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40 строки
1.1 KiB
Plaintext
40 строки
1.1 KiB
Plaintext
allocation growing API
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======================
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Dynamically growing an array using realloc() is error prone and boring.
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Define your array with:
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* a pointer (`item`) that points at the array, initialized to `NULL`
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(although please name the variable based on its contents, not on its
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type);
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* an integer variable (`alloc`) that keeps track of how big the current
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allocation is, initialized to `0`;
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* another integer variable (`nr`) to keep track of how many elements the
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array currently has, initialized to `0`.
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Then before adding `n`th element to the item, call `ALLOC_GROW(item, n,
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alloc)`. This ensures that the array can hold at least `n` elements by
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calling `realloc(3)` and adjusting `alloc` variable.
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------------
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sometype *item;
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size_t nr;
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size_t alloc
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for (i = 0; i < nr; i++)
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if (we like item[i] already)
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return;
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/* we did not like any existing one, so add one */
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ALLOC_GROW(item, nr + 1, alloc);
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item[nr++] = value you like;
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------------
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You are responsible for updating the `nr` variable.
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If you need to specify the number of elements to allocate explicitly
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then use the macro `REALLOC_ARRAY(item, alloc)` instead of `ALLOC_GROW`.
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