Re: [EE] Ideas about improving safety in C language

What's wrong with std::string

Ryan

On Wed, 16 Apr 2025 at 02:32, Isaac Marino Bavaresco <
[email protected]> wrote:

> 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
>
>
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