/src/icu/source/common/ucmndata.cpp

Source (jump to first uncovered line)
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
*
*   Copyright (C) 1999-2011, 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 interface 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;
    /**
     * Variable-length array declared with length 1 to disable bounds checkers.
     * The actual array length is in the count field.
     */
    PointerTOCEntry   entry[1];
}  PointerTOC;


/* definition of OffsetTOC struct types moved to ucmndata.h */

/*-----------------------------------------------------------------------------*
 *                                                                             *
 *    entry point lookup implementations                                       *
 *                                                                             *
 *-----------------------------------------------------------------------------*/

#ifndef MIN
#define MIN(a,b) (((a)<(b)) ? (a) : (b))
#endif

/**
 * Compare strings where we know the shared prefix length,
 * and advance the prefix length as we find that the strings share even more characters.
 */
static int32_t
strcmpAfterPrefix(const char *s1, const char *s2, int32_t *pPrefixLength) {
    int32_t pl=*pPrefixLength;
    int32_t cmp=0;
    s1+=pl;
    s2+=pl;
    for(;;) {
        int32_t c1=(uint8_t)*s1++;
        int32_t c2=(uint8_t)*s2++;
        cmp=c1-c2;
        if(cmp!=0 || c1==0) {  /* different or done */
            break;
        }
        ++pl;  /* increment shared same-prefix length */
    }
    *pPrefixLength=pl;
    return cmp;
}

static int32_t
offsetTOCPrefixBinarySearch(const char *s, const char *names,
                            const UDataOffsetTOCEntry *toc, int32_t count) {
    int32_t start=0;
    int32_t limit=count;
    /*
     * Remember the shared prefix between s, start and limit,
     * and don't compare that shared prefix again.
     * The shared prefix should get longer as we narrow the [start, limit[ range.
     */
    int32_t startPrefixLength=0;
    int32_t limitPrefixLength=0;
    if(count==0) {
        return -1;
    }
    /*
     * Prime the prefix lengths so that we don't keep prefixLength at 0 until
     * both the start and limit indexes have moved.
     * At the same time, we find if s is one of the start and (limit-1) names,
     * and if not, exclude them from the actual binary search.
     */
    if(0==strcmpAfterPrefix(s, names+toc[0].nameOffset, &startPrefixLength)) {
        return 0;
    }
    ++start;
    --limit;
    if(0==strcmpAfterPrefix(s, names+toc[limit].nameOffset, &limitPrefixLength)) {
        return limit;
    }
    while(start<limit) {
        int32_t i=(start+limit)/2;
        int32_t prefixLength=MIN(startPrefixLength, limitPrefixLength);
        int32_t cmp=strcmpAfterPrefix(s, names+toc[i].nameOffset, &prefixLength);
        if(cmp<0) {
            limit=i;
            limitPrefixLength=prefixLength;
        } else if(cmp==0) {
            return i;
        } else {
            start=i+1;
            startPrefixLength=prefixLength;
        }
    }
    return -1;
}

static int32_t
pointerTOCPrefixBinarySearch(const char *s, const PointerTOCEntry *toc, int32_t count) {
    int32_t start=0;
    int32_t limit=count;
    /*
     * Remember the shared prefix between s, start and limit,
     * and don't compare that shared prefix again.
     * The shared prefix should get longer as we narrow the [start, limit[ range.
     */
    int32_t startPrefixLength=0;
    int32_t limitPrefixLength=0;
    if(count==0) {
        return -1;
    }
    /*
     * Prime the prefix lengths so that we don't keep prefixLength at 0 until
     * both the start and limit indexes have moved.
     * At the same time, we find if s is one of the start and (limit-1) names,
     * and if not, exclude them from the actual binary search.
     */
    if(0==strcmpAfterPrefix(s, toc[0].entryName, &startPrefixLength)) {
        return 0;
    }
    ++start;
    --limit;
    if(0==strcmpAfterPrefix(s, toc[limit].entryName, &limitPrefixLength)) {
        return limit;
    }
    while(start<limit) {
        int32_t i=(start+limit)/2;
        int32_t prefixLength=MIN(startPrefixLength, limitPrefixLength);
        int32_t cmp=strcmpAfterPrefix(s, toc[i].entryName, &prefixLength);
        if(cmp<0) {
            limit=i;
            limitPrefixLength=prefixLength;
        } else if(cmp==0) {
            return i;
        } else {
            start=i+1;
            startPrefixLength=prefixLength;
        }
    }
    return -1;
}

