1/**************************************************************************
2 *
3 * Copyright 2009 VMware, Inc.
4 * Copyright 2012 Marek Olšák <maraeo@gmail.com>
5 * All Rights Reserved.
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the
9 * "Software"), to deal in the Software without restriction, including
10 * without limitation the rights to use, copy, modify, merge, publish,
11 * distribute, sub license, and/or sell copies of the Software, and to
12 * permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice (including the
16 * next paragraph) shall be included in all copies or substantial portions
17 * of the Software.
18 *
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
22 * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
23 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
24 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
25 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 *
27 **************************************************************************/
28
29/* A simple allocator that suballocates memory from a large buffer. */
30
31#include "pipe/p_defines.h"
32#include "util/u_inlines.h"
33#include "pipe/p_context.h"
34#include "util/u_memory.h"
35#include "util/u_math.h"
36
37#include "u_suballoc.h"
38
39
40struct u_suballocator {
41   struct pipe_context *pipe;
42
43   unsigned size;          /* Size of the whole buffer, in bytes. */
44   unsigned bind;          /* Bitmask of PIPE_BIND_* flags. */
45   enum pipe_resource_usage usage;
46   boolean zero_buffer_memory; /* If the buffer contents should be zeroed. */
47
48   struct pipe_resource *buffer;   /* The buffer we suballocate from. */
49   unsigned offset; /* Aligned offset pointing at the first unused byte. */
50};
51
52
53/**
54 * Create a suballocator.
55 *
56 * \p zero_buffer_memory determines whether the buffer contents should be
57 * cleared to 0 after the allocation.
58 */
59struct u_suballocator *
60u_suballocator_create(struct pipe_context *pipe, unsigned size, unsigned bind,
61                      enum pipe_resource_usage usage,
62		      boolean zero_buffer_memory)
63{
64   struct u_suballocator *allocator = CALLOC_STRUCT(u_suballocator);
65   if (!allocator)
66      return NULL;
67
68   allocator->pipe = pipe;
69   allocator->size = size;
70   allocator->bind = bind;
71   allocator->usage = usage;
72   allocator->zero_buffer_memory = zero_buffer_memory;
73   return allocator;
74}
75
76void
77u_suballocator_destroy(struct u_suballocator *allocator)
78{
79   pipe_resource_reference(&allocator->buffer, NULL);
80   FREE(allocator);
81}
82
83void
84u_suballocator_alloc(struct u_suballocator *allocator, unsigned size,
85                     unsigned alignment, unsigned *out_offset,
86                     struct pipe_resource **outbuf)
87{
88   allocator->offset = align(allocator->offset, alignment);
89
90   /* Don't allow allocations larger than the buffer size. */
91   if (size > allocator->size)
92      goto fail;
93
94   /* Make sure we have enough space in the buffer. */
95   if (!allocator->buffer ||
96       allocator->offset + size > allocator->size) {
97      /* Allocate a new buffer. */
98      pipe_resource_reference(&allocator->buffer, NULL);
99      allocator->offset = 0;
100      allocator->buffer =
101         pipe_buffer_create(allocator->pipe->screen, allocator->bind,
102                            allocator->usage, allocator->size);
103      if (!allocator->buffer)
104         goto fail;
105
106      /* Clear the memory if needed. */
107      if (allocator->zero_buffer_memory) {
108         struct pipe_transfer *transfer = NULL;
109         void *ptr;
110
111         ptr = pipe_buffer_map(allocator->pipe, allocator->buffer,
112			       PIPE_TRANSFER_WRITE, &transfer);
113         memset(ptr, 0, allocator->size);
114         pipe_buffer_unmap(allocator->pipe, transfer);
115      }
116   }
117
118   assert(allocator->offset % alignment == 0);
119   assert(allocator->offset < allocator->buffer->width0);
120   assert(allocator->offset + size <= allocator->buffer->width0);
121
122   /* Return the buffer. */
123   *out_offset = allocator->offset;
124   pipe_resource_reference(outbuf, allocator->buffer);
125
126   allocator->offset += size;
127   return;
128
129fail:
130   pipe_resource_reference(outbuf, NULL);
131}
132