LZW Decompression in C - c
I have an LZW compressor/decompressor written in C.
The initial table consists of ASCII characters and then each now string to be saved into the table consists of a prefix and a character both saved in a list as int.
My compression works but my decompression leaves some characters out.
The input:
<title>Agile</title><body><h1>Agile</h1></body></html>
The output I get (notice the missing 'e' and '<'):
<title>Agile</title><body><h1>Agil</h1></body>/html>
This is the code I use (the relevant part):
void expand(int * input, int inputSize) {
// int prevcode, currcode
int previousCode; int currentCode;
int nextCode = 256; // start with the same dictionary of 255 characters
dictionaryInit();
// prevcode = read in a code
previousCode = input[0];
int pointer = 1;
// while (there is still data to read)
while (pointer < inputSize) {
// currcode = read in a code
currentCode = input[pointer++];
if (currentCode >= nextCode) printf("!"); // XXX not yet implemented!
currentCode = decode(currentCode);
// add a new code to the string table
dictionaryAdd(previousCode, currentCode, nextCode++);
// prevcode = currcode
previousCode = currentCode;
}
}
int decode(int code) {
int character; int temp;
if (code > 255) { // decode
character = dictionaryCharacter(code);
temp = decode(dictionaryPrefix(code)); // recursion
} else {
character = code; // ASCII
temp = code;
}
appendCharacter(character); // save to output
return temp;
}
Can you spot it? I'd be grateful.
Your decode function returns the first character in the string. You need this character in order to add it to the dictionary, but you should not set previousCode to it. So your code should look like:
...
firstChar = decode(currentCode);
dictionaryAdd(previousCode, firstChar, nextCode++);
previousCode = currentCode;
...
Related
My string has hidden characters and is longer than what I can visually see?
Problem
I have a function which assigns data from reading a Bluetooth connection to a char array QualArray[4][30], although it appears that the length of each char array is 1 char greater than the number of characters that visually appear in the array, suggesting a hidden character?
Furthermore, I add these strings to another string called 'resource' using strcpy(), and the length of the string resource is 5 chars more than what it should be (so the 4 additional hidden characters from QualArray makes sense but there is apparently another hidden char added??) I have printed a "_" at the start and end of the string to see if there are any empty chars at either side but there aren't.
Somehow there are hidden chars in my strings but I don't know why, any help would greatly be appreciated!
Code
char resource[160] = "/macros/s/AKfycbzTAkuhTqJfi-EofdpOjBxKNlDe18fdTkOPHMOuOwvl9zbDqfPHwbb1/exec?"; //must be pre-defined buffer
char staticresource[160] = "/macros/s/AKfycbzTAkuhTqJfi-EofdpOjBxKNlDe18fdTkOPHMOuOwvl9zbDqfPHwbb1/exec?Cooker=RiceCooker&Meal=Rice&Portion=3&Method=Boil";
char QualArray[5][30]; // [Qparam][charnum]
char CookerQuery[20] = "&Cooker=";
char MealQuery[15] = "&Meal=";
char PortionQuery[15] = "&Portion=";
char MethodQuery[15] = "&Method=";
void CollectQualitativeData() {
int Qparam=0;
int charnum = 0;
while(Qparam < 4) { // While Qualitative data has not been collectedQualDataCollected = 0
if (SerialBT.available()) {
char incomingChar = SerialBT.read();
if (QualArray[Qparam] !="" && incomingChar == '\n') { // If the message isnt empty and the recieved char is nothing (ie if at end of word) if (message !=""
Serial.print(QualArray[Qparam]);
Serial.print("_");
Serial.print(" length = ");
Serial.println(strlen(QualArray[Qparam]));
Qparam++;
charnum = 0;
}
if (incomingChar != '\n'){ // If the incomingChar is different than \n, concatenate that char character to QualArray.