U_CDECL_BEGIN
static uint32_t U_CALLCONV
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 * U_CALLCONV
offsetTOCLookupFn(const UDataMemory *pData,
                  const char *tocEntryName,
                  int32_t *pLength,
                  UErrorCode *pErrorCode) {
    (void)pErrorCode;
    const UDataOffsetTOC  *toc = (UDataOffsetTOC *)pData->toc;
    if(toc!=NULL) {
        const char *base=(const char *)toc;
        int32_t number, count=(int32_t)toc->count;

        /* 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(number=0; number<count; ++number) {
            fprintf(stderr, "\tx%d: %s\n", number, &base[toc->entry[number].nameOffset]);
        }
#endif
        number=offsetTOCPrefixBinarySearch(tocEntryName, base, toc->entry, count);
        if(number>=0) {
            /* found it */
            const UDataOffsetTOCEntry *entry=toc->entry+number;
#ifdef UDATA_DEBUG
            fprintf(stderr, "%s: Found.\n", tocEntryName);
#endif
            if((number+1) < count) {
                *pLength = (int32_t)(entry[1].dataOffset - entry->dataOffset);
            } else {
                *pLength = -1;
            }
            return (const DataHeader *)(base+entry->dataOffset);
        } else {
#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 U_CALLCONV pointerTOCEntryCount(const UDataMemory *pData) {
    const PointerTOC *toc = (PointerTOC *)pData->toc;
    return (uint32_t)((toc != NULL) ? (toc->count) : 0);
}

static const DataHeader * U_CALLCONV pointerTOCLookupFn(const UDataMemory *pData,
                   const char *name,
                   int32_t *pLength,
                   UErrorCode *pErrorCode) {
    (void)pErrorCode;
    if(pData->toc!=NULL) {
        const PointerTOC *toc = (PointerTOC *)pData->toc;
        int32_t number, count=(int32_t)toc->count;

#if defined (UDATA_DEBUG_DUMP)
        /* list the contents of the TOC each time .. not recommended */
        for(number=0; number<count; ++number) {
            fprintf(stderr, "\tx%d: %s\n", number, toc->entry[number].entryName);
        }
#endif
        number=pointerTOCPrefixBinarySearch(name, toc->entry, count);
        if(number>=0) {
            /* found it */
#ifdef UDATA_DEBUG
            fprintf(stderr, "%s: Found.\n", toc->entry[number].entryName);
#endif
            *pLength=-1;
            return UDataMemory_normalizeDataPointer(toc->entry[number].pHeader);
        } else {
#ifdef UDATA_DEBUG
            fprintf(stderr, "%s: Not found.\n", name);
#endif
            return NULL;
        }
    } else {
        return pData->pHeader;
    }
}
U_CDECL_END


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==NULL || udm->pHeader==NULL) {
      *err=U_INVALID_FORMAT_ERROR;
    } else 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
 */

