Adding upstream version 3.40.1.upstream/3.40.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2212 insertions, 0 deletions

diff --git a/ext/misc/zipfile.c b/ext/misc/zipfile.c
new file mode 100644
index 0000000..f818fbc
--- /dev/null
+++ b/ext/misc/zipfile.c
@@ -0,0 +1,2212 @@
+/*
+** 2017-12-26
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This file implements a virtual table for reading and writing ZIP archive
+** files.
+**
+** Usage example:
+**
+**     SELECT name, sz, datetime(mtime,'unixepoch') FROM zipfile($filename);
+**
+** Current limitations:
+**
+**    *  No support for encryption
+**    *  No support for ZIP archives spanning multiple files
+**    *  No support for zip64 extensions
+**    *  Only the "inflate/deflate" (zlib) compression method is supported
+*/
+#include "sqlite3ext.h"
+SQLITE_EXTENSION_INIT1
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include <zlib.h>
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+#ifndef SQLITE_AMALGAMATION
+
+#ifndef UINT32_TYPE
+# ifdef HAVE_UINT32_T
+#  define UINT32_TYPE uint32_t
+# else
+#  define UINT32_TYPE unsigned int
+# endif
+#endif
+#ifndef UINT16_TYPE
+# ifdef HAVE_UINT16_T
+#  define UINT16_TYPE uint16_t
+# else
+#  define UINT16_TYPE unsigned short int
+# endif
+#endif
+typedef sqlite3_int64 i64;
+typedef unsigned char u8;
+typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
+typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+
+#if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
+# define SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS 1
+#endif
+#if defined(SQLITE_OMIT_AUXILIARY_SAFETY_CHECKS)
+# define ALWAYS(X)      (1)
+# define NEVER(X)       (0)
+#elif !defined(NDEBUG)
+# define ALWAYS(X)      ((X)?1:(assert(0),0))
+# define NEVER(X)       ((X)?(assert(0),1):0)
+#else
+# define ALWAYS(X)      (X)
+# define NEVER(X)       (X)
+#endif
+
+#endif   /* SQLITE_AMALGAMATION */
+
+/*
+** Definitions for mode bitmasks S_IFDIR, S_IFREG and S_IFLNK.
+**
+** In some ways it would be better to obtain these values from system 
+** header files. But, the dependency is undesirable and (a) these
+** have been stable for decades, (b) the values are part of POSIX and
+** are also made explicit in [man stat], and (c) are part of the 
+** file format for zip archives.
+*/
+#ifndef S_IFDIR
+# define S_IFDIR 0040000
+#endif
+#ifndef S_IFREG
+# define S_IFREG 0100000
+#endif
+#ifndef S_IFLNK
+# define S_IFLNK 0120000
+#endif
+
+static const char ZIPFILE_SCHEMA[] = 
+  "CREATE TABLE y("
+    "name PRIMARY KEY,"  /* 0: Name of file in zip archive */
+    "mode,"              /* 1: POSIX mode for file */
+    "mtime,"             /* 2: Last modification time (secs since 1970)*/
+    "sz,"                /* 3: Size of object */
+    "rawdata,"           /* 4: Raw data */
+    "data,"              /* 5: Uncompressed data */
+    "method,"            /* 6: Compression method (integer) */
+    "z HIDDEN"           /* 7: Name of zip file */
+  ") WITHOUT ROWID;";
+
+#define ZIPFILE_F_COLUMN_IDX 7    /* Index of column "file" in the above */
+#define ZIPFILE_BUFFER_SIZE (64*1024)
+
+
+/*
+** Magic numbers used to read and write zip files.
+**
+** ZIPFILE_NEWENTRY_MADEBY:
+**   Use this value for the "version-made-by" field in new zip file
+**   entries. The upper byte indicates "unix", and the lower byte 
+**   indicates that the zip file matches pkzip specification 3.0. 
+**   This is what info-zip seems to do.
+**
+** ZIPFILE_NEWENTRY_REQUIRED:
+**   Value for "version-required-to-extract" field of new entries.
+**   Version 2.0 is required to support folders and deflate compression.
+**
+** ZIPFILE_NEWENTRY_FLAGS:
+**   Value for "general-purpose-bit-flags" field of new entries. Bit
+**   11 means "utf-8 filename and comment".
+**
+** ZIPFILE_SIGNATURE_CDS:
+**   First 4 bytes of a valid CDS record.
+**
+** ZIPFILE_SIGNATURE_LFH:
+**   First 4 bytes of a valid LFH record.
+**
+** ZIPFILE_SIGNATURE_EOCD
+**   First 4 bytes of a valid EOCD record.
+*/
+#define ZIPFILE_EXTRA_TIMESTAMP   0x5455
+#define ZIPFILE_NEWENTRY_MADEBY   ((3<<8) + 30)
+#define ZIPFILE_NEWENTRY_REQUIRED 20
+#define ZIPFILE_NEWENTRY_FLAGS    0x800
+#define ZIPFILE_SIGNATURE_CDS     0x02014b50
+#define ZIPFILE_SIGNATURE_LFH     0x04034b50
+#define ZIPFILE_SIGNATURE_EOCD    0x06054b50
+
+/*
+** The sizes of the fixed-size part of each of the three main data 
+** structures in a zip archive.
+*/
+#define ZIPFILE_LFH_FIXED_SZ      30
+#define ZIPFILE_EOCD_FIXED_SZ     22
+#define ZIPFILE_CDS_FIXED_SZ      46
+
+/*
+*** 4.3.16  End of central directory record:
+***
+***   end of central dir signature    4 bytes  (0x06054b50)
+***   number of this disk             2 bytes
+***   number of the disk with the
+***   start of the central directory  2 bytes
+***   total number of entries in the
+***   central directory on this disk  2 bytes
+***   total number of entries in
+***   the central directory           2 bytes
+***   size of the central directory   4 bytes
+***   offset of start of central
+***   directory with respect to
+***   the starting disk number        4 bytes
+***   .ZIP file comment length        2 bytes
+***   .ZIP file comment       (variable size)
+*/
+typedef struct ZipfileEOCD ZipfileEOCD;
+struct ZipfileEOCD {
+  u16 iDisk;
+  u16 iFirstDisk;
+  u16 nEntry;
+  u16 nEntryTotal;
+  u32 nSize;
+  u32 iOffset;
+};
+
+/*
+*** 4.3.12  Central directory structure:
+***
+*** ...
+***
+***   central file header signature   4 bytes  (0x02014b50)
+***   version made by                 2 bytes
+***   version needed to extract       2 bytes
+***   general purpose bit flag        2 bytes
+***   compression method              2 bytes
+***   last mod file time              2 bytes
+***   last mod file date              2 bytes
+***   crc-32                          4 bytes
+***   compressed size                 4 bytes
+***   uncompressed size               4 bytes
+***   file name length                2 bytes
+***   extra field length              2 bytes
+***   file comment length             2 bytes
+***   disk number start               2 bytes
+***   internal file attributes        2 bytes
+***   external file attributes        4 bytes
+***   relative offset of local header 4 bytes
+*/
+typedef struct ZipfileCDS ZipfileCDS;
+struct ZipfileCDS {
+  u16 iVersionMadeBy;
+  u16 iVersionExtract;
+  u16 flags;
+  u16 iCompression;
+  u16 mTime;
+  u16 mDate;
+  u32 crc32;
+  u32 szCompressed;
+  u32 szUncompressed;
+  u16 nFile;
+  u16 nExtra;
+  u16 nComment;
+  u16 iDiskStart;
+  u16 iInternalAttr;
+  u32 iExternalAttr;
+  u32 iOffset;
+  char *zFile;                    /* Filename (sqlite3_malloc()) */
+};
+
+/*
+*** 4.3.7  Local file header:
+***
+***   local file header signature     4 bytes  (0x04034b50)
+***   version needed to extract       2 bytes
+***   general purpose bit flag        2 bytes
+***   compression method              2 bytes
+***   last mod file time              2 bytes
+***   last mod file date              2 bytes
+***   crc-32                          4 bytes
+***   compressed size                 4 bytes
+***   uncompressed size               4 bytes
+***   file name length                2 bytes
+***   extra field length              2 bytes
+***   
+*/
+typedef struct ZipfileLFH ZipfileLFH;
+struct ZipfileLFH {
+  u16 iVersionExtract;
+  u16 flags;
+  u16 iCompression;
+  u16 mTime;
+  u16 mDate;
+  u32 crc32;
+  u32 szCompressed;
+  u32 szUncompressed;
+  u16 nFile;
+  u16 nExtra;
+};
+
+typedef struct ZipfileEntry ZipfileEntry;
+struct ZipfileEntry {
+  ZipfileCDS cds;            /* Parsed CDS record */
+  u32 mUnixTime;             /* Modification time, in UNIX format */
+  u8 *aExtra;                /* cds.nExtra+cds.nComment bytes of extra data */
+  i64 iDataOff;              /* Offset to data in file (if aData==0) */
+  u8 *aData;                 /* cds.szCompressed bytes of compressed data */
+  ZipfileEntry *pNext;       /* Next element in in-memory CDS */
+};
+
+/* 
+** Cursor type for zipfile tables.
+*/
+typedef struct ZipfileCsr ZipfileCsr;
+struct ZipfileCsr {
+  sqlite3_vtab_cursor base;  /* Base class - must be first */
+  i64 iId;                   /* Cursor ID */
+  u8 bEof;                   /* True when at EOF */
+  u8 bNoop;                  /* If next xNext() call is no-op */
+
+  /* Used outside of write transactions */
+  FILE *pFile;               /* Zip file */
+  i64 iNextOff;              /* Offset of next record in central directory */
+  ZipfileEOCD eocd;          /* Parse of central directory record */
+
+  ZipfileEntry *pFreeEntry;  /* Free this list when cursor is closed or reset */
+  ZipfileEntry *pCurrent;    /* Current entry */
+  ZipfileCsr *pCsrNext;      /* Next cursor on same virtual table */
+};
+
+typedef struct ZipfileTab ZipfileTab;
+struct ZipfileTab {
+  sqlite3_vtab base;         /* Base class - must be first */
+  char *zFile;               /* Zip file this table accesses (may be NULL) */
+  sqlite3 *db;               /* Host database connection */
+  u8 *aBuffer;               /* Temporary buffer used for various tasks */
+
+  ZipfileCsr *pCsrList;      /* List of cursors */
+  i64 iNextCsrid;
+
+  /* The following are used by write transactions only */
+  ZipfileEntry *pFirstEntry; /* Linked list of all files (if pWriteFd!=0) */
+  ZipfileEntry *pLastEntry;  /* Last element in pFirstEntry list */
+  FILE *pWriteFd;            /* File handle open on zip archive */
+  i64 szCurrent;             /* Current size of zip archive */
+  i64 szOrig;                /* Size of archive at start of transaction */
+};
+
+/*
+** Set the error message contained in context ctx to the results of
+** vprintf(zFmt, ...).