if (charnum <30) { // if greater than maximum specified array val then ignore
QualArray[Qparam][charnum] = incomingChar;
charnum++;
}
} else {
}
}
delay(20);
}
}
void setup() {
Serial.begin(115200);
SerialBT.begin("ESP32test"); //Bluetooth device name
//Serial.println("The device started, now you can pair it with bluetooth!");
CollectQualitativeData();
Serial.println("Complete");
Serial.println(QualArray[0]);
Serial.println(QualArray[1]);
Serial.println(QualArray[2]);
Serial.println(QualArray[3]);
Serial.println(QualArray[4]);
strcat(resource,CookerQuery); // resource + Resource_variables
strcat(resource,QualArray[0]);
strcat(resource,MealQuery); // resource + Resource_variables
strcat(resource,QualArray[1]);
strcat(resource,PortionQuery); // resource + Resource_variables
strcat(resource,QualArray[2]);
strcat(resource,MethodQuery); // resource + Resource_variables
strcat(resource,QualArray[3]);
Serial.print("resource=_");
Serial.print(resource);
Serial.println("_");
Serial.print("staticresource=_");
Serial.print(staticresource);
Serial.println("_");
Serial.print("length static=");
Serial.println(strlen(staticresource));
Serial.print("length resource=");
Serial.println(strlen(resource));
}
https://github.com/Conwon99/4th-Year-Project/blob/main/StringLengthIssue
Serial Monitor Debugging
RiceCooker_ length = 11
Rice_ length = 5
3_ length = 2
Boil_ length = 5
Complete
RiceCooker
Rice
3
Boil
resource=_/macros/s/AKfycbzTAkuhTqJfi-EofdpOjBxKNlDe18fdTkOPHMOuOwvl9zbDqfPHwbb1/exec&Cooker=RiceCooker&Meal=Ric&Portion=3&Method=Boil_
staticresource=_/macros/s/AKfycbzTAkuhTqJfi-EofdpOjBxKNlDe18fdTkOPHMOuOwvl9zbDqfPHwbb1/exec?Cooker=RiceCooker&Meal=Rice&Portion=3&Method=Boil_
length static=125
length resource=130
char[] has null-terminator value \0 and it is counted as the length of the array. Just use std::vector and String. Anyway, your code is uncompilable. I'll rewrite for you:
#include <BluetoothSerial.h>
#include <vector>
const char resource[] PROGMEM = "/macros/s/AKfycbzTAkuhTqJfi-EofdpOjBxKNlDe18fdTkOPHMOuOwvl9zbDqfPHwbb1/exec?"; //must be pre-defined buffer
const char staticresource[] PROGMEM = "/macros/s/AKfycbzTAkuhTqJfi-EofdpOjBxKNlDe18fdTkOPHMOuOwvl9zbDqfPHwbb1/exec?Cooker=RiceCooker&Meal=Rice&Portion=3&Method=Boil";
const char cookerQuery[] PROGMEM = "&Cooker=";
const char mealQuery[] PROGMEM = "&Meal=";
const char portionQuery[] PROGMEM = "&Portion=";
const char methodQuery[] PROGMEM = "&Method=";
std::vector<String> qualArray;
BluetoothSerial SerialBT;
void CollectQualitativeData() {
while (qualArray.size() < 4 ) {
if (SerialBT.available()) {
String incomingChar = SerialBT.readStringUntil('\n');
qualArray.push_back(incomingChar);
}
delay(20);
}
}
void setup() {
Serial.begin(115200);
SerialBT.begin("ESP32test");
CollectQualitativeData();
Serial.println("Complete");
for (int i = 0; i < qualArray.size(); i++) {
Serial.println(qualArray[i]);
}
String res(resource);
res += cookerQuery + qualArray[0];
res += mealQuery + qualArray[1];
res += portionQuery + qualArray[2];
res += methodQuery + qualArray[3];
Serial.println(res);
}
void loop() {}
Working with byte array I get an "invalid conversion from char* to byte"
I am reading and writing to an RFID tag using MFRC522.h
I can currently read the UID of a card and dump it to "UIDChar"
The UID of a card typically is 8 characters.
UID Example: 467EE9A9
I can use the mfrc522.MIFARE_SetUid function to write this UID to a new card. In order to do this I have to set the newUID to:
0x46,0x7E,0xE9,0xA9f
I have written this into my code.
What I am wanting to do is convert the UID string into a byte array so that I can use that in place of my manually written 0x46,0x7E,0xE9,0xA9.
I use the convert function to convert the UID into that format.
It can that be displayed with "buf".
Serial.println(buf);
Now my problem. If I replace the
byte newUid[] = {0x46,0x7E,0xE9,0xA9f};
with
byte newUid[] = {buf};
I get the error
invalid conversion from 'char*' to 'byte {aka unsigned char}'
How can I set my "newUid" as "buf"?
