1/***
2  This file is part of PulseAudio.
3
4  Copyright 2004-2006 Lennart Poettering
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, see <http://www.gnu.org/licenses/>.
18***/
19
20#ifdef HAVE_CONFIG_H
21#include <config.h>
22#endif
23
24#include <stdio.h>
25#include <stdlib.h>
26#include <string.h>
27
28#include <pulse/xmalloc.h>
29#include <pulsecore/macro.h>
30
31#include "mcalign.h"
32
33struct pa_mcalign {
34    size_t base;
35    pa_memchunk leftover, current;
36};
37
38pa_mcalign *pa_mcalign_new(size_t base) {
39    pa_mcalign *m;
40    pa_assert(base);
41
42    m = pa_xnew(pa_mcalign, 1);
43
44    m->base = base;
45    pa_memchunk_reset(&m->leftover);
46    pa_memchunk_reset(&m->current);
47
48    return m;
49}
50
51void pa_mcalign_free(pa_mcalign *m) {
52    pa_assert(m);
53
54    if (m->leftover.memblock)
55        pa_memblock_unref(m->leftover.memblock);
56
57    if (m->current.memblock)
58        pa_memblock_unref(m->current.memblock);
59
60    pa_xfree(m);
61}
62
63void pa_mcalign_push(pa_mcalign *m, const pa_memchunk *c) {
64    pa_assert(m);
65    pa_assert(c);
66
67    pa_assert(c->memblock);
68    pa_assert(c->length > 0);
69
70    pa_assert(!m->current.memblock);
71
72    /* Append to the leftover memory block */
73    if (m->leftover.memblock) {
74
75        /* Try to merge */
76        if (m->leftover.memblock == c->memblock &&
77            m->leftover.index + m->leftover.length == c->index) {
78
79            /* Merge */
80            m->leftover.length += c->length;
81
82            /* If the new chunk is larger than m->base, move it to current */
83            if (m->leftover.length >= m->base) {
84                m->current = m->leftover;
85                pa_memchunk_reset(&m->leftover);
86            }
87
88        } else {
89            size_t l;
90            void *lo_data, *m_data;
91
92            /* We have to copy */
93            pa_assert(m->leftover.length < m->base);
94            l = m->base - m->leftover.length;
95
96            if (l > c->length)
97                l = c->length;
98
99            /* Can we use the current block? */
100            pa_memchunk_make_writable(&m->leftover, m->base);
101
102            lo_data = pa_memblock_acquire(m->leftover.memblock);
103            m_data = pa_memblock_acquire(c->memblock);
104            memcpy((uint8_t*) lo_data + m->leftover.index + m->leftover.length, (uint8_t*) m_data + c->index, l);
105            pa_memblock_release(m->leftover.memblock);
106            pa_memblock_release(c->memblock);
107            m->leftover.length += l;
108
109            pa_assert(m->leftover.length <= m->base);
110            pa_assert(m->leftover.length <= pa_memblock_get_length(m->leftover.memblock));
111
112            if (c->length > l) {
113                /* Save the remainder of the memory block */
114                m->current = *c;
115                m->current.index += l;
116                m->current.length -= l;
117                pa_memblock_ref(m->current.memblock);
118            }
119        }
120    } else {
121        /* Nothing to merge or copy, just store it */
122
123        if (c->length >= m->base)
124            m->current = *c;
125        else
126            m->leftover = *c;
127
128        pa_memblock_ref(c->memblock);
129    }
130}
131
132int pa_mcalign_pop(pa_mcalign *m, pa_memchunk *c) {
133    pa_assert(m);
134    pa_assert(c);
135
136    /* First test if there's a leftover memory block available */
137    if (m->leftover.memblock) {
138        pa_assert(m->leftover.length > 0);
139        pa_assert(m->leftover.length <= m->base);
140
141        /* The leftover memory block is not yet complete */
142        if (m->leftover.length < m->base)
143            return -1;
144
145        /* Return the leftover memory block */
146        *c = m->leftover;
147        pa_memchunk_reset(&m->leftover);
148
149        /* If the current memblock is too small move it the leftover */
150        if (m->current.memblock && m->current.length < m->base) {
151            m->leftover = m->current;
152            pa_memchunk_reset(&m->current);
153        }
154
155        return 0;
156    }
157
158    /* Now let's see if there is other data available */
159    if (m->current.memblock) {
160        size_t l;
161        pa_assert(m->current.length >= m->base);
162
163        /* The length of the returned memory block */
164        l = m->current.length;
165        l /= m->base;
166        l *= m->base;
167        pa_assert(l > 0);
168
169        /* Prepare the returned block */
170        *c = m->current;
171        pa_memblock_ref(c->memblock);
172        c->length = l;
173
174        /* Drop that from the current memory block */
175        pa_assert(l <= m->current.length);
176        m->current.index += l;
177        m->current.length -= l;
178
179        /* In case the whole block was dropped ... */
180        if (m->current.length == 0)
181            pa_memblock_unref(m->current.memblock);
182        else {
183            /* Move the remainder to leftover */
184            pa_assert(m->current.length < m->base && !m->leftover.memblock);
185
186            m->leftover = m->current;
187        }
188
189        pa_memchunk_reset(&m->current);
190
191        return 0;
192    }
193
194    /* There's simply nothing */
195    return -1;
196}
197
198size_t pa_mcalign_csize(pa_mcalign *m, size_t l) {
199    pa_assert(m);
200    pa_assert(l > 0);
201
202    pa_assert(!m->current.memblock);
203
204    if (m->leftover.memblock)
205        l += m->leftover.length;
206
207    return (l/m->base)*m->base;
208}
209
210void pa_mcalign_flush(pa_mcalign *m) {
211    pa_memchunk chunk;
212    pa_assert(m);
213
214    while (pa_mcalign_pop(m, &chunk) >= 0)
215        pa_memblock_unref(chunk.memblock);
216}
217