char* result = nullptr;
unsigned int len = 32;
result = (unsigned char*)malloc(sizeof(char) * len);
HMAC_CTX ctx;
HMAC_CTX_init(&ctx);
HMAC_Init_ex(&ctx, pKey, strlen(pKey), EVP_sha256(), NULL);
HMAC_Update(&ctx, (unsigned char*)&pData, strlen(pData));
HMAC_Final(&ctx, result, &len);
HMAC_CTX_cleanup(&ctx);
return base64_encode(result, len);
}
std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len)
{
std::string ret;
int i = 0;
int j = 0;
unsigned char char_array_3[3];
unsigned char char_array_4[4];
while (in_len--) {
char_array_3[i++] = *(bytes_to_encode++);
if (i == 3) {
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
char_array_4[3] = char_array_3[2] & 0x3f;
for (i = 0; (i <4); i++)
ret += base64_chars[char_array_4[i]];
i = 0;
}
}
if (i)
{
for (j = i; j < 3; j++)
char_array_3[j] = '\0';
char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
for (j = 0; (j < i + 1); j++)
ret += base64_chars[char_array_4[j]];
while ((i++ < 3))
ret += '=';
}
return ret;
}
I just included base64 conversion for completeness, but it is already different before it.
Why don't you use HMAC function itself? I have tried with this code and both C++ and c# code result in same HMAC :
std::string getSignature(std::string stringToSign, std::string key)
{
const char* pKey = key.c_str();
const char* pData = stringToSign.c_str();
unsigned char* result = nullptr;
unsigned int len = 32;
result = (unsigned char*)malloc(sizeof(char) * len);
int nkeyLen = strlen(pKey);
int dataLen = strlen(pData);
result = HMAC(EVP_sha256(), pKey, nkeyLen, (unsigned char*)pData, dataLen, NULL, NULL);
return base64_encode(result, len);
}
Is there any documentation on what RNG algorithm PowerShell's Get-Random cmdlet officially uses in PowerShell 5.1?
I did some investigating (via decompiling), and it seems Get-Random is just a wrapper for the native .NET Random class. I can confirm this by getting the same values on PowerShell 2.0 (Windows 7) vs C# (targeting .NET 4.5.2). However, Powershell 5.1 (Windows 10) seems to output different numbers.
PowerShell 2.0:
Get-Random -SetSeed 0 -Minimum 0 -Maximum 2147483647
# Produces 1559595546
PowerShell 5.1:
Get-Random -SetSeed 0 -Minimum 0 -Maximum 2147483647
# Produces: 1866861594
C#:
new Random(0).Next(0, 2147483647);
# Produces 1559595546
I did read that after PowerShell 2.0, Get-Random is supposed to support 64-bit numbers, but I set the minimum and maximum above to the 32-bit range for proper testing. Even different seeds, or altering the ranges to something like [0, 100] still yields different results on PowerShell 5.1.
My end goal is basically trying to reproduce random numbers produced in PowerShell 5.1 in either C++ or C# for sake of performance. I already have the C# Random class translated to C++.
You can view Power Shell's Get Random implementation on GitHub.
Comments in the source code show it is using its own generator which have comments indicating it has some deviations from the .net / CRL implementation.
In particular, it has its own PolymorphicRandomNumberGenerator class that provides a "re-implementation" of methods using the NextBytes() primitive based on the CLR implementation:
/// <summary>
/// Provides an adapter API for random numbers that may be either cryptographically random, or
/// generated with the regular pseudo-random number generator. Re-implementations of
/// methods using the NextBytes() primitive based on the CLR implementation:
/// http://referencesource.microsoft.com/#mscorlib/system/random.cs
/// </summary>
internal class PolymorphicRandomNumberGenerator
For example:
/// <summary>
/// Generates a non-negative random integer.
