/*

 * High-level PhysicsFS archiver for simple unpacked file formats.

 *

 * This is a framework that basic archivers build on top of. It's for simple

 *  formats that can just hand back a list of files and the offsets of their

 *  uncompressed data. There are an alarming number of formats like this.

 *

 * RULES: Archive entries must be uncompressed, must not have separate subdir

 *  entries (but can have subdirs), must be case insensitive LOW ASCII

 *  filenames <= 56 bytes. No symlinks, etc. We can relax some of these rules

 *  as necessary.

 *

 * Please see the file LICENSE.txt in the source's root directory.

 *

 *  This file written by Ryan C. Gordon.

 */

#define __PHYSICSFS_INTERNAL__

#include "physfs_internal.h"

typedef struct

{

    PHYSFS_Io *io;

    PHYSFS_uint32 entryCount;

    UNPKentry *entries;

} UNPKinfo;

typedef struct

{

    PHYSFS_Io *io;

    UNPKentry *entry;

    PHYSFS_uint32 curPos;

} UNPKfileinfo;

void UNPK_closeArchive(PHYSFS_Dir *opaque)

{

    UNPKinfo *info = ((UNPKinfo *) opaque);

    info->io->destroy(info->io);

    allocator.Free(info->entries);

    allocator.Free(info);

} /* UNPK_closeArchive */

static PHYSFS_sint64 UNPK_read(PHYSFS_Io *io, void *buffer, PHYSFS_uint64 len)

{

    UNPKfileinfo *finfo = (UNPKfileinfo *) io->opaque;

    const UNPKentry *entry = finfo->entry;

    const PHYSFS_uint64 bytesLeft = (PHYSFS_uint64)(entry->size-finfo->curPos);

    PHYSFS_sint64 rc;

    if (bytesLeft < len)

        len = bytesLeft;

    rc = finfo->io->read(finfo->io, buffer, len);

    if (rc > 0)

        finfo->curPos += (PHYSFS_uint32) rc;

    return rc;

} /* UNPK_read */

static PHYSFS_sint64 UNPK_write(PHYSFS_Io *io, const void *b, PHYSFS_uint64 len)

{

    BAIL_MACRO(PHYSFS_ERR_READ_ONLY, -1);

} /* UNPK_write */

static PHYSFS_sint64 UNPK_tell(PHYSFS_Io *io)

{

    return ((UNPKfileinfo *) io->opaque)->curPos;

} /* UNPK_tell */

static int UNPK_seek(PHYSFS_Io *io, PHYSFS_uint64 offset)

{

    UNPKfileinfo *finfo = (UNPKfileinfo *) io->opaque;

    const UNPKentry *entry = finfo->entry;

    int rc;

    BAIL_IF_MACRO(offset >= entry->size, PHYSFS_ERR_PAST_EOF, 0);

    rc = finfo->io->seek(finfo->io, entry->startPos + offset);

    if (rc)

        finfo->curPos = (PHYSFS_uint32) offset;

    return rc;

} /* UNPK_seek */

static PHYSFS_sint64 UNPK_length(PHYSFS_Io *io)

{

    const UNPKfileinfo *finfo = (UNPKfileinfo *) io->opaque;

    return ((PHYSFS_sint64) finfo->entry->size);

} /* UNPK_length */

static PHYSFS_Io *UNPK_duplicate(PHYSFS_Io *_io)

{

    UNPKfileinfo *origfinfo = (UNPKfileinfo *) _io->opaque;

    PHYSFS_Io *io = NULL;

    PHYSFS_Io *retval = (PHYSFS_Io *) allocator.Malloc(sizeof (PHYSFS_Io));

    UNPKfileinfo *finfo = (UNPKfileinfo *) allocator.Malloc(sizeof (UNPKfileinfo));

    GOTO_IF_MACRO(!retval, PHYSFS_ERR_OUT_OF_MEMORY, UNPK_duplicate_failed);

