chm_lib.c 50.2 KB
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/***************************************************************************
 *             chm_lib.c - CHM archive manipulation routines               *
 *                           -------------------                           *
 *                                                                         *
 *  author:     Jed Wing <jedwin@ugcs.caltech.edu>                         *
 *  version:    0.3                                                        *
 *  notes:      These routines are meant for the manipulation of microsoft *
 *              .chm (compiled html help) files, but may likely be used    *
 *              for the manipulation of any ITSS archive, if ever ITSS     *
 *              archives are used for any other purpose.                   *
 *                                                                         *
 *              Note also that the section names are statically handled.   *
 *              To be entirely correct, the section names should be read   *
 *              from the section names meta-file, and then the various     *
 *              content sections and the "transforms" to apply to the data *
 *              they contain should be inferred from the section name and  *
 *              the meta-files referenced using that name; however, all of *
 *              the files I've been able to get my hands on appear to have *
 *              only two sections: Uncompressed and MSCompressed.          *
 *              Additionally, the ITSS.DLL file included with Windows does *
 *              not appear to handle any different transforms than the     *
 *              simple LZX-transform.  Furthermore, the list of transforms *
 *              to apply is broken, in that only half the required space   *
 *              is allocated for the list.  (It appears as though the      *
 *              space is allocated for ASCII strings, but the strings are  *
 *              written as unicode.  As a result, only the first half of   *
 *              the string appears.)  So this is probably not too big of   *
 *              a deal, at least until CHM v4 (MS .lit files), which also  *
 *              incorporate encryption, of some description.               *
 *                                                                         *
 ***************************************************************************/

/***************************************************************************
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 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 *
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 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 * Adapted for Wine by Mike McCormack                                      *
 *                                                                         *
 ***************************************************************************/


#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "windef.h"
#include "winbase.h"
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#include "winnls.h"
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#include "chm_lib.h"
#include "lzx.h"

#define CHM_ACQUIRE_LOCK(a) do {                        \
        EnterCriticalSection(&(a));                     \
    } while(0)
#define CHM_RELEASE_LOCK(a) do {                        \
        LeaveCriticalSection(&(a));                     \
    } while(0)

#define CHM_NULL_FD (INVALID_HANDLE_VALUE)
#define CHM_CLOSE_FILE(fd) CloseHandle((fd))

/*
 * defines related to tuning
 */
#ifndef CHM_MAX_BLOCKS_CACHED
#define CHM_MAX_BLOCKS_CACHED 5
#endif
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#define CHM_PARAM_MAX_BLOCKS_CACHED 0
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/*
 * architecture specific defines
 *
 * Note: as soon as C99 is more widespread, the below defines should
 * probably just use the C99 sized-int types.
 *
 * The following settings will probably work for many platforms.  The sizes
 * don't have to be exactly correct, but the types must accommodate at least as
 * many bits as they specify.
 */

/* i386, 32-bit, Windows */
typedef BYTE   UChar;
typedef SHORT  Int16;
typedef USHORT UInt16;
typedef LONG   Int32;
typedef DWORD      UInt32;
typedef LONGLONG   Int64;
typedef ULONGLONG  UInt64;

/* utilities for unmarshalling data */
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static BOOL _unmarshal_char_array(unsigned char **pData,
                                  unsigned int *pLenRemain,
                                  char *dest,
                                  int count)
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{
    if (count <= 0  ||  (unsigned int)count > *pLenRemain)
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        return FALSE;
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    memcpy(dest, (*pData), count);
    *pData += count;
    *pLenRemain -= count;
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    return TRUE;
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}

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static BOOL _unmarshal_uchar_array(unsigned char **pData,
                                   unsigned int *pLenRemain,
                                   unsigned char *dest,
                                   int count)
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{
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    if (count <= 0  || (unsigned int)count > *pLenRemain)
        return FALSE;
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    memcpy(dest, (*pData), count);
    *pData += count;
    *pLenRemain -= count;
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    return TRUE;
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}

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static BOOL _unmarshal_int32(unsigned char **pData,
                             unsigned int *pLenRemain,
                             Int32 *dest)
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{
    if (4 > *pLenRemain)
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        return FALSE;
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    *dest = (*pData)[0] | (*pData)[1]<<8 | (*pData)[2]<<16 | (*pData)[3]<<24;
    *pData += 4;
    *pLenRemain -= 4;
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    return TRUE;
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}

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static BOOL _unmarshal_uint32(unsigned char **pData,
                              unsigned int *pLenRemain,
                              UInt32 *dest)
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{
    if (4 > *pLenRemain)
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        return FALSE;
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    *dest = (*pData)[0] | (*pData)[1]<<8 | (*pData)[2]<<16 | (*pData)[3]<<24;
    *pData += 4;
    *pLenRemain -= 4;
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    return TRUE;
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}

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static BOOL _unmarshal_int64(unsigned char **pData,
                             unsigned int *pLenRemain,
                             Int64 *dest)
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{
    Int64 temp;
    int i;
    if (8 > *pLenRemain)
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        return FALSE;
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    temp=0;
    for(i=8; i>0; i--)
    {
        temp <<= 8;
        temp |= (*pData)[i-1];
    }
    *dest = temp;
    *pData += 8;
    *pLenRemain -= 8;
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    return TRUE;
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}

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static BOOL _unmarshal_uint64(unsigned char **pData,
                              unsigned int *pLenRemain,
                              UInt64 *dest)
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{
    UInt64 temp;
    int i;
    if (8 > *pLenRemain)
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        return FALSE;
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    temp=0;
    for(i=8; i>0; i--)
    {
        temp <<= 8;
        temp |= (*pData)[i-1];
    }
    *dest = temp;
    *pData += 8;
    *pLenRemain -= 8;
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    return TRUE;
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}

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static BOOL _unmarshal_uuid(unsigned char **pData,
                            unsigned int *pDataLen,
                            unsigned char *dest)
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{
    return _unmarshal_uchar_array(pData, pDataLen, dest, 16);
}

/*
 * structures local to this module
 */

/* structure of ITSF headers */
#define _CHM_ITSF_V2_LEN (0x58)
#define _CHM_ITSF_V3_LEN (0x60)
struct chmItsfHeader
{
    char        signature[4];           /*  0 (ITSF) */
    Int32       version;                /*  4 */
    Int32       header_len;             /*  8 */
    Int32       unknown_000c;           /*  c */
    UInt32      last_modified;          /* 10 */
    UInt32      lang_id;                /* 14 */
    UChar       dir_uuid[16];           /* 18 */
    UChar       stream_uuid[16];        /* 28 */
    UInt64      unknown_offset;         /* 38 */
    UInt64      unknown_len;            /* 40 */
    UInt64      dir_offset;             /* 48 */
    UInt64      dir_len;                /* 50 */
    UInt64      data_offset;            /* 58 (Not present before V3) */
}; /* __attribute__ ((aligned (1))); */