+*/
+static void zipfileCtxErrorMsg(sqlite3_context *ctx, const char *zFmt, ...){
+  char *zMsg = 0;
+  va_list ap;
+  va_start(ap, zFmt);
+  zMsg = sqlite3_vmprintf(zFmt, ap);
+  sqlite3_result_error(ctx, zMsg, -1);
+  sqlite3_free(zMsg);
+  va_end(ap);
+}
+
+/*
+** If string zIn is quoted, dequote it in place. Otherwise, if the string
+** is not quoted, do nothing.
+*/
+static void zipfileDequote(char *zIn){
+  char q = zIn[0];
+  if( q=='"' || q=='\'' || q=='`' || q=='[' ){
+    int iIn = 1;
+    int iOut = 0;
+    if( q=='[' ) q = ']';
+    while( ALWAYS(zIn[iIn]) ){
+      char c = zIn[iIn++];
+      if( c==q && zIn[iIn++]!=q ) break;
+      zIn[iOut++] = c;
+    }
+    zIn[iOut] = '\0';
+  }
+}
+
+/*
+** Construct a new ZipfileTab virtual table object.
+** 
+**   argv[0]   -> module name  ("zipfile")
+**   argv[1]   -> database name
+**   argv[2]   -> table name
+**   argv[...] -> "column name" and other module argument fields.
+*/
+static int zipfileConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  int nByte = sizeof(ZipfileTab) + ZIPFILE_BUFFER_SIZE;
+  int nFile = 0;
+  const char *zFile = 0;
+  ZipfileTab *pNew = 0;
+  int rc;
+
+  /* If the table name is not "zipfile", require that the argument be
+  ** specified. This stops zipfile tables from being created as:
+  **
+  **   CREATE VIRTUAL TABLE zzz USING zipfile();
+  **
+  ** It does not prevent:
+  **
+  **   CREATE VIRTUAL TABLE zipfile USING zipfile();
+  */
+  assert( 0==sqlite3_stricmp(argv[0], "zipfile") );
+  if( (0!=sqlite3_stricmp(argv[2], "zipfile") && argc<4) || argc>4 ){
+    *pzErr = sqlite3_mprintf("zipfile constructor requires one argument");
+    return SQLITE_ERROR;
+  }
+
+  if( argc>3 ){
+    zFile = argv[3];
+    nFile = (int)strlen(zFile)+1;
+  }
+
+  rc = sqlite3_declare_vtab(db, ZIPFILE_SCHEMA);
+  if( rc==SQLITE_OK ){
+    pNew = (ZipfileTab*)sqlite3_malloc64((sqlite3_int64)nByte+nFile);
+    if( pNew==0 ) return SQLITE_NOMEM;
+    memset(pNew, 0, nByte+nFile);
+    pNew->db = db;
+    pNew->aBuffer = (u8*)&pNew[1];
+    if( zFile ){
+      pNew->zFile = (char*)&pNew->aBuffer[ZIPFILE_BUFFER_SIZE];
+      memcpy(pNew->zFile, zFile, nFile);
+      zipfileDequote(pNew->zFile);
+    }
+  }
+  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
+  *ppVtab = (sqlite3_vtab*)pNew;
+  return rc;
+}
+
+/*
+** Free the ZipfileEntry structure indicated by the only argument.
+*/
+static void zipfileEntryFree(ZipfileEntry *p){
+  if( p ){
+    sqlite3_free(p->cds.zFile);
+    sqlite3_free(p);
+  }
+}
+
+/*
+** Release resources that should be freed at the end of a write 
+** transaction.
+*/
+static void zipfileCleanupTransaction(ZipfileTab *pTab){
+  ZipfileEntry *pEntry;
+  ZipfileEntry *pNext;
+
+  if( pTab->pWriteFd ){
+    fclose(pTab->pWriteFd);
+    pTab->pWriteFd = 0;
+  }
+  for(pEntry=pTab->pFirstEntry; pEntry; pEntry=pNext){
+    pNext = pEntry->pNext;
+    zipfileEntryFree(pEntry);
+  }
+  pTab->pFirstEntry = 0;
+  pTab->pLastEntry = 0;
+  pTab->szCurrent = 0;
+  pTab->szOrig = 0;
+}
+
+/*
+** This method is the destructor for zipfile vtab objects.
+*/
+static int zipfileDisconnect(sqlite3_vtab *pVtab){
+  zipfileCleanupTransaction((ZipfileTab*)pVtab);
+  sqlite3_free(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** Constructor for a new ZipfileCsr object.
+*/
+static int zipfileOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCsr){
+  ZipfileTab *pTab = (ZipfileTab*)p;
+  ZipfileCsr *pCsr;
+  pCsr = sqlite3_malloc(sizeof(*pCsr));
+  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
+  if( pCsr==0 ){
+    return SQLITE_NOMEM;
+  }
+  memset(pCsr, 0, sizeof(*pCsr));
+  pCsr->iId = ++pTab->iNextCsrid;
+  pCsr->pCsrNext = pTab->pCsrList;
+  pTab->pCsrList = pCsr;
+  return SQLITE_OK;
+}
+
+/*
+** Reset a cursor back to the state it was in when first returned
+** by zipfileOpen().
+*/
+static void zipfileResetCursor(ZipfileCsr *pCsr){
+  ZipfileEntry *p;
+  ZipfileEntry *pNext;
+
+  pCsr->bEof = 0;
+  if( pCsr->pFile ){
+    fclose(pCsr->pFile);
+    pCsr->pFile = 0;
+    zipfileEntryFree(pCsr->pCurrent);
+    pCsr->pCurrent = 0;
+  }
+
+  for(p=pCsr->pFreeEntry; p; p=pNext){
+    pNext = p->pNext;
+    zipfileEntryFree(p);
+  }
+}
+
+/*
+** Destructor for an ZipfileCsr.
+*/
+static int zipfileClose(sqlite3_vtab_cursor *cur){
+  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
+  ZipfileTab *pTab = (ZipfileTab*)(pCsr->base.pVtab);
+  ZipfileCsr **pp;
+  zipfileResetCursor(pCsr);
+
+  /* Remove this cursor from the ZipfileTab.pCsrList list. */
+  for(pp=&pTab->pCsrList; *pp!=pCsr; pp=&((*pp)->pCsrNext));
+  *pp = pCsr->pCsrNext;
+
+  sqlite3_free(pCsr);
+  return SQLITE_OK;
+}
+
+/*
+** Set the error message for the virtual table associated with cursor
+** pCsr to the results of vprintf(zFmt, ...).
+*/
+static void zipfileTableErr(ZipfileTab *pTab, const char *zFmt, ...){
+  va_list ap;
+  va_start(ap, zFmt);
+  sqlite3_free(pTab->base.zErrMsg);
+  pTab->base.zErrMsg = sqlite3_vmprintf(zFmt, ap);
+  va_end(ap);
+}
+static void zipfileCursorErr(ZipfileCsr *pCsr, const char *zFmt, ...){
+  va_list ap;
+  va_start(ap, zFmt);
+  sqlite3_free(pCsr->base.pVtab->zErrMsg);
+  pCsr->base.pVtab->zErrMsg = sqlite3_vmprintf(zFmt, ap);
+  va_end(ap);
+}
+
+/*
+** Read nRead bytes of data from offset iOff of file pFile into buffer
+** aRead[]. Return SQLITE_OK if successful, or an SQLite error code
+** otherwise. 
+**
+** If an error does occur, output variable (*pzErrmsg) may be set to point
+** to an English language error message. It is the responsibility of the
+** caller to eventually free this buffer using
+** sqlite3_free().
+*/
+static int zipfileReadData(
+  FILE *pFile,                    /* Read from this file */
+  u8 *aRead,                      /* Read into this buffer */
+  int nRead,                      /* Number of bytes to read */
+  i64 iOff,                       /* Offset to read from */
+  char **pzErrmsg                 /* OUT: Error message (from sqlite3_malloc) */
+){
+  size_t n;
+  fseek(pFile, (long)iOff, SEEK_SET);
+  n = fread(aRead, 1, nRead, pFile);
+  if( (int)n!=nRead ){
+    *pzErrmsg = sqlite3_mprintf("error in fread()");
+    return SQLITE_ERROR;
+  }
+  return SQLITE_OK;
+}
+
+static int zipfileAppendData(
+  ZipfileTab *pTab,
+  const u8 *aWrite,
+  int nWrite
+){
+  if( nWrite>0 ){
+    size_t n = nWrite;
+    fseek(pTab->pWriteFd, (long)pTab->szCurrent, SEEK_SET);
+    n = fwrite(aWrite, 1, nWrite, pTab->pWriteFd);
+    if( (int)n!=nWrite ){
+      pTab->base.zErrMsg = sqlite3_mprintf("error in fwrite()");
+      return SQLITE_ERROR;
+    }
+    pTab->szCurrent += nWrite;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Read and return a 16-bit little-endian unsigned integer from buffer aBuf.
+*/
+static u16 zipfileGetU16(const u8 *aBuf){
+  return (aBuf[1] << 8) + aBuf[0];
+}
+
+/*
+** Read and return a 32-bit little-endian unsigned integer from buffer aBuf.
+*/
+static u32 zipfileGetU32(const u8 *aBuf){
+  if( aBuf==0 ) return 0;
+  return ((u32)(aBuf[3]) << 24)
+       + ((u32)(aBuf[2]) << 16)
+       + ((u32)(aBuf[1]) <<  8)
+       + ((u32)(aBuf[0]) <<  0);
+}
+
+/*
+** Write a 16-bit little endiate integer into buffer aBuf.
+*/
+static void zipfilePutU16(u8 *aBuf, u16 val){
+  aBuf[0] = val & 0xFF;
+  aBuf[1] = (val>>8) & 0xFF;
+}
+
+/*
+** Write a 32-bit little endiate integer into buffer aBuf.
+*/
+static void zipfilePutU32(u8 *aBuf, u32 val){
+  aBuf[0] = val & 0xFF;
+  aBuf[1] = (val>>8) & 0xFF;
+  aBuf[2] = (val>>16) & 0xFF;
+  aBuf[3] = (val>>24) & 0xFF;
+}
+
+#define zipfileRead32(aBuf) ( aBuf+=4, zipfileGetU32(aBuf-4) )
+#define zipfileRead16(aBuf) ( aBuf+=2, zipfileGetU16(aBuf-2) )
+
+#define zipfileWrite32(aBuf,val) { zipfilePutU32(aBuf,val); aBuf+=4; }
+#define zipfileWrite16(aBuf,val) { zipfilePutU16(aBuf,val); aBuf+=2; }
+
+/*
+** Magic numbers used to read CDS records.
+*/
+#define ZIPFILE_CDS_NFILE_OFF        28
+#define ZIPFILE_CDS_SZCOMPRESSED_OFF 20
+
+/*
+** Decode the CDS record in buffer aBuf into (*pCDS). Return SQLITE_ERROR
+** if the record is not well-formed, or SQLITE_OK otherwise.