Coverage Report

Created: 2025-01-28 06:38

Line	Count	Source (jump to first uncovered line)
1		// © 2016 and later: Unicode, Inc. and others.
2		// License & terms of use: http://www.unicode.org/copyright.html
3		/*
4		******************************************************************************
5		*
6		* Copyright (C) 1999-2011, International Business Machines
7		* Corporation and others. All Rights Reserved.
8		*
9		******************************************************************************/
10
11
12		/*------------------------------------------------------------------------------
13		*
14		* UCommonData An abstract interface for dealing with ICU Common Data Files.
15		* ICU Common Data Files are a grouping of a number of individual
16		* data items (resources, converters, tables, anything) into a
17		* single file or dll. The combined format includes a table of
18		* contents for locating the individual items by name.
19		*
20		* Two formats for the table of contents are supported, which is
21		* why there is an abstract interface involved.
22		*
23		*/
24
25		#include "unicode/utypes.h"
26		#include "unicode/udata.h"
27		#include "cstring.h"
28		#include "ucmndata.h"
29		#include "udatamem.h"
30
31		#if defined(UDATA_DEBUG) \|\| defined(UDATA_DEBUG_DUMP)
32		# include <stdio.h>
33		#endif
34
35		U_CFUNC uint16_t
36	0	udata_getHeaderSize(const DataHeader *udh) {
37	0	if(udh==NULL) {
38	0	return 0;
39	0	} else if(udh->info.isBigEndian==U_IS_BIG_ENDIAN) {
40		/* same endianness */
41	0	return udh->dataHeader.headerSize;
42	0	} else {
43		/* opposite endianness */
44	0	uint16_t x=udh->dataHeader.headerSize;
45	0	return (uint16_t)((x<<8)\|(x>>8));
46	0	}
47	0	}
48
49		U_CFUNC uint16_t
50	0	udata_getInfoSize(const UDataInfo *info) {
51	0	if(info==NULL) {
52	0	return 0;
53	0	} else if(info->isBigEndian==U_IS_BIG_ENDIAN) {
54		/* same endianness */
55	0	return info->size;
56	0	} else {
57		/* opposite endianness */
58	0	uint16_t x=info->size;
59	0	return (uint16_t)((x<<8)\|(x>>8));
60	0	}
61	0	}
62
63		/-----------------------------------------------------------------------------
64		* *
65		* Pointer TOCs. TODO: This form of table-of-contents should be removed *
66		* because DLLs must be relocated on loading to correct the *
67		* pointer values and this operation makes shared memory *
68		* mapping of the data much less likely to work. *
69		* *
70		-----------------------------------------------------------------------------/
71		typedef struct {
72		const char *entryName;
73		const DataHeader *pHeader;
74		} PointerTOCEntry;
75
76
77		typedef struct {
78		uint32_t count;
79		uint32_t reserved;
80		/**
81		* Variable-length array declared with length 1 to disable bounds checkers.
82		* The actual array length is in the count field.
83		*/
84		PointerTOCEntry entry[1];
85		} PointerTOC;
86
87
88		/* definition of OffsetTOC struct types moved to ucmndata.h */
89
90		/-----------------------------------------------------------------------------
91		* *
92		* entry point lookup implementations *
93		* *
94		-----------------------------------------------------------------------------/
95
96		#ifndef MIN
97	0	#define MIN(a,b) (((a)<(b)) ? (a) : (b))
98		#endif
99
100		/**
101		* Compare strings where we know the shared prefix length,
