icuSources/common/udatamem.c

   1 /*
   2 ******************************************************************************
   3 *
   4 *   Copyright (C) 1999-2010, International Business Machines
   5 *   Corporation and others.  All Rights Reserved.
   6 *
   7 ******************************************************************************/
   8
   9
  10 /*----------------------------------------------------------------------------------
  11  *
  12  *  UDataMemory     A class-like struct that serves as a handle to a piece of memory
  13  *                  that contains some ICU data (resource, converters, whatever.)
  14  *
  15  *                  When an application opens ICU data (with udata_open, for example,
  16  *                  a UDataMemory * is returned.
  17  *
  18  *----------------------------------------------------------------------------------*/
  19
  20 #include "unicode/utypes.h"
  21 #include "cmemory.h"
  22 #include "unicode/udata.h"
  23
  24 #include "udatamem.h"
  25
  26 U_CFUNC void UDataMemory_init(UDataMemory *This) {
  27     uprv_memset(This, 0, sizeof(UDataMemory));
  28     This->length=-1;
  29 }
  30
  31
  32 U_CFUNC void UDatamemory_assign(UDataMemory *dest, UDataMemory *source) {
  33     /* UDataMemory Assignment.  Destination UDataMemory must be initialized first.  */
  34     UBool mallocedFlag = dest->heapAllocated;
  35     uprv_memcpy(dest, source, sizeof(UDataMemory));
  36     dest->heapAllocated = mallocedFlag;
  37 }
  38
  39 U_CFUNC UDataMemory *UDataMemory_createNewInstance(UErrorCode *pErr) {
  40     UDataMemory *This;
  41
  42     if (U_FAILURE(*pErr)) {
  43         return NULL;
  44     }
  45     This = uprv_malloc(sizeof(UDataMemory));
  46     if (This == NULL) {
  47         *pErr = U_MEMORY_ALLOCATION_ERROR; }
  48     else {
  49         UDataMemory_init(This);
  50         This->heapAllocated = TRUE;
  51     }
  52     return This;
  53 }
  54
  55
  56 U_CFUNC const DataHeader *
  57 UDataMemory_normalizeDataPointer(const void *p) {
  58     /* allow the data to be optionally prepended with an alignment-forcing double value */
  59     const DataHeader *pdh = (const DataHeader *)p;
  60     if(pdh==NULL || (pdh->dataHeader.magic1==0xda && pdh->dataHeader.magic2==0x27)) {
  61         return pdh;
  62     } else {
  63 #ifdef OS400
  64         /*
  65         TODO: Fix this once the compiler implements this feature. Keep in sync with genccode.c
  66
  67         This is here because this platform can't currently put
  68         const data into the read-only pages of an object or
  69         shared library (service program). Only strings are allowed in read-only
  70         pages, so we use char * strings to store the data.
  71
  72         In order to prevent the beginning of the data from ever matching the
  73         magic numbers we must skip the initial double.
  74         [grhoten 4/24/2003]
  75         */
  76         return (const DataHeader *)*((const void **)p+1);
  77 #else
  78         return (const DataHeader *)((const double *)p+1);
  79 #endif
  80     }
  81 }
  82
  83
  84 U_CFUNC void UDataMemory_setData (UDataMemory *This, const void *dataAddr) {
  85     This->pHeader = UDataMemory_normalizeDataPointer(dataAddr);
  86 }
  87
  88
  89 U_CAPI void U_EXPORT2
  90 udata_close(UDataMemory *pData) {
  91     if(pData!=NULL) {
  92         uprv_unmapFile(pData);
  93         if(pData->heapAllocated ) {
  94             uprv_free(pData);
  95         } else {
  96             UDataMemory_init(pData);
  97         }
  98     }
  99 }
 100
 101 U_CAPI const void * U_EXPORT2
 102 udata_getMemory(UDataMemory *pData) {
 103     if(pData!=NULL && pData->pHeader!=NULL) {
 104         return (char *)(pData->pHeader)+udata_getHeaderSize(pData->pHeader);
 105     } else {
 106         return NULL;
 107     }
 108 }
 109
 110 /**
 111  * Get the length of the data item if possible.
 112  * The length may be up to 15 bytes larger than the actual data.
 113  *
 114  * TODO Consider making this function public.
 115  * It would have to return the actual length in more cases.
 116  * For example, the length of the last item in a .dat package could be
 117  * computed from the size of the whole .dat package minus the offset of the
 118  * last item.
 119  * The size of a file that was directly memory-mapped could be determined
 120  * using some system API.
 121  *
 122  * In order to get perfect values for all data items, we may have to add a
 123  * length field to UDataInfo, but that complicates data generation
 124  * and may be overkill.
 125  *
 126  * @param pData The data item.
 127  * @return the length of the data item, or -1 if not known
 128  * @internal Currently used only in cintltst/udatatst.c
 129  */
 130 U_CAPI int32_t U_EXPORT2
 131 udata_getLength(const UDataMemory *pData) {
 132     if(pData!=NULL && pData->pHeader!=NULL && pData->length>=0) {
 133         /*
 134          * subtract the header size,
 135          * return only the size of the actual data starting at udata_getMemory()
 136          */
 137         return pData->length-udata_getHeaderSize(pData->pHeader);
 138     } else {
 139         return -1;
 140     }
 141 }
 142
 143 /**
 144  * Get the memory including the data header.
 145  * Used in cintltst/udatatst.c
 146  * @internal
 147  */
 148 U_CAPI const void * U_EXPORT2
 149 udata_getRawMemory(const UDataMemory *pData) {
 150     if(pData!=NULL && pData->pHeader!=NULL) {
 151         return pData->pHeader;
 152     } else {
 153         return NULL;
 154     }
 155 }
 156
 157 U_CFUNC UBool UDataMemory_isLoaded(const UDataMemory *This) {
 158     return This->pHeader != NULL;
 159 }