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authorLibravatar Junio C Hamano <gitster@pobox.com>2010-01-30 16:03:10 -0800
committerLibravatar Junio C Hamano <gitster@pobox.com>2010-01-30 16:03:10 -0800
commit00d3278c8534a8244ae3447189401111e017fd5d (patch)
treef1c19903bc10ffe4816642040080fb6cfd5da376 /Documentation/technical/api-allocation-growing.txt
parentt6000lib: Fix permission (diff)
parentAdd a small patch-mode testing library (diff)
downloadtgif-00d3278c8534a8244ae3447189401111e017fd5d.tar.xz
Merge commit 'b319ef7' into jc/maint-fix-test-perm
* commit 'b319ef7': (8132 commits) Add a small patch-mode testing library git-apply--interactive: Refactor patch mode code t8005: Nobody writes Russian in shift_jis Fix severe breakage in "git-apply --whitespace=fix" Update release notes for 1.6.4 After renaming a section, print any trailing variable definitions Make section_name_match start on '[', and return the length on success send-email: detect cycles in alias expansion Show the presence of untracked files in the bash prompt. SunOS grep does not understand -C<n> nor -e Fix export_marks() error handling. git repack: keep commits hidden by a graft Add a test showing that 'git repack' throws away grafted-away parents git branch: clean up detached branch handling git branch: avoid unnecessary object lookups git branch: fix performance problem git svn: fix shallow clone when upstream revision is too new do_one_ref(): null_sha1 check is not about broken ref configure.ac: properly unset NEEDS_SSL_WITH_CRYPTO when sha1 func is missing janitor: useless checks before free ...
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+allocation growing API
+======================
+
+Dynamically growing an array using realloc() is error prone and boring.
+
+Define your array with:
+
+* a pointer (`ary`) that points at the array, initialized to `NULL`;
+
+* an integer variable (`alloc`) that keeps track of how big the current
+ allocation is, initialized to `0`;
+
+* another integer variable (`nr`) to keep track of how many elements the
+ array currently has, initialized to `0`.
+
+Then before adding `n`th element to the array, call `ALLOC_GROW(ary, n,
+alloc)`. This ensures that the array can hold at least `n` elements by
+calling `realloc(3)` and adjusting `alloc` variable.
+
+------------
+sometype *ary;
+size_t nr;
+size_t alloc
+
+for (i = 0; i < nr; i++)
+ if (we like ary[i] already)
+ return;
+
+/* we did not like any existing one, so add one */
+ALLOC_GROW(ary, nr + 1, alloc);
+ary[nr++] = value you like;
+------------
+
+You are responsible for updating the `nr` variable.