I'm writing some strings to a file using the following function...
void writeText(const char* desc){
FILE * pFile;
pFile = fopen ("CycleTestInfo.txt","a+");
fputs (desc,pFile);
fclose(pFile);
}
...inside of a for loop:
for(int i=0; i<numCycles; i++){
string cycle("---NEW CYCLE ");
cycle+=(char)i;
cycle+= "---\r\n";
writeText(cycle.c_str());
}
I have two issues though.i doesnt show up in my textfile and the newline does not appear for the first string written in my text file. For example, if numCycles is 4, I get the following output in my textfile.
---NEW CYCLE Cycle Done!
---NEW CYCLE ---
Cycle Done!
---NEW CYCLE ---
Cycle Done!
---NEW CYCLE ---
Cycle Done!
When I want it to look like this:
---NEW CYCLE 1---
Cycle Done!
....
i doesnt show up in my textfile
It's because you are writing character with ASCII value 1. Value of character '1' is different and can be easily retrieved by adding value of '0' to i like this: char c = '0' + i;
the newline does not appear for the first string written in my text file
First time i is equal to 0 which is also the value of the terminating character '\0'
Check out this article: C++ Character Constants
I doubt (char)i is the way to go there, you should try (char)((int)'0' + i)
Related
In my MPI code in C, i'm receiving a word from each of my slave processes. I want to add all these words to an char array in master side (part of code below). I can print these words but not collect them into a single char array.
(I consider max word length as 10, and number of slave's as slavenumber)
char* word = (char*)malloc(sizeof(char)*10);
char words[slavenumber*10];
for (int p = 0; p<slavenumber; p++){
MPI_Recv(word, 10, MPI_CHAR, p, 0,MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("Word: %s\n", word); //it works fine
words[p*10] = *word; //This does not work, i think there is a problem here.
}
printf(words); //This does not work correctly, it gives something like: ��>;&�>W�
Can anybody help me on this?
Let's break it down line by line
// allocate a buffer large enough to hold 10 elements of type `char`
char* word = (char*)malloc(sizeof(char)*10);
// define a variable-length-array large enough to
// hold 10*slavenumber elements of `char`
char words[slavenumber*10];
for (int p = 0; p<slavenumber; p++){
// dereference `word` which is exactly the same as writing
// `word[0]` assigning it to `words[p*10]`
words[p*10] = *word;
// words[p*10+1] to words[p*10+9] are unchanged,
// i.e. uninitialized
}
// printing from an array. For this to work properly all
// accessed elements must be initialized and the buffer
// terminated by a null byte. You have neither
printf(words);
Because you left elements uninitialized and didn't null terminate, you're invoking undefined behavior. Be happy that you didn't get demons crawl out of your nose.
In seriousness though, in C you can copy strings by mere assignment. Your usage case calls for strncpy.
for (int p = 0; p<slavenumber; p++){
strncpy(&words[p*10], word, 10);
}
I have an array that I want to load up from a binary file:
parameter c_ROWS = 8;
parameter c_COLS = 16;
reg [15:0] r_Image_Raw[0:c_ROWS-1][0:c_COLS-1];
My input file is binary data, 256 bytes long (same total space as r_Image_Raw). I tried using $fread to accomplish this, but it only works through the 4th column of the last row:
n_File_ID = $fopen(s_File_Name, "r");
n_Temp = $fread(r_Image_Raw, n_File_ID);
I also tried using $fscanf for this, but I get an error about packed types when opening the synthesis tool:
while (!$feof(n_File_ID))
n_Temp = $fscanf(n_File_ID, "%h", r_Image_Raw);
I feel like this should be easy to do. Do I have create a 2D for loop and loop through the r_Image_Raw variable, reading in 16 bits at a time? I feel like it should not be that complicated.
I realized my mistake. It should be:
n_File_ID = $fopen(s_File_Name, "rb");
n_Temp = $fread(r_Image_Raw, n_File_ID);
I was using "r" and not "rb" to specify that it was a binary file. Interestingly enough, "r" does work for the majority of the data, but it is unable read in the last ~13 locations from the file.