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static BOOL _unmarshal_itsf_header(unsigned char **pData,
                                   unsigned int *pDataLen,
                                   struct chmItsfHeader *dest)
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{
    /* we only know how to deal with the 0x58 and 0x60 byte structures */
    if (*pDataLen != _CHM_ITSF_V2_LEN  &&  *pDataLen != _CHM_ITSF_V3_LEN)
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        return FALSE;
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    /* unmarshal common fields */
    _unmarshal_char_array(pData, pDataLen,  dest->signature, 4);
    _unmarshal_int32     (pData, pDataLen, &dest->version);
    _unmarshal_int32     (pData, pDataLen, &dest->header_len);
    _unmarshal_int32     (pData, pDataLen, &dest->unknown_000c);
    _unmarshal_uint32    (pData, pDataLen, &dest->last_modified);
    _unmarshal_uint32    (pData, pDataLen, &dest->lang_id);
    _unmarshal_uuid      (pData, pDataLen,  dest->dir_uuid);
    _unmarshal_uuid      (pData, pDataLen,  dest->stream_uuid);
    _unmarshal_uint64    (pData, pDataLen, &dest->unknown_offset);
    _unmarshal_uint64    (pData, pDataLen, &dest->unknown_len);
    _unmarshal_uint64    (pData, pDataLen, &dest->dir_offset);
    _unmarshal_uint64    (pData, pDataLen, &dest->dir_len);

    /* error check the data */
    /* XXX: should also check UUIDs, probably, though with a version 3 file,
     * current MS tools do not seem to use them.
     */
    if (memcmp(dest->signature, "ITSF", 4) != 0)
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        return FALSE;
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    if (dest->version == 2)
    {
        if (dest->header_len < _CHM_ITSF_V2_LEN)
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            return FALSE;
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    }
    else if (dest->version == 3)
    {
        if (dest->header_len < _CHM_ITSF_V3_LEN)
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            return FALSE;
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    }
    else
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        return FALSE;
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    /* now, if we have a V3 structure, unmarshal the rest.
     * otherwise, compute it
     */
    if (dest->version == 3)
    {
        if (*pDataLen != 0)
            _unmarshal_uint64(pData, pDataLen, &dest->data_offset);
        else
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            return FALSE;
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    }
    else
        dest->data_offset = dest->dir_offset + dest->dir_len;

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    return TRUE;
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}

/* structure of ITSP headers */
#define _CHM_ITSP_V1_LEN (0x54)
struct chmItspHeader
{
    char        signature[4];           /*  0 (ITSP) */
    Int32       version;                /*  4 */
    Int32       header_len;             /*  8 */
    Int32       unknown_000c;           /*  c */
    UInt32      block_len;              /* 10 */
    Int32       blockidx_intvl;         /* 14 */
    Int32       index_depth;            /* 18 */
    Int32       index_root;             /* 1c */
    Int32       index_head;             /* 20 */
    Int32       unknown_0024;           /* 24 */
    UInt32      num_blocks;             /* 28 */
    Int32       unknown_002c;           /* 2c */
    UInt32      lang_id;                /* 30 */
    UChar       system_uuid[16];        /* 34 */
    UChar       unknown_0044[16];       /* 44 */
}; /* __attribute__ ((aligned (1))); */

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static BOOL _unmarshal_itsp_header(unsigned char **pData,
                                   unsigned int *pDataLen,
                                   struct chmItspHeader *dest)
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{
    /* we only know how to deal with a 0x54 byte structures */
    if (*pDataLen != _CHM_ITSP_V1_LEN)
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        return FALSE;
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    /* unmarshal fields */
    _unmarshal_char_array(pData, pDataLen,  dest->signature, 4);
    _unmarshal_int32     (pData, pDataLen, &dest->version);
    _unmarshal_int32     (pData, pDataLen, &dest->header_len);
    _unmarshal_int32     (pData, pDataLen, &dest->unknown_000c);
    _unmarshal_uint32    (pData, pDataLen, &dest->block_len);
    _unmarshal_int32     (pData, pDataLen, &dest->blockidx_intvl);
    _unmarshal_int32     (pData, pDataLen, &dest->index_depth);
    _unmarshal_int32     (pData, pDataLen, &dest->index_root);
    _unmarshal_int32     (pData, pDataLen, &dest->index_head);
    _unmarshal_int32     (pData, pDataLen, &dest->unknown_0024);
    _unmarshal_uint32    (pData, pDataLen, &dest->num_blocks);
    _unmarshal_int32     (pData, pDataLen, &dest->unknown_002c);
    _unmarshal_uint32    (pData, pDataLen, &dest->lang_id);
    _unmarshal_uuid      (pData, pDataLen,  dest->system_uuid);
    _unmarshal_uchar_array(pData, pDataLen, dest->unknown_0044, 16);

    /* error check the data */
    if (memcmp(dest->signature, "ITSP", 4) != 0)
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        return FALSE;
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    if (dest->version != 1)
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        return FALSE;
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    if (dest->header_len != _CHM_ITSP_V1_LEN)
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        return FALSE;
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    return TRUE;
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}

/* structure of PMGL headers */
static const char _chm_pmgl_marker[4] = "PMGL";
#define _CHM_PMGL_LEN (0x14)
struct chmPmglHeader
{
    char        signature[4];           /*  0 (PMGL) */
    UInt32      free_space;             /*  4 */
    UInt32      unknown_0008;           /*  8 */
    Int32       block_prev;             /*  c */
    Int32       block_next;             /* 10 */
}; /* __attribute__ ((aligned (1))); */

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static BOOL _unmarshal_pmgl_header(unsigned char **pData,
                                   unsigned int *pDataLen,
                                   struct chmPmglHeader *dest)
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{
    /* we only know how to deal with a 0x14 byte structures */
    if (*pDataLen != _CHM_PMGL_LEN)
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        return FALSE;
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    /* unmarshal fields */
    _unmarshal_char_array(pData, pDataLen,  dest->signature, 4);
    _unmarshal_uint32    (pData, pDataLen, &dest->free_space);
    _unmarshal_uint32    (pData, pDataLen, &dest->unknown_0008);
    _unmarshal_int32     (pData, pDataLen, &dest->block_prev);
    _unmarshal_int32     (pData, pDataLen, &dest->block_next);

