path: root/saa.c

#include "compiler.h"
#include "nasmlib.h"
#include "saa.h"

/* Aggregate SAA components smaller than this */
#define SAA_BLKSHIFT	16
#define SAA_BLKLEN	((size_t)1 << SAA_BLKSHIFT)

struct SAA *saa_init(size_t elem_len)
{
    struct SAA *s;
    char *data;

    s = nasm_zalloc(sizeof(struct SAA));

    if (elem_len >= SAA_BLKLEN)
	s->blk_len = elem_len;
    else
	s->blk_len = SAA_BLKLEN - (SAA_BLKLEN % elem_len);

    s->elem_len = elem_len;
    s->length = s->blk_len;
    data = nasm_malloc(s->blk_len);
    s->nblkptrs = s->nblks = 1;
    s->blk_ptrs = nasm_malloc(sizeof(char *));
    s->blk_ptrs[0] = data;
    s->wblk = s->rblk = &s->blk_ptrs[0];

    return s;
}

void saa_free(struct SAA *s)
{
    char **p;
    size_t n;

    for (p = s->blk_ptrs, n = s->nblks; n; p++, n--)
	nasm_free(*p);

    nasm_free(s->blk_ptrs);
    nasm_free(s);
}

/* Add one allocation block to an SAA */
static void saa_extend(struct SAA *s)
{
    size_t blkn = s->nblks++;

    if (blkn >= s->nblkptrs) {
	size_t rindex = s->rblk - s->blk_ptrs;
	size_t windex = s->wblk - s->blk_ptrs;

	s->nblkptrs <<= 1;
	s->blk_ptrs = nasm_realloc(s->blk_ptrs, s->nblkptrs*sizeof(char *));

	s->rblk = s->blk_ptrs + rindex;
	s->wblk = s->blk_ptrs + windex;
    }

    s->blk_ptrs[blkn] = nasm_malloc(s->blk_len);
    s->length += s->blk_len;
}

void *saa_wstruct(struct SAA *s)
{
    void *p;

    if (s->wpos % s->elem_len)
	    nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
			      "misaligned wpos in saa_wstruct");

    if (s->wpos + s->elem_len > s->blk_len) {
	if (s->wpos != s->blk_len)
	    nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
			      "unfilled block in saa_wstruct");

	if (s->wptr + s->elem_len > s->length)
	    saa_extend(s);
	s->wblk++;
	s->wpos = 0;
    }

    p = *s->wblk + s->wpos;
    s->wpos += s->elem_len;
    s->wptr += s->elem_len;

    if (s->wptr > s->datalen)
	s->datalen = s->wptr;

    return p;
}

void saa_wbytes(struct SAA *s, const void *data, size_t len)
{
    const char *d = data;

    while (len) {
        size_t l = s->blk_len - s->wpos;
        if (l > len)
            l = len;
        if (l) {
            if (d) {
                memcpy(*s->wblk + s->wpos, d, l);
                d += l;
            } else
                memset(*s->wblk + s->wpos, 0, l);
            s->wpos += l;
	    s->wptr += l;
            len -= l;

	    if (s->datalen < s->wptr)
		s->datalen = s->wptr;
        }
        if (len) {
	    if (s->wptr >= s->length)
		saa_extend(s);
	    s->wblk++;
	    s->wpos = 0;
	}
    }
}

void saa_rewind(struct SAA *s)
{
    s->rblk = s->blk_ptrs;
    s->rpos = s->rptr = 0;
}

void *saa_rstruct(struct SAA *s)
{
    void *p;

    if (s->rptr + s->elem_len > s->datalen)
	return NULL;

    if (s->rpos % s->elem_len)
	    nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
			      "misaligned rpos in saa_rstruct");

    if (s->rpos + s->elem_len > s->blk_len) {
	s->rblk++;
	s->rpos = 0;
    }

    p = *s->rblk + s->rpos;
    s->rpos += s->elem_len;
    s->rptr += s->elem_len;

    return p;
}

const void *saa_rbytes(struct SAA *s, size_t *lenp)
{
    const void *p;
    size_t len;

    if (s->rptr >= s->datalen) {
	*lenp = 0;
	return NULL;
    }

    if (s->rpos >= s->blk_len) {
	s->rblk++;
	s->rpos = 0;
    }

    len = *lenp;
    if (len > s->datalen - s->rptr)
	len = s->datalen - s->rptr;
    if (len > s->blk_len - s->rpos)
	len = s->blk_len - s->rpos;

