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Merge branch 'as/api-allocation-doc' into maint

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* as/api-allocation-doc:
  api-allocation-growing.txt: encourage better variable naming
This commit is contained in:
Junio C Hamano
2013-01-11 16:51:01 -08:00
parent d0f945622b 5062f9e1b5
commit ab60f2ce2d
1 changed files with 8 additions and 6 deletions
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14
Documentation/technical/api-allocation-growing.txt
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@ -5,7 +5,9 @@ Dynamically growing an array using realloc() is error prone and boring.
Define your array with: Define your array with:
* a pointer (`ary`) that points at the array, initialized to `NULL`; * a pointer (`item`) that points at the array, initialized to `NULL`
(although please name the variable based on its contents, not on its
type);
* an integer variable (`alloc`) that keeps track of how big the current * an integer variable (`alloc`) that keeps track of how big the current
allocation is, initialized to `0`; allocation is, initialized to `0`;
@ -13,22 +15,22 @@ Define your array with:
* another integer variable (`nr`) to keep track of how many elements the * another integer variable (`nr`) to keep track of how many elements the
array currently has, initialized to `0`. array currently has, initialized to `0`.
Then before adding `n`th element to the array, call `ALLOC_GROW(ary, n, Then before adding `n`th element to the item, call `ALLOC_GROW(item, n,
alloc)`. This ensures that the array can hold at least `n` elements by alloc)`. This ensures that the array can hold at least `n` elements by
calling `realloc(3)` and adjusting `alloc` variable. calling `realloc(3)` and adjusting `alloc` variable.
------------ ------------
sometype *ary; sometype *item;
size_t nr; size_t nr;
size_t alloc size_t alloc
for (i = 0; i < nr; i++) for (i = 0; i < nr; i++)
if (we like ary[i] already) if (we like item[i] already)
return; return;
/* we did not like any existing one, so add one */ /* we did not like any existing one, so add one */
ALLOC_GROW(ary, nr + 1, alloc); ALLOC_GROW(item, nr + 1, alloc);
ary[nr++] = value you like; item[nr++] = value you like;
------------ ------------
You are responsible for updating the `nr` variable. You are responsible for updating the `nr` variable.