    /* check structure */
    if (memcmp(dest->signature, _chm_pmgl_marker, 4) != 0)
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        return FALSE;
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    return TRUE;
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}

/* structure of PMGI headers */
static const char _chm_pmgi_marker[4] = "PMGI";
#define _CHM_PMGI_LEN (0x08)
struct chmPmgiHeader
{
    char        signature[4];           /*  0 (PMGI) */
    UInt32      free_space;             /*  4 */
}; /* __attribute__ ((aligned (1))); */

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static BOOL _unmarshal_pmgi_header(unsigned char **pData,
                                   unsigned int *pDataLen,
                                   struct chmPmgiHeader *dest)
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{
    /* we only know how to deal with a 0x8 byte structures */
    if (*pDataLen != _CHM_PMGI_LEN)
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        return FALSE;
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    /* unmarshal fields */
    _unmarshal_char_array(pData, pDataLen,  dest->signature, 4);
    _unmarshal_uint32    (pData, pDataLen, &dest->free_space);

    /* check structure */
    if (memcmp(dest->signature, _chm_pmgi_marker, 4) != 0)
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        return FALSE;
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    return TRUE;
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}

/* structure of LZXC reset table */
#define _CHM_LZXC_RESETTABLE_V1_LEN (0x28)
struct chmLzxcResetTable
{
    UInt32      version;
    UInt32      block_count;
    UInt32      unknown;
    UInt32      table_offset;
    UInt64      uncompressed_len;
    UInt64      compressed_len;
    UInt64      block_len;     
}; /* __attribute__ ((aligned (1))); */

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static BOOL _unmarshal_lzxc_reset_table(unsigned char **pData,
                                        unsigned int *pDataLen,
                                        struct chmLzxcResetTable *dest)
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{
    /* we only know how to deal with a 0x28 byte structures */
    if (*pDataLen != _CHM_LZXC_RESETTABLE_V1_LEN)
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        return FALSE;
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    /* unmarshal fields */
    _unmarshal_uint32    (pData, pDataLen, &dest->version);
    _unmarshal_uint32    (pData, pDataLen, &dest->block_count);
    _unmarshal_uint32    (pData, pDataLen, &dest->unknown);
    _unmarshal_uint32    (pData, pDataLen, &dest->table_offset);
    _unmarshal_uint64    (pData, pDataLen, &dest->uncompressed_len);
    _unmarshal_uint64    (pData, pDataLen, &dest->compressed_len);
    _unmarshal_uint64    (pData, pDataLen, &dest->block_len);

    /* check structure */
    if (dest->version != 2)
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        return FALSE;
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    return TRUE;
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}

/* structure of LZXC control data block */
#define _CHM_LZXC_MIN_LEN (0x18)
#define _CHM_LZXC_V2_LEN (0x1c)
struct chmLzxcControlData
{
    UInt32      size;                   /*  0        */
    char        signature[4];           /*  4 (LZXC) */
    UInt32      version;                /*  8        */
    UInt32      resetInterval;          /*  c        */
    UInt32      windowSize;             /* 10        */
    UInt32      windowsPerReset;        /* 14        */
    UInt32      unknown_18;             /* 18        */
};

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static BOOL _unmarshal_lzxc_control_data(unsigned char **pData,
                                         unsigned int *pDataLen,
                                         struct chmLzxcControlData *dest)
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{
    /* we want at least 0x18 bytes */
    if (*pDataLen < _CHM_LZXC_MIN_LEN)
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        return FALSE;
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    /* unmarshal fields */
    _unmarshal_uint32    (pData, pDataLen, &dest->size);
    _unmarshal_char_array(pData, pDataLen,  dest->signature, 4);
    _unmarshal_uint32    (pData, pDataLen, &dest->version);
    _unmarshal_uint32    (pData, pDataLen, &dest->resetInterval);
    _unmarshal_uint32    (pData, pDataLen, &dest->windowSize);
    _unmarshal_uint32    (pData, pDataLen, &dest->windowsPerReset);

    if (*pDataLen >= _CHM_LZXC_V2_LEN)
        _unmarshal_uint32    (pData, pDataLen, &dest->unknown_18);
    else
        dest->unknown_18 = 0;

    if (dest->version == 2)
    {
        dest->resetInterval *= 0x8000;
        dest->windowSize *= 0x8000;
    }
    if (dest->windowSize == 0  ||  dest->resetInterval == 0)
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        return FALSE;
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    /* for now, only support resetInterval a multiple of windowSize/2 */
    if (dest->windowSize == 1)
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        return FALSE;
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    if ((dest->resetInterval % (dest->windowSize/2)) != 0)
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        return FALSE;
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    /* check structure */
    if (memcmp(dest->signature, "LZXC", 4) != 0)
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        return FALSE;
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    return TRUE;
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}

/* the structure used for chm file handles */
struct chmFile
{
    HANDLE              fd;

    CRITICAL_SECTION    mutex;
    CRITICAL_SECTION    lzx_mutex;
    CRITICAL_SECTION    cache_mutex;

    UInt64              dir_offset;
    UInt64              dir_len;    
    UInt64              data_offset;
    Int32               index_root;
    Int32               index_head;
    UInt32              block_len;     

    UInt64              span;
    struct chmUnitInfo  rt_unit;
    struct chmUnitInfo  cn_unit;
    struct chmLzxcResetTable reset_table;

    /* LZX control data */
    int                 compression_enabled;
    UInt32              window_size;
    UInt32              reset_interval;
    UInt32              reset_blkcount;

    /* decompressor state */
    struct LZXstate    *lzx_state;
    int                 lzx_last_block;

    /* cache for decompressed blocks */
    UChar             **cache_blocks;
    Int64              *cache_block_indices;
    Int32               cache_num_blocks;
};

/*
 * utility functions local to this module
 */

/* utility function to handle differences between {pread,read}(64)? */
static Int64 _chm_fetch_bytes(struct chmFile *h,
                              UChar *buf,
                              UInt64 os,
                              Int64 len)
{
    Int64 readLen=0;
    if (h->fd  ==  CHM_NULL_FD)
        return readLen;

    CHM_ACQUIRE_LOCK(h->mutex);
    /* NOTE: this might be better done with CreateFileMapping, et cetera... */
    {
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        LARGE_INTEGER old_pos, new_pos;
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        DWORD actualLen=0;

        /* awkward Win32 Seek/Tell */
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        new_pos.QuadPart = 0;
        SetFilePointerEx( h->fd, new_pos, &old_pos, FILE_CURRENT );
        new_pos.QuadPart = os;
        SetFilePointerEx( h->fd, new_pos, NULL, FILE_BEGIN );
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        /* read the data */
        if (ReadFile(h->fd,
                     buf,
                     (DWORD)len,
                     &actualLen,
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                     NULL))
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            readLen = actualLen;
        else
            readLen = 0;

