// give some data, advancing position but not forgetting yet.
static mpg_ssize_t bc_give( bufferchain_t *bc, byte *out, mpg_ssize_t size )
{
buffy_t *b = bc->first;
mpg_ssize_t gotcount = 0;
mpg_ssize_t offset = 0;
if( bc->size - bc->pos < size )
return bc_need_more( bc );
// find the current buffer
while( b != NULL && ( offset + b->size ) <= bc->pos )
{
offset += b->size;
b = b->next;
}
// now start copying from there
while( gotcount < size && ( b != NULL ))
{
mpg_ssize_t loff = bc->pos - offset;
mpg_ssize_t chunk = size - gotcount; // amount of bytes to get from here...
if( chunk > b->size - loff )
chunk = b->size - loff;
memcpy( out + gotcount, b->data + loff, chunk );
gotcount += chunk;
bc->pos += chunk;
offset += b->size;
b = b->next;
}
return gotcount;
}
/* Skip some bytes and return the new position.
The buffers are still there, just the read pointer is moved! */
static ssize_t bc_skip(struct bufferchain *bc, ssize_t count)
{
if(count >= 0)
{
if(bc->size - bc->pos < count) return bc_need_more(bc);
else return bc->pos += count;
}
else return READER_ERROR;
}
// skip some bytes and return the new position.
// the buffers are still there, just the read pointer is moved!
static mpg_ssize_t bc_skip( bufferchain_t *bc, mpg_ssize_t count )
{
if( count >= 0 )
{
if( bc->size - bc->pos < count )
return bc_need_more( bc );
return bc->pos += count;
}
return MPG123_ERR;
}
/* Give some data, advancing position but not forgetting yet. */
static ssize_t bc_give(struct bufferchain *bc, unsigned char *out, ssize_t size)
{
struct buffy *b = bc->first;
ssize_t gotcount = 0;
ssize_t offset = 0;
if(bc->size - bc->pos < size) return bc_need_more(bc);
/* find the current buffer */
while(b != NULL && (offset + b->size) <= bc->pos)
{
offset += b->size;
b = b->next;
}
/* now start copying from there */
while(gotcount < size && (b != NULL))
{
ssize_t loff = bc->pos - offset;
ssize_t chunk = size - gotcount; /* amount of bytes to get from here... */
if(chunk > b->size - loff) chunk = b->size - loff;
#ifdef EXTRA_DEBUG
debug3("copying %liB from %p+%li",(long)chunk, b->data, (long)loff);
*/
#endif
memcpy(out+gotcount, b->data+loff, chunk);
gotcount += chunk;
bc->pos += chunk;
offset += b->size;
b = b->next;
}
#ifdef EXTRA_DEBUG
debug2("got %li bytes, pos advanced to %li", (long)gotcount, (long)bc->pos);
#endif
return gotcount;
}