+*/
+static int zipfileReadCDS(u8 *aBuf, ZipfileCDS *pCDS){
+  u8 *aRead = aBuf;
+  u32 sig = zipfileRead32(aRead);
+  int rc = SQLITE_OK;
+  if( sig!=ZIPFILE_SIGNATURE_CDS ){
+    rc = SQLITE_ERROR;
+  }else{
+    pCDS->iVersionMadeBy = zipfileRead16(aRead);
+    pCDS->iVersionExtract = zipfileRead16(aRead);
+    pCDS->flags = zipfileRead16(aRead);
+    pCDS->iCompression = zipfileRead16(aRead);
+    pCDS->mTime = zipfileRead16(aRead);
+    pCDS->mDate = zipfileRead16(aRead);
+    pCDS->crc32 = zipfileRead32(aRead);
+    pCDS->szCompressed = zipfileRead32(aRead);
+    pCDS->szUncompressed = zipfileRead32(aRead);
+    assert( aRead==&aBuf[ZIPFILE_CDS_NFILE_OFF] );
+    pCDS->nFile = zipfileRead16(aRead);
+    pCDS->nExtra = zipfileRead16(aRead);
+    pCDS->nComment = zipfileRead16(aRead);
+    pCDS->iDiskStart = zipfileRead16(aRead);
+    pCDS->iInternalAttr = zipfileRead16(aRead);
+    pCDS->iExternalAttr = zipfileRead32(aRead);
+    pCDS->iOffset = zipfileRead32(aRead);
+    assert( aRead==&aBuf[ZIPFILE_CDS_FIXED_SZ] );
+  }
+
+  return rc;
+}
+
+/*
+** Decode the LFH record in buffer aBuf into (*pLFH). Return SQLITE_ERROR
+** if the record is not well-formed, or SQLITE_OK otherwise.
+*/
+static int zipfileReadLFH(
+  u8 *aBuffer,
+  ZipfileLFH *pLFH
+){
+  u8 *aRead = aBuffer;
+  int rc = SQLITE_OK;
+
+  u32 sig = zipfileRead32(aRead);
+  if( sig!=ZIPFILE_SIGNATURE_LFH ){
+    rc = SQLITE_ERROR;
+  }else{
+    pLFH->iVersionExtract = zipfileRead16(aRead);
+    pLFH->flags = zipfileRead16(aRead);
+    pLFH->iCompression = zipfileRead16(aRead);
+    pLFH->mTime = zipfileRead16(aRead);
+    pLFH->mDate = zipfileRead16(aRead);
+    pLFH->crc32 = zipfileRead32(aRead);
+    pLFH->szCompressed = zipfileRead32(aRead);
+    pLFH->szUncompressed = zipfileRead32(aRead);
+    pLFH->nFile = zipfileRead16(aRead);
+    pLFH->nExtra = zipfileRead16(aRead);
+  }
+  return rc;
+}
+
+
+/*
+** Buffer aExtra (size nExtra bytes) contains zip archive "extra" fields.
+** Scan through this buffer to find an "extra-timestamp" field. If one
+** exists, extract the 32-bit modification-timestamp from it and store
+** the value in output parameter *pmTime.
+**
+** Zero is returned if no extra-timestamp record could be found (and so
+** *pmTime is left unchanged), or non-zero otherwise.
+**
+** The general format of an extra field is:
+**
+**   Header ID    2 bytes
+**   Data Size    2 bytes
+**   Data         N bytes
+*/
+static int zipfileScanExtra(u8 *aExtra, int nExtra, u32 *pmTime){
+  int ret = 0;
+  u8 *p = aExtra;
+  u8 *pEnd = &aExtra[nExtra];
+
+  while( p<pEnd ){
+    u16 id = zipfileRead16(p);
+    u16 nByte = zipfileRead16(p);
+
+    switch( id ){
+      case ZIPFILE_EXTRA_TIMESTAMP: {
+        u8 b = p[0];
+        if( b & 0x01 ){     /* 0x01 -> modtime is present */
+          *pmTime = zipfileGetU32(&p[1]);
+          ret = 1;
+        }
+        break;
+      }
+    }
+
+    p += nByte;
+  }
+  return ret;
+}
+
+/*
+** Convert the standard MS-DOS timestamp stored in the mTime and mDate
+** fields of the CDS structure passed as the only argument to a 32-bit
+** UNIX seconds-since-the-epoch timestamp. Return the result.
+**
+** "Standard" MS-DOS time format:
+**
+**   File modification time:
+**     Bits 00-04: seconds divided by 2
+**     Bits 05-10: minute
+**     Bits 11-15: hour
+**   File modification date:
+**     Bits 00-04: day
+**     Bits 05-08: month (1-12)
+**     Bits 09-15: years from 1980 
+**
+** https://msdn.microsoft.com/en-us/library/9kkf9tah.aspx
+*/
+static u32 zipfileMtime(ZipfileCDS *pCDS){
+  int Y,M,D,X1,X2,A,B,sec,min,hr;
+  i64 JDsec;
+  Y = (1980 + ((pCDS->mDate >> 9) & 0x7F));
+  M = ((pCDS->mDate >> 5) & 0x0F);
+  D = (pCDS->mDate & 0x1F);
+  sec = (pCDS->mTime & 0x1F)*2;
+  min = (pCDS->mTime >> 5) & 0x3F;
+  hr = (pCDS->mTime >> 11) & 0x1F;
+  if( M<=2 ){
+    Y--;
+    M += 12;
+  }
+  X1 = 36525*(Y+4716)/100;
+  X2 = 306001*(M+1)/10000;
+  A = Y/100;
+  B = 2 - A + (A/4);
+  JDsec = (i64)((X1 + X2 + D + B - 1524.5)*86400) + hr*3600 + min*60 + sec;
+  return (u32)(JDsec - (i64)24405875*(i64)8640);
+}
+
+/*
+** The opposite of zipfileMtime(). This function populates the mTime and
+** mDate fields of the CDS structure passed as the first argument according
+** to the UNIX timestamp value passed as the second.
+*/
+static void zipfileMtimeToDos(ZipfileCDS *pCds, u32 mUnixTime){
+  /* Convert unix timestamp to JD (2440588 is noon on 1/1/1970) */
+  i64 JD = (i64)2440588 + mUnixTime / (24*60*60);
+
+  int A, B, C, D, E;
+  int yr, mon, day;
+  int hr, min, sec;
+
+  A = (int)((JD - 1867216.25)/36524.25);
+  A = (int)(JD + 1 + A - (A/4));
+  B = A + 1524;
+  C = (int)((B - 122.1)/365.25);
+  D = (36525*(C&32767))/100;
+  E = (int)((B-D)/30.6001);
+
+  day = B - D - (int)(30.6001*E);
+  mon = (E<14 ? E-1 : E-13);
+  yr = mon>2 ? C-4716 : C-4715;
+
+  hr = (mUnixTime % (24*60*60)) / (60*60);
+  min = (mUnixTime % (60*60)) / 60;
+  sec = (mUnixTime % 60);
+
+  if( yr>=1980 ){
+    pCds->mDate = (u16)(day + (mon << 5) + ((yr-1980) << 9));
+    pCds->mTime = (u16)(sec/2 + (min<<5) + (hr<<11));
+  }else{
+    pCds->mDate = pCds->mTime = 0;
+  }
+
+  assert( mUnixTime<315507600 
+       || mUnixTime==zipfileMtime(pCds) 
+       || ((mUnixTime % 2) && mUnixTime-1==zipfileMtime(pCds)) 
+       /* || (mUnixTime % 2) */
+  );
+}
+
+/*
+** If aBlob is not NULL, then it is a pointer to a buffer (nBlob bytes in
+** size) containing an entire zip archive image. Or, if aBlob is NULL,
+** then pFile is a file-handle open on a zip file. In either case, this
+** function creates a ZipfileEntry object based on the zip archive entry
+** for which the CDS record is at offset iOff.
+**
+** If successful, SQLITE_OK is returned and (*ppEntry) set to point to
+** the new object. Otherwise, an SQLite error code is returned and the
+** final value of (*ppEntry) undefined.
+*/
+static int zipfileGetEntry(
+  ZipfileTab *pTab,               /* Store any error message here */
+  const u8 *aBlob,                /* Pointer to in-memory file image */
+  int nBlob,                      /* Size of aBlob[] in bytes */
+  FILE *pFile,                    /* If aBlob==0, read from this file */
+  i64 iOff,                       /* Offset of CDS record */
+  ZipfileEntry **ppEntry          /* OUT: Pointer to new object */
+){
+  u8 *aRead;
+  char **pzErr = &pTab->base.zErrMsg;
+  int rc = SQLITE_OK;
+
+  if( aBlob==0 ){
+    aRead = pTab->aBuffer;
+    rc = zipfileReadData(pFile, aRead, ZIPFILE_CDS_FIXED_SZ, iOff, pzErr);
+  }else{
+    aRead = (u8*)&aBlob[iOff];
+  }
+
+  if( rc==SQLITE_OK ){
+    sqlite3_int64 nAlloc;
+    ZipfileEntry *pNew;
+
+    int nFile = zipfileGetU16(&aRead[ZIPFILE_CDS_NFILE_OFF]);
+    int nExtra = zipfileGetU16(&aRead[ZIPFILE_CDS_NFILE_OFF+2]);
+    nExtra += zipfileGetU16(&aRead[ZIPFILE_CDS_NFILE_OFF+4]);
+
+    nAlloc = sizeof(ZipfileEntry) + nExtra;
+    if( aBlob ){
+      nAlloc += zipfileGetU32(&aRead[ZIPFILE_CDS_SZCOMPRESSED_OFF]);
+    }
+
+    pNew = (ZipfileEntry*)sqlite3_malloc64(nAlloc);
+    if( pNew==0 ){
+      rc = SQLITE_NOMEM;
+    }else{
+      memset(pNew, 0, sizeof(ZipfileEntry));
+      rc = zipfileReadCDS(aRead, &pNew->cds);
+      if( rc!=SQLITE_OK ){
+        *pzErr = sqlite3_mprintf("failed to read CDS at offset %lld", iOff);
+      }else if( aBlob==0 ){
+        rc = zipfileReadData(
+            pFile, aRead, nExtra+nFile, iOff+ZIPFILE_CDS_FIXED_SZ, pzErr
+        );
+      }else{
+        aRead = (u8*)&aBlob[iOff + ZIPFILE_CDS_FIXED_SZ];
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      u32 *pt = &pNew->mUnixTime;
+      pNew->cds.zFile = sqlite3_mprintf("%.*s", nFile, aRead); 
+      pNew->aExtra = (u8*)&pNew[1];
+      memcpy(pNew->aExtra, &aRead[nFile], nExtra);
+      if( pNew->cds.zFile==0 ){
+        rc = SQLITE_NOMEM;
+      }else if( 0==zipfileScanExtra(&aRead[nFile], pNew->cds.nExtra, pt) ){
+        pNew->mUnixTime = zipfileMtime(&pNew->cds);
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      static const int szFix = ZIPFILE_LFH_FIXED_SZ;
+      ZipfileLFH lfh;
+      if( pFile ){
+        rc = zipfileReadData(pFile, aRead, szFix, pNew->cds.iOffset, pzErr);
+      }else{
+        aRead = (u8*)&aBlob[pNew->cds.iOffset];
+      }
+
+      if( rc==SQLITE_OK ) rc = zipfileReadLFH(aRead, &lfh);
+      if( rc==SQLITE_OK ){
+        pNew->iDataOff =  pNew->cds.iOffset + ZIPFILE_LFH_FIXED_SZ;
+        pNew->iDataOff += lfh.nFile + lfh.nExtra;
+        if( aBlob && pNew->cds.szCompressed ){
+          pNew->aData = &pNew->aExtra[nExtra];
+          memcpy(pNew->aData, &aBlob[pNew->iDataOff], pNew->cds.szCompressed);
+        }
+      }else{
+        *pzErr = sqlite3_mprintf("failed to read LFH at offset %d", 
+            (int)pNew->cds.iOffset
+        );
+      }
+    }
+
+    if( rc!=SQLITE_OK ){
+      zipfileEntryFree(pNew);
+    }else{
+      *ppEntry = pNew;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Advance an ZipfileCsr to its next row of output.