        /* restore original position */
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        SetFilePointerEx( h->fd, old_pos, NULL, FILE_BEGIN );
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    }
    CHM_RELEASE_LOCK(h->mutex);
    return readLen;
}

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/*
 * set a parameter on the file handle.
 * valid parameter types:
 *          CHM_PARAM_MAX_BLOCKS_CACHED:
 *                 how many decompressed blocks should be cached?  A simple
 *                 caching scheme is used, wherein the index of the block is
 *                 used as a hash value, and hash collision results in the
 *                 invalidation of the previously cached block.
 */
static void chm_set_param(struct chmFile *h,
                          int paramType,
                          int paramVal)
{
    switch (paramType)
    {
        case CHM_PARAM_MAX_BLOCKS_CACHED:
            CHM_ACQUIRE_LOCK(h->cache_mutex);
            if (paramVal != h->cache_num_blocks)
            {
                UChar **newBlocks;
                Int64 *newIndices;
                int     i;

                /* allocate new cached blocks */
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                newBlocks = HeapAlloc(GetProcessHeap(), 0, paramVal * sizeof (UChar *));
                newIndices = HeapAlloc(GetProcessHeap(), 0, paramVal * sizeof (UInt64));
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                for (i=0; i<paramVal; i++)
                {
                    newBlocks[i] = NULL;
                    newIndices[i] = 0;
                }

                /* re-distribute old cached blocks */
                if (h->cache_blocks)
                {
                    for (i=0; i<h->cache_num_blocks; i++)
                    {
                        int newSlot = (int)(h->cache_block_indices[i] % paramVal);

                        if (h->cache_blocks[i])
                        {
                            /* in case of collision, destroy newcomer */
                            if (newBlocks[newSlot])
                            {
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                                HeapFree(GetProcessHeap(), 0, h->cache_blocks[i]);
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                                h->cache_blocks[i] = NULL;
                            }
                            else
                            {
                                newBlocks[newSlot] = h->cache_blocks[i];
                                newIndices[newSlot] =
                                            h->cache_block_indices[i];
                            }
                        }
                    }

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                    HeapFree(GetProcessHeap(), 0, h->cache_blocks);
                    HeapFree(GetProcessHeap(), 0, h->cache_block_indices);
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                }

                /* now, set new values */
                h->cache_blocks = newBlocks;
                h->cache_block_indices = newIndices;
                h->cache_num_blocks = paramVal;
            }
            CHM_RELEASE_LOCK(h->cache_mutex);
            break;

        default:
            break;
    }
}

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/* open an ITS archive */
struct chmFile *chm_openW(const WCHAR *filename)
{
    unsigned char               sbuffer[256];
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    unsigned int                sremain;
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    unsigned char              *sbufpos;
    struct chmFile             *newHandle=NULL;
    struct chmItsfHeader        itsfHeader;
    struct chmItspHeader        itspHeader;
#if 0
    struct chmUnitInfo          uiSpan;
#endif
    struct chmUnitInfo          uiLzxc;
    struct chmLzxcControlData   ctlData;

    /* allocate handle */
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    newHandle = HeapAlloc(GetProcessHeap(), 0, sizeof(struct chmFile));
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    newHandle->fd = CHM_NULL_FD;
    newHandle->lzx_state = NULL;
    newHandle->cache_blocks = NULL;
    newHandle->cache_block_indices = NULL;
    newHandle->cache_num_blocks = 0;

    /* open file */
    if ((newHandle->fd=CreateFileW(filename,
                                   GENERIC_READ,
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                                   FILE_SHARE_READ,
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                                   NULL,
                                   OPEN_EXISTING,
                                   FILE_ATTRIBUTE_NORMAL,
                                   NULL)) == CHM_NULL_FD)
    {
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        HeapFree(GetProcessHeap(), 0, newHandle);
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        return NULL;
    }

    /* initialize mutexes, if needed */
    InitializeCriticalSection(&newHandle->mutex);
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    newHandle->mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": chmFile.mutex");
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    InitializeCriticalSection(&newHandle->lzx_mutex);
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    newHandle->lzx_mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": chmFile.lzx_mutex");
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    InitializeCriticalSection(&newHandle->cache_mutex);
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    newHandle->cache_mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": chmFile.cache_mutex");
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    /* read and verify header */
    sremain = _CHM_ITSF_V3_LEN;
    sbufpos = sbuffer;
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    if (_chm_fetch_bytes(newHandle, sbuffer, 0, sremain) != sremain    ||
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        !_unmarshal_itsf_header(&sbufpos, &sremain, &itsfHeader))
    {
        chm_close(newHandle);
        return NULL;
    }

    /* stash important values from header */
    newHandle->dir_offset  = itsfHeader.dir_offset;
    newHandle->dir_len     = itsfHeader.dir_len;
    newHandle->data_offset = itsfHeader.data_offset;

    /* now, read and verify the directory header chunk */
    sremain = _CHM_ITSP_V1_LEN;
    sbufpos = sbuffer;
    if (_chm_fetch_bytes(newHandle, sbuffer,
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                         itsfHeader.dir_offset, sremain) != sremain    ||
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        !_unmarshal_itsp_header(&sbufpos, &sremain, &itspHeader))
    {
        chm_close(newHandle);
        return NULL;
    }

    /* grab essential information from ITSP header */
    newHandle->dir_offset += itspHeader.header_len;
    newHandle->dir_len    -= itspHeader.header_len;
    newHandle->index_root  = itspHeader.index_root;
    newHandle->index_head  = itspHeader.index_head;
    newHandle->block_len   = itspHeader.block_len;

    /* if the index root is -1, this means we don't have any PMGI blocks.
     * as a result, we must use the sole PMGL block as the index root
     */
    if (newHandle->index_root == -1)
        newHandle->index_root = newHandle->index_head;

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    /* initialize cache */
    chm_set_param(newHandle, CHM_PARAM_MAX_BLOCKS_CACHED,
                  CHM_MAX_BLOCKS_CACHED);

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    /* By default, compression is enabled. */
    newHandle->compression_enabled = 1;

