Check in the pristine copy of ICU 4.6...

icu46/source/common/ucmndata.c

+/*
+******************************************************************************
+*
+*   Copyright (C) 1999-2010, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************/
+
+
+/*------------------------------------------------------------------------------
+ *
+ *   UCommonData   An abstract interface for dealing with ICU Common Data Files.
+ *                 ICU Common Data Files are a grouping of a number of individual
+ *                 data items (resources, converters, tables, anything) into a
+ *                 single file or dll.  The combined format includes a table of
+ *                 contents for locating the individual items by name.
+ *
+ *                 Two formats for the table of contents are supported, which is
+ *                 why there is an abstract inteface involved.
+ *
+ */
+
+#include "unicode/utypes.h"
+#include "unicode/udata.h"
+#include "cstring.h"
+#include "ucmndata.h"
+#include "udatamem.h"
+
+#if defined(UDATA_DEBUG) || defined(UDATA_DEBUG_DUMP)
+#   include <stdio.h>
+#endif
+
+U_CFUNC uint16_t
+udata_getHeaderSize(const DataHeader *udh) {
+    if(udh==NULL) {
+        return 0;
+    } else if(udh->info.isBigEndian==U_IS_BIG_ENDIAN) {
+        /* same endianness */
+        return udh->dataHeader.headerSize;
+    } else {
+        /* opposite endianness */
+        uint16_t x=udh->dataHeader.headerSize;
+        return (uint16_t)((x<<8)|(x>>8));
+    }
+}
+
+U_CFUNC uint16_t
+udata_getInfoSize(const UDataInfo *info) {
+    if(info==NULL) {
+        return 0;
+    } else if(info->isBigEndian==U_IS_BIG_ENDIAN) {
+        /* same endianness */
+        return info->size;
+    } else {
+        /* opposite endianness */
+        uint16_t x=info->size;
+        return (uint16_t)((x<<8)|(x>>8));
+    }
+}
+
+/*-----------------------------------------------------------------------------*
+ *                                                                             *
+ *  Pointer TOCs.   TODO: This form of table-of-contents should be removed     *
+ *                  because DLLs must be relocated on loading to correct the   *
+ *                  pointer values and this operation makes shared memory      *
+ *                  mapping of the data much less likely to work.              *
+ *                                                                             *
+ *-----------------------------------------------------------------------------*/
+typedef struct {
+    const char       *entryName;
+    const DataHeader *pHeader;
+} PointerTOCEntry;
+
+
+typedef struct  {
+    uint32_t          count;
+    uint32_t          reserved;
+    PointerTOCEntry   entry[2];   /* Actual size is from count. */
+}  PointerTOC;
+
+
+/* definition of OffsetTOC struct types moved to ucmndata.h */
+
+/*-----------------------------------------------------------------------------*
+ *                                                                             *
+ *    entry point lookup implementations                                       *
+ *                                                                             *
+ *-----------------------------------------------------------------------------*/
+static uint32_t offsetTOCEntryCount(const UDataMemory *pData) {
+    int32_t          retVal=0;
+    const UDataOffsetTOC *toc = (UDataOffsetTOC *)pData->toc;
+    if (toc != NULL) {
+        retVal = toc->count;
+    }
+    return retVal;
+}
+
+
+static const DataHeader *
+offsetTOCLookupFn(const UDataMemory *pData,
+                  const char *tocEntryName,
+                  int32_t *pLength,
+                  UErrorCode *pErrorCode) {
+    const UDataOffsetTOC  *toc = (UDataOffsetTOC *)pData->toc;
+    if(toc!=NULL) {
+        const char *base=(const char *)toc;
+        uint32_t start, limit, number, lastNumber;
+        int32_t strResult;
+        const UDataOffsetTOCEntry *entry;
+
+        /* perform a binary search for the data in the common data's table of contents */
+#if defined (UDATA_DEBUG_DUMP)
+        /* list the contents of the TOC each time .. not recommended */
+        for(start=0;start<toc->count;start++) {
+          fprintf(stderr, "\tx%d: %s\n", start, &base[toc->entry[start].nameOffset]);
+        }
+#endif
+
+        start=0;
+        limit=toc->count;         /* number of names in this table of contents */
+        lastNumber=limit;
+        entry=toc->entry;
+        for (;;) {
+            number = (start+limit)/2;
+            if (lastNumber == number) { /* Have we moved? */
+                break;  /* We haven't moved, and it wasn't found; */
+                        /* or the empty stub common data library was used during build. */
+            }
+            lastNumber = number;
+            strResult = uprv_strcmp(tocEntryName, base+entry[number].nameOffset);
+            if(strResult<0) {
+                limit=number;
+            } else if (strResult>0) {
+                start=number;
+            }
+            else {
+                /* found it */
+#ifdef UDATA_DEBUG
+                fprintf(stderr, "%s: Found.\n", tocEntryName);
+#endif
+                entry += number; /* Alias the entry to the current entry. */
+                if((number+1) < toc->count) {
+                    *pLength = (int32_t)(entry[1].dataOffset - entry->dataOffset);
+                } else {
+                    *pLength = -1;
+                }
+                return (const DataHeader *)(base+entry->dataOffset);
+            }
+        }
+#ifdef UDATA_DEBUG
