code.delx.au - pulseaudio/blob - src/pulsecore/mcalign.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2004-2006 Lennart Poettering
   7
   8   PulseAudio is free software; you can redistribute it and/or modify
   9   it under the terms of the GNU Lesser General Public License as
  10   published by the Free Software Foundation; either version 2.1 of the
  11   License, or (at your option) any later version.
  12
  13   PulseAudio is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public
  19   License along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <assert.h>
  31 #include <string.h>
  32
  33 #include <pulse/xmalloc.h>
  34
  35 #include "mcalign.h"
  36
  37 struct pa_mcalign {
  38     size_t base;
  39     pa_memchunk leftover, current;
  40 };
  41
  42 pa_mcalign *pa_mcalign_new(size_t base) {
  43     pa_mcalign *m;
  44     assert(base);
  45
  46     m = pa_xnew(pa_mcalign, 1);
  47
  48     m->base = base;
  49     pa_memchunk_reset(&m->leftover);
  50     pa_memchunk_reset(&m->current);
  51
  52     return m;
  53 }
  54
  55 void pa_mcalign_free(pa_mcalign *m) {
  56     assert(m);
  57
  58     if (m->leftover.memblock)
  59         pa_memblock_unref(m->leftover.memblock);
  60
  61     if (m->current.memblock)
  62         pa_memblock_unref(m->current.memblock);
  63
  64     pa_xfree(m);
  65 }
  66
  67 void pa_mcalign_push(pa_mcalign *m, const pa_memchunk *c) {
  68     assert(m);
  69     assert(c);
  70
  71     assert(c->memblock);
  72     assert(c->length > 0);
  73
  74     assert(!m->current.memblock);
  75
  76     /* Append to the leftover memory block */
  77     if (m->leftover.memblock) {
  78
  79         /* Try to merge */
  80         if (m->leftover.memblock == c->memblock &&
  81             m->leftover.index + m->leftover.length == c->index) {
  82
  83             /* Merge */
  84             m->leftover.length += c->length;
  85
  86             /* If the new chunk is larger than m->base, move it to current */
  87             if (m->leftover.length >= m->base) {
  88                 m->current = m->leftover;
  89                 pa_memchunk_reset(&m->leftover);
  90             }
  91
  92         } else {
  93             size_t l;
  94
  95             /* We have to copy */
  96             assert(m->leftover.length < m->base);
  97             l = m->base - m->leftover.length;
  98
  99             if (l > c->length)
 100                 l = c->length;
 101
 102             /* Can we use the current block? */
 103             pa_memchunk_make_writable(&m->leftover, m->base);
 104
 105             memcpy((uint8_t*) m->leftover.memblock->data + m->leftover.index + m->leftover.length, (uint8_t*) c->memblock->data + c->index, l);
 106             m->leftover.length += l;
 107
 108             assert(m->leftover.length <= m->base && m->leftover.length <= m->leftover.memblock->length);
 109
 110             if (c->length > l) {
 111                 /* Save the remainder of the memory block */
 112                 m->current = *c;
 113                 m->current.index += l;
 114                 m->current.length -= l;
 115                 pa_memblock_ref(m->current.memblock);
 116             }
 117         }
 118     } else {
 119         /* Nothing to merge or copy, just store it */
 120
 121         if (c->length >= m->base)
 122             m->current = *c;
 123         else
 124             m->leftover = *c;
 125
 126         pa_memblock_ref(c->memblock);
 127     }
 128 }
 129
 130 int pa_mcalign_pop(pa_mcalign *m, pa_memchunk *c) {
 131     assert(m);
 132     assert(c);
 133
 134     /* First test if there's a leftover memory block available */
 135     if (m->leftover.memblock) {
 136         assert(m->leftover.length > 0 && m->leftover.length <= m->base);
 137
 138         /* The leftover memory block is not yet complete */
 139         if (m->leftover.length < m->base)
 140             return -1;
 141
 142         /* Return the leftover memory block */
 143         *c = m->leftover;
 144         pa_memchunk_reset(&m->leftover);
 145
 146         /* If the current memblock is too small move it the leftover */
 147         if (m->current.memblock && m->current.length < m->base) {
 148             m->leftover = m->current;
 149             pa_memchunk_reset(&m->current);
 150         }
 151
 152         return 0;
 153     }
 154
 155     /* Now let's see if there is other data available */
 156     if (m->current.memblock) {
 157         size_t l;
 158         assert(m->current.length >= m->base);
 159
 160         /* The length of the returned memory block */
 161         l = m->current.length;
 162         l /= m->base;
 163         l *= m->base;
 164         assert(l > 0);
 165
 166         /* Prepare the returned block */
 167         *c = m->current;
 168         pa_memblock_ref(c->memblock);
 169         c->length = l;
 170
 171         /* Drop that from the current memory block */
 172         assert(l <= m->current.length);
 173         m->current.index += l;
 174         m->current.length -= l;
 175
 176         /* In case the whole block was dropped ... */
 177         if (m->current.length == 0)
 178             pa_memblock_unref(m->current.memblock);
 179         else {
 180             /* Move the raimainder to leftover */
 181             assert(m->current.length < m->base && !m->leftover.memblock);
 182
 183             m->leftover = m->current;
 184         }
 185
 186         pa_memchunk_reset(&m->current);
 187
 188         return 0;
 189     }
 190
 191     /* There's simply nothing */
 192     return -1;
 193
 194 }
 195
 196 size_t pa_mcalign_csize(pa_mcalign *m, size_t l) {
 197     assert(m);
 198     assert(l > 0);
 199
 200     assert(!m->current.memblock);
 201
 202     if (m->leftover.memblock)
 203         l += m->leftover.length;
 204
 205     return (l/m->base)*m->base;
 206 }