102		* and advance the prefix length as we find that the strings share even more characters.
103		*/
104		static int32_t
105	0	strcmpAfterPrefix(const char s1, const char s2, int32_t *pPrefixLength) {
106	0	int32_t pl=*pPrefixLength;
107	0	int32_t cmp=0;
108	0	s1+=pl;
109	0	s2+=pl;
110	0	for(;;) {
111	0	int32_t c1=(uint8_t)*s1++;
112	0	int32_t c2=(uint8_t)*s2++;
113	0	cmp=c1-c2;
114	0	if(cmp!=0 \|\| c1==0) { /* different or done */
115	0	break;
116	0	}
117	0	++pl; /* increment shared same-prefix length */
118	0	}
119	0	*pPrefixLength=pl;
120	0	return cmp;
121	0	}
122
123		static int32_t
124		offsetTOCPrefixBinarySearch(const char s, const char names,
125	0	const UDataOffsetTOCEntry *toc, int32_t count) {
126	0	int32_t start=0;
127	0	int32_t limit=count;
128		/*
129		* Remember the shared prefix between s, start and limit,
130		* and don't compare that shared prefix again.
131		* The shared prefix should get longer as we narrow the [start, limit[ range.
132		*/
133	0	int32_t startPrefixLength=0;
134	0	int32_t limitPrefixLength=0;
135	0	if(count==0) {
136	0	return -1;
137	0	}
138		/*
139		* Prime the prefix lengths so that we don't keep prefixLength at 0 until
140		* both the start and limit indexes have moved.
141		* At the same time, we find if s is one of the start and (limit-1) names,
142		* and if not, exclude them from the actual binary search.
143		*/
144	0	if(0==strcmpAfterPrefix(s, names+toc[0].nameOffset, &startPrefixLength)) {
145	0	return 0;
146	0	}
147	0	++start;
148	0	--limit;
149	0	if(0==strcmpAfterPrefix(s, names+toc[limit].nameOffset, &limitPrefixLength)) {
150	0	return limit;
151	0	}
152	0	while(start<limit) {
153	0	int32_t i=(start+limit)/2;
154	0	int32_t prefixLength=MIN(startPrefixLength, limitPrefixLength);
155	0	int32_t cmp=strcmpAfterPrefix(s, names+toc[i].nameOffset, &prefixLength);
156	0	if(cmp<0) {
157	0	limit=i;
158	0	limitPrefixLength=prefixLength;
159	0	} else if(cmp==0) {
160	0	return i;
161	0	} else {
162	0	start=i+1;
163	0	startPrefixLength=prefixLength;
164	0	}
165	0	}
166	0	return -1;
167	0	}
168
169		static int32_t
170	0	pointerTOCPrefixBinarySearch(const char s, const PointerTOCEntry toc, int32_t count) {
171	0	int32_t start=0;
172	0	int32_t limit=count;
173		/*
174		* Remember the shared prefix between s, start and limit,
175		* and don't compare that shared prefix again.
176		* The shared prefix should get longer as we narrow the [start, limit[ range.
177		*/
178	0	int32_t startPrefixLength=0;
179	0	int32_t limitPrefixLength=0;
180	0	if(count==0) {
181	0	return -1;
182	0	}
183		/*
184		* Prime the prefix lengths so that we don't keep prefixLength at 0 until
185		* both the start and limit indexes have moved.
186		* At the same time, we find if s is one of the start and (limit-1) names,
187		* and if not, exclude them from the actual binary search.
188		*/
189	0	if(0==strcmpAfterPrefix(s, toc[0].entryName, &startPrefixLength)) {
190	0	return 0;
191	0	}
192	0	++start;
193	0	--limit;
194	0	if(0==strcmpAfterPrefix(s, toc[limit].entryName, &limitPrefixLength)) {
195	0	return limit;
196	0	}
197	0	while(start<limit) {
198	0	int32_t i=(start+limit)/2;
199	0	int32_t prefixLength=MIN(startPrefixLength, limitPrefixLength);
200	0	int32_t cmp=strcmpAfterPrefix(s, toc[i].entryName, &prefixLength);
