nasm/raa.h

/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 1996-2009 The NASM Authors - All Rights Reserved
 *   See the file AUTHORS included with the NASM distribution for
 *   the specific copyright holders.
 *
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 *   modification, are permitted provided that the following
 *   conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *     
 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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#ifndef NASM_RAA_H
#define NASM_RAA_H 1

#include "compiler.h"

/*
 * Routines to manage a dynamic random access array of int64_ts which
 * may grow in size to be more than the largest single malloc'able
 * chunk.
 */

#define RAA_BLKSHIFT	15      /* 2**this many longs allocated at once */
#define RAA_BLKSIZE	(1 << RAA_BLKSHIFT)
#define RAA_LAYERSHIFT	15      /* 2**this many _pointers_ allocated */
#define RAA_LAYERSIZE	(1 << RAA_LAYERSHIFT)

typedef struct RAA RAA;
typedef union RAA_UNION RAA_UNION;
typedef struct RAA_LEAF RAA_LEAF;
typedef struct RAA_BRANCH RAA_BRANCH;

struct RAA {
    /*
     * Number of layers below this one to get to the real data. 0
     * means this structure is a leaf, holding RAA_BLKSIZE real
     * data items; 1 and above mean it's a branch, holding
     * RAA_LAYERSIZE pointers to the next level branch or leaf
     * structures.
     */
    int layers;

    /*
     * Number of real data items spanned by one position in the
     * `data' array at this level. This number is 0 trivially, for
     * a leaf (level 0): for a level 1 branch it should be
     * RAA_BLKSHIFT, and for a level 2 branch it's
     * RAA_LAYERSHIFT+RAA_BLKSHIFT.
     */
    int shift;

    union RAA_UNION {
        struct RAA_LEAF {
            int64_t data[RAA_BLKSIZE];
        } l;
        struct RAA_BRANCH {
            struct RAA *data[RAA_LAYERSIZE];
        } b;
    } u;
};

struct RAA *raa_init(void);
void raa_free(struct RAA *);
int64_t raa_read(struct RAA *, int32_t);
struct RAA *raa_write(struct RAA *r, int32_t posn, int64_t value);

#endif                          /* NASM_RAA_H */