+        fprintf(stderr, "%s: Not found.\n", tocEntryName);
+#endif
+        return NULL;
+    } else {
+#ifdef UDATA_DEBUG
+        fprintf(stderr, "returning header\n");
+#endif
+
+        return pData->pHeader;
+    }
+}
+
+
+static uint32_t pointerTOCEntryCount(const UDataMemory *pData) {
+    const PointerTOC *toc = (PointerTOC *)pData->toc;
+    return (uint32_t)((toc != NULL) ? (toc->count) : 0);
+}
+
+
+static const DataHeader *pointerTOCLookupFn(const UDataMemory *pData,
+                   const char *name,
+                   int32_t *pLength,
+                   UErrorCode *pErrorCode) {
+    if(pData->toc!=NULL) {
+        const PointerTOC *toc = (PointerTOC *)pData->toc;
+        uint32_t start, limit, number, lastNumber;
+        int32_t strResult;
+
+#if defined (UDATA_DEBUG_DUMP)
+        /* list the contents of the TOC each time .. not recommended */
+        for(start=0;start<toc->count;start++) {
+            fprintf(stderr, "\tx%d: %s\n", start, toc->entry[start].entryName);
+        }
+#endif
+
+        /* perform a binary search for the data in the common data's table of contents */
+        start=0;
+        limit=toc->count;
+        lastNumber=limit;
+
+        for (;;) {
+            number = (start+limit)/2;
+            if (lastNumber == number) { /* Have we moved? */
+                break;  /* We haven't moved, and it wasn't found, */
+                        /* or the empty stub common data library was used during build. */
+            }
+            lastNumber = number;
+            strResult = uprv_strcmp(name, toc->entry[number].entryName);
+            if(strResult<0) {
+                limit=number;
+            } else if (strResult>0) {
+                start=number;
+            }
+            else {
+                /* found it */
+#ifdef UDATA_DEBUG
+                fprintf(stderr, "%s: Found.\n", toc->entry[number].entryName);
+#endif
+                *pLength=-1;
+                return UDataMemory_normalizeDataPointer(toc->entry[number].pHeader);
+            }
+        }
+#ifdef UDATA_DEBUG
+        fprintf(stderr, "%s: Not found.\n", name);
+#endif
+        return NULL;
+    } else {
+        return pData->pHeader;
+    }
+}
+
+static const commonDataFuncs CmnDFuncs = {offsetTOCLookupFn,  offsetTOCEntryCount};
+static const commonDataFuncs ToCPFuncs = {pointerTOCLookupFn, pointerTOCEntryCount};
+
+
+
+/*----------------------------------------------------------------------*
+ *                                                                      *
+ *  checkCommonData   Validate the format of a common data file.        *
+ *                    Fill in the virtual function ptr based on TOC type *
+ *                    If the data is invalid, close the UDataMemory     *
+ *                    and set the appropriate error code.               *
+ *                                                                      *
+ *----------------------------------------------------------------------*/
+U_CFUNC void udata_checkCommonData(UDataMemory *udm, UErrorCode *err) {
+    if (U_FAILURE(*err)) {
+        return;
+    }
+
+    if(!(udm->pHeader->dataHeader.magic1==0xda &&
+        udm->pHeader->dataHeader.magic2==0x27 &&
+        udm->pHeader->info.isBigEndian==U_IS_BIG_ENDIAN &&
+        udm->pHeader->info.charsetFamily==U_CHARSET_FAMILY)
+        ) {
+        /* header not valid */
+        *err=U_INVALID_FORMAT_ERROR;
+    }
+    else if (udm->pHeader->info.dataFormat[0]==0x43 &&
+        udm->pHeader->info.dataFormat[1]==0x6d &&
+        udm->pHeader->info.dataFormat[2]==0x6e &&
+        udm->pHeader->info.dataFormat[3]==0x44 &&
+        udm->pHeader->info.formatVersion[0]==1
+        ) {
+        /* dataFormat="CmnD" */
+        udm->vFuncs = &CmnDFuncs;
+        udm->toc=(const char *)udm->pHeader+udata_getHeaderSize(udm->pHeader);
+    }
+    else if(udm->pHeader->info.dataFormat[0]==0x54 &&
+        udm->pHeader->info.dataFormat[1]==0x6f &&
+        udm->pHeader->info.dataFormat[2]==0x43 &&
+        udm->pHeader->info.dataFormat[3]==0x50 &&
+        udm->pHeader->info.formatVersion[0]==1
+        ) {
+        /* dataFormat="ToCP" */
+        udm->vFuncs = &ToCPFuncs;
+        udm->toc=(const char *)udm->pHeader+udata_getHeaderSize(udm->pHeader);
+    }
+    else {
+        /* dataFormat not recognized */
+        *err=U_INVALID_FORMAT_ERROR;
+    }
+
+    if (U_FAILURE(*err)) {
+        /* If the data is no good and we memory-mapped it ourselves,
+         *  close the memory mapping so it doesn't leak.  Note that this has
+         *  no effect on non-memory mapped data, other than clearing fields in udm.
+         */
+        udata_close(udm);
+    }
+}
+
+/*
+ * TODO: Add a udata_swapPackageHeader() function that swaps an ICU .dat package
+ * header but not its sub-items.
+ * This function will be needed for automatic runtime swapping.
+ * Sub-items should not be swapped to limit the swapping to the parts of the
+ * package that are actually used.
+ *
+ * Since lengths of items are implicit in the order and offsets of their
+ * ToC entries, and since offsets are relative to the start of the ToC,
+ * a swapped version may need to generate a different data structure
+ * with pointers to the original data items and with their lengths
+ * (-1 for the last one if it is not known), and maybe even pointers to the
+ * swapped versions of the items.
+ * These pointers to swapped versions would establish a cache;
+ * instead, each open data item could simply own the storage for its swapped
+ * data. This fits better with the current design.
+ *
+ * markus 2003sep18 Jitterbug 2235
+ */