201	0	if(cmp<0) {
202	0	limit=i;
203	0	limitPrefixLength=prefixLength;
204	0	} else if(cmp==0) {
205	0	return i;
206	0	} else {
207	0	start=i+1;
208	0	startPrefixLength=prefixLength;
209	0	}
210	0	}
211	0	return -1;
212	0	}
213
214		U_CDECL_BEGIN
215		static uint32_t U_CALLCONV
216	0	offsetTOCEntryCount(const UDataMemory *pData) {
217	0	int32_t retVal=0;
218	0	const UDataOffsetTOC toc = (UDataOffsetTOC )pData->toc;
219	0	if (toc != NULL) {
220	0	retVal = toc->count;
221	0	}
222	0	return retVal;
223	0	}
224
225		static const DataHeader * U_CALLCONV
226		offsetTOCLookupFn(const UDataMemory *pData,
227		const char *tocEntryName,
228		int32_t *pLength,
229	0	UErrorCode *pErrorCode) {
230	0	(void)pErrorCode;
231	0	const UDataOffsetTOC toc = (UDataOffsetTOC )pData->toc;
232	0	if(toc!=NULL) {
233	0	const char base=(const char )toc;
234	0	int32_t number, count=(int32_t)toc->count;
235
236		/* perform a binary search for the data in the common data's table of contents */
237		#if defined (UDATA_DEBUG_DUMP)
238		/* list the contents of the TOC each time .. not recommended */
239		for(number=0; number<count; ++number) {
240		fprintf(stderr, "\tx%d: %s\n", number, &base[toc->entry[number].nameOffset]);
241		}
242		#endif
243	0	number=offsetTOCPrefixBinarySearch(tocEntryName, base, toc->entry, count);
244	0	if(number>=0) {
245		/* found it */
246	0	const UDataOffsetTOCEntry *entry=toc->entry+number;
247		#ifdef UDATA_DEBUG
248		fprintf(stderr, "%s: Found.\n", tocEntryName);
249		#endif
250	0	if((number+1) < count) {
251	0	*pLength = (int32_t)(entry[1].dataOffset - entry->dataOffset);
252	0	} else {
253	0	*pLength = -1;
254	0	}
255	0	return (const DataHeader *)(base+entry->dataOffset);
256	0	} else {
257		#ifdef UDATA_DEBUG
258		fprintf(stderr, "%s: Not found.\n", tocEntryName);
259		#endif
260	0	return NULL;
261	0	}
262	0	} else {
263		#ifdef UDATA_DEBUG
264		fprintf(stderr, "returning header\n");
265		#endif
266
267	0	return pData->pHeader;
268	0	}
269	0	}
270
271
272	0	static uint32_t U_CALLCONV pointerTOCEntryCount(const UDataMemory *pData) {
273	0	const PointerTOC toc = (PointerTOC )pData->toc;
274	0	return (uint32_t)((toc != NULL) ? (toc->count) : 0);
275	0	}
276
277		static const DataHeader * U_CALLCONV pointerTOCLookupFn(const UDataMemory *pData,
278		const char *name,
279		int32_t *pLength,
280	0	UErrorCode *pErrorCode) {
281	0	(void)pErrorCode;
282	0	if(pData->toc!=NULL) {
283	0	const PointerTOC toc = (PointerTOC )pData->toc;
284	0	int32_t number, count=(int32_t)toc->count;
285
286		#if defined (UDATA_DEBUG_DUMP)
287		/* list the contents of the TOC each time .. not recommended */
288		for(number=0; number<count; ++number) {
289		fprintf(stderr, "\tx%d: %s\n", number, toc->entry[number].entryName);
290		}
291		#endif
292	0	number=pointerTOCPrefixBinarySearch(name, toc->entry, count);
293	0	if(number>=0) {
294		/* found it */
295		#ifdef UDATA_DEBUG
296		fprintf(stderr, "%s: Found.\n", toc->entry[number].entryName);
297		#endif
298	0	*pLength=-1;
299	0	return UDataMemory_normalizeDataPointer(toc->entry[number].pHeader);
300	0	} else {
301		#ifdef UDATA_DEBUG
302		fprintf(stderr, "%s: Not found.\n", name);
303		#endif
304	0	return NULL;
305	0	}
306	0	} else {
307	0	return pData->pHeader;
308	0	}
309	0	}
310		U_CDECL_END
311
312