/// </summary>
/// <returns>A non-negative random integer.</returns>
internal int Next()
{
int result;
// The CLR implementation just fudges
// Int32.MaxValue down to (Int32.MaxValue - 1). This implementation
// errs on the side of correctness.
do
{
result = InternalSample();
}
while (result == Int32.MaxValue);
if (result < 0)
{
result += Int32.MaxValue;
}
return result;
}
The powershell implementation, while using the same underlying System.Random, will use different methods to generate the random values depending on the input. With your issue the power shell implementation does this:
var rnd = new Random(0);
int result;
byte[] data = new byte[sizeof(int)];
rnd.NextBytes(data);
result = BitConverter.ToInt32(data, 0);
console.log("result = {0}", result);
// result = 1866861594
Where which does not match the output of:
var rresult = new Random(0).Next(0, int.MaxValue);
console.log("result = {0}", result);
// result = 1559595546
Here's my ported C++ code for the PowerShell 5.0 PRNG, if it's of any use to anyone else searching. Confirmed it produces the same numbers as PowerShell 5.1 on Windows 10.
It utilizes my Random class that is a ported version of the .NET RNG, which I separated a bit to make both inherit from a common interface (Random.h) and renamed to RandomDotNet: https://stackoverflow.com/a/39338606/1301139
Random.h
#include <limits>
#include <Windows.h>
#pragma once
class Random
{
public:
virtual ~Random() {}
virtual int Next() = 0;
virtual int Next(int minValue, int maxValue) = 0;
virtual int Next(int maxValue) = 0;
virtual void NextBytes(BYTE *buffer, int bufferLen) {};
virtual double NextDouble() = 0;
};
RandomPS5.h
#include <limits>
#include <Windows.h>
#include "Random.h"
#pragma once
class RandomPS5 : public Random
{
protected:
double InternalSampleLargeRange();
int InternalSample();
int BytesToInt(BYTE *dword);
Random *pseudoGenerator;
public:
RandomPS5(int seed);
~RandomPS5();
int Next();
int Next(int minValue, int maxValue);
int Next(int maxValue);
double NextDouble();
void NextBytes(BYTE *buffer, int bufferLen);
};
RandomPS5.cpp
#include "stdafx.h"
#include "RandomPS5.h"
#include "RandomDotNet.h"
#include <limits.h>
#include <math.h>
#include <stdexcept>
#include <string>
// Naive conversion of BitConverter.ToInt32
int RandomPS5::BytesToInt(BYTE *b) {
int Int32 = 0;
Int32 = (Int32 << 8) + b[3];
Int32 = (Int32 << 8) + b[2];
Int32 = (Int32 << 8) + b[1];
Int32 = (Int32 << 8) + b[0];
return Int32;
}
RandomPS5::RandomPS5(int seed) {
pseudoGenerator = new RandomDotNet(seed);
}
RandomPS5::~RandomPS5(){
delete pseudoGenerator;
}
double RandomPS5::NextDouble() {
return Next() * (1.0 / 0x7FFFFFFF);
}
int RandomPS5::Next() {
int result;
do {
result = InternalSample();
} while (result == 0x7FFFFFFF);
if (result < 0) {
result += 0x7FFFFFFF;
}
return result;
}
int RandomPS5::Next(int maxValue) {
if (maxValue<0) {
throw std::invalid_argument("maxValue must be positive");
}
return Next(0, maxValue);
}
int RandomPS5::Next(int minValue, int maxValue) {
if (minValue > maxValue)
{
throw std::invalid_argument("minValue is larger than maxValue");
}
long range = (long)maxValue - (long)minValue;
if (range <= 0x7FFFFFFF)
{
return ((int)(NextDouble() * range) + minValue);
}
else
{
double largeSample = this->InternalSampleLargeRange() * (1.0 / (2 * 0x7FFFFFFF));
int result = (int)((long)(largeSample * range) + minValue);
return result;
}
}