+*/
+static int zipfileNext(sqlite3_vtab_cursor *cur){
+  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
+  int rc = SQLITE_OK;
+
+  if( pCsr->pFile ){
+    i64 iEof = pCsr->eocd.iOffset + pCsr->eocd.nSize;
+    zipfileEntryFree(pCsr->pCurrent);
+    pCsr->pCurrent = 0;
+    if( pCsr->iNextOff>=iEof ){
+      pCsr->bEof = 1;
+    }else{
+      ZipfileEntry *p = 0;
+      ZipfileTab *pTab = (ZipfileTab*)(cur->pVtab);
+      rc = zipfileGetEntry(pTab, 0, 0, pCsr->pFile, pCsr->iNextOff, &p);
+      if( rc==SQLITE_OK ){
+        pCsr->iNextOff += ZIPFILE_CDS_FIXED_SZ;
+        pCsr->iNextOff += (int)p->cds.nExtra + p->cds.nFile + p->cds.nComment;
+      }
+      pCsr->pCurrent = p;
+    }
+  }else{
+    if( !pCsr->bNoop ){
+      pCsr->pCurrent = pCsr->pCurrent->pNext;
+    }
+    if( pCsr->pCurrent==0 ){
+      pCsr->bEof = 1;
+    }
+  }
+
+  pCsr->bNoop = 0;
+  return rc;
+}
+
+static void zipfileFree(void *p) { 
+  sqlite3_free(p); 
+}
+
+/*
+** Buffer aIn (size nIn bytes) contains compressed data. Uncompressed, the
+** size is nOut bytes. This function uncompresses the data and sets the
+** return value in context pCtx to the result (a blob).
+**
+** If an error occurs, an error code is left in pCtx instead.
+*/
+static void zipfileInflate(
+  sqlite3_context *pCtx,          /* Store result here */
+  const u8 *aIn,                  /* Compressed data */
+  int nIn,                        /* Size of buffer aIn[] in bytes */
+  int nOut                        /* Expected output size */
+){
+  u8 *aRes = sqlite3_malloc(nOut);
+  if( aRes==0 ){
+    sqlite3_result_error_nomem(pCtx);
+  }else{
+    int err;
+    z_stream str;
+    memset(&str, 0, sizeof(str));
+
+    str.next_in = (Byte*)aIn;
+    str.avail_in = nIn;
+    str.next_out = (Byte*)aRes;
+    str.avail_out = nOut;
+
+    err = inflateInit2(&str, -15);
+    if( err!=Z_OK ){
+      zipfileCtxErrorMsg(pCtx, "inflateInit2() failed (%d)", err);
+    }else{
+      err = inflate(&str, Z_NO_FLUSH);
+      if( err!=Z_STREAM_END ){
+        zipfileCtxErrorMsg(pCtx, "inflate() failed (%d)", err);
+      }else{
+        sqlite3_result_blob(pCtx, aRes, nOut, zipfileFree);
+        aRes = 0;
+      }
+    }
+    sqlite3_free(aRes);
+    inflateEnd(&str);
+  }
+}
+
+/*
+** Buffer aIn (size nIn bytes) contains uncompressed data. This function
+** compresses it and sets (*ppOut) to point to a buffer containing the
+** compressed data. The caller is responsible for eventually calling
+** sqlite3_free() to release buffer (*ppOut). Before returning, (*pnOut) 
+** is set to the size of buffer (*ppOut) in bytes.
+**
+** If no error occurs, SQLITE_OK is returned. Otherwise, an SQLite error
+** code is returned and an error message left in virtual-table handle
+** pTab. The values of (*ppOut) and (*pnOut) are left unchanged in this
+** case.
+*/
+static int zipfileDeflate(
+  const u8 *aIn, int nIn,         /* Input */
+  u8 **ppOut, int *pnOut,         /* Output */
+  char **pzErr                    /* OUT: Error message */
+){
+  int rc = SQLITE_OK;
+  sqlite3_int64 nAlloc;
+  z_stream str;
+  u8 *aOut;
+
+  memset(&str, 0, sizeof(str));
+  str.next_in = (Bytef*)aIn;
+  str.avail_in = nIn;
+  deflateInit2(&str, 9, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY);
+
+  nAlloc = deflateBound(&str, nIn);
+  aOut = (u8*)sqlite3_malloc64(nAlloc);
+  if( aOut==0 ){
+    rc = SQLITE_NOMEM;
+  }else{
+    int res;
+    str.next_out = aOut;
+    str.avail_out = nAlloc;
+    res = deflate(&str, Z_FINISH);
+    if( res==Z_STREAM_END ){
+      *ppOut = aOut;
+      *pnOut = (int)str.total_out;
+    }else{
+      sqlite3_free(aOut);
+      *pzErr = sqlite3_mprintf("zipfile: deflate() error");
+      rc = SQLITE_ERROR;
+    }
+    deflateEnd(&str);
+  }
+
+  return rc;
+}
+
+
+/*
+** Return values of columns for the row at which the series_cursor
+** is currently pointing.
+*/
+static int zipfileColumn(
+  sqlite3_vtab_cursor *cur,   /* The cursor */
+  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
+  int i                       /* Which column to return */
+){
+  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
+  ZipfileCDS *pCDS = &pCsr->pCurrent->cds;
+  int rc = SQLITE_OK;
+  switch( i ){
+    case 0:   /* name */
+      sqlite3_result_text(ctx, pCDS->zFile, -1, SQLITE_TRANSIENT);
+      break;
+    case 1:   /* mode */
+      /* TODO: Whether or not the following is correct surely depends on
+      ** the platform on which the archive was created.  */
+      sqlite3_result_int(ctx, pCDS->iExternalAttr >> 16);
+      break;
+    case 2: { /* mtime */
+      sqlite3_result_int64(ctx, pCsr->pCurrent->mUnixTime);
+      break;
+    }
+    case 3: { /* sz */
+      if( sqlite3_vtab_nochange(ctx)==0 ){
+        sqlite3_result_int64(ctx, pCDS->szUncompressed);
+      }
+      break;
+    }
+    case 4:   /* rawdata */
+      if( sqlite3_vtab_nochange(ctx) ) break;
+    case 5: { /* data */
+      if( i==4 || pCDS->iCompression==0 || pCDS->iCompression==8 ){
+        int sz = pCDS->szCompressed;
+        int szFinal = pCDS->szUncompressed;
+        if( szFinal>0 ){
+          u8 *aBuf;
+          u8 *aFree = 0;
+          if( pCsr->pCurrent->aData ){
+            aBuf = pCsr->pCurrent->aData;
+          }else{
+            aBuf = aFree = sqlite3_malloc64(sz);
+            if( aBuf==0 ){
+              rc = SQLITE_NOMEM;
+            }else{
+              FILE *pFile = pCsr->pFile;
+              if( pFile==0 ){
+                pFile = ((ZipfileTab*)(pCsr->base.pVtab))->pWriteFd;
+              }
+              rc = zipfileReadData(pFile, aBuf, sz, pCsr->pCurrent->iDataOff,
+                  &pCsr->base.pVtab->zErrMsg
+              );
+            }
+          }
+          if( rc==SQLITE_OK ){
+            if( i==5 && pCDS->iCompression ){
+              zipfileInflate(ctx, aBuf, sz, szFinal);
+            }else{
+              sqlite3_result_blob(ctx, aBuf, sz, SQLITE_TRANSIENT);
+            }
+          }
+          sqlite3_free(aFree);
+        }else{
+          /* Figure out if this is a directory or a zero-sized file. Consider
+          ** it to be a directory either if the mode suggests so, or if
+          ** the final character in the name is '/'.  */
+          u32 mode = pCDS->iExternalAttr >> 16;
+          if( !(mode & S_IFDIR) && pCDS->zFile[pCDS->nFile-1]!='/' ){
+            sqlite3_result_blob(ctx, "", 0, SQLITE_STATIC);
+          }
+        }
+      }
+      break;
+    }
+    case 6:   /* method */
+      sqlite3_result_int(ctx, pCDS->iCompression);
+      break;
+    default:  /* z */
+      assert( i==7 );
+      sqlite3_result_int64(ctx, pCsr->iId);
+      break;
+  }
+
+  return rc;
+}
+
+/*
+** Return TRUE if the cursor is at EOF.
+*/
+static int zipfileEof(sqlite3_vtab_cursor *cur){
+  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
+  return pCsr->bEof;
+}
+
+/*
+** If aBlob is not NULL, then it points to a buffer nBlob bytes in size
+** containing an entire zip archive image. Or, if aBlob is NULL, then pFile
+** is guaranteed to be a file-handle open on a zip file.
+**
+** This function attempts to locate the EOCD record within the zip archive
+** and populate *pEOCD with the results of decoding it. SQLITE_OK is
+** returned if successful. Otherwise, an SQLite error code is returned and
+** an English language error message may be left in virtual-table pTab.