313		static const commonDataFuncs CmnDFuncs = {offsetTOCLookupFn, offsetTOCEntryCount};
314		static const commonDataFuncs ToCPFuncs = {pointerTOCLookupFn, pointerTOCEntryCount};
315
316
317
318		/----------------------------------------------------------------------
319		* *
320		* checkCommonData Validate the format of a common data file. *
321		* Fill in the virtual function ptr based on TOC type *
322		* If the data is invalid, close the UDataMemory *
323		* and set the appropriate error code. *
324		* *
325		----------------------------------------------------------------------/
326	0	U_CFUNC void udata_checkCommonData(UDataMemory udm, UErrorCode err) {
327	0	if (U_FAILURE(*err)) {
328	0	return;
329	0	}
330
331	0	if(udm==NULL \|\| udm->pHeader==NULL) {
332	0	*err=U_INVALID_FORMAT_ERROR;
333	0	} else if(!(udm->pHeader->dataHeader.magic1==0xda &&
334	0	udm->pHeader->dataHeader.magic2==0x27 &&
335	0	udm->pHeader->info.isBigEndian==U_IS_BIG_ENDIAN &&
336	0	udm->pHeader->info.charsetFamily==U_CHARSET_FAMILY)
337	0	) {
338		/* header not valid */
339	0	*err=U_INVALID_FORMAT_ERROR;
340	0	}
341	0	else if (udm->pHeader->info.dataFormat[0]==0x43 &&
342	0	udm->pHeader->info.dataFormat[1]==0x6d &&
343	0	udm->pHeader->info.dataFormat[2]==0x6e &&
344	0	udm->pHeader->info.dataFormat[3]==0x44 &&
345	0	udm->pHeader->info.formatVersion[0]==1
346	0	) {
347		/* dataFormat="CmnD" */
348	0	udm->vFuncs = &CmnDFuncs;
349	0	udm->toc=(const char *)udm->pHeader+udata_getHeaderSize(udm->pHeader);
350	0	}
351	0	else if(udm->pHeader->info.dataFormat[0]==0x54 &&
352	0	udm->pHeader->info.dataFormat[1]==0x6f &&
353	0	udm->pHeader->info.dataFormat[2]==0x43 &&
354	0	udm->pHeader->info.dataFormat[3]==0x50 &&
355	0	udm->pHeader->info.formatVersion[0]==1
356	0	) {
357		/* dataFormat="ToCP" */
358	0	udm->vFuncs = &ToCPFuncs;
359	0	udm->toc=(const char *)udm->pHeader+udata_getHeaderSize(udm->pHeader);
360	0	}
361	0	else {
362		/* dataFormat not recognized */
363	0	*err=U_INVALID_FORMAT_ERROR;
364	0	}
365
366	0	if (U_FAILURE(*err)) {
367		/* If the data is no good and we memory-mapped it ourselves,
368		* close the memory mapping so it doesn't leak. Note that this has
369		* no effect on non-memory mapped data, other than clearing fields in udm.
370		*/
371	0	udata_close(udm);
372	0	}
373	0	}
374
375		/*
376		* TODO: Add a udata_swapPackageHeader() function that swaps an ICU .dat package
377		* header but not its sub-items.
378		* This function will be needed for automatic runtime swapping.
379		* Sub-items should not be swapped to limit the swapping to the parts of the
380		* package that are actually used.
381		*
382		* Since lengths of items are implicit in the order and offsets of their
383		* ToC entries, and since offsets are relative to the start of the ToC,
384		* a swapped version may need to generate a different data structure
385		* with pointers to the original data items and with their lengths
386		* (-1 for the last one if it is not known), and maybe even pointers to the
387		* swapped versions of the items.
388		* These pointers to swapped versions would establish a cache;
389		* instead, each open data item could simply own the storage for its swapped
390		* data. This fits better with the current design.
391		*
392		* markus 2003sep18 Jitterbug 2235
393		*/