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  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. }
  133.