    *lenp = len;
    p = *s->rblk + s->rpos;

    s->rpos += len;
    s->rptr += len;

    return p;
}

void saa_rnbytes(struct SAA *s, void *data, size_t len)
{
    char *d = data;

    if (s->rptr + len > s->datalen) {
	nasm_malloc_error(ERR_PANIC|ERR_NOFILE, "overrun in saa_rnbytes");
	return;
    }

    while (len) {
        size_t l;
	const void *p;

	l = len;
	p = saa_rbytes(s, &l);

	memcpy(d, p, l);
	d   += l;
	len -= l;
    }
}

/* Same as saa_rnbytes, except position the counter first */
void saa_fread(struct SAA *s, size_t posn, void *data, size_t len)
{
    size_t ix;

    if (posn+len > s->datalen) {
	nasm_malloc_error(ERR_PANIC|ERR_NOFILE, "overrun in saa_fread");
	return;
    }

    if (s->blk_len == SAA_BLKLEN) {
	ix = posn >> SAA_BLKSHIFT;
	s->rpos = posn & (SAA_BLKLEN-1);
    } else {
	ix = posn / s->blk_len;
	s->rpos = posn % s->blk_len;
    }
    s->rptr = posn;
    s->rblk = &s->blk_ptrs[ix];

    saa_rnbytes(s, data, len);
}

/* Same as saa_wbytes, except position the counter first */
void saa_fwrite(struct SAA *s, size_t posn, const void *data, size_t len)
{
    size_t ix;

    if (posn > s->datalen) {
	/* Seek beyond the end of the existing array not supported */
	nasm_malloc_error(ERR_PANIC|ERR_NOFILE, "overrun in saa_fwrite");
	return;
    }
    
    if (s->blk_len == SAA_BLKLEN) {
	ix = posn >> SAA_BLKSHIFT;
	s->wpos = posn & (SAA_BLKLEN-1);
    } else {
	ix = posn / s->blk_len;
	s->wpos = posn % s->blk_len;
    }
    s->wptr = posn;
    s->wblk = &s->blk_ptrs[ix];

    if (!s->wpos) {
	s->wpos = s->blk_len;
	s->wblk--;
    }

    saa_wbytes(s, data, len);
}

void saa_fpwrite(struct SAA *s, FILE * fp)
{
    const char *data;
    size_t len;

    saa_rewind(s);
    while (len = s->datalen, (data = saa_rbytes(s, &len)) != NULL)
        fwrite(data, 1, len, fp);
}

void saa_write8(struct SAA *s, uint8_t v)
{
    saa_wbytes(s, &v, 1);
}

#ifdef WORDS_LITTEENDIAN

void saa_write16(struct SAA *s, uint16_t v)
{
    saa_wbytes(s, &v, 2);
}

void saa_write32(struct SAA *s, uint32_t v)
{
    saa_wbytes(s, &v, 4);
}

void saa_write64(struct SAA *s, uint64_t v)
{
    saa_wbytes(s, &v, 8);
}

#else /* not WORDS_LITTLEENDIAN */

void saa_write16(struct SAA *s, uint16_t v)
{
    uint8_t b[2];

    b[0] = v;
    b[1] = v >> 8;
    saa_wbytes(s, b, 2);
}

void saa_write32(struct SAA *s, uint32_t v)
{
    uint8_t b[4];

    b[0] = v;
    b[1] = v >> 8;
    b[2] = v >> 16;
    b[3] = v >> 24;
    saa_wbytes(s, b, 4);
}

void saa_write64(struct SAA *s, uint64_t v)
{
    uint8_t b[8];

    b[0] = v;
    b[1] = v >> 8;
    b[2] = v >> 16;
    b[3] = v >> 24;
    b[4] = v >> 32;
    b[5] = v >> 40;
    b[6] = v >> 48;
    b[7] = v >> 56;
    saa_wbytes(s, b, 8);
}

#endif	/* WORDS_LITTLEENDIAN */

/* write unsigned LEB128 value to SAA */
void saa_wleb128u(struct SAA *psaa, int value)
{
  char temp[64], *ptemp;
  uint8_t byte;
  int len;

  ptemp = temp;
  len = 0;
  do
  {
     byte = value & 127;
     value >>= 7;
     if (value != 0) /* more bytes to come */
        byte |= 0x80;
     *ptemp = byte;
     ptemp++;
     len++;
  } while (value != 0);
  saa_wbytes(psaa, temp, len);
}

/* write signed LEB128 value to SAA */
void saa_wleb128s(struct SAA *psaa, int value)
{
  char temp[64], *ptemp;
  uint8_t byte;
  bool more, negative;
  int size, len;

  ptemp = temp;
  more = 1;
  negative = (value < 0);
  size = sizeof(int) * 8;
  len = 0;
  while(more)
  {
    byte = value & 0x7f;
    value >>= 7;
    if (negative)
     /* sign extend */
     value |= - (1 <<(size - 7));
    /* sign bit of byte is second high order bit (0x40) */
    if ((value == 0 && ! (byte & 0x40)) ||
       ((value == -1) && (byte & 0x40)))
       more = 0;
    else
      byte |= 0x80;
    *ptemp = byte;
    ptemp++;
    len++;
  }
  saa_wbytes(psaa, temp, len);
}