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.TH BIN 2
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.SH NAME
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binalloc, bingrow, binfree \- grouped memory allocation
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.br
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.B #include <bin.h>
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.PP
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.ta \w'\fLvoid* 'u
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.PP
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.B
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typedef struct Bin	Bin;
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.PP
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.B
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void	*binalloc(Bin **bp, ulong size, int clr);
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.PP
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.B
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void	*bingrow(Bin **bp, void *op, ulong osize,
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.br
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.B
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	ulong size, int clr);
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.PP
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.B
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void	binfree(Bin **bp);
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.SH DESCRIPTION
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These routines provide simple grouped memory allocation and deallocation.
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Items allocated with
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.I binalloc
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are added to the
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.I Bin
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pointed to by
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.IR bp .
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All items in a bin may be freed with one call to
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.IR binfree ;
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there is no way to free a single item.
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.PP
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.I Binalloc
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returns a pointer to a new block of at least
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.I size
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bytes.
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The block is suitably aligned for storage of any type of object.
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No two active pointers from
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.I binalloc
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will have the same value.
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The call
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.B binalloc(0)
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returns a valid pointer rather than null.
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If
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.I clr
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is non-zero, the allocated memory is set to 0;
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otherwise, the contents are undefined.
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.PP
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.I Bingrow
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is used to extend the size of a block of memory returned by
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.IR binalloc .
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.I Bp
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must point to the same bin group used to allocate the original block,
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and
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.I osize
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must be the last size used to allocate or grow the block.
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A pointer to a block of at least
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.I size
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bytes is returned, with the same contents in the first
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.I osize
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locations.
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If
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.I clr
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is non-zero, the remaining bytes are set to 0,
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and are undefined otherwise.
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If
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.I op
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is
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.BR nil ,
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it and
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.I osize
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are ignored, and the result is the same as calling
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.IR binalloc .
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.PP
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.I Binalloc
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and
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.I bingrow
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allocate large chunks of memory using
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.IR malloc (2)
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and return pieces of these chunks.
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The chunks are
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.IR free 'd
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upon a call to
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.IR binfree .
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.SH SOURCE
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.B /sys/src/libbin
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.SH SEE ALSO
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.IR malloc (2)
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.SH DIAGNOSTICS
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.I binalloc
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and
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.I bingrow
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return 0 if there is no available memory.