+*/
+static int zipfileReadEOCD(
+  ZipfileTab *pTab,               /* Return errors here */
+  const u8 *aBlob,                /* Pointer to in-memory file image */
+  int nBlob,                      /* Size of aBlob[] in bytes */
+  FILE *pFile,                    /* Read from this file if aBlob==0 */
+  ZipfileEOCD *pEOCD              /* Object to populate */
+){
+  u8 *aRead = pTab->aBuffer;      /* Temporary buffer */
+  int nRead;                      /* Bytes to read from file */
+  int rc = SQLITE_OK;
+
+  memset(pEOCD, 0, sizeof(ZipfileEOCD));
+  if( aBlob==0 ){
+    i64 iOff;                     /* Offset to read from */
+    i64 szFile;                   /* Total size of file in bytes */
+    fseek(pFile, 0, SEEK_END);
+    szFile = (i64)ftell(pFile);
+    if( szFile==0 ){
+      return SQLITE_OK;
+    }
+    nRead = (int)(MIN(szFile, ZIPFILE_BUFFER_SIZE));
+    iOff = szFile - nRead;
+    rc = zipfileReadData(pFile, aRead, nRead, iOff, &pTab->base.zErrMsg);
+  }else{
+    nRead = (int)(MIN(nBlob, ZIPFILE_BUFFER_SIZE));
+    aRead = (u8*)&aBlob[nBlob-nRead];
+  }
+
+  if( rc==SQLITE_OK ){
+    int i;
+
+    /* Scan backwards looking for the signature bytes */
+    for(i=nRead-20; i>=0; i--){
+      if( aRead[i]==0x50 && aRead[i+1]==0x4b 
+       && aRead[i+2]==0x05 && aRead[i+3]==0x06 
+      ){
+        break;
+      }
+    }
+    if( i<0 ){
+      pTab->base.zErrMsg = sqlite3_mprintf(
+          "cannot find end of central directory record"
+      );
+      return SQLITE_ERROR;
+    }
+
+    aRead += i+4;
+    pEOCD->iDisk = zipfileRead16(aRead);
+    pEOCD->iFirstDisk = zipfileRead16(aRead);
+    pEOCD->nEntry = zipfileRead16(aRead);
+    pEOCD->nEntryTotal = zipfileRead16(aRead);
+    pEOCD->nSize = zipfileRead32(aRead);
+    pEOCD->iOffset = zipfileRead32(aRead);
+  }
+
+  return rc;
+}
+
+/*
+** Add object pNew to the linked list that begins at ZipfileTab.pFirstEntry 
+** and ends with pLastEntry. If argument pBefore is NULL, then pNew is added
+** to the end of the list. Otherwise, it is added to the list immediately
+** before pBefore (which is guaranteed to be a part of said list).
+*/
+static void zipfileAddEntry(
+  ZipfileTab *pTab, 
+  ZipfileEntry *pBefore, 
+  ZipfileEntry *pNew
+){
+  assert( (pTab->pFirstEntry==0)==(pTab->pLastEntry==0) );
+  assert( pNew->pNext==0 );
+  if( pBefore==0 ){
+    if( pTab->pFirstEntry==0 ){
+      pTab->pFirstEntry = pTab->pLastEntry = pNew;
+    }else{
+      assert( pTab->pLastEntry->pNext==0 );
+      pTab->pLastEntry->pNext = pNew;
+      pTab->pLastEntry = pNew;
+    }
+  }else{
+    ZipfileEntry **pp;
+    for(pp=&pTab->pFirstEntry; *pp!=pBefore; pp=&((*pp)->pNext));
+    pNew->pNext = pBefore;
+    *pp = pNew;
+  }
+}
+
+static int zipfileLoadDirectory(ZipfileTab *pTab, const u8 *aBlob, int nBlob){
+  ZipfileEOCD eocd;
+  int rc;
+  int i;
+  i64 iOff;
+
+  rc = zipfileReadEOCD(pTab, aBlob, nBlob, pTab->pWriteFd, &eocd);
+  iOff = eocd.iOffset;
+  for(i=0; rc==SQLITE_OK && i<eocd.nEntry; i++){
+    ZipfileEntry *pNew = 0;
+    rc = zipfileGetEntry(pTab, aBlob, nBlob, pTab->pWriteFd, iOff, &pNew);
+
+    if( rc==SQLITE_OK ){
+      zipfileAddEntry(pTab, 0, pNew);
+      iOff += ZIPFILE_CDS_FIXED_SZ;
+      iOff += (int)pNew->cds.nExtra + pNew->cds.nFile + pNew->cds.nComment;
+    }
+  }
+  return rc;
+}
+
+/*
+** xFilter callback.
+*/
+static int zipfileFilter(
+  sqlite3_vtab_cursor *cur, 
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  ZipfileTab *pTab = (ZipfileTab*)cur->pVtab;
+  ZipfileCsr *pCsr = (ZipfileCsr*)cur;
+  const char *zFile = 0;          /* Zip file to scan */
+  int rc = SQLITE_OK;             /* Return Code */
+  int bInMemory = 0;              /* True for an in-memory zipfile */
+
+  zipfileResetCursor(pCsr);
+
+  if( pTab->zFile ){
+    zFile = pTab->zFile;
+  }else if( idxNum==0 ){
+    zipfileCursorErr(pCsr, "zipfile() function requires an argument");
+    return SQLITE_ERROR;
+  }else if( sqlite3_value_type(argv[0])==SQLITE_BLOB ){
+    static const u8 aEmptyBlob = 0;
+    const u8 *aBlob = (const u8*)sqlite3_value_blob(argv[0]);
+    int nBlob = sqlite3_value_bytes(argv[0]);
+    assert( pTab->pFirstEntry==0 );
+    if( aBlob==0 ){
+      aBlob = &aEmptyBlob;
+      nBlob = 0;
+    }
+    rc = zipfileLoadDirectory(pTab, aBlob, nBlob);
+    pCsr->pFreeEntry = pTab->pFirstEntry;
+    pTab->pFirstEntry = pTab->pLastEntry = 0;
+    if( rc!=SQLITE_OK ) return rc;
+    bInMemory = 1;
+  }else{
+    zFile = (const char*)sqlite3_value_text(argv[0]);
+  }
+
+  if( 0==pTab->pWriteFd && 0==bInMemory ){
+    pCsr->pFile = fopen(zFile, "rb");
+    if( pCsr->pFile==0 ){
+      zipfileCursorErr(pCsr, "cannot open file: %s", zFile);
+      rc = SQLITE_ERROR;
+    }else{
+      rc = zipfileReadEOCD(pTab, 0, 0, pCsr->pFile, &pCsr->eocd);
+      if( rc==SQLITE_OK ){
+        if( pCsr->eocd.nEntry==0 ){
+          pCsr->bEof = 1;
+        }else{
+          pCsr->iNextOff = pCsr->eocd.iOffset;
+          rc = zipfileNext(cur);
+        }
+      }
+    }
+  }else{
+    pCsr->bNoop = 1;
+    pCsr->pCurrent = pCsr->pFreeEntry ? pCsr->pFreeEntry : pTab->pFirstEntry;
+    rc = zipfileNext(cur);
+  }
+
+  return rc;
+}
+
+/*
+** xBestIndex callback.
+*/
+static int zipfileBestIndex(
+  sqlite3_vtab *tab,
+  sqlite3_index_info *pIdxInfo
+){
+  int i;
+  int idx = -1;
+  int unusable = 0;
+
+  for(i=0; i<pIdxInfo->nConstraint; i++){
+    const struct sqlite3_index_constraint *pCons = &pIdxInfo->aConstraint[i];
+    if( pCons->iColumn!=ZIPFILE_F_COLUMN_IDX ) continue;
+    if( pCons->usable==0 ){
+      unusable = 1;
+    }else if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ ){
+      idx = i;
+    }
+  }
+  pIdxInfo->estimatedCost = 1000.0;
+  if( idx>=0 ){
+    pIdxInfo->aConstraintUsage[idx].argvIndex = 1;
+    pIdxInfo->aConstraintUsage[idx].omit = 1;
+    pIdxInfo->idxNum = 1;
+  }else if( unusable ){
+    return SQLITE_CONSTRAINT;
+  }
+  return SQLITE_OK;
+}
+
+static ZipfileEntry *zipfileNewEntry(const char *zPath){
+  ZipfileEntry *pNew;
+  pNew = sqlite3_malloc(sizeof(ZipfileEntry));
+  if( pNew ){
+    memset(pNew, 0, sizeof(ZipfileEntry));
+    pNew->cds.zFile = sqlite3_mprintf("%s", zPath);
+    if( pNew->cds.zFile==0 ){
+      sqlite3_free(pNew);
+      pNew = 0;
+    }
+  }
+  return pNew;
+}
+
+static int zipfileSerializeLFH(ZipfileEntry *pEntry, u8 *aBuf){
+  ZipfileCDS *pCds = &pEntry->cds;
+  u8 *a = aBuf;
+
+  pCds->nExtra = 9;
+
+  /* Write the LFH itself */
+  zipfileWrite32(a, ZIPFILE_SIGNATURE_LFH);
+  zipfileWrite16(a, pCds->iVersionExtract);
+  zipfileWrite16(a, pCds->flags);
+  zipfileWrite16(a, pCds->iCompression);
+  zipfileWrite16(a, pCds->mTime);
+  zipfileWrite16(a, pCds->mDate);
+  zipfileWrite32(a, pCds->crc32);
+  zipfileWrite32(a, pCds->szCompressed);
+  zipfileWrite32(a, pCds->szUncompressed);
+  zipfileWrite16(a, (u16)pCds->nFile);
+  zipfileWrite16(a, pCds->nExtra);
+  assert( a==&aBuf[ZIPFILE_LFH_FIXED_SZ] );
+
+  /* Add the file name */
+  memcpy(a, pCds->zFile, (int)pCds->nFile);
+  a += (int)pCds->nFile;
+
+  /* The "extra" data */
+  zipfileWrite16(a, ZIPFILE_EXTRA_TIMESTAMP);
+  zipfileWrite16(a, 5);
+  *a++ = 0x01;
+  zipfileWrite32(a, pEntry->mUnixTime);
+
+  return a-aBuf;
+}
+
+static int zipfileAppendEntry(
+  ZipfileTab *pTab,
+  ZipfileEntry *pEntry,
+  const u8 *pData,
+  int nData
+){
+  u8 *aBuf = pTab->aBuffer;
+  int nBuf;
+  int rc;
+
+  nBuf = zipfileSerializeLFH(pEntry, aBuf);
+  rc = zipfileAppendData(pTab, aBuf, nBuf);
+  if( rc==SQLITE_OK ){
+    pEntry->iDataOff = pTab->szCurrent;
+    rc = zipfileAppendData(pTab, pData, nData);
+  }
+
+  return rc;
+}
+
+static int zipfileGetMode(
+  sqlite3_value *pVal, 
+  int bIsDir,                     /* If true, default to directory */
+  u32 *pMode,                     /* OUT: Mode value */
+  char **pzErr                    /* OUT: Error message */
+){
+  const char *z = (const char*)sqlite3_value_text(pVal);
+  u32 mode = 0;
+  if( z==0 ){
+    mode = (bIsDir ? (S_IFDIR + 0755) : (S_IFREG + 0644));
+  }else if( z[0]>='0' && z[0]<='9' ){
+    mode = (unsigned int)sqlite3_value_int(pVal);
+  }else{
+    const char zTemplate[11] = "-rwxrwxrwx";
+    int i;
+    if( strlen(z)!=10 ) goto parse_error;
+    switch( z[0] ){
+      case '-': mode |= S_IFREG; break;
+      case 'd': mode |= S_IFDIR; break;
+      case 'l': mode |= S_IFLNK; break;
+      default: goto parse_error;
+    }
+    for(i=1; i<10; i++){
+      if( z[i]==zTemplate[i] ) mode |= 1 << (9-i);
+      else if( z[i]!='-' ) goto parse_error;
+    }
+  }
+  if( ((mode & S_IFDIR)==0)==bIsDir ){
+    /* The "mode" attribute is a directory, but data has been specified.