    /* prefetch most commonly needed unit infos */
    if (CHM_RESOLVE_SUCCESS != chm_resolve_object(newHandle,
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                                                  L"::DataSpace/Storage/MSCompressed/Transform/"
                                                  "{7FC28940-9D31-11D0-9B27-00A0C91E9C7C}/"
                                                  "InstanceData/ResetTable",
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                                                  &newHandle->rt_unit)    ||
        newHandle->rt_unit.space == CHM_COMPRESSED                        ||
        CHM_RESOLVE_SUCCESS != chm_resolve_object(newHandle,
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                                                  L"::DataSpace/Storage/MSCompressed/Content",
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                                                  &newHandle->cn_unit)    ||
        newHandle->cn_unit.space == CHM_COMPRESSED                        ||
        CHM_RESOLVE_SUCCESS != chm_resolve_object(newHandle,
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                                                  L"::DataSpace/Storage/MSCompressed/ControlData",
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                                                  &uiLzxc)                ||
        uiLzxc.space == CHM_COMPRESSED)
    {
        newHandle->compression_enabled = 0;
    }

    /* read reset table info */
    if (newHandle->compression_enabled)
    {
        sremain = _CHM_LZXC_RESETTABLE_V1_LEN;
        sbufpos = sbuffer;
        if (chm_retrieve_object(newHandle, &newHandle->rt_unit, sbuffer,
                                0, sremain) != sremain                        ||
            !_unmarshal_lzxc_reset_table(&sbufpos, &sremain,
                                         &newHandle->reset_table))
        {
            newHandle->compression_enabled = 0;
        }
    }

    /* read control data */
    if (newHandle->compression_enabled)
    {
        sremain = (unsigned long)uiLzxc.length;
        sbufpos = sbuffer;
        if (chm_retrieve_object(newHandle, &uiLzxc, sbuffer,
                                0, sremain) != sremain                       ||
            !_unmarshal_lzxc_control_data(&sbufpos, &sremain,
                                          &ctlData))
        {
            newHandle->compression_enabled = 0;
        }
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        else
        {
            newHandle->window_size = ctlData.windowSize;
            newHandle->reset_interval = ctlData.resetInterval;
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/* Jed, Mon Jun 28: Experimentally, it appears that the reset block count */
/*       must be multiplied by this formerly unknown ctrl data field in   */
/*       order to decompress some files.                                  */
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            newHandle->reset_blkcount = newHandle->reset_interval / (newHandle->window_size / 2) *
                                        ctlData.windowsPerReset;
        }
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    }

    return newHandle;
}

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/* Duplicate an ITS archive handle */
struct chmFile *chm_dup(struct chmFile *oldHandle)
{
    struct chmFile *newHandle=NULL;

    newHandle = HeapAlloc(GetProcessHeap(), 0, sizeof(struct chmFile));
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    *newHandle = *oldHandle;
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    /* duplicate fd handle */
    DuplicateHandle(GetCurrentProcess(), oldHandle->fd,
                    GetCurrentProcess(), &(newHandle->fd),
                    0, FALSE, DUPLICATE_SAME_ACCESS);
    newHandle->lzx_state = NULL;
    newHandle->cache_blocks = NULL;
    newHandle->cache_block_indices = NULL;
    newHandle->cache_num_blocks = 0;

    /* initialize mutexes, if needed */
    InitializeCriticalSection(&newHandle->mutex);
    newHandle->mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": chmFile.mutex");
    InitializeCriticalSection(&newHandle->lzx_mutex);
    newHandle->lzx_mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": chmFile.lzx_mutex");
    InitializeCriticalSection(&newHandle->cache_mutex);
    newHandle->cache_mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": chmFile.cache_mutex");

    /* initialize cache */
    chm_set_param(newHandle, CHM_PARAM_MAX_BLOCKS_CACHED,
                  CHM_MAX_BLOCKS_CACHED);

    return newHandle;
}

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/* close an ITS archive */
void chm_close(struct chmFile *h)
{
    if (h != NULL)
    {
        if (h->fd != CHM_NULL_FD)
            CHM_CLOSE_FILE(h->fd);
        h->fd = CHM_NULL_FD;

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        h->mutex.DebugInfo->Spare[0] = 0;
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        DeleteCriticalSection(&h->mutex);
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        h->lzx_mutex.DebugInfo->Spare[0] = 0;
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        DeleteCriticalSection(&h->lzx_mutex);
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        h->cache_mutex.DebugInfo->Spare[0] = 0;
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        DeleteCriticalSection(&h->cache_mutex);

        if (h->lzx_state)
            LZXteardown(h->lzx_state);
        h->lzx_state = NULL;

        if (h->cache_blocks)
        {
            int i;
            for (i=0; i<h->cache_num_blocks; i++)
            {
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                HeapFree(GetProcessHeap(), 0, h->cache_blocks[i]);
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            }
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            HeapFree(GetProcessHeap(), 0, h->cache_blocks);
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            h->cache_blocks = NULL;
        }

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        HeapFree(GetProcessHeap(), 0, h->cache_block_indices);
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        h->cache_block_indices = NULL;

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        HeapFree(GetProcessHeap(), 0, h);
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    }
}

/*
 * helper methods for chm_resolve_object
 */

/* skip a compressed dword */
static void _chm_skip_cword(UChar **pEntry)
{
    while (*(*pEntry)++ >= 0x80)
        ;
}

/* skip the data from a PMGL entry */
static void _chm_skip_PMGL_entry_data(UChar **pEntry)
{
    _chm_skip_cword(pEntry);
    _chm_skip_cword(pEntry);
    _chm_skip_cword(pEntry);
}

/* parse a compressed dword */
static UInt64 _chm_parse_cword(UChar **pEntry)
{
    UInt64 accum = 0;
    UChar temp;
    while ((temp=*(*pEntry)++) >= 0x80)
    {
        accum <<= 7;
        accum += temp & 0x7f;
    }

    return (accum << 7) + temp;
}

/* parse a utf-8 string into an ASCII char buffer */
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static BOOL _chm_parse_UTF8(UChar **pEntry, UInt64 count, WCHAR *path)
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{
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    DWORD length = MultiByteToWideChar(CP_UTF8, 0, (char *)*pEntry, count, path, CHM_MAX_PATHLEN);
    path[length] = '\0';
    *pEntry += count;
    return !!length;
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}

/* parse a PMGL entry into a chmUnitInfo struct; return 1 on success. */
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static BOOL _chm_parse_PMGL_entry(UChar **pEntry, struct chmUnitInfo *ui)
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{
    UInt64 strLen;

    /* parse str len */
    strLen = _chm_parse_cword(pEntry);
    if (strLen > CHM_MAX_PATHLEN)
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        return FALSE;
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    /* parse path */
    if (! _chm_parse_UTF8(pEntry, strLen, ui->path))
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        return FALSE;
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    /* parse info */
    ui->space  = (int)_chm_parse_cword(pEntry);
    ui->start  = _chm_parse_cword(pEntry);
    ui->length = _chm_parse_cword(pEntry);
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    return TRUE;
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}

