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

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