int RandomPS5::InternalSample() {
BYTE *data = (BYTE*)malloc(sizeof(int));
this->NextBytes(data, sizeof(int));
int result = BytesToInt(data);
free(data);
return result;
}
double RandomPS5::InternalSampleLargeRange() {
double result;
do{
result = this->InternalSample();
} while (result == 0x7FFFFFFF);
result += 0x7FFFFFFF;
return result;
}
void RandomPS5::NextBytes(BYTE *buffer, int bufferLen) {
this->pseudoGenerator->NextBytes(buffer, bufferLen);
}
Main.cpp
#include "RandomDotNet.h"
#include "RandomPS5.h"
#include <Windows.h>
// Length of charset string
#define CHARSETLEN 62
// Random charset
const char charset[CHARSETLEN + 1] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
// Function that processes a record like PowerShell does for -ObjectList
void processRecord(CHAR *string, int len, Random *r) {
// Processed characters
int processed = 0;
int i, indexToReplace;
CHAR temp;
// Iterate the charset
for (i = 0; i < CHARSETLEN; ++i) {
if (processed < len) {
string[processed] = charset[i];
}
else if (r->Next(processed + 1) < len) {
string[r->Next(len)] = charset[i];
}
++processed;
}
// Iterate selected items to return them in "random" order
for (i = 0; i < len; ++i) {
// Get random index
indexToReplace = r->Next(i, len);
if (i != indexToReplace) {
// Swap
temp = string[i];
string[i] = string[indexToReplace];
string[indexToReplace] = temp;
}
}
// Terminate the string
string[len] = '\0';
}
int main(int argc, char* argv[]){
// Example usage with a given seed
Random *r = new RandomPS5(1000);
// Length of random string
int len = 49;
// Random string buffer
CHAR *buffer = (CHAR*)malloc(len + 1);
// ([char[]](Get-Random -Input $(48..57 + 65..90 + 97..122) -Count 49 -SetSeed 1000)) -Join ""
processRecord(buffer, len, r);
// Produces: y6FLfcKrpINqgP25GXS7Z0dVBmJOzntlQ3hjbHMAU1ExkewWY
printf("Random string: %s", buffer);
delete r;
return 0;
}
I'm trying to convert a couple of simple CRC calculating functions from C to C#, but I seem to be getting incorrect results.
The C functions are:
#define CRC32_POLYNOMIAL 0xEDB88320
unsigned long CRC32Value(int i)
{
int j;
unsigned long ulCRC;
ulCRC = i;
for (j=8;j>0;j--)
{
if (ulCRC & 1)
ulCRC = (ulCRC >> 1)^CRC32_POLYNOMIAL;
else
ulCRC >>= 1;
}
return ulCRC;
}
unsigned long CalculateBlockCRC32(
unsigned long ulCount,
unsigned char *ucBuffer)
{
unsigned long ulTemp1;
unsigned long ulTemp2; unsigned long ulCRC = 0;
while (ulCount-- != 0)
{
ulTemp1 = (ulCRC >> 8) & 0x00FFFFFFL;
ulTemp2 = CRC32Value(((int)ulCRC^*ucBuffer++)&0xff);
ulCRC = ulTemp1^ulTemp2;
}
return(ulCRC);
}
These are well defined, they are taken from a user manual. My C# versions of these functions are:
private ulong CRC32POLYNOMIAL = 0xEDB88320L;
private ulong CRC32Value(int i)
{
int j;
ulong ulCRC = (ulong)i;
for (j = 8; j > 0; j--)
{
if (ulCRC % 2 == 1)
{
ulCRC = (ulCRC >> 1) ^ CRC32POLYNOMIAL;
}
else
{
ulCRC >>= 1;
}
}
return ulCRC;
}
private ulong CalculateBlockCRC32(ulong ulCount, byte[] ucBuffer)
{
ulong ulTemp1;
ulong ulTemp2;
ulong ulCRC=0;
int bufind=0;
while (ulCount-- != 0)
{
ulTemp1 = (ulCRC >> 8) & 0x00FFFFFFL;
ulTemp2 = CRC32Value(((int)ulCRC ^ ucBuffer[bufind]) & 0xFF);
ulCRC = ulTemp1 ^ ulTemp2;
bufind++;
}
return ulCRC;
}
As I mentioned, there are discrepancies between the C version and the C# version. One possible source is my understanding of the C expression ulCRC & 1 which I believe will only be true for odd numbers.
