feldspar_array.h

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#ifndef FELDSPAR_ARRAY_H
#define FELDSPAR_ARRAY_H

#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>

// TODO qualify the names to avoid clashes with Haskell names

struct array
{
    void*    buffer;   /* pointer to the buffer of elements */
    int32_t  length;   /* number of elements in the array */
    int32_t  elemSize; /* size of elements in bytes; (- sizeof(struct array)) for nested arrays */
    uint32_t bytes;    /* The number of bytes the buffer can hold */
};

/* Indexing into an array: */
/* Result: element of type 'type' */
#define at(type,arr,idx) (((type*)((arr)->buffer))[idx])


/* Deep array copy */
static inline void copyArray(struct array *to, struct array *from)
{
    assert(to);
    assert(from);
    if( from->elemSize < 0 )
    {
        unsigned i;
        for( i = 0; i < from->length; ++i )
            copyArray( &at(struct array, to, i), &at(struct array, from, i) );
    }
    else
    {
        assert(to->buffer);
        assert(from->buffer);
        memcpy( to->buffer, from->buffer, to->length * to->elemSize );
    }
}

/* Deep array copy to a given position */
static inline void copyArrayPos(struct array *to, unsigned pos, struct array *from)
{
    assert(to);
    assert(from);
    if( from->elemSize < 0 )
    {
        unsigned i;
        for( i = 0; i < from->length; ++i )
            copyArray( &at(struct array, to, i + pos), &at(struct array, from, i) );
    }
    else
    {
        assert(to->buffer);
        assert(from->buffer);
        memcpy( (char*)(to->buffer) + pos * to->elemSize, from->buffer, to->length * to->elemSize );
    }
}


/* Deep array copy with a given length */
void copyArrayLen(struct array *to, struct array *from, int32_t len);

/* Array length */
static inline int32_t getLength(struct array *arr)
{
  assert(arr);
  return arr->length;
}

/* (Re)set array length */
static inline void setLength(struct array *arr, int32_t len)
{
  assert(arr);
  assert(arr->bytes >= arr->length * abs(arr->elemSize));
  arr->length = len;
}

/* Reset array length by increasing it */
void increaseLength(struct array *arr, int32_t len);

#endif