+    ** Or vice-versa - no data but "mode" is a file or symlink.  */
+    *pzErr = sqlite3_mprintf("zipfile: mode does not match data");
+    return SQLITE_CONSTRAINT;
+  }
+  *pMode = mode;
+  return SQLITE_OK;
+
+ parse_error:
+  *pzErr = sqlite3_mprintf("zipfile: parse error in mode: %s", z);
+  return SQLITE_ERROR;
+}
+
+/*
+** Both (const char*) arguments point to nul-terminated strings. Argument
+** nB is the value of strlen(zB). This function returns 0 if the strings are
+** identical, ignoring any trailing '/' character in either path.  */
+static int zipfileComparePath(const char *zA, const char *zB, int nB){
+  int nA = (int)strlen(zA);
+  if( nA>0 && zA[nA-1]=='/' ) nA--;
+  if( nB>0 && zB[nB-1]=='/' ) nB--;
+  if( nA==nB && memcmp(zA, zB, nA)==0 ) return 0;
+  return 1;
+}
+
+static int zipfileBegin(sqlite3_vtab *pVtab){
+  ZipfileTab *pTab = (ZipfileTab*)pVtab;
+  int rc = SQLITE_OK;
+
+  assert( pTab->pWriteFd==0 );
+  if( pTab->zFile==0 || pTab->zFile[0]==0 ){
+    pTab->base.zErrMsg = sqlite3_mprintf("zipfile: missing filename");
+    return SQLITE_ERROR;
+  }
+
+  /* Open a write fd on the file. Also load the entire central directory
+  ** structure into memory. During the transaction any new file data is 
+  ** appended to the archive file, but the central directory is accumulated
+  ** in main-memory until the transaction is committed.  */
+  pTab->pWriteFd = fopen(pTab->zFile, "ab+");
+  if( pTab->pWriteFd==0 ){
+    pTab->base.zErrMsg = sqlite3_mprintf(
+        "zipfile: failed to open file %s for writing", pTab->zFile
+        );
+    rc = SQLITE_ERROR;
+  }else{
+    fseek(pTab->pWriteFd, 0, SEEK_END);
+    pTab->szCurrent = pTab->szOrig = (i64)ftell(pTab->pWriteFd);
+    rc = zipfileLoadDirectory(pTab, 0, 0);
+  }
+
+  if( rc!=SQLITE_OK ){
+    zipfileCleanupTransaction(pTab);
+  }
+
+  return rc;
+}
+
+/*
+** Return the current time as a 32-bit timestamp in UNIX epoch format (like
+** time(2)).
+*/
+static u32 zipfileTime(void){
+  sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
+  u32 ret;
+  if( pVfs==0 ) return 0;
+  if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){
+    i64 ms;
+    pVfs->xCurrentTimeInt64(pVfs, &ms);
+    ret = (u32)((ms/1000) - ((i64)24405875 * 8640));
+  }else{
+    double day;
+    pVfs->xCurrentTime(pVfs, &day);
+    ret = (u32)((day - 2440587.5) * 86400);
+  }
+  return ret;
+}
+
+/*
+** Return a 32-bit timestamp in UNIX epoch format.
+**
+** If the value passed as the only argument is either NULL or an SQL NULL,
+** return the current time. Otherwise, return the value stored in (*pVal)
+** cast to a 32-bit unsigned integer.
+*/
+static u32 zipfileGetTime(sqlite3_value *pVal){
+  if( pVal==0 || sqlite3_value_type(pVal)==SQLITE_NULL ){
+    return zipfileTime();
+  }
+  return (u32)sqlite3_value_int64(pVal);
+}
+
+/*
+** Unless it is NULL, entry pOld is currently part of the pTab->pFirstEntry
+** linked list.  Remove it from the list and free the object.
+*/
+static void zipfileRemoveEntryFromList(ZipfileTab *pTab, ZipfileEntry *pOld){
+  if( pOld ){
+    ZipfileEntry **pp;
+    for(pp=&pTab->pFirstEntry; (*pp)!=pOld; pp=&((*pp)->pNext));
+    *pp = (*pp)->pNext;
+    zipfileEntryFree(pOld);
+  }
+}
+
+/*
+** xUpdate method.
+*/
+static int zipfileUpdate(
+  sqlite3_vtab *pVtab, 
+  int nVal, 
+  sqlite3_value **apVal, 
+  sqlite_int64 *pRowid
+){
+  ZipfileTab *pTab = (ZipfileTab*)pVtab;
+  int rc = SQLITE_OK;             /* Return Code */
+  ZipfileEntry *pNew = 0;         /* New in-memory CDS entry */
+
+  u32 mode = 0;                   /* Mode for new entry */
+  u32 mTime = 0;                  /* Modification time for new entry */
+  i64 sz = 0;                     /* Uncompressed size */
+  const char *zPath = 0;          /* Path for new entry */
+  int nPath = 0;                  /* strlen(zPath) */
+  const u8 *pData = 0;            /* Pointer to buffer containing content */
+  int nData = 0;                  /* Size of pData buffer in bytes */
+  int iMethod = 0;                /* Compression method for new entry */
+  u8 *pFree = 0;                  /* Free this */
+  char *zFree = 0;                /* Also free this */
+  ZipfileEntry *pOld = 0;
+  ZipfileEntry *pOld2 = 0;
+  int bUpdate = 0;                /* True for an update that modifies "name" */
+  int bIsDir = 0;
+  u32 iCrc32 = 0;
+
+  if( pTab->pWriteFd==0 ){
+    rc = zipfileBegin(pVtab);
+    if( rc!=SQLITE_OK ) return rc;
+  }
+
+  /* If this is a DELETE or UPDATE, find the archive entry to delete. */
+  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
+    const char *zDelete = (const char*)sqlite3_value_text(apVal[0]);
+    int nDelete = (int)strlen(zDelete);
+    if( nVal>1 ){
+      const char *zUpdate = (const char*)sqlite3_value_text(apVal[1]);
+      if( zUpdate && zipfileComparePath(zUpdate, zDelete, nDelete)!=0 ){
+        bUpdate = 1;
+      }
+    }
+    for(pOld=pTab->pFirstEntry; 1; pOld=pOld->pNext){
+      if( zipfileComparePath(pOld->cds.zFile, zDelete, nDelete)==0 ){
+        break;
+      }
+      assert( pOld->pNext );
+    }
+  }
+
+  if( nVal>1 ){
+    /* Check that "sz" and "rawdata" are both NULL: */
+    if( sqlite3_value_type(apVal[5])!=SQLITE_NULL ){
+      zipfileTableErr(pTab, "sz must be NULL");
+      rc = SQLITE_CONSTRAINT;
+    }
+    if( sqlite3_value_type(apVal[6])!=SQLITE_NULL ){
+      zipfileTableErr(pTab, "rawdata must be NULL"); 
+      rc = SQLITE_CONSTRAINT;
+    }
+
+    if( rc==SQLITE_OK ){
+      if( sqlite3_value_type(apVal[7])==SQLITE_NULL ){
+        /* data=NULL. A directory */
+        bIsDir = 1;
+      }else{
+        /* Value specified for "data", and possibly "method". This must be
+        ** a regular file or a symlink. */
+        const u8 *aIn = sqlite3_value_blob(apVal[7]);
+        int nIn = sqlite3_value_bytes(apVal[7]);
+        int bAuto = sqlite3_value_type(apVal[8])==SQLITE_NULL;
+
+        iMethod = sqlite3_value_int(apVal[8]);
+        sz = nIn;
+        pData = aIn;
+        nData = nIn;
+        if( iMethod!=0 && iMethod!=8 ){
+          zipfileTableErr(pTab, "unknown compression method: %d", iMethod);
+          rc = SQLITE_CONSTRAINT;
+        }else{
+          if( bAuto || iMethod ){
+            int nCmp;
+            rc = zipfileDeflate(aIn, nIn, &pFree, &nCmp, &pTab->base.zErrMsg);
+            if( rc==SQLITE_OK ){
+              if( iMethod || nCmp<nIn ){
+                iMethod = 8;
+                pData = pFree;
+                nData = nCmp;
+              }
+            }
+          }
+          iCrc32 = crc32(0, aIn, nIn);
+        }
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      rc = zipfileGetMode(apVal[3], bIsDir, &mode, &pTab->base.zErrMsg);
+    }
+
+    if( rc==SQLITE_OK ){
+      zPath = (const char*)sqlite3_value_text(apVal[2]);
+      if( zPath==0 ) zPath = "";
+      nPath = (int)strlen(zPath);
+      mTime = zipfileGetTime(apVal[4]);
+    }
+
+    if( rc==SQLITE_OK && bIsDir ){
+      /* For a directory, check that the last character in the path is a
+      ** '/'. This appears to be required for compatibility with info-zip
+      ** (the unzip command on unix). It does not create directories
+      ** otherwise.  */
+      if( nPath<=0 || zPath[nPath-1]!='/' ){
+        zFree = sqlite3_mprintf("%s/", zPath);
+        zPath = (const char*)zFree;
+        if( zFree==0 ){
+          rc = SQLITE_NOMEM;
+          nPath = 0;
+        }else{
+          nPath = (int)strlen(zPath);
+        }
+      }
+    }
+
+    /* Check that we're not inserting a duplicate entry -OR- updating an
+    ** entry with a path, thereby making it into a duplicate. */
+    if( (pOld==0 || bUpdate) && rc==SQLITE_OK ){
+      ZipfileEntry *p;
+      for(p=pTab->pFirstEntry; p; p=p->pNext){
+        if( zipfileComparePath(p->cds.zFile, zPath, nPath)==0 ){
+          switch( sqlite3_vtab_on_conflict(pTab->db) ){
+            case SQLITE_IGNORE: {
+              goto zipfile_update_done;
+            }
+            case SQLITE_REPLACE: {
+              pOld2 = p;
+              break;
+            }
+            default: {
+              zipfileTableErr(pTab, "duplicate name: \"%s\"", zPath);
+              rc = SQLITE_CONSTRAINT;
+              break;
+            }
+          }
+          break;
+        }
+      }
+    }
+
+    if( rc==SQLITE_OK ){
+      /* Create the new CDS record. */
+      pNew = zipfileNewEntry(zPath);
+      if( pNew==0 ){
+        rc = SQLITE_NOMEM;
+      }else{
+        pNew->cds.iVersionMadeBy = ZIPFILE_NEWENTRY_MADEBY;
+        pNew->cds.iVersionExtract = ZIPFILE_NEWENTRY_REQUIRED;
+        pNew->cds.flags = ZIPFILE_NEWENTRY_FLAGS;
+        pNew->cds.iCompression = (u16)iMethod;
+        zipfileMtimeToDos(&pNew->cds, mTime);
+        pNew->cds.crc32 = iCrc32;
+        pNew->cds.szCompressed = nData;
+        pNew->cds.szUncompressed = (u32)sz;
+        pNew->cds.iExternalAttr = (mode<<16);
+        pNew->cds.iOffset = (u32)pTab->szCurrent;
+        pNew->cds.nFile = (u16)nPath;
+        pNew->mUnixTime = (u32)mTime;
+        rc = zipfileAppendEntry(pTab, pNew, pData, nData);
+        zipfileAddEntry(pTab, pOld, pNew);
+      }
+    }
+  }
+
+  if( rc==SQLITE_OK && (pOld || pOld2) ){
+    ZipfileCsr *pCsr;
+    for(pCsr=pTab->pCsrList; pCsr; pCsr=pCsr->pCsrNext){
+      if( pCsr->pCurrent && (pCsr->pCurrent==pOld || pCsr->pCurrent==pOld2) ){
+        pCsr->pCurrent = pCsr->pCurrent->pNext;
+        pCsr->bNoop = 1;
+      }
+    }
+
+    zipfileRemoveEntryFromList(pTab, pOld);
+    zipfileRemoveEntryFromList(pTab, pOld2);
+  }
+
+zipfile_update_done:
+  sqlite3_free(pFree);
+  sqlite3_free(zFree);
+  return rc;
+}
+
+static int zipfileSerializeEOCD(ZipfileEOCD *p, u8 *aBuf){
+  u8 *a = aBuf;
+  zipfileWrite32(a, ZIPFILE_SIGNATURE_EOCD);
+  zipfileWrite16(a, p->iDisk);
+  zipfileWrite16(a, p->iFirstDisk);
+  zipfileWrite16(a, p->nEntry);
+  zipfileWrite16(a, p->nEntryTotal);
+  zipfileWrite32(a, p->nSize);
+  zipfileWrite32(a, p->iOffset);
+  zipfileWrite16(a, 0);        /* Size of trailing comment in bytes*/
+
+  return a-aBuf;
+}
+
+static int zipfileAppendEOCD(ZipfileTab *pTab, ZipfileEOCD *p){
+  int nBuf = zipfileSerializeEOCD(p, pTab->aBuffer);
+  assert( nBuf==ZIPFILE_EOCD_FIXED_SZ );
+  return zipfileAppendData(pTab, pTab->aBuffer, nBuf);
+}
+
+/*
+** Serialize the CDS structure into buffer aBuf[]. Return the number
+** of bytes written.