Try this.
f_bin = $fopen(s_File_Name,"rb");
for (r = 0; r < c_ROWS; r = r+1) begin
for (c = 0; c < c_COLS; c = c+1) begin
f = $fread(r16,f_bin);
r_Image_Raw[r][c] = r16;
end
end
See that $fread(r16,f_bin) first param is reg, second - file!
Below an example for reading from a binary file with systemverilog.
As shown in IEEE SV Standard documentation, the "nchar_code" will return the number of bytes/chars read. In case EOF have been already reached on last read this number will be zero.
Please, notice that "nchar_code" can be zero but EOF has not been reached, this happens if you have spaces or returns at the end of the data file.
You can control the number of bytes to be read with the $fread function. This is done with the type definition of the "data_write_temp" or "mem" of the below examples. If the "data_write_temp" variable is 16bits long then it will read 16bits each time the $fread is called. Besides, $fread will return "nchar_code=2" because 16bits are 2bytes. In case, "data_write_temp" is 32bits as in the example, the $fread will read nchar_code=4bytes(32bits). You can also define an array and the $fread function will try to fill that array.
Lets define a multidimensional array mem.
logic [31:0] mem [0:2][0:4][5:8];
In the example word contents, wzyx,
-w shows the start of the word
-z corresponds to words of the [0:2] dimension (3 blocks).
-y corresponds to words of the [0:4] dimension (5 rows).
-x corresponds to words of the [5:8] dimension (4 columns).
The file will be structure as below (notice #z shows the z dimension blocks):
#0 w005 w006 w007 w008
w015 w016 w017 w018
w025 w026 w027 w028
w035 w036 w037 w038
w045 w046 w047 w048
#1 w105 w106 w107 w108
w115 w116 w117 w118
w125 w126 w127 w128
w135 w136 w137 w138
w145 w146 w147 w148
#2 w205 w206 w207 w208
w215 w216 w217 w218
w225 w226 w227 w228
w235 w236 w237 w238
w245 w246 w247 w248
In the previous structure, the numbers shows the index of each dimension.
e.g. w048 means, the word w (32bits) value on index z =0, index y= 4 and index x= 8.
Now, you have many ways to read this.
You can read all in a single shot using the type "mem" declared above, or you can do a while loop until EOF reading pieces of 32bits using a "data_write_temp" variable of 32bits. The loop is interesting if you want to do something some checks for every word piece and you are not interested having a memory value.
In case multidimensional array / single shot read is chosen, then you can either use $fread or use an specific function $readmemh defined in SV standard.
$readmemh("mem.data", mem, 1, (3*5*4));
is equivalent to
$readmemh("mem.data", mem);
The $readmemh spare you the need to open/close the file.
If you use $fread for one shot read
logic [31:0] mem [0:2][0:4][5:8];
register_init_id = $fopen("mem.data","rb");
nchar_code = $fread(mem, register_init_id);
if (nchar_code!=(3*5*4)*4)) begin
`uvm_error("do_read_file", $sformatf("Was not possible to read the whole expected bytes"));
end
$fclose(register_init_id);
In case you wanted to do a loop using 32b word read. Then see the following example.
The example uses the data which is read from the file to write to AHB Bus using an AHB Verification Component.
logic [31:0] data_write_temp;
...
//DO REGISTER FILE
register_init_id = $fopen("../../software/binary.bin","rb");
if (register_init_id==0) begin `uvm_error("do_read_file", $sformatf("Was not possible to open the register_init_id file")); end
count_32b_words=0;
while(!$feof(register_init_id)) begin
nchar_code = $fread(data_write_temp, register_init_id);
if ((nchar_code!=4)||(nchar_code==0)) begin
if (nchar_code!=0) begin
`uvm_error("do_read_file", $sformatf("Was not possible to read from file a whole 4bytes word:%0d",nchar_code));
end
end else begin
tmp_ahb_address = (pnio_pkg::conf_ahb_register_init_file_part1 + 4*count_32b_words);
data_write_temp = (data_write_temp << 8*( (tmp_ahb_address)%(DATAWIDTH/(8))));//bit shift if necessary not aligned to 4 bytes
`uvm_create_on(m_ahb_xfer,p_sequencer.ahb0_seqr);
assert(m_ahb_xfer.randomize(* solvefaildebug *) with {
write == 1;//perform a write
HADDR == tmp_ahb_address;
HSIZE == SIZE_32_BIT;
HBURST == HBURST_SINGLE;
HXDATA.size() == 1; //only one data for single bust
HXDATA[0] == data_write_temp;
}) else $fatal (0, "Randomization failed"); //end assert
`uvm_send(m_ahb_xfer);
count_32b_words++;
end //end if there is a word read
end //end while
$fclose(register_init_id);
I was trying to progressively remove each /* */ comment pair on the same line by using the tranwrd function. However, the replacement doesn't happen for some reason.
