nanocoat/lib/base/seekableMemory.c

   1 /* -*- Mode: C; indent-tabs-mode: t; tab-width: 4 -*-
   2 // ---------------------------------------------------------------------------
   3 // SquirrelJME
   4 //     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
   5 // ---------------------------------------------------------------------------
   6 // SquirrelJME is under the Mozilla Public License Version 2.0.
   7 // See license.mkd for licensing and copyright information.
   8 // -------------------------------------------------------------------------*/
   9
  10 #include <string.h>
  11
  12 #include "sjme/seekable.h"
  13 #include "sjme/debug.h"
  14 #include "sjme/closeable.h"
  15
  16 /**
  17  * Memory initialization info.
  18  *
  19  * @since 2024/08/12
  20  */
  21 typedef struct sjme_seekable_memoryInitData
  22 {
  23         /** The base pointer. */
  24         sjme_pointer base;
  25
  26         /** The memory region size. */
  27         sjme_jint length;
  28 } sjme_seekable_memoryInitData;
  29
  30 static sjme_errorCode sjme_seekable_memoryClose(
  31         sjme_attrInNotNull sjme_seekable inSeekable,
  32         sjme_attrInNotNull sjme_seekable_implState* inImplState)
  33 {
  34         if (inSeekable == NULL || inImplState == NULL)
  35                 return SJME_ERROR_NULL_ARGUMENTS;
  36
  37         /* Nothing needs to be done for memory regions. */
  38         return SJME_ERROR_NONE;
  39 }
  40
  41 static sjme_errorCode sjme_seekable_memoryInit(
  42         sjme_attrInNotNull sjme_seekable inSeekable,
  43         sjme_attrInNotNull sjme_seekable_implState* inImplState,
  44         sjme_attrInNullable sjme_pointer data)
  45 {
  46         sjme_seekable_memoryInitData* init;
  47
  48         if (inSeekable == NULL || inImplState == NULL || data == NULL)
  49                 return SJME_ERROR_NULL_ARGUMENTS;
  50
  51         /* Recover init data. */
  52         init = data;
  53
  54         /* Set parameters. */
  55         inImplState->handle = init->base;
  56         inImplState->length = init->length;
  57
  58         /* Success! */
  59         return SJME_ERROR_NONE;
  60 }
  61
  62 static sjme_errorCode sjme_seekable_memoryRead(
  63         sjme_attrInNotNull sjme_seekable inSeekable,
  64         sjme_attrInNotNull sjme_seekable_implState* inImplState,
  65         sjme_attrOutNotNullBuf(length) sjme_buffer outBuf,
  66         sjme_attrInPositive sjme_jint base,
  67         sjme_attrInPositiveNonZero sjme_jint length)
  68 {
  69         if (inSeekable == NULL || inImplState == NULL || outBuf == NULL)
  70                 return SJME_ERROR_NULL_ARGUMENTS;
  71
  72         if (base < 0 || length < 0 || (base + length) < 0 ||
  73                 (base + length) > inImplState->length)
  74                 return SJME_ERROR_INDEX_OUT_OF_BOUNDS;
  75
  76         /* Direct memory copy. */
  77         memmove(outBuf, SJME_POINTER_OFFSET(inImplState->handle, base),
  78                 length);
  79
  80         /* Success! */
  81         return SJME_ERROR_NONE;
  82 }
  83
  84 static sjme_errorCode sjme_seekable_memorySize(
  85         sjme_attrInNotNull sjme_seekable inSeekable,
  86         sjme_attrInNotNull sjme_seekable_implState* inImplState,
  87         sjme_attrOutNotNull sjme_jint* outSize)
  88 {
  89         if (inSeekable == NULL || inImplState == NULL || outSize == NULL)
  90                 return SJME_ERROR_NULL_ARGUMENTS;
  91
  92         /* Just copy from the implementation state. */
  93         *outSize = inImplState->length;
  94         return SJME_ERROR_NONE;
  95 }
  96
  97 static const sjme_seekable_functions sjme_seekable_memoryFunctions =
  98 {
  99         .close = sjme_seekable_memoryClose,
 100         .init = sjme_seekable_memoryInit,
 101         .read = sjme_seekable_memoryRead,
 102         .size = sjme_seekable_memorySize,
 103 };
 104
 105 sjme_errorCode sjme_seekable_openMemory(
 106         sjme_attrInNotNull sjme_alloc_pool* inPool,
 107         sjme_attrOutNotNull sjme_seekable* outSeekable,
 108         sjme_attrInNotNull sjme_pointer base,
 109         sjme_attrInPositive sjme_jint length)
 110 {
 111         uintptr_t rawBase;
 112         sjme_seekable_memoryInitData init;
 113
 114         if (inPool == NULL || outSeekable == NULL || base == NULL)
 115                 return SJME_ERROR_NULL_ARGUMENTS;
 116
 117         /* Check for overflow. */
 118         rawBase = (uintptr_t)base;
 119         if (length < 0 || (rawBase + length) < rawBase)
 120                 return SJME_ERROR_INDEX_OUT_OF_BOUNDS;
 121
 122         /* Setup initialization data. */
 123         memset(&init, 0, sizeof(init));
 124         init.base = base;
 125         init.length = length;
 126
 127         /* Forward initialize. */
 128         return sjme_seekable_open(inPool, outSeekable,
 129                 &sjme_seekable_memoryFunctions,
 130                 &init, NULL);
 131 }