I call the C# function like this:
string contents = "some data";
byte[] toBeHexed = Encoding.ASCII.GetBytes(contents);
ulong calculatedCRC = this.CalculateBlockCRC32((ulong)toBeHexed.Length, toBeHexed);
And the C function is called like this:
char *Buff="some data";
unsigned long iLen = strlen(Buff);
unsigned long CRC = CalculateBlockCRC32(iLen, (unsigned char*) Buff);
I believe that I am calling the functions with the same data in each language, is that correct? If anyone could shed some light on this I would be very grateful.
As it has been already pointed by #Adriano Repetti you should use UInt32 datatype in place of the ulong type(it is 64 bit unsigned UInt64, whereas in VC++ unsigned long is only 32 bit unsigned type)
private UInt32 CRC32POLYNOMIAL = 0xEDB88320;
private UInt32 CRC32Value(int i)
{
int j;
UInt32 ulCRC = (UInt32)i;
for (j = 8; j > 0; j--)
{
if (ulCRC % 2 == 1)
{
ulCRC = (ulCRC >> 1) ^ CRC32POLYNOMIAL;
}
else
{
ulCRC >>= 1;
}
}
return ulCRC;
}
private UInt32 CalculateBlockCRC32(UInt32 ulCount, byte[] ucBuffer)
{
UInt32 ulTemp1;
UInt32 ulTemp2;
UInt32 ulCRC = 0;
int bufind = 0;
while (ulCount-- != 0)
{
ulTemp1 = (ulCRC >> 8) & 0x00FFFFFF;
ulTemp2 = CRC32Value(((int)ulCRC ^ ucBuffer[bufind]) & 0xFF);
ulCRC = ulTemp1 ^ ulTemp2;
bufind++;
}
return ulCRC;
}
string contents = "12";
byte[] toBeHexed = Encoding.ASCII.GetBytes(contents);
UInt32 calculatedCRC = CalculateBlockCRC32((UInt32)toBeHexed.Length, toBeHexed);
Usually in C# it doesn't matter whether you use C# data type name(recommended by Microsoft) or ECMA type name. But in this and similar cases with bit level manipulation it can greatly clarify the intent and prevent mistakes.
In C it is always a good idea to use typedefs from stdint.h. They make the same job, as ECMA types in C# - clarify the intent, and also guarantee the length and sign of used datatypes(C compilers may use different lengths for the same types, because standard doesn't specify exact sizes):
#include <stdint.h>
#define CRC32_POLYNOMIAL ((uint32_t)0xEDB88320)
uint32_t CRC32Value(uint32_t i)
{
uint32_t j;
uint32_t ulCRC;
ulCRC = i;
for (j = 8; j > 0; j--)
{
if (ulCRC & 1)
ulCRC = (ulCRC >> 1) ^ CRC32_POLYNOMIAL;
else
ulCRC >>= 1;
}
return ulCRC;
}
uint32_t CalculateBlockCRC32(
size_t ulCount,
uint8_t *ucBuffer)
{
uint32_t ulTemp1;
uint32_t ulTemp2;
uint32_t ulCRC = 0;
while (ulCount-- != 0)
{
ulTemp1 = (ulCRC >> 8) & ((uint32_t)0x00FFFFFF);
ulTemp2 = CRC32Value((ulCRC^*ucBuffer++)&0xff);
ulCRC = ulTemp1^ulTemp2;
}
return(ulCRC);
}
char *Buff = "12";
size_t iLen = strlen(Buff);
uint32_t CRC = CalculateBlockCRC32(iLen, (uint8_t *) Buff);
printf("%u", CRC);
I am trying to adapt this code that can perform conversions to and from Base 52, which I am using to store RGB color information from C# to C++:
public static string ColourToBase52(Color colour)
{
int value = colour.ToArgb() & 0x00FFFFFF; // Mask off the alpha channel.