Here's the code:
data _null_;
str="/* Comment 1 */ /* Comment 2 */ /* Comment 3 */ /* Comment 4 */";
do while(1);
startc=find(str,"/*");
endc=find(str,"*/");
put startc endc;
if startc = 0 then leave;
else do;
temp=substr(str,startc,endc-startc+2);
put "temp: " temp;
str=tranwrd(str,temp,"");
put "str: " str;
end;
end;
run;
The code goes into infinite loop because although temp gets the value of "/* Comment 1 */", TRANWRD is unable to make a replacement for some reason.
You need to TRIM the argument for finding (temp). Otherwise it has extraneous spaces on the end. Remember, string variables in SAS always have their full length - so if it is a 200 long string with "ABCDE" in it, it really is "ABCDE " (up to 200).
data _null_;
str="/* Comment 1 */ /* Comment 2 */ /* Comment 3 */ /* Comment 4 */";
do while(1);
startc=find(str,"/*");
endc=find(str,"*/");
put startc endc;
if startc = 0 then leave;
else do;
temp=substr(str,startc,endc-startc+2);
put "temp: |" temp "|";
str=tranwrd(str,trim(temp),"");
put "str: " str;
end;
end;
run;
See the | | around temp; it has at least one extra space around it. Your example was fortuitous in that you incorrectly added 2 to the length (should add one); since all of your temp arguments are identical in length this wouldn't have come up if you had added 1, but in a real world example this is presumably not the case.
Further, if you want it replaced with nothing, as opposed to a single space, you need to use TRANSTRN and TRIMN (which I think are 9.2+). The above code really replaces it with a single space. SAS does not have a concept of "", character null/missing is always " ". TRIMN and TRANSTRN allow you to make this replacement as a sort of workaround.
I am in a pickle right now. I'm having trouble taking in an input of example
1994 The Shawshank Redemption
1994 Pulp Fiction
2008 The Dark Knight
1957 12 Angry Men
I first take in the number into an integer, then I need to take in the name of the Movie into a string using a character array, however i have not been able to get this done.
here is the code atm
while(scanf("%d", &myear) != EOF)
{
i = 0;
while(scanf("%[^\n]", &ch))
{
title[i] = ch;
i++;
}
addNode(makeData(title,myear));
}
The title array is arbitrarily large and the function is to add the data as a node to a linked list. right now the output I keep getting for each node is as follows
" hank Redemption"
" ion"
" Knight"
" Men"
Yes, it oddly prints a space in front of the cut-off title. I checked the variables and it adds the space in the data. (I am not printing the year as that is taken in correctly)
How can I fix this?
You are using the wrong type of argument passed to scanf() -- instead of scanning a character, try scanning to the string buffer immediately. %[^\n] scans an entire string up to (but not including) the newline. It does not scan only one character.
(Marginal secondary problem: I don't know from where you people are getting the idea that scanf() returns EOF at end of input, but it doesn't - you'd be better off reading the documentation instead of making incorrect assumptions.)
I hope you see now: scanf() is hard to get right. It's evil. Why not input the whole line at once then parse it using sane functions?
char buf[LINE_MAX];
while (fgets(buf, sizeof buf, stdin) != NULL) {
int year = strtol(buf, NULL, 0);
const char *p = strchr(buf, ' ');
if (p != NULL) {
char name[LINE_MAX];
strcpy(name, p + 1); // safe because strlen(p) <= sizeof(name)
}
}
I've got this
WCHAR fileName[1];
as a returned value from a function (it's a sys 32 function so I am not able to change the returned type). I need to make fileName to be null terminated so I am trying to append '\0' to it, but nothing seems to work.
Once I get a null terminated WCHAR I will need to pass it to another sys 32 function so I need it to stay as WCHAR.
