[EE] Ideas about improving safety in C language

Hi folks,

I was thinking about the current discussion about C/C++ language safety, 
and I recalled an old idea I had long ago about creating a new string 
format and library.

It could be possible for one person alone to implement and use it 
privately, but of course it would be even better if it becomes a 
standard, perhaps with support from the compilers.

I don't know whether something similar was already suggested or is being 
used, but I would like to know your opinion about it.


Cheers,

Isaac


Proposed New C string format:

Bytes:
<descriptor> [<references_counter>] <allocated_size_indicator> 
[<used_size_indicator> [<number_of_characters>]] [<characters>...]

Descriptor: (bits) 0aabbccr (bit seven is reserved to indicate future 
new formats, most probably two-byte descriptors)

It would be good to have an encoding field (to indicate ASCII, ANSI, 
UTF-8, UTF-16, etc.), but there is not enough bits in a byte and the 
fields I chose are more important. Perhaps it can be included in a 
two-byte descriptor format.

Some details like the obligatory presence of an ending '\0' character or 
not must be discussed. If the ending '\0' is required, it would be very 
simple to use the new format  with the traditional C library functions.


aa = Area:
00    Static
01    Stack (automatic)
10    Dynamic
11    Dynamic with references counter

bb = Length Indicators Bits
00     8 bits
01    16 bits
10    32 bits
11    64 bits (perhaps this value could be used for other purpose, most 
probably 64-bits will never be used).

cc = Length Indicators Present
00    Only Allocated Size Indicator (used for read-only or fixed size 
strings)
01    Allocated Size and Used Size Indicators
10    Allocated Size, Used Size and Number of Characters Indicators
11    *Reserved*

Size Indicators: All-ones means not informed. Could be used so the 
length is to be calculated when the string is accessed for the first 
time, saving the need for calculating the length of every string in 
advance. It would require '\0' ended strings. Needs more thought.

r = Read Only
0    Read-Write
1    Read-Only


-- 
O software antivírus Avast realizou uma checagem de vírus neste e-mail.
www.avast.com
-- 
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
https://mailman.mit.edu/mailman/listinfo/piclist