#define SS_PIN 0 //D2
#define RST_PIN 2 //D1
#include <SPI.h>
#include <MFRC522.h>
/* For RFID */
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
char buf[40]; // For string to byte array convertor
void convert(char *s)
{
int i, j, k;
buf[0] = 0x0;
for (j = 0, i = 0, k = 0; j < strlen(s); j++)
{
if (i++ == 0) {
buf[k++] = '0';
buf[k++] = 'x';
}
buf[k++] = s[j];
if (i == 2) {
if(j != strlen(s) -1) buf[k++] = ',';
i = 0;
}
}
buf[k] = 0x0;
}
void clone() {
/* RFID Read */
// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent())
{
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial())
{
return;
}
//Show UID on serial monitor
Serial.println();
Serial.print(" UID tag :");
// Very basic UID dump
unsigned int hex_num;
hex_num = mfrc522.uid.uidByte[0] << 24;
hex_num += mfrc522.uid.uidByte[1] << 16;
hex_num += mfrc522.uid.uidByte[2] << 8;
hex_num += mfrc522.uid.uidByte[3];
// Get UID
int NFC_id = (int)hex_num;
Serial.print(NFC_id, HEX);
// Convert UID to string using an int and a base (hexadecimal)
String stringUID = String(NFC_id, HEX);
char UIDChar[10];
stringUID.toCharArray(UIDChar,10);
delay(1000);
Serial.println();
// Convert to uppercase
for (int i = 0; i < strlen(UIDChar); i++ )
{
if ( UIDChar[i] == NULL ) break;
UIDChar[i] = toupper(UIDChar[i]);
}
//Serial.print( &UIDChar[0] );
Serial.println();
convert(UIDChar);
Serial.println(buf);
/* RFID Write */
// Set new UID
// Change your UID hex string to 4 byte array
// I get error if I use byte newUid[] = {buf};
/* ERROR HERE */
byte newUid[] = {0x46,0x7E,0xE9,0xA9};
if ( mfrc522.MIFARE_SetUid(newUid, (byte)4, true) ) {
Serial.println( "Wrote new UID to card." );
}
// Halt PICC and re-select it so DumpToSerial doesn't get confused
mfrc522.PICC_HaltA();
if ( ! mfrc522.PICC_IsNewCardPresent() || ! mfrc522.PICC_ReadCardSerial() ) {
return;
}
// Dump the new memory contents
Serial.println( "New UID and contents:" );
mfrc522.PICC_DumpToSerial(&(mfrc522.uid));
}
void setup() {
Serial.begin ( 115200 );
/* RFID */
SPI.begin(); // Initiate SPI bus
mfrc522.PCD_Init(); // Initiate MFRC522
clone();
}
void loop() {
}
When you write
byte newUid[] = {buf};
you are trying to initialise newUid with a single element (there's only one item inside your {}), and that element is buf, which is a char* (or a char[]). That's why you get the error - you are trying to assign an array with one char* to a variable whose elements are bytes.
Without reading your full code in detail, I don't know why you are trying to do this assignment, rather than just use your buf array as it is. But to fix the problem, you probably just want to use
byte* newUid = buf;
Initializing an array of structure in C
I'm using the LXLE 14.04 distribution of Linux. I want to write a C program to read commands, interpret and perform them. I'd like the program to be efficient, and I do not want to use a linked list. The commands are operations on sets. Each set can contain any of the values from 0 through 127 inclusive. I decided to represent a set as an array of characters, containing 128 bits. If bit at position pos is turned on then the number pos is in the set and if the bit at position pos is turned off then the number pos is not present in the set. For example, if the bit at position 4 is 1, then the number 4 is present in the set, if the bit at position 11 is 1 then the number 11 is present in the set.
The program should read commands and interpret them in a certain way. There are a few commands: read_set, print_set, union_set, intersect_set, sub_set and halt.
For example, the command read_set A,1,2,14,-1 in the terminal will cause the reading of values of the list into the specified set in the command. In this case the specified set in the command is A. The end of the list is represented by -1. So after writing this command, the set A will contain the elements 1,2,14.
