ref: 671f0330ac07dac46c5800005c2ef9590dfdf43e
dir: /src/fifo.h/
/* 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