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     pa_memblock_stat *memblock_stat;
  39 };
  40
  41 pa_mcalign *pa_mcalign_new(size_t base, pa_memblock_stat *s) {
  42     pa_mcalign *m;
  43     assert(base);
  44
  45     m = pa_xnew(pa_mcalign, 1);
  46
  47     m->base = base;
  48     pa_memchunk_reset(&m->leftover);
  49     pa_memchunk_reset(&m->current);
  50     m->memblock_stat = s;
  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->memblock_stat, 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 }