This is what I have so far. Below is the file set.h
#include <stdio.h>
typedef struct
{
char array[16]; /*Takes 128 bits of storage*/
}set;
extern set A , B , C , D , E , F;
This is the file main.c
#include <stdio.h>
#include "set.h"
#include <string.h>
#include <stdlib.h>
set A , B , C , D , E , F; /*Variable definition*/
set sets[6];
/*Below I want to initialize sets so that set[0] = A set[1] = B etc*/
sets[0].array = A.array;
sets[1].array = B.array;
sets[2].array = C.array;
sets[3].array = D.array;
sets[4].array = E.array;
sets[5].array = F.array;
void read_set(set s,char all_command[])
{
int i, number = 0 , pos;
char* str_num = strtok(NULL,"A, ");
unsigned int flag = 1;
printf("I am in the function read_set right now\n");
while(str_num != NULL) /*without str_num != NULL get segmentation fault*/
{
number = atoi(str_num);
if(number == -1)
return;
printf("number%d ",number);
printf("str_num %c\n",*str_num);
i = number/8; /*Array index*/
pos = number%8; /*bit position*/
flag = flag << pos;
s.array[i] = s.array[i] | flag;
str_num = strtok(NULL, ", ");
if(s.array[i] & flag)
printf("Bit at position %d is turned on\n",pos);
else
printf("Bit at position %d is turned off\n",pos);
flag = 1;
}
}
typedef struct
{
char *command;
void (*func)(set,char*);
} entry;
entry chart[] = { {"read_set",&read_set} };
void (*getFunc(char *comm) ) (set,char*)
{
int i;
for(i=0; i<2; i++)
{
if( strcmp(chart[i].command,comm) == 0)
return chart[i].func;
}
return NULL;
}
int main()
{
#define PER_CMD 256
char all_comm[PER_CMD];
void (*ptr_one)(set,char*) = NULL;
char* comm; char* letter;
while( (strcmp(all_comm,"halt") != 0 ) & (all_comm != NULL))
{
printf("Please enter a command");
gets(all_comm);
comm = strtok(all_comm,", ");
ptr_one = getFunc(comm);
letter = strtok(NULL,",");
ptr_one(sets[*letter-'A'],all_comm);
all_comm[0] = '\0';
letter[0] = '\0';
}
return 0;
}
I defined a command structure called chart that has a command name and function pointer for each command. Then I have created an array of these
structures which can be matched within a loop.
In the main function, I've created a pointer called ptr_one. ptr_one holds the value of the proper function depending on the command entered by the user.
The problem is, that since user decides which set to use,I need to represent the sets as some variable, so that different sets can be sent to the function ptr_one. I thought about
creating an array in main.c like so
set sets[6];
sets[0] = A;
sets[1] = B;
sets[2] = C;
sets[3] = D;
sets[4] = E;
sets[5] = F;
And then call the function ptr_one in the main function like this ptr_one(sets[*letter-'A'] , all_command).
That way, I convert my character into a set.
The problem is that while writing the above code I got the following compile error:
error: expected ���=���, ���,���, ���;���, ���asm��� or ���attribute��� before ���.��� token
I also tried the following in the file main.c
sets[0].array = A.array;
sets[1].array = B.array;
sets[2].array = C.array;
sets[3].array = D.array;
sets[4].array = E.array;
sets[5].array = F.array;
But I got this compile error expected ���=���, ���,���, ���;���, ���asm��� or ���attribute��� before ���.��� token
I know similar questions have been asked, by they don't seem to help in my
specific case. I tired this set sets[6] = { {A.array},{B.array},{C.array},{D.array},{E.array},{F.array} } too but it did not compile.
What's my mistake and how can I initialize sets so that it holds the sets A though F?
Parsing code for GPS NMEA string
i am trying to parse the incoming GPGGA NMEA GPS string using Arduino uno and below code.
What i am trying to do is that i am using only GPGGA NMEA string to get the values of Latitude, longitude and altitude.In my below code, i had put certain checks to check if incoming string is GPGGA or not, and then store the further string in a array which can be further parsed suing strtok function and all the 3 GPS coordinates can be easily find out.
But i am unable to figure out how to store only GPGGA string and not the further string.I am using a for loop but it isn't working.
I am not trying to use any library.I had came across certain existing codes like this.