Could anyone give me any suggestion please?
================================================
Thanks a lot for all your help. Looks like my problem has to do with more than missing a null terminated string.
//This works:
WCHAR szPath1[50] = L"\\Invalid2.txt.txt";
dwResult = FbwfCommitFile(szDrive, pPath1); //Successful
//This does not:
std::wstring l_fn(L"\\");
//Because Cache_detail->fileName is \Invalid2.txt.txt and I need two
l_fn.append(Cache_detail->fileName);
l_fn += L""; //To ensure null terminated
fprintf(output, "l_fn.c_str: %ls\n", l_fn.c_str()); //Prints "\\Invalid2.txt.txt"
iCommitErr = FbwfCommitFile(L"C:", (WCHAR*)l_fn.c_str()); //Unsuccessful
//Then when I do a comparison on these two they are unequal.
int iCompareResult = l_fn.compare(pPath1); // returns -1
So I need to figure out how these two ended up to be different.
Thanks a lot!
Since you mentioned fbwffindfirst/fbwffindnext in a comment, you're talking about the file name returned in FbwfCacheDetail. So from the fileNameLength field you know length for the fileName in bytes. The length of fileName in WCHAR's is fileNameLength/sizeof(WCHAR). So the simple answer is that you can set
fileName[fileNameLength/sizeof(WCHAR)+1] = L'\0'
Now this is important you need to make sure that the buffer you send for the cacheDetail parameter into fbwffindfirst/fbwffindnext is sizeof(WCHAR) bytes larger than you need, the above code snippet may run outside the bounds of your array. So for the size parameter of fbwffindfirst/fbwffindnext pass in the buffer size - sizeof(WCHAR).
For example this:
// *** Caution: This example has no error checking, nor has it been compiled ***
ULONG error;
ULONG size;
FbwfCacheDetail *cacheDetail;
// Make an intial call to find how big of a buffer we need
size = 0;
error = FbwfFindFirst(volume, NULL, &size);
if (error == ERROR_MORE_DATA) {
// Allocate more than we need
cacheDetail = (FbwfCacheDetail*)malloc(size + sizeof(WCHAR));
// Don't tell this call about the bytes we allocated for the null
error = FbwfFindFirstFile(volume, cacheDetail, &size);
cacheDetail->fileName[cacheDetail->fileNameLength/sizeof(WCHAR)+1] = L"\0";
// ... Use fileName as a null terminated string ...
// Have to free what we allocate
free(cacheDetail);
}
Of course you'll have to change a good bit to fit in with your code (plus you'll have to call fbwffindnext as well)
If you are interested in why the FbwfCacheDetail struct ends with a WCHAR[1] field, see this blog post. It's a pretty common pattern in the Windows API.
Use L'\0', not '\0'.
As each character of a WCHAR is 16-bit in size, you should perhaps append \0\0 to it, but I'm not sure if this works. By the way, WCHAR fileName[1]; is creating a WCHAR of length 1, perhaps you want something like WCHAR fileName[1024]; instead.
WCHAR fileName[1]; is an array of 1 character, so if null terminated it will contain only the null terminator L'\0'.
Which API function are you calling?
Edited
The fileName member in FbwfCacheDetail is only 1 character which is a common technique used when the length of the array is unknown and the member is the last member in a structure. As you have likely already noticed if your allocated buffer is is only sizeof (FbwfCacheDetail) long then FbwfFindFirst returns ERROR_NOT_ENOUGH_MEMORY.
So if I understand, what you desire to do it output the non NULL terminated filename using fprintf. This can be done as follows
fprintf (outputfile, L"%.*ls", cacheDetail.fileNameLength, cacheDetail.fileName);
This will print only the first fileNameLength characters of fileName.
An alternative approach would be to append a NULL terminator to the end of fileName. First you'll need to ensure that the buffer is long enough which can be done by subtracting sizeof (WCHAR) from the size argument you pass to FbwfFindFirst. So if you allocate a buffer of 1000 bytes, you'll pass 998 to FbwfFindFirst, reserving the last two bytes in the buffer for your own use. Then to add the NULL terminator and output the file name use
cacheDetail.fileName[cacheDetail.fileNameLength] = L'\0';
fprintf (outputfile, L"%ls", cacheDetail.fileName);