return ToBase52(value);
}
public static Color ColourFromBase52(string colour)
{
int value = FromBase52(colour);
return Color.FromArgb(unchecked((int)(0xFF000000 | value)));
}
public static string ToBase52(int value)
{
char[] baseChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
int targetBase = baseChars.Length;
int i = 32;
char[] buffer = new char[i];
do
{
buffer[--i] = baseChars[value % targetBase];
value = value / targetBase;
}
while (value > 0);
char[] result = new char[32 - i];
Array.Copy(buffer, i, result, 0, 32 - i);
return new string(result).PadLeft(5, 'a');
}
public static int FromBase52(string value)
{
char[] baseChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
int targetbase = baseChars.Length;
int multiplier = 1;
int result = 0;
for (int i = value.Length-1; i >= 0; --i)
{
int digit = Array.IndexOf(baseChars, value[i]);
result += digit*multiplier;
multiplier *= targetbase;
}
return result;
}
For my C++ code, I have opted to combine the functions that get and return the color value as an integer with the Base 52 conversion functions:
struct DIFColor *DIFBase52ToColor(std::string c)
{
const char *baseChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
int targetBase = 52;
int multiplier = 1;
int result = 0;
const char *d = c.c_str();
for (int i = c.length() - 1; i >= 0; --i)
{
int digit = DIFGetPositionInArray(baseChars, sizeof(baseChars), c[i]);
result += digit * multiplier;
multiplier = multiplier * targetBase;
}
uint8_t b = result & 255;
uint8_t g = (result >> 8) & 255;
uint8_t r = (result >> 16) * 255;
return CreateDIFColor(r,g,b);
}
std::string DIFColorToBase52(struct DIFColor *c)
{
int rgb = ((c->r&0x0ff)<<16)|((c->g&0x0ff)<<8)|(c->b&0x0ff);
const char *baseChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
int targetBase = 52;
int i = 32;
char *buffer = new char[i];
do
{
buffer[--i] = baseChars[rgb % targetBase];
rgb = rgb / targetBase;
}
while (rgb > 0);
char *result = new char[32 - i];
DIFCopyCharArray((const char *)buffer, i, 0, 32 - i, result);
std::string s((const char*)result);
s.insert(s.begin(), 5 - s.size(), 'a');
return s;
}
I also had to create two functions for array manipulation:
int DIFGetPositionInArray(const char *array, size_t size, const char c)
{
for (size_t i = 0; i < size; i++)
{
if (array[i] == c)
return (int)i;
}
return -1;
}
void DIFCopyCharArray(const char* source, int wheretostart, int wheretocopy, int numtocopy, char *dest)
{
int c = wheretocopy;
for(int i = wheretostart; i <= numtocopy; i++)
{
dest[c] = source[i];
c++;
}
}
However, when I tried to test it with a sanity check, it failed:
255,255,255 = 'aah1U' in Base52 RGB
aah1U = 1,245,59 in RGB
It also seems that every time I run the sanity check, a different value is produced:
255,255,255 = 'aah13' in Base52 RGB
aah13 = 1,245,59 in RGB
255,255,255 = 'aah1j' in Base52 RGB
aah1j = 1,245,59 in RGB
The expected output was:
255,255,255 = 'cpqEN' in Base52 RGB
cpqEN = 255,255,255 in RGB
Making me think that this is possibly a pointer problem.
The error is probably that you don't terminate the result string anywhere, which leads to undefined behavior in the following:
std::string s((const char*)result);
This is because the std::string constructor looks for the terminator when copying the C-style string you pass to it.
You can solve it two ways: Either add the terminator character '\0' to result, or tell the std::string constructor the length of result.
The problem lies in the fact that the array copy function is incorrect. It should be:
void DIFCopyCharArray(const char* source, int wheretostart, int wheretocopy, int numtocopy, char *dest)
{
int c = wheretocopy;
for(int i = wheretostart; c <= numtocopy; i++)
{
dest[c] = source[i];
c++;
}
dest[c] = '\0';
}
Also, the array search function does not work because sizeof(baseChars) returns 4, which is not the number of elements.
Use a function like this:
int DIFGetPositionInArray(const char *array, int arrayElements, const char c)
{
for (int i = 0; i < arrayElements; i++)
{
if (array[i] == c)
return i;
}
return -1;
}
And call it like this;
DIFGetPositionInArray(baseChars,52,d[i]);