Here is the GPGGA string information link
i am trying to have following functionlity
i) Check if incoming string is GPGGA
ii) If yes, then store the following string upto EOL or upto * (followed by checksum for the array) in a array, array length is variable(i am unable to find out solution for this)
iii) Then parse the stored array(this is done, i tried this with a different array)
#include <SoftwareSerial.h>
SoftwareSerial mySerial(10,11); // 10 RX / 11 TX
void setup()
{
Serial.begin(9600);
mySerial.begin(9600);
}
void loop()
{
uint8_t x;
char gpsdata[65];
if((mySerial.available()))
{
char c = mySerial.read();
if(c == '$')
{char c1 = mySerial.read();
if(c1 == 'G')
{char c2 = mySerial.read();
if(c2 == 'P')
{char c3 = mySerial.read();
if(c3 == 'G')
{char c4 = mySerial.read();
if(c4 == 'G')
{char c5 = mySerial.read();
if(c5 == 'A')
{for(x=0;x<65;x++)
{
gpsdata[x]=mySerial.read();
while (gpsdata[x] == '\r' || gpsdata[x] == '\n')
{
break;
}
}
}
else{
Serial.println("Not a GPGGA string");
}
}
}
}
}
}
}
Serial.println(gpsdata);
}
Edit 1:
Considering Joachim Pileborg, editing the for loop in the code.
I am adding a pic to show the undefined output of the code.
Input for the code:
$GPGGA,092750.000,5321.6802,N,00630.3372,W,1,8,1.03,61.7,M,55.2,M,,*76
$GPGSA,A,3,10,07,05,02,29,04,08,13,,,,,1.72,1.03,1.38*0A
$GPGSV,3,1,11,10,63,137,17,07,61,098,15,05,59,290,20,08,54,157,30*70
$GPGSV,3,2,11,02,39,223,19,13,28,070,17,26,23,252,,04,14,186,14*79
$GPGSV,3,3,11,29,09,301,24,16,09,020,,36,,,*76
$GPRMC,092750.000,A,5321.6802,N,00630.3372,W,0.02,31.66,280511,,,A*43
$GPGGA,092751.000,5321.6802,N,00630.3371,W,1,8,1.03,61.7,M,55.3,M,,*75
$GPGSA,A,3,10,07,05,02,29,04,08,13,,,,,1.72,1.03,1.38*0A
$GPGSV,3,1,11,10,63,137,17,07,61,098,15,05,59,290,20,08,54,157,30*70
$GPGSV,3,2,11,02,39,223,16,13,28,070,17,26,23,252,,04,14,186,15*77
$GPGSV,3,3,11,29,09,301,24,16,09,020,,36,,,*76
$GPRMC,092751.000,A,5321.6802,N,00630.3371,W,0.06,31.66,280511,,,A*45
After a quick check of the linked article on the NMEA 0183 protocol, this jumped out at me: <CR><LF> ends the message. This means, that instead of just read indiscriminately from the serial port, you should be looking for that sequence. If found, you should terminate the string, and break out of the loop. Also, you might want to zero-initialize the data string to begin with, to easily see if there actually is any data in it to print (using e.g. strlen).
You could use some functions from the C library libnmea. Theres functions to split a sentence into values by comma and then parse them.
Offering this as a suggestion in support of what you are doing...
Would it not be useful to replace all of the nested if()s in your loop with something like:
EDIT added global string to copy myString into once captured
char globalString[100];//declare a global sufficiently large to hold you results
void loop()
{
int chars = mySerial.available();
int i;
char *myString;
if (chars>0)
{
myString = calloc(chars+1, sizeof(char));
for(i=0;i<chars;i++)
{
myString[i] = mySerial.read();
//test for EOF
if((myString[i] == '\n') ||(myString[i] == '\r'))
{
//pick this...
myString[i]=0;//strip carriage - return line feed(or skip)
//OR pick this... (one or the other. i.e.,I do not know the requirements for your string)
if(i<chars)
{
myString[i+1] = mySerial.read() //get remaining '\r' or '\n'
myString[i+2]=0;//add null term if necessary
}
break;
}
}
if(strstr(myString, "GPGGA") == NULL)
{
Serial.println("Not a GPGGA string");
//EDIT
strcpy(globalString, "");//if failed, do not want globalString populated
}
else
{ //EDIT
strcpy(globalString, myString);
}
}
//free(myString) //somewhere when you are done with it
}
Now, the return value from mySerial.available() tells you exactly how many bytes to read, you can read the entire buffer, and test for validity all in one.