+*/
+static int zipfileSerializeCDS(ZipfileEntry *pEntry, u8 *aBuf){
+  u8 *a = aBuf;
+  ZipfileCDS *pCDS = &pEntry->cds;
+
+  if( pEntry->aExtra==0 ){
+    pCDS->nExtra = 9;
+  }
+
+  zipfileWrite32(a, ZIPFILE_SIGNATURE_CDS);
+  zipfileWrite16(a, pCDS->iVersionMadeBy);
+  zipfileWrite16(a, pCDS->iVersionExtract);
+  zipfileWrite16(a, pCDS->flags);
+  zipfileWrite16(a, pCDS->iCompression);
+  zipfileWrite16(a, pCDS->mTime);
+  zipfileWrite16(a, pCDS->mDate);
+  zipfileWrite32(a, pCDS->crc32);
+  zipfileWrite32(a, pCDS->szCompressed);
+  zipfileWrite32(a, pCDS->szUncompressed);
+  assert( a==&aBuf[ZIPFILE_CDS_NFILE_OFF] );
+  zipfileWrite16(a, pCDS->nFile);
+  zipfileWrite16(a, pCDS->nExtra);
+  zipfileWrite16(a, pCDS->nComment);
+  zipfileWrite16(a, pCDS->iDiskStart);
+  zipfileWrite16(a, pCDS->iInternalAttr);
+  zipfileWrite32(a, pCDS->iExternalAttr);
+  zipfileWrite32(a, pCDS->iOffset);
+
+  memcpy(a, pCDS->zFile, pCDS->nFile);
+  a += pCDS->nFile;
+
+  if( pEntry->aExtra ){
+    int n = (int)pCDS->nExtra + (int)pCDS->nComment;
+    memcpy(a, pEntry->aExtra, n);
+    a += n;
+  }else{
+    assert( pCDS->nExtra==9 );
+    zipfileWrite16(a, ZIPFILE_EXTRA_TIMESTAMP);
+    zipfileWrite16(a, 5);
+    *a++ = 0x01;
+    zipfileWrite32(a, pEntry->mUnixTime);
+  }
+
+  return a-aBuf;
+}
+
+static int zipfileCommit(sqlite3_vtab *pVtab){
+  ZipfileTab *pTab = (ZipfileTab*)pVtab;
+  int rc = SQLITE_OK;
+  if( pTab->pWriteFd ){
+    i64 iOffset = pTab->szCurrent;
+    ZipfileEntry *p;
+    ZipfileEOCD eocd;
+    int nEntry = 0;
+
+    /* Write out all entries */
+    for(p=pTab->pFirstEntry; rc==SQLITE_OK && p; p=p->pNext){
+      int n = zipfileSerializeCDS(p, pTab->aBuffer);
+      rc = zipfileAppendData(pTab, pTab->aBuffer, n);
+      nEntry++;
+    }
+
+    /* Write out the EOCD record */
+    eocd.iDisk = 0;
+    eocd.iFirstDisk = 0;
+    eocd.nEntry = (u16)nEntry;
+    eocd.nEntryTotal = (u16)nEntry;
+    eocd.nSize = (u32)(pTab->szCurrent - iOffset);
+    eocd.iOffset = (u32)iOffset;
+    rc = zipfileAppendEOCD(pTab, &eocd);
+
+    zipfileCleanupTransaction(pTab);
+  }
+  return rc;
+}
+
+static int zipfileRollback(sqlite3_vtab *pVtab){
+  return zipfileCommit(pVtab);
+}
+
+static ZipfileCsr *zipfileFindCursor(ZipfileTab *pTab, i64 iId){
+  ZipfileCsr *pCsr;
+  for(pCsr=pTab->pCsrList; pCsr; pCsr=pCsr->pCsrNext){
+    if( iId==pCsr->iId ) break;
+  }
+  return pCsr;
+}
+
+static void zipfileFunctionCds(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  ZipfileCsr *pCsr;
+  ZipfileTab *pTab = (ZipfileTab*)sqlite3_user_data(context);
+  assert( argc>0 );
+
+  pCsr = zipfileFindCursor(pTab, sqlite3_value_int64(argv[0]));
+  if( pCsr ){
+    ZipfileCDS *p = &pCsr->pCurrent->cds;
+    char *zRes = sqlite3_mprintf("{"
+        "\"version-made-by\" : %u, "
+        "\"version-to-extract\" : %u, "
+        "\"flags\" : %u, "
+        "\"compression\" : %u, "
+        "\"time\" : %u, "
+        "\"date\" : %u, "
+        "\"crc32\" : %u, "
+        "\"compressed-size\" : %u, "
+        "\"uncompressed-size\" : %u, "
+        "\"file-name-length\" : %u, "
+        "\"extra-field-length\" : %u, "
+        "\"file-comment-length\" : %u, "
+        "\"disk-number-start\" : %u, "
+        "\"internal-attr\" : %u, "
+        "\"external-attr\" : %u, "
+        "\"offset\" : %u }",
+        (u32)p->iVersionMadeBy, (u32)p->iVersionExtract,
+        (u32)p->flags, (u32)p->iCompression,
+        (u32)p->mTime, (u32)p->mDate,
+        (u32)p->crc32, (u32)p->szCompressed,
+        (u32)p->szUncompressed, (u32)p->nFile,
+        (u32)p->nExtra, (u32)p->nComment,
+        (u32)p->iDiskStart, (u32)p->iInternalAttr,
+        (u32)p->iExternalAttr, (u32)p->iOffset
+    );
+
+    if( zRes==0 ){
+      sqlite3_result_error_nomem(context);
+    }else{
+      sqlite3_result_text(context, zRes, -1, SQLITE_TRANSIENT);
+      sqlite3_free(zRes);
+    }
+  }
+}
+
+/*
+** xFindFunction method.
+*/
+static int zipfileFindFunction(
+  sqlite3_vtab *pVtab,            /* Virtual table handle */
+  int nArg,                       /* Number of SQL function arguments */
+  const char *zName,              /* Name of SQL function */
+  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
+  void **ppArg                    /* OUT: User data for *pxFunc */
+){
+  if( sqlite3_stricmp("zipfile_cds", zName)==0 ){
+    *pxFunc = zipfileFunctionCds;
+    *ppArg = (void*)pVtab;
+    return 1;
+  }
+  return 0;
+}
+
+typedef struct ZipfileBuffer ZipfileBuffer;
+struct ZipfileBuffer {
+  u8 *a;                          /* Pointer to buffer */
+  int n;                          /* Size of buffer in bytes */
+  int nAlloc;                     /* Byte allocated at a[] */
+};
+
+typedef struct ZipfileCtx ZipfileCtx;
+struct ZipfileCtx {
+  int nEntry;
+  ZipfileBuffer body;
+  ZipfileBuffer cds;
+};
+
+static int zipfileBufferGrow(ZipfileBuffer *pBuf, int nByte){
+  if( pBuf->n+nByte>pBuf->nAlloc ){
+    u8 *aNew;
+    sqlite3_int64 nNew = pBuf->n ? pBuf->n*2 : 512;
+    int nReq = pBuf->n + nByte;
+
+    while( nNew<nReq ) nNew = nNew*2;
+    aNew = sqlite3_realloc64(pBuf->a, nNew);
+    if( aNew==0 ) return SQLITE_NOMEM;
+    pBuf->a = aNew;
+    pBuf->nAlloc = (int)nNew;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** xStep() callback for the zipfile() aggregate. This can be called in
+** any of the following ways:
+**
+**   SELECT zipfile(name,data) ...
+**   SELECT zipfile(name,mode,mtime,data) ...
+**   SELECT zipfile(name,mode,mtime,data,method) ...
