>>>Try this (modified from Cetin code) for testing if the replaced string is being split during FREADs:
>>>
>>>>
>>>#DEFINE MAXBUFFER 65536
>>>lhIn = FOPEN(lcFileIn)
>>>lhOut = FCREATE(lcFileOut)
>>>DO WHILE NOT FEOF(m.lhIn )
>>> lcBuffer = FREAD(m.lhIn, MAXBUFFER)
>>> DO CASE
>>> CASE RIGHT(lcBuffer,3) = 'AD0'
>>> FSEEK(m.lhIn, -3, 1)
>>> lcBuffer = LEFT(lcBuffer,LEN(lcBuffer)-3)
>>> CASE RIGHT(lcBuffer,2) = 'AD'
>>> FSEEK(m.lhIn, -2, 1)
>>> lcBuffer = LEFT(lcBuffer,LEN(lcBuffer)-2)
>>> CASE RIGHT(lcBuffer,1) = 'A'
>>> FSEEK(m.lhIn, -1, 1)
>>> lcBuffer = LEFT(lcBuffer,LEN(lcBuffer)-1)
>>> ENDCASE
>>> FWRITE(m.lhOut,STRTRAN(lcBuffer,'AD00','BR77'),MAXBUFFER)
>>>ENDDO
>>>FCLOSE(m.lhIn)
>>>FCLOSE(m.lhOut)
>>
>>this is incorrect.
>>you cannot mix a right find/replace with a left find/replace
>
>I am not sure what you mean cannot mix a right find/replace with a left find replace. The above code looks at the last 3 bytes to determine if they can possibly be part of the search string. If there is a possiblity, then the position in the file is moved by the number of possible matching bytes (FSEEK) and the possible matching bytes is removed from the read buffer before any string replacement is made.

This is the issue.
example:

find "AD0A" replace with "BR77"  
lcBuffer = ".....AD0A"
the line
    CASE RIGHT(lcBuffer,1) = 'A'
find the A, remove it and you lose a raplacement!

> When the next FREAD occurs, it now from the adjusted position in the file which will now read back in the possible >matching bytes at the start of the new buffer. This is repeated until the entire buffer is read in and the string >translated.