I have a project that will need to pull the same information out of the same sentence.
I got this out of a log file
import serial
import time
ser = serial.Serial(1)
ser.read(1)
read_val = ("nothing")
gpsfile="gpscord.dat"
l=0
megabuffer=''
def buffThis(s):
global megabuffer
megabuffer +=s
def buffLines():
global megabuffer
megalist=megabuffer.splitlines()
megabuffer=megalist.pop()
return megalist
def readcom():
ser.write("ati")
time.sleep(3)
read_val = ser.read(size=500)
lines=read_val.split('\n')
for l in lines:
if l.startswith("$GPGGA"):
if l[:len(l)-3].endswith("*"):
outfile=open('gps.dat','w')
outfile.write(l.rstrip())
outfile.close()
readcom()
while 1==1:
readcom()
answer=raw_input('not looping , CTRL+C to abort')
The result is this:
gps.dat
$GPGGA,225714.656,5021.0474,N,00412.4420,W,0,00,50.0,0.0,M,18.0,M,0.0,0000*5B
Using "malloc" every single time you read a string is an enormous amount of computational overhead. (And didn't see the corresponding free() function call. Without that, you never get that memory back until program termination or system runs out of memory.) Just pick the size of the longest string you will ever need, add 10 to it, and declare that your string array size. Set once and done. There are several C functions for getting substrings out of a string, strtok() using the coma is probably the least overhead. You are on an embedded microcontroller. Keep it small, keep overhead down. :)
#include <stdio.h>
#include <string.h>
#define GNSS_HEADER_LENGTH 5
#define GNSS_PACKET_START '$'
#define GNSS_TOKEN_SEPARATOR ','
#define bool int
#define FALSE 0
#define TRUE 1
//To trim a string contains \r\n
void str_trim(char *str){
while(*str){
if(*str == '\r' || *str == '\n'){
*str = '\0';
}
str++;
}
}
/**
* To parse GNSS data by header and the index separated by comma
*
* $GPGSV,1,1,03,23,39,328,30,18,39,008,27,15,33,035,33,1*5A
* $GNRMC,170412.000,V,,,,,,,240322,,,N,V*2D
* $GNGGA,170412.000,,,,,0,0,,,M,,M,,*57
*
* #data_ptr the pointer points to gps data
* #header the header for parsing GPGSV
* #repeat_index the header may repeat for many lines
* so the header index is for identifying repeated header
* #token_index is the index of the parsing data separated by ","
* the start is 1
* #result to store the result of the parser input
*
* #result bool - parsed successfully
**/
bool parse_gnss_token(char *data_ptr, char *header, int repeat_index, int token_index, char *result) {
bool gnss_parsed_result = FALSE; // To check GNSS data parsing is success
bool on_header = FALSE;
// For header
int header_repeat_counter = 0;
int header_char_index = 0; // each char in header index
// For counting comma
int counted_token_index = 0;
// To hold the result character index
bool data_found = FALSE;
char *result_start = result;
char header_found[10];
while (*data_ptr) {
// 1. Packet start
if (*data_ptr == GNSS_PACKET_START) {
on_header = TRUE;
header_char_index = 0; // to index each character in header
data_found = FALSE; // is data part found
data_ptr++;
}
// 2. For header parsing
if (on_header) {
if (*data_ptr == GNSS_TOKEN_SEPARATOR || header_char_index >= GNSS_HEADER_LENGTH) {
on_header = FALSE;
} else {
header_found[header_char_index] = *data_ptr;
if (header_char_index == GNSS_HEADER_LENGTH - 1) { // Now Header found
header_found[header_char_index + 1] = '\0';
on_header = FALSE;
if (!strcmp(header, header_found)) {
// Some headers may repeat - to identify it set the repeat index
