/* Addressable FIFO buffer    Copyright (c) 2007 robs@users.sourceforge.net * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or (at * your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA */ #ifndef fifo_included#define fifo_included #include <string.h> #ifndef FIFO_SIZE_T#define FIFO_SIZE_T size_t#endif typedef struct {  char * data;  size_t allocation;   /* Number of bytes allocated for data. */  size_t item_size;    /* Size of each item in data */  size_t begin;        /* Offset of the first byte to read. */  size_t end;          /* 1 + Offset of the last byte byte to read. */} fifo_t; #define FIFO_MIN 0x4000 UNUSED static void fifo_clear(fifo_t * f){  f->end = f->begin = 0;} UNUSED static void * fifo_reserve(fifo_t * f, FIFO_SIZE_T n){  n *= f->item_size;   if (f->begin == f->end)    fifo_clear(f);   while (1) {    if (f->end + n <= f->allocation) {      void *p = f->data + f->end;       f->end += n;      return p;    }    if (f->begin > FIFO_MIN) {      memmove(f->data, f->data + f->begin, f->end - f->begin);      f->end -= f->begin;      f->begin = 0;      continue;    }    f->allocation += n;    f->data = lsx_realloc(f->data, f->allocation);  }} UNUSED static void * fifo_write(fifo_t * f, FIFO_SIZE_T n, void const * data){  void * s = fifo_reserve(f, n);  if (data)    memcpy(s, data, n * f->item_size);  return s;} UNUSED static void fifo_trim_to(fifo_t * f, FIFO_SIZE_T n){  n *= f->item_size;  f->end = f->begin + n;} UNUSED static void fifo_trim_by(fifo_t * f, FIFO_SIZE_T n){  n *= f->item_size;  f->end -= n;} UNUSED static FIFO_SIZE_T fifo_occupancy(fifo_t * f){  return (f->end - f->begin) / f->item_size;} UNUSED static void * fifo_read(fifo_t * f, FIFO_SIZE_T n, void * data){  char * ret = f->data + f->begin;  n *= f->item_size;  if (n > (FIFO_SIZE_T)(f->end - f->begin))    return NULL;  if (data)    memcpy(data, ret, (size_t)n);  f->begin += n;  return ret;} #define fifo_read_ptr(f) fifo_read(f, (FIFO_SIZE_T)0, NULL) UNUSED static void fifo_delete(fifo_t * f){  free(f->data);} UNUSED static void fifo_create(fifo_t * f, FIFO_SIZE_T item_size){  f->item_size = item_size;  f->allocation = FIFO_MIN;  f->data = lsx_malloc(f->allocation);  fifo_clear(f);} #endif