/* find an exact entry in PMGL; return NULL if we fail */
static UChar *_chm_find_in_PMGL(UChar *page_buf,
                         UInt32 block_len,
                         const WCHAR *objPath)
{
    /* XXX: modify this to do a binary search using the nice index structure
     *      that is provided for us.
     */
    struct chmPmglHeader header;
    UInt32 hremain;
    UChar *end;
    UChar *cur;
    UChar *temp;
    UInt64 strLen;
    WCHAR buffer[CHM_MAX_PATHLEN+1];

    /* figure out where to start and end */
    cur = page_buf;
    hremain = _CHM_PMGL_LEN;
    if (! _unmarshal_pmgl_header(&cur, &hremain, &header))
        return NULL;
    end = page_buf + block_len - (header.free_space);

    /* now, scan progressively */
    while (cur < end)
    {
        /* grab the name */
        temp = cur;
        strLen = _chm_parse_cword(&cur);
        if (! _chm_parse_UTF8(&cur, strLen, buffer))
            return NULL;

        /* check if it is the right name */
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        if (! wcsicmp(buffer, objPath))
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            return temp;

        _chm_skip_PMGL_entry_data(&cur);
    }

    return NULL;
}

/* find which block should be searched next for the entry; -1 if no block */
static Int32 _chm_find_in_PMGI(UChar *page_buf,
                        UInt32 block_len,
                        const WCHAR *objPath)
{
    /* XXX: modify this to do a binary search using the nice index structure
     *      that is provided for us
     */
    struct chmPmgiHeader header;
    UInt32 hremain;
    int page=-1;
    UChar *end;
    UChar *cur;
    UInt64 strLen;
    WCHAR buffer[CHM_MAX_PATHLEN+1];

    /* figure out where to start and end */
    cur = page_buf;
    hremain = _CHM_PMGI_LEN;
    if (! _unmarshal_pmgi_header(&cur, &hremain, &header))
        return -1;
    end = page_buf + block_len - (header.free_space);

    /* now, scan progressively */
    while (cur < end)
    {
        /* grab the name */
        strLen = _chm_parse_cword(&cur);
        if (! _chm_parse_UTF8(&cur, strLen, buffer))
            return -1;

        /* check if it is the right name */
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        if (wcsicmp(buffer, objPath) > 0)
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            return page;

        /* load next value for path */
        page = (int)_chm_parse_cword(&cur);
    }

    return page;
}

/* resolve a particular object from the archive */
int chm_resolve_object(struct chmFile *h,
                       const WCHAR *objPath,
                       struct chmUnitInfo *ui)
{
    /*
     * XXX: implement caching scheme for dir pages
     */

    Int32 curPage;

    /* buffer to hold whatever page we're looking at */
    UChar *page_buf = HeapAlloc(GetProcessHeap(), 0, h->block_len);

    /* starting page */
    curPage = h->index_root;

    /* until we have either returned or given up */
    while (curPage != -1)
    {

        /* try to fetch the index page */
        if (_chm_fetch_bytes(h, page_buf,
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                             h->dir_offset + (UInt64)curPage*h->block_len,
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                             h->block_len) != h->block_len)
	{
	    HeapFree(GetProcessHeap(), 0, page_buf);
            return CHM_RESOLVE_FAILURE;
	}

        /* now, if it is a leaf node: */
        if (memcmp(page_buf, _chm_pmgl_marker, 4) == 0)
        {
            /* scan block */
            UChar *pEntry = _chm_find_in_PMGL(page_buf,
                                              h->block_len,
                                              objPath);
            if (pEntry == NULL)
            {
	        HeapFree(GetProcessHeap(), 0, page_buf);
                return CHM_RESOLVE_FAILURE;
            }

            /* parse entry and return */
            _chm_parse_PMGL_entry(&pEntry, ui);
	    HeapFree(GetProcessHeap(), 0, page_buf);
            return CHM_RESOLVE_SUCCESS;
        }

        /* else, if it is a branch node: */
        else if (memcmp(page_buf, _chm_pmgi_marker, 4) == 0)
            curPage = _chm_find_in_PMGI(page_buf, h->block_len, objPath);

        /* else, we are confused.  give up. */
        else
        {
	    HeapFree(GetProcessHeap(), 0, page_buf);
            return CHM_RESOLVE_FAILURE;
        }
    }

    /* didn't find anything.  fail. */
    HeapFree(GetProcessHeap(), 0, page_buf);
    return CHM_RESOLVE_FAILURE;
}

/*
 * utility methods for dealing with compressed data
 */

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/* get the bounds of a compressed block. Returns FALSE on failure */
static BOOL _chm_get_cmpblock_bounds(struct chmFile *h,
                                     UInt64 block,
                                     UInt64 *start,
                                     Int64 *len)
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{
    UChar buffer[8], *dummy;
    UInt32 remain;

    /* for all but the last block, use the reset table */
    if (block < h->reset_table.block_count-1)
    {
        /* unpack the start address */
        dummy = buffer;
        remain = 8;
        if (_chm_fetch_bytes(h, buffer,
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                             h->data_offset
                                + h->rt_unit.start
                                + h->reset_table.table_offset
                                + block*8,
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                             remain) != remain                            ||
            !_unmarshal_uint64(&dummy, &remain, start))
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            return FALSE;
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        /* unpack the end address */
        dummy = buffer;
        remain = 8;
        if (_chm_fetch_bytes(h, buffer,
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                             h->data_offset
                                + h->rt_unit.start
                                + h->reset_table.table_offset
                                + block*8 + 8,
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                         remain) != remain                                ||
            !_unmarshal_int64(&dummy, &remain, len))
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            return FALSE;
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    }

    /* for the last block, use the span in addition to the reset table */
    else
    {
        /* unpack the start address */
        dummy = buffer;
        remain = 8;
        if (_chm_fetch_bytes(h, buffer,
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                             h->data_offset
                                + h->rt_unit.start
                                + h->reset_table.table_offset
                                + block*8,
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                             remain) != remain                            ||
            !_unmarshal_uint64(&dummy, &remain, start))
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            return FALSE;
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        *len = h->reset_table.compressed_len;
    }

    /* compute the length and absolute start address */
    *len -= *start;
    *start += h->data_offset + h->cn_unit.start;

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    return TRUE;
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}

