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@ -1,5 +1,5 @@
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@node Obstacks
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@chapter Obstacks
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@subsection Obstacks
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@cindex obstacks
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An @dfn{obstack} is a pool of memory containing a stack of objects. You
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@ -33,7 +33,7 @@ the padding needed to start each object on a suitable boundary.
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@end menu
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@node Creating Obstacks
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@section Creating Obstacks
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@subsubsection Creating Obstacks
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The utilities for manipulating obstacks are declared in the header
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file @file{obstack.h}.
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@ -74,7 +74,7 @@ directly or indirectly. You must also supply a function to free a chunk.
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These matters are described in the following section.
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@node Preparing for Obstacks
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@section Preparing for Using Obstacks
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@subsubsection Preparing for Using Obstacks
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Each source file in which you plan to use the obstack functions
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must include the header file @file{obstack.h}, like this:
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@ -160,7 +160,7 @@ obstack_alloc_failed_handler = &my_obstack_alloc_failed;
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@end defvar
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@node Allocation in an Obstack
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@section Allocation in an Obstack
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@subsubsection Allocation in an Obstack
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@cindex allocation (obstacks)
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The most direct way to allocate an object in an obstack is with
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@ -233,7 +233,7 @@ Contrast this with the previous example of @code{savestring} using
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@code{malloc} (@pxref{Basic Allocation, , , libc, The GNU C Library Reference Manual}).
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@node Freeing Obstack Objects
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@section Freeing Objects in an Obstack
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@subsubsection Freeing Objects in an Obstack
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@cindex freeing (obstacks)
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To free an object allocated in an obstack, use the function
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@ -265,7 +265,7 @@ frees the chunk (@pxref{Preparing for Obstacks}). Then other
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obstacks, or non-obstack allocation, can reuse the space of the chunk.
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@node Obstack Functions
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@section Obstack Functions and Macros
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@subsubsection Obstack Functions and Macros
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@cindex macros
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The interfaces for using obstacks may be defined either as functions or
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@ -321,7 +321,7 @@ various language extensions in GNU C permit defining the macros so as to
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compute each argument only once.
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@node Growing Objects
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@section Growing Objects
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@subsubsection Growing Objects
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@cindex growing objects (in obstacks)
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@cindex changing the size of a block (obstacks)
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@ -435,7 +435,7 @@ the current object smaller. Just don't try to shrink it beyond zero
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length---there's no telling what will happen if you do that.
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@node Extra Fast Growing
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@section Extra Fast Growing Objects
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@subsubsection Extra Fast Growing Objects
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@cindex efficiency and obstacks
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The usual functions for growing objects incur overhead for checking
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@ -538,7 +538,7 @@ add_string (struct obstack *obstack, const char *ptr, int len)
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@end smallexample
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@node Status of an Obstack
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@section Status of an Obstack
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@subsubsection Status of an Obstack
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@cindex obstack status
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@cindex status of obstack
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@ -580,12 +580,13 @@ obstack_next_free (@var{obstack-ptr}) - obstack_base (@var{obstack-ptr})
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@end deftypefun
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@node Obstacks Data Alignment
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@section Alignment of Data in Obstacks
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@subsubsection Alignment of Data in Obstacks
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@cindex alignment (in obstacks)
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Each obstack has an @dfn{alignment boundary}; each object allocated in
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the obstack automatically starts on an address that is a multiple of the
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specified boundary. By default, this boundary is 4 bytes.
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specified boundary. By default, this boundary is aligned so that
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the object can hold any type of data.
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To access an obstack's alignment boundary, use the macro
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@code{obstack_alignment_mask}, whose function prototype looks like
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@ -597,7 +598,9 @@ this:
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The value is a bit mask; a bit that is 1 indicates that the corresponding
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bit in the address of an object should be 0. The mask value should be one
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less than a power of 2; the effect is that all object addresses are
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multiples of that power of 2. The default value of the mask is 3, so that
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multiples of that power of 2. The default value of the mask is a value
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that allows aligned objects to hold any type of data: for example, if
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its value is 3, any type of data can be stored at locations whose
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addresses are multiples of 4. A mask value of 0 means an object can start
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on any multiple of 1 (that is, no alignment is required).
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@ -620,7 +623,7 @@ This will finish a zero-length object and then do proper alignment for
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the next object.
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@node Obstack Chunks
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@section Obstack Chunks
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@subsubsection Obstack Chunks
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@cindex efficiency of chunks
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@cindex chunks
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@ -676,7 +679,7 @@ if (obstack_chunk_size (obstack_ptr) < @var{new-chunk-size})
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@end smallexample
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@node Summary of Obstacks
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@section Summary of Obstack Functions
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@subsubsection Summary of Obstack Functions
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Here is a summary of all the functions associated with obstacks. Each
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takes the address of an obstack (@code{struct obstack *}) as its first
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DJ Delorie