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   unsigned flags;         /* bitmask of PIPE_RESOURCE_FLAG_x */
47   boolean zero_buffer_memory; /* If the buffer contents should be zeroed. */
48
49   struct pipe_resource *buffer;   /* The buffer we suballocate from. */
50   unsigned offset; /* Aligned offset pointing at the first unused byte. */
51};
52
53
54/**
55 * Create a suballocator.
56 *
57 * \param flags               bitmask of PIPE_RESOURCE_FLAG_x
58 * \param zero_buffer_memory  determines whether the buffer contents should be
59 *                            cleared to 0 after the allocation.
60 *
61 */
62struct u_suballocator *
63u_suballocator_create(struct pipe_context *pipe, unsigned size, unsigned bind,
64                      enum pipe_resource_usage usage, unsigned flags,
65		      boolean zero_buffer_memory)
66{
67   struct u_suballocator *allocator = CALLOC_STRUCT(u_suballocator);
68   if (!allocator)
69      return NULL;
70
71   allocator->pipe = pipe;
72   allocator->size = size;
73   allocator->bind = bind;
74   allocator->usage = usage;
75   allocator->flags = flags;
76   allocator->zero_buffer_memory = zero_buffer_memory;
77   return allocator;
78}
79
80void
81u_suballocator_destroy(struct u_suballocator *allocator)
82{
83   pipe_resource_reference(&allocator->buffer, NULL);
84   FREE(allocator);
85}
86
87void
88u_suballocator_alloc(struct u_suballocator *allocator, unsigned size,
89                     unsigned alignment, unsigned *out_offset,
90                     struct pipe_resource **outbuf)
91{
92   allocator->offset = align(allocator->offset, alignment);
93
94   /* Don't allow allocations larger than the buffer size. */
95   if (size > allocator->size)
96      goto fail;
97
98   /* Make sure we have enough space in the buffer. */
99   if (!allocator->buffer ||
100       allocator->offset + size > allocator->size) {
101      /* Allocate a new buffer. */
102      pipe_resource_reference(&allocator->buffer, NULL);
103      allocator->offset = 0;
104
105      struct pipe_resource templ;
106      memset(&templ, 0, sizeof(templ));
107      templ.target = PIPE_BUFFER;
108      templ.format = PIPE_FORMAT_R8_UNORM;
109      templ.bind = allocator->bind;
110      templ.usage = allocator->usage;
111      templ.flags = allocator->flags;
112      templ.width0 = allocator->size;
113      templ.height0 = 1;
114      templ.depth0 = 1;
115      templ.array_size = 1;
116
117      struct pipe_screen *screen = allocator->pipe->screen;
118      allocator->buffer = screen->resource_create(screen, &templ);
119      if (!allocator->buffer)
120         goto fail;
121
122      /* Clear the memory if needed. */
123      if (allocator->zero_buffer_memory) {
124         struct pipe_context *pipe = allocator->pipe;
125
126         if (pipe->clear_buffer) {
127            unsigned clear_value = 0;
128
129            pipe->clear_buffer(pipe, allocator->buffer, 0, allocator->size,
130                               &clear_value, 4);
131         } else {
132            struct pipe_transfer *transfer = NULL;
133            void *ptr = pipe_buffer_map(pipe, allocator->buffer,
134                                        PIPE_TRANSFER_WRITE, &transfer);
135            memset(ptr, 0, allocator->size);
136            pipe_buffer_unmap(pipe, transfer);
137         }
138      }
139   }
140
141   assert(allocator->offset % alignment == 0);
142   assert(allocator->offset < allocator->buffer->width0);
143   assert(allocator->offset + size <= allocator->buffer->width0);
144
145   /* Return the buffer. */
146   *out_offset = allocator->offset;
147   pipe_resource_reference(outbuf, allocator->buffer);
148
149   allocator->offset += size;
150   return;
151
152fail:
153   pipe_resource_reference(outbuf, NULL);
154}
155