/* decompress the block.  must have lzx_mutex. */
static Int64 _chm_decompress_block(struct chmFile *h,
                                   UInt64 block,
                                   UChar **ubuffer)
{
    UChar *cbuffer = HeapAlloc( GetProcessHeap(), 0,
                              ((unsigned int)h->reset_table.block_len + 6144));
    UInt64 cmpStart;                                    /* compressed start  */
    Int64 cmpLen;                                       /* compressed len    */
    int indexSlot;                                      /* cache index slot  */
    UChar *lbuffer;                                     /* local buffer ptr  */
Austin English's avatar
Austin English committed
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    UInt32 blockAlign = (UInt32)(block % h->reset_blkcount); /* reset interval align */
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    UInt32 i;                                           /* local loop index  */

    /* let the caching system pull its weight! */
    if (block - blockAlign <= h->lzx_last_block  &&
        block              >= h->lzx_last_block)
        blockAlign = (block - h->lzx_last_block);

    /* check if we need previous blocks */
    if (blockAlign != 0)
    {
        /* fetch all required previous blocks since last reset */
        for (i = blockAlign; i > 0; i--)
        {
            UInt32 curBlockIdx = block - i;

            /* check if we most recently decompressed the previous block */
            if (h->lzx_last_block != curBlockIdx)
            {
                if ((curBlockIdx % h->reset_blkcount) == 0)
                {
#ifdef CHM_DEBUG
                    fprintf(stderr, "***RESET (1)***\n");
#endif
                    LZXreset(h->lzx_state);
                }

                indexSlot = (int)((curBlockIdx) % h->cache_num_blocks);
                h->cache_block_indices[indexSlot] = curBlockIdx;
                if (! h->cache_blocks[indexSlot])
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                    h->cache_blocks[indexSlot] =
                      HeapAlloc(GetProcessHeap(), 0,
                                (unsigned int)(h->reset_table.block_len));
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                lbuffer = h->cache_blocks[indexSlot];

                /* decompress the previous block */
#ifdef CHM_DEBUG
                fprintf(stderr, "Decompressing block #%4d (EXTRA)\n", curBlockIdx);
#endif
                if (!_chm_get_cmpblock_bounds(h, curBlockIdx, &cmpStart, &cmpLen) ||
                    _chm_fetch_bytes(h, cbuffer, cmpStart, cmpLen) != cmpLen      ||
                    LZXdecompress(h->lzx_state, cbuffer, lbuffer, (int)cmpLen,
                                  (int)h->reset_table.block_len) != DECR_OK)
                {
#ifdef CHM_DEBUG
                    fprintf(stderr, "   (DECOMPRESS FAILED!)\n");
#endif
                    HeapFree(GetProcessHeap(), 0, cbuffer);
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                    return 0;
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                }

                h->lzx_last_block = (int)curBlockIdx;
            }
        }
    }
    else
    {
        if ((block % h->reset_blkcount) == 0)
        {
#ifdef CHM_DEBUG
            fprintf(stderr, "***RESET (2)***\n");
#endif
            LZXreset(h->lzx_state);
        }
    }

    /* allocate slot in cache */
    indexSlot = (int)(block % h->cache_num_blocks);
    h->cache_block_indices[indexSlot] = block;
    if (! h->cache_blocks[indexSlot])
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        h->cache_blocks[indexSlot] =
          HeapAlloc(GetProcessHeap(), 0, ((unsigned int)h->reset_table.block_len));
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    lbuffer = h->cache_blocks[indexSlot];
    *ubuffer = lbuffer;

    /* decompress the block we actually want */
#ifdef CHM_DEBUG
    fprintf(stderr, "Decompressing block #%4d (REAL )\n", block);
#endif
    if (! _chm_get_cmpblock_bounds(h, block, &cmpStart, &cmpLen)          ||
        _chm_fetch_bytes(h, cbuffer, cmpStart, cmpLen) != cmpLen          ||
        LZXdecompress(h->lzx_state, cbuffer, lbuffer, (int)cmpLen,
                      (int)h->reset_table.block_len) != DECR_OK)
    {
#ifdef CHM_DEBUG
        fprintf(stderr, "   (DECOMPRESS FAILED!)\n");
#endif
        HeapFree(GetProcessHeap(), 0, cbuffer);
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        return 0;
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    }
    h->lzx_last_block = (int)block;

    /* XXX: modify LZX routines to return the length of the data they
     * decompressed and return that instead, for an extra sanity check.
     */
    HeapFree(GetProcessHeap(), 0, cbuffer);
    return h->reset_table.block_len;
}

/* grab a region from a compressed block */
static Int64 _chm_decompress_region(struct chmFile *h,
                                    UChar *buf,
                                    UInt64 start,
                                    Int64 len)
{
    UInt64 nBlock, nOffset;
    UInt64 nLen;
    UInt64 gotLen;
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    UChar *ubuffer = NULL;
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        if (len <= 0)
1273
                return 0;
1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300

    /* figure out what we need to read */
    nBlock = start / h->reset_table.block_len;
    nOffset = start % h->reset_table.block_len;
    nLen = len;
    if (nLen > (h->reset_table.block_len - nOffset))
        nLen = h->reset_table.block_len - nOffset;

    /* if block is cached, return data from it. */
    CHM_ACQUIRE_LOCK(h->lzx_mutex);
    CHM_ACQUIRE_LOCK(h->cache_mutex);
    if (h->cache_block_indices[nBlock % h->cache_num_blocks] == nBlock    &&
        h->cache_blocks[nBlock % h->cache_num_blocks] != NULL)
    {
        memcpy(buf,
               h->cache_blocks[nBlock % h->cache_num_blocks] + nOffset,
               (unsigned int)nLen);
        CHM_RELEASE_LOCK(h->cache_mutex);
        CHM_RELEASE_LOCK(h->lzx_mutex);
        return nLen;
    }
    CHM_RELEASE_LOCK(h->cache_mutex);

    /* data request not satisfied, so... start up the decompressor machine */
    if (! h->lzx_state)
    {
        h->lzx_last_block = -1;
1301
        h->lzx_state = LZXinit(h->window_size);
1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321
    }

    /* decompress some data */
    gotLen = _chm_decompress_block(h, nBlock, &ubuffer);
    if (gotLen < nLen)
        nLen = gotLen;
    memcpy(buf, ubuffer+nOffset, (unsigned int)nLen);
    CHM_RELEASE_LOCK(h->lzx_mutex);
    return nLen;
}

/* retrieve (part of) an object */
LONGINT64 chm_retrieve_object(struct chmFile *h,
                               struct chmUnitInfo *ui,
                               unsigned char *buf,
                               LONGUINT64 addr,
                               LONGINT64 len)
{
    /* must be valid file handle */
    if (h == NULL)
1322
        return 0;
1323 1324

