So . . . I guess depending on what preceded my need to search a string for a specific character sometimes I used strchr and sometimes strstr. This is not an error of course one can certainly search for a single character as "B" for example. After observing my inconsistency I decided to try to time searching with each method. Timing with ticks is always tricky because of other system activities but if you do it enough times you will get a sense of which procedure is faster.
Probably not a surprise to anyone strchr has a slight edge over strstr, maybe less than 3% faster.
Then I figured why not test wcschr and wcsstr while I was at it. Since I was using "B" I just use L"B" . Again wcschr was a bit faster by a small margin maybe < 2% faster.
Now here comes the reason for the post - I decided to try wcsstr vs wcschr with a character out of the first 256 characters. Here is where is gets very interesting.
Searching for 号 showed that wcschr was still a bit faster than wcsstr looking for the character.
BUT wait there is more:The wcschr results appeared to be far far faster than searching with wcschr for a wide B char.
So another test just wcschr for 号 vs. for B. In repeated testing, finding 号 was about ~200x faster than finding B !!
Here is the basic code but of course you'll not have my Write_to_Log procedure, but it is enough if you want to try this yourself. Yes it ran 3 times at 9 million searches each time, also checked that it was actually found at the end...
Of course if you ran it just once you'll never notice the difference.....
long long loup;
wchar_t tmp[2000], *p_tmp; p_tmp = tmp;
wchar_t tmp3[2000], *p_tmp3; p_tmp3 = tmp3;
wchar_t *p_found=NULL;
for (loup = 0;loup<1001; loup++)
{p_tmp[loup] = L'称'; }
p_tmp[1001] = L'号';p_tmp[1002] = 0;
for (loup = 0;loup<1001; loup++)
{p_tmp3[loup] = L'A';}
p_tmp3[1001] = L'B';p_tmp[1002] = 0;
int oloup;
for (oloup=0;oloup<3; oloup++)
{
Write_To_Log("C://temp//trace.log","Start wcschr uni B",TRUE,0);
for (loup=0; loup < 9000000; loup++)
{ p_found = wcschr(p_tmp3,L'B'); }
Write_To_Log("C://temp//trace.log","End wcschr uni B",TRUE,0);
if (p_found == NULL)
{ Write_To_Log("C://temp//trace.log","wcschr uni not found",FALSE,0);}
p_found = NULL;
Write_To_Log("C://temp//trace.log","Start wcschr uni 号",TRUE,0);
for (loup=0; loup < 9000000; loup++)
{ p_found = wcschr(p_tmp,L'号'); }
Write_To_Log("C://temp//trace.log","End wcschr uni 号",TRUE,0);
if (p_found == NULL)
{ Write_To_Log("C://temp//trace.log","wcschr uni not found",FALSE,0);}
}
Why is wcschr for 号 so much faster than wcschr for B ??
ANYWAY - maybe this will stir up the forum
Happy New Year,
John Z
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