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POA good C equivalent of STL vector?
 

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    <p>I've noticed that at several places in our code base we use dynamically expanding arrays, i.e. a base array coupled with an element counter and a "max elements" value. </p> <p>What I want to do is replace these with a common data structure and utility functions, for the usual object-oriented reasons. The array elements can be either basic data types or structs, I need fast random access to the elements, and preferably a type-safe implementation. </p> <p>So, basically, what I would like to use is an STL vector, but the code base is restricted to C89 so I have to come up with something else :-)</p> <p>I gave it some thought and whipped up this initial draft, just to show what I'm aiming at:</p> <pre><code>/* Type-safe dynamic list in C89 */ #define list_declare(type) typedef struct _##type##_list_t { type * base_array; size_t elements; size_t max_size; } type##_list_t #define list(type) type##_list_t #define list_new(type, initial_size) { calloc(initial_size, sizeof(type)), 0, initial_size } #define list_free(list) free(list.base_array) #define list_set(list, place, element) if ( list.elements &lt; list.max_size ) { list.base_array[place] = element; } else { /* Array index out of bounds */ } #define list_add(list, element) if ( list.elements &lt; list.max_size ) { list.base_array[list.elements++] = element; } else { /* Expand array then add */ } #define list_get(list, n) list.base_array[n] /* Sample usage: */ list_declare(int); int main(void) { list(int) integers = list_new(int, 10); printf("list[0] = %d\n", list_get(integers, 0)); list_add(integers, 4); printf("list[0] = %d\n", list_get(integers, 0)); list_set(integers, 0, 3); printf("list[0] = %d\n", list_get(integers, 0)); list_free(integers); return EXIT_SUCCESS; } </code></pre> <p>...however, there must be someone else who has done this before. I'm aware of the FreeBSD sys/queue.h implementation of a similar concept for some different queues, but I can't find anything like that for arrays. </p> <p>Is anyone here any wiser?</p>
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    1. COAt the very least, either get rid of the macros and replace them with functions, or fix them so that they work like functions. The latter involves wrapping any macro that's more than a single expression/statement with `do { ... } while (0)`.
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    2. COWhy would I want to get rid of the macros? Replacing them with functions would defeat the type independence, it would no longer be a generic solution. Also, why would I want to wrap with do ... while? That would make it impossible return values from the function-like macros.
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    3. CO@christoffer: Re-read R's comment. Note the use of "or" - those function macros are awful, you should improve them by "fixing" them, as R says. This makes using a function macro less surprising. I'd personally prefer if the function macros were capitalized, for good measure.
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