    /* starting address must be in correct range */
1325
    if (addr >= ui->length)
1326
        return 0;
1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337

    /* clip length */
    if (addr + len > ui->length)
        len = ui->length - addr;

    /* if the file is uncompressed, it's simple */
    if (ui->space == CHM_UNCOMPRESSED)
    {
        /* read data */
        return _chm_fetch_bytes(h,
                                buf,
1338
                                h->data_offset + ui->start + addr,
1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
                                len);
    }

    /* else if the file is compressed, it's a little trickier */
    else /* ui->space == CHM_COMPRESSED */
    {
        Int64 swath=0, total=0;

        /* if compression is not enabled for this file... */
        if (! h->compression_enabled)
            return total;

        do {

            /* swill another mouthful */
            swath = _chm_decompress_region(h, buf, ui->start + addr, len);

            /* if we didn't get any... */
            if (swath == 0)
                return total;

            /* update stats */
            total += swath;
            len -= swath;
            addr += swath;
            buf += swath;

        } while (len != 0);

        return total;
    }
}

1372 1373 1374 1375 1376
BOOL chm_enumerate_dir(struct chmFile *h,
                       const WCHAR *prefix,
                       int what,
                       CHM_ENUMERATOR e,
                       void *context)
1377 1378 1379 1380 1381 1382 1383 1384
{
    /*
     * XXX: do this efficiently (i.e. using the tree index)
     */

    Int32 curPage;

    /* buffer to hold whatever page we're looking at */
1385
    UChar *page_buf = HeapAlloc(GetProcessHeap(), 0, h->block_len);
1386 1387 1388
    struct chmPmglHeader header;
    UChar *end;
    UChar *cur;
1389
    unsigned int lenRemain;
1390

1391 1392
    /* set to TRUE once we've started */
    BOOL it_has_begun = FALSE;
1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408

    /* the current ui */
    struct chmUnitInfo ui;
    int flag;
    UInt64 ui_path_len;

    /* the length of the prefix */
    WCHAR prefixRectified[CHM_MAX_PATHLEN+1];
    int prefixLen;
    WCHAR lastPath[CHM_MAX_PATHLEN];
    int lastPathLen;

    /* starting page */
    curPage = h->index_head;

    /* initialize pathname state */
1409
    lstrcpynW(prefixRectified, prefix, CHM_MAX_PATHLEN);
1410
    prefixLen = lstrlenW(prefixRectified);
1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429
    if (prefixLen != 0)
    {
        if (prefixRectified[prefixLen-1] != '/')
        {
            prefixRectified[prefixLen] = '/';
            prefixRectified[prefixLen+1] = '\0';
            ++prefixLen;
        }
    }
    lastPath[0] = '\0';
    lastPathLen = -1;

    /* until we have either returned or given up */
    while (curPage != -1)
    {

        /* try to fetch the index page */
        if (_chm_fetch_bytes(h,
                             page_buf,
1430
                             h->dir_offset + (UInt64)curPage*h->block_len,
1431 1432 1433
                             h->block_len) != h->block_len)
        {
            HeapFree(GetProcessHeap(), 0, page_buf);
1434
            return FALSE;
1435 1436 1437 1438 1439 1440 1441 1442
        }

        /* figure out start and end for this page */
        cur = page_buf;
        lenRemain = _CHM_PMGL_LEN;
        if (! _unmarshal_pmgl_header(&cur, &lenRemain, &header))
        {
            HeapFree(GetProcessHeap(), 0, page_buf);
1443
            return FALSE;
1444 1445 1446 1447 1448 1449 1450 1451 1452
        }
        end = page_buf + h->block_len - (header.free_space);

        /* loop over this page */
        while (cur < end)
        {
            if (! _chm_parse_PMGL_entry(&cur, &ui))
            {
                HeapFree(GetProcessHeap(), 0, page_buf);
1453
                return FALSE;
1454 1455 1456 1457 1458
            }

            /* check if we should start */
            if (! it_has_begun)
            {
1459
                if (ui.length == 0  &&  wcsnicmp(ui.path, prefixRectified, prefixLen) == 0)
1460
                    it_has_begun = TRUE;
1461 1462 1463 1464 1465 1466 1467 1468 1469 1470
                else
                    continue;

                if (ui.path[prefixLen] == '\0')
                    continue;
            }

            /* check if we should stop */
            else
            {
1471
                if (wcsnicmp(ui.path, prefixRectified, prefixLen) != 0)
1472 1473
                {
                    HeapFree(GetProcessHeap(), 0, page_buf);
1474
                    return TRUE;
1475 1476 1477 1478 1479 1480
                }
            }

            /* check if we should include this path */
            if (lastPathLen != -1)
            {
1481
                if (wcsnicmp(ui.path, lastPath, lastPathLen) == 0)
1482 1483
                    continue;
            }
1484 1485
            lstrcpyW(lastPath, ui.path);
            lastPathLen = lstrlenW(lastPath);
1486 1487

            /* get the length of the path */
1488
            ui_path_len = lstrlenW(ui.path)-1;
1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519

            /* check for DIRS */
            if (ui.path[ui_path_len] == '/'  &&  !(what & CHM_ENUMERATE_DIRS))
                continue;

            /* check for FILES */
            if (ui.path[ui_path_len] != '/'  &&  !(what & CHM_ENUMERATE_FILES))
                continue;

            /* check for NORMAL vs. META */
            if (ui.path[0] == '/')
            {

                /* check for NORMAL vs. SPECIAL */
                if (ui.path[1] == '#'  ||  ui.path[1] == '$')
                    flag = CHM_ENUMERATE_SPECIAL;
                else
                    flag = CHM_ENUMERATE_NORMAL;
            }
            else
                flag = CHM_ENUMERATE_META;
            if (! (what & flag))
                continue;

            /* call the enumerator */
            {
                int status = (*e)(h, &ui, context);
                switch (status)
                {
                    case CHM_ENUMERATOR_FAILURE:
                        HeapFree(GetProcessHeap(), 0, page_buf);
1520
                        return FALSE;
1521 1522 1523 1524
                    case CHM_ENUMERATOR_CONTINUE:
                        break;
                    case CHM_ENUMERATOR_SUCCESS:
                        HeapFree(GetProcessHeap(), 0, page_buf);
1525
                        return TRUE;
1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536
                    default:
                        break;
                }
            }
        }

        /* advance to next page */
        curPage = header.block_next;
    }

    HeapFree(GetProcessHeap(), 0, page_buf);
1537
    return TRUE;
1538
}