+*/
+static void zipfileStep(sqlite3_context *pCtx, int nVal, sqlite3_value **apVal){
+  ZipfileCtx *p;                  /* Aggregate function context */
+  ZipfileEntry e;                 /* New entry to add to zip archive */
+
+  sqlite3_value *pName = 0;
+  sqlite3_value *pMode = 0;
+  sqlite3_value *pMtime = 0;
+  sqlite3_value *pData = 0;
+  sqlite3_value *pMethod = 0;
+
+  int bIsDir = 0;
+  u32 mode;
+  int rc = SQLITE_OK;
+  char *zErr = 0;
+
+  int iMethod = -1;               /* Compression method to use (0 or 8) */
+
+  const u8 *aData = 0;            /* Possibly compressed data for new entry */
+  int nData = 0;                  /* Size of aData[] in bytes */
+  int szUncompressed = 0;         /* Size of data before compression */
+  u8 *aFree = 0;                  /* Free this before returning */
+  u32 iCrc32 = 0;                 /* crc32 of uncompressed data */
+
+  char *zName = 0;                /* Path (name) of new entry */
+  int nName = 0;                  /* Size of zName in bytes */
+  char *zFree = 0;                /* Free this before returning */
+  int nByte;
+
+  memset(&e, 0, sizeof(e));
+  p = (ZipfileCtx*)sqlite3_aggregate_context(pCtx, sizeof(ZipfileCtx));
+  if( p==0 ) return;
+
+  /* Martial the arguments into stack variables */
+  if( nVal!=2 && nVal!=4 && nVal!=5 ){
+    zErr = sqlite3_mprintf("wrong number of arguments to function zipfile()");
+    rc = SQLITE_ERROR;
+    goto zipfile_step_out;
+  }
+  pName = apVal[0];
+  if( nVal==2 ){
+    pData = apVal[1];
+  }else{
+    pMode = apVal[1];
+    pMtime = apVal[2];
+    pData = apVal[3];
+    if( nVal==5 ){
+      pMethod = apVal[4];
+    }
+  }
+
+  /* Check that the 'name' parameter looks ok. */
+  zName = (char*)sqlite3_value_text(pName);
+  nName = sqlite3_value_bytes(pName);
+  if( zName==0 ){
+    zErr = sqlite3_mprintf("first argument to zipfile() must be non-NULL");
+    rc = SQLITE_ERROR;
+    goto zipfile_step_out;
+  }
+
+  /* Inspect the 'method' parameter. This must be either 0 (store), 8 (use
+  ** deflate compression) or NULL (choose automatically).  */
+  if( pMethod && SQLITE_NULL!=sqlite3_value_type(pMethod) ){
+    iMethod = (int)sqlite3_value_int64(pMethod);
+    if( iMethod!=0 && iMethod!=8 ){
+      zErr = sqlite3_mprintf("illegal method value: %d", iMethod);
+      rc = SQLITE_ERROR;
+      goto zipfile_step_out;
+    }
+  }
+
+  /* Now inspect the data. If this is NULL, then the new entry must be a
+  ** directory.  Otherwise, figure out whether or not the data should
+  ** be deflated or simply stored in the zip archive. */
+  if( sqlite3_value_type(pData)==SQLITE_NULL ){
+    bIsDir = 1;
+    iMethod = 0;
+  }else{
+    aData = sqlite3_value_blob(pData);
+    szUncompressed = nData = sqlite3_value_bytes(pData);
+    iCrc32 = crc32(0, aData, nData);
+    if( iMethod<0 || iMethod==8 ){
+      int nOut = 0;
+      rc = zipfileDeflate(aData, nData, &aFree, &nOut, &zErr);
+      if( rc!=SQLITE_OK ){
+        goto zipfile_step_out;
+      }
+      if( iMethod==8 || nOut<nData ){
+        aData = aFree;
+        nData = nOut;
+        iMethod = 8;
+      }else{
+        iMethod = 0;
+      }
+    }
+  }
+
+  /* Decode the "mode" argument. */
+  rc = zipfileGetMode(pMode, bIsDir, &mode, &zErr);
+  if( rc ) goto zipfile_step_out;
+
+  /* Decode the "mtime" argument. */
+  e.mUnixTime = zipfileGetTime(pMtime);
+
+  /* If this is a directory entry, ensure that there is exactly one '/'
+  ** at the end of the path. Or, if this is not a directory and the path
+  ** ends in '/' it is an error. */
+  if( bIsDir==0 ){
+    if( nName>0 && zName[nName-1]=='/' ){
+      zErr = sqlite3_mprintf("non-directory name must not end with /");
+      rc = SQLITE_ERROR;
+      goto zipfile_step_out;
+    }
+  }else{
+    if( nName==0 || zName[nName-1]!='/' ){
+      zName = zFree = sqlite3_mprintf("%s/", zName);
+      if( zName==0 ){
+        rc = SQLITE_NOMEM;
+        goto zipfile_step_out;
+      }
+      nName = (int)strlen(zName);
+    }else{
+      while( nName>1 && zName[nName-2]=='/' ) nName--;
+    }
+  }
+
+  /* Assemble the ZipfileEntry object for the new zip archive entry */
+  e.cds.iVersionMadeBy = ZIPFILE_NEWENTRY_MADEBY;
+  e.cds.iVersionExtract = ZIPFILE_NEWENTRY_REQUIRED;
+  e.cds.flags = ZIPFILE_NEWENTRY_FLAGS;
+  e.cds.iCompression = (u16)iMethod;
+  zipfileMtimeToDos(&e.cds, (u32)e.mUnixTime);
+  e.cds.crc32 = iCrc32;
+  e.cds.szCompressed = nData;
+  e.cds.szUncompressed = szUncompressed;
+  e.cds.iExternalAttr = (mode<<16);
+  e.cds.iOffset = p->body.n;
+  e.cds.nFile = (u16)nName;
+  e.cds.zFile = zName;
+
+  /* Append the LFH to the body of the new archive */
+  nByte = ZIPFILE_LFH_FIXED_SZ + e.cds.nFile + 9;
+  if( (rc = zipfileBufferGrow(&p->body, nByte)) ) goto zipfile_step_out;
+  p->body.n += zipfileSerializeLFH(&e, &p->body.a[p->body.n]);
+
+  /* Append the data to the body of the new archive */
+  if( nData>0 ){
+    if( (rc = zipfileBufferGrow(&p->body, nData)) ) goto zipfile_step_out;
+    memcpy(&p->body.a[p->body.n], aData, nData);
+    p->body.n += nData;
+  }
+
+  /* Append the CDS record to the directory of the new archive */
+  nByte = ZIPFILE_CDS_FIXED_SZ + e.cds.nFile + 9;
+  if( (rc = zipfileBufferGrow(&p->cds, nByte)) ) goto zipfile_step_out;
+  p->cds.n += zipfileSerializeCDS(&e, &p->cds.a[p->cds.n]);
+
+  /* Increment the count of entries in the archive */
+  p->nEntry++;
+
+ zipfile_step_out:
+  sqlite3_free(aFree);
+  sqlite3_free(zFree);
+  if( rc ){
+    if( zErr ){
+      sqlite3_result_error(pCtx, zErr, -1);
+    }else{
+      sqlite3_result_error_code(pCtx, rc);
+    }
+  }
+  sqlite3_free(zErr);
+}
+
+/*
+** xFinalize() callback for zipfile aggregate function.
+*/
+static void zipfileFinal(sqlite3_context *pCtx){
+  ZipfileCtx *p;
+  ZipfileEOCD eocd;
+  sqlite3_int64 nZip;
+  u8 *aZip;
+
+  p = (ZipfileCtx*)sqlite3_aggregate_context(pCtx, sizeof(ZipfileCtx));
+  if( p==0 ) return;
+  if( p->nEntry>0 ){
+    memset(&eocd, 0, sizeof(eocd));
+    eocd.nEntry = (u16)p->nEntry;
+    eocd.nEntryTotal = (u16)p->nEntry;
+    eocd.nSize = p->cds.n;
+    eocd.iOffset = p->body.n;
+
+    nZip = p->body.n + p->cds.n + ZIPFILE_EOCD_FIXED_SZ;
+    aZip = (u8*)sqlite3_malloc64(nZip);
+    if( aZip==0 ){
+      sqlite3_result_error_nomem(pCtx);
+    }else{
+      memcpy(aZip, p->body.a, p->body.n);
+      memcpy(&aZip[p->body.n], p->cds.a, p->cds.n);
+      zipfileSerializeEOCD(&eocd, &aZip[p->body.n + p->cds.n]);
+      sqlite3_result_blob(pCtx, aZip, (int)nZip, zipfileFree);
+    }
+  }
+
+  sqlite3_free(p->body.a);
+  sqlite3_free(p->cds.a);
+}
+
+
+/*
+** Register the "zipfile" virtual table.
+*/
+static int zipfileRegister(sqlite3 *db){
+  static sqlite3_module zipfileModule = {
+    1,                         /* iVersion */
+    zipfileConnect,            /* xCreate */
+    zipfileConnect,            /* xConnect */
+    zipfileBestIndex,          /* xBestIndex */
+    zipfileDisconnect,         /* xDisconnect */
+    zipfileDisconnect,         /* xDestroy */
+    zipfileOpen,               /* xOpen - open a cursor */
+    zipfileClose,              /* xClose - close a cursor */
+    zipfileFilter,             /* xFilter - configure scan constraints */
+    zipfileNext,               /* xNext - advance a cursor */
+    zipfileEof,                /* xEof - check for end of scan */
+    zipfileColumn,             /* xColumn - read data */
+    0,                         /* xRowid - read data */
+    zipfileUpdate,             /* xUpdate */
+    zipfileBegin,              /* xBegin */
+    0,                         /* xSync */
+    zipfileCommit,             /* xCommit */
+    zipfileRollback,           /* xRollback */
+    zipfileFindFunction,       /* xFindMethod */
+    0,                         /* xRename */
+    0,                         /* xSavepoint */
+    0,                         /* xRelease */
+    0,                         /* xRollback */
+    0                          /* xShadowName */
+  };
+
+  int rc = sqlite3_create_module(db, "zipfile"  , &zipfileModule, 0);
+  if( rc==SQLITE_OK ) rc = sqlite3_overload_function(db, "zipfile_cds", -1);
+  if( rc==SQLITE_OK ){
+    rc = sqlite3_create_function(db, "zipfile", -1, SQLITE_UTF8, 0, 0, 
+        zipfileStep, zipfileFinal
+    );
+  }
+  assert( sizeof(i64)==8 );
+  assert( sizeof(u32)==4 );
+  assert( sizeof(u16)==2 );
+  assert( sizeof(u8)==1 );
+  return rc;
+}
+#else         /* SQLITE_OMIT_VIRTUALTABLE */
+# define zipfileRegister(x) SQLITE_OK
+#endif
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_zipfile_init(
+  sqlite3 *db, 
+  char **pzErrMsg, 
+  const sqlite3_api_routines *pApi
+){
+  SQLITE_EXTENSION_INIT2(pApi);
+  (void)pzErrMsg;  /* Unused parameter */
+  return zipfileRegister(db);
+}