src/gallium/auxiliary/util/u_suballoc.c

   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
  40 struct u_suballocator {
  41    struct pipe_context *pipe;
  42
  43    unsigned size;          /* Size of the whole buffer, in bytes. */
  44    unsigned alignment;     /* Alignment of each sub-allocation. */
  45    unsigned bind;          /* Bitmask of PIPE_BIND_* flags. */
  46    unsigned usage;         /* One of PIPE_USAGE_* flags. */
  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  * \p zero_buffer_memory determines whether the buffer contents should be
  58  * cleared to 0 after the allocation.
  59  */
  60 struct u_suballocator *
  61 u_suballocator_create(struct pipe_context *pipe, unsigned size,
  62                       unsigned alignment, unsigned bind, unsigned usage,
  63                       boolean zero_buffer_memory)
  64 {
  65    struct u_suballocator *allocator = CALLOC_STRUCT(u_suballocator);
  66    if (!allocator)
  67       return NULL;
  68
  69    allocator->pipe = pipe;
  70    allocator->size = align(size, alignment);
  71    allocator->alignment = alignment;
  72    allocator->bind = bind;
  73    allocator->usage = usage;
  74    allocator->zero_buffer_memory = zero_buffer_memory;
  75    return allocator;
  76 }
  77
  78 void
  79 u_suballocator_destroy(struct u_suballocator *allocator)
  80 {
  81    pipe_resource_reference(&allocator->buffer, NULL);
  82    FREE(allocator);
  83 }
  84
  85 void
  86 u_suballocator_alloc(struct u_suballocator *allocator, unsigned size,
  87                      unsigned *out_offset, struct pipe_resource **outbuf)
  88 {
  89    unsigned alloc_size = align(size, allocator->alignment);
  90
  91    /* Don't allow allocations larger than the buffer size. */
  92    if (alloc_size > allocator->size)
  93       goto fail;
  94
  95    /* Make sure we have enough space in the buffer. */
  96    if (!allocator->buffer ||
  97        allocator->offset + alloc_size > allocator->size) {
  98       /* Allocate a new buffer. */
  99       pipe_resource_reference(&allocator->buffer, NULL);
 100       allocator->offset = 0;
 101       allocator->buffer =
 102          pipe_buffer_create(allocator->pipe->screen, allocator->bind,
 103                             allocator->usage, allocator->size);
 104       if (!allocator->buffer)
 105          goto fail;
 106
 107       /* Clear the memory if needed. */
 108       if (allocator->zero_buffer_memory) {
 109          struct pipe_transfer *transfer = NULL;
 110          void *ptr;
 111
 112          ptr = pipe_buffer_map(allocator->pipe, allocator->buffer,
 113                                PIPE_TRANSFER_WRITE, &transfer);
 114          memset(ptr, 0, allocator->size);
 115          pipe_buffer_unmap(allocator->pipe, transfer);
 116       }
 117    }
 118
 119    assert(allocator->offset % allocator->alignment == 0);
 120    assert(allocator->offset < allocator->buffer->width0);
 121    assert(allocator->offset + alloc_size <= allocator->buffer->width0);
 122
 123    /* Return the buffer. */
 124    *out_offset = allocator->offset;
 125    pipe_resource_reference(outbuf, allocator->buffer);
 126
 127    allocator->offset += alloc_size;
 128    return;
 129
 130 fail:
 131    pipe_resource_reference(outbuf, NULL);
 132 }