if (header_repeat_counter == repeat_index) {
//printf("Header: %s\r\n", header_found );
data_found = TRUE;
}
header_repeat_counter++;
}
}
header_char_index++;
}
}
// 3. data found
if (data_found) {
// To get the index data separated by comma
if (counted_token_index == token_index && *data_ptr != GNSS_TOKEN_SEPARATOR) {
// the data to parse
*result++ = *data_ptr;
gnss_parsed_result = TRUE;
}
if (*data_ptr == GNSS_TOKEN_SEPARATOR) { // if ,
counted_token_index++; // The comma counter for index
}
// Break if the counted_token_index(token_counter) greater than token_index(search_token)
if (counted_token_index > token_index) {
break;
}
}
// Appending \0 to the end
*result = '\0';
// To trim the data if ends with \r or \n
str_trim(result_start);
// Input data
data_ptr++;
}
return gnss_parsed_result;
}
int main()
{
char res[100];
char *nem = "\
$GNRMC,080817.000,A,0852.089246,N,07636.289920,E,0.00,139.61,270322,,,A,V*04\r\n\\r\n\
$GNGGA,080817.000,0852.089246,N,07636.289920,E,1,5,1.41,11.246,M,-93.835,M,,*5E\r\n\
$GNVTG,139.61,T,,M,0.00,N,0.00,K,A*2F\r\n\
$GNGSA,A,3,30,19,17,14,13,,,,,,,,1.72,1.41,0.98,1*0A\r\n\
$GNGSA,A,3,,,,,,,,,,,,,1.72,1.41,0.98,3*02\r\n\
$GNGSA,A,3,,,,,,,,,,,,,1.72,1.41,0.98,6*07\r\n\
$GPGSV,3,1,12,06,64,177,,30,60,138,15,19,51,322,18,17,42,356,27,1*68\r\n\
$GPGSV,3,2,12,14,36,033,17,07,34,142,17,13,32,267,17,02,21,208,,1*6C\r\n\
$GPGSV,3,3,12,15,05,286,,01,05,037,,03,03,083,,20,02,208,,1*6B\r\n\
$GAGSV,1,1,00,7*73\r\n\
$GIGSV,1,1,00,1*7D\r\n\
$GNGLL,0852.089246,N,07636.289920,E,080817.000,A,A*43\r\n\
$PQTMANTENNASTATUS,1,0,1*4F\r\n";
printf("Parsing GNRMC\r\n");
printf("===============\r\n");
for(int i=1;i<=16;i++){
parse_gnss_token(nem, "GNRMC", 0, i, res);
printf("Index: %d, Result: %s\r\n", i, res);
}
printf("Parsing GNVTG (First Parameter)\r\n");
printf("================================");
// GNVTG - Header, 0 - Repeat Index(if header is repeating), 1 - Value Index,
parse_gnss_token(nem, "GNVTG", 0, 1, res);
printf("\r\nGNVTG: %s\r\n", res);
return 0;
}
Remove the duplicate from a String Using Pointers
#include<stdio.h>
char *removedps(char *x)
{
int Ar[256] = {0};
int ip=0;
int op=0;
char temp;
while(*(x+ip))
{
temp = (*(x+ip));
if (!Ar[temp]) {
Ar[temp] = 1;
*(x+ip) = *(x+op);
op++;
}
ip++;
*(x+op) = '\0';
}
return x;
}
int main()
{
char lo[] = "0001";
printf("%s",removedps(lo));
}
My code is not working
I have tried hard to see the error
All I GET IS the first character .
My idea is simple
make an array of 256 places
insert Zero into them
Then insert 1 for each character inside the string (on that position of the array)
your assignment looks to be the error here. op is "out postiion", ip is "in position" so it should be *(x+op) = *(x+ip); not the other way.
because *(x+op) = '\0';
is always run every iteration of the loop.
I'd probablly do it more like this ( using your method, which I probablly wouldn't use personally)
char *removedps(char *x)
{
int Ar[256] = {0};
char* start = x;
while(*x)
{
if (Ar[*x])
{ // remove the repeated character
memmove(x, x+1, strlen(x));
}
else
{
Ar[*x] = 1;
x++;
}
}
return start;
}
also, I'd name it remove_duplicate_chars or something, not a fan of cryptic abbreviations.
At the end of the loop, you do *(x+op)='\0';, and then, in the next iteration, you do *(x+ip)=*(x+op);, so from the 2sd iteration, you put there 0.
try do something like:
for (op=ip=0;x[ip];ip++) {
if (!Ar[x[ip]]++) x[op++]=x[ip];
}
x[op]=0;