    GOTO_IF_MACRO(!finfo, PHYSFS_ERR_OUT_OF_MEMORY, UNPK_duplicate_failed);

    io = origfinfo->io->duplicate(origfinfo->io);

    if (!io) goto UNPK_duplicate_failed;

    finfo->io = io;

    finfo->entry = origfinfo->entry;

    finfo->curPos = 0;

    memcpy(retval, _io, sizeof (PHYSFS_Io));

    retval->opaque = finfo;

    return retval;

UNPK_duplicate_failed:

    if (finfo != NULL) allocator.Free(finfo);

    if (retval != NULL) allocator.Free(retval);

    if (io != NULL) io->destroy(io);

    return NULL;

} /* UNPK_duplicate */

static int UNPK_flush(PHYSFS_Io *io) { return 1;  /* no write support. */ }

static void UNPK_destroy(PHYSFS_Io *io)

{

    UNPKfileinfo *finfo = (UNPKfileinfo *) io->opaque;

    finfo->io->destroy(finfo->io);

    allocator.Free(finfo);

    allocator.Free(io);

} /* UNPK_destroy */

static const PHYSFS_Io UNPK_Io =

{

    CURRENT_PHYSFS_IO_API_VERSION, NULL,

    UNPK_read,

    UNPK_write,

    UNPK_seek,

    UNPK_tell,

    UNPK_length,

    UNPK_duplicate,

    UNPK_flush,

    UNPK_destroy

};

static int entryCmp(void *_a, size_t one, size_t two)

{

    if (one != two)

    {

        const UNPKentry *a = (const UNPKentry *) _a;

        return __PHYSFS_stricmpASCII(a[one].name, a[two].name);

    } /* if */

    return 0;

} /* entryCmp */

static void entrySwap(void *_a, size_t one, size_t two)

{

    if (one != two)

    {

        UNPKentry tmp;

        UNPKentry *first = &(((UNPKentry *) _a)[one]);

        UNPKentry *second = &(((UNPKentry *) _a)[two]);

        memcpy(&tmp, first, sizeof (UNPKentry));

        memcpy(first, second, sizeof (UNPKentry));

        memcpy(second, &tmp, sizeof (UNPKentry));

    } /* if */

} /* entrySwap */

static PHYSFS_sint32 findStartOfDir(UNPKinfo *info, const char *path,

                                    int stop_on_first_find)

{

    PHYSFS_sint32 lo = 0;

    PHYSFS_sint32 hi = (PHYSFS_sint32) (info->entryCount - 1);

    PHYSFS_sint32 middle;

    PHYSFS_uint32 dlen = (PHYSFS_uint32) strlen(path);

    PHYSFS_sint32 retval = -1;

    const char *name;

    int rc;

    if (*path == '\0')  /* root dir? */

        return 0;

    if ((dlen > 0) && (path[dlen - 1] == '/')) /* ignore trailing slash. */

        dlen--;

    while (lo <= hi)

    {

        middle = lo + ((hi - lo) / 2);

        name = info->entries[middle].name;

        rc = __PHYSFS_strnicmpASCII(path, name, dlen);

        if (rc == 0)

        {

            char ch = name[dlen];

            if (ch < '/') /* make sure this isn't just a substr match. */

                rc = -1;

            else if (ch > '/')

                rc = 1;

            else

            {

                if (stop_on_first_find) /* Just checking dir's existance? */

                    return middle;

                if (name[dlen + 1] == '\0') /* Skip initial dir entry. */

                    return (middle + 1);

                /* there might be more entries earlier in the list. */

                retval = middle;

                hi = middle - 1;

            } /* else */

        } /* if */

        if (rc > 0)

            lo = middle + 1;

        else

            hi = middle - 1;

    } /* while */

    return retval;

} /* findStartOfDir */

/*

 * Moved to seperate function so we can use alloca then immediately throw

 *  away the allocated stack space...

 */

static void doEnumCallback(PHYSFS_EnumFilesCallback cb, void *callbackdata,

                           const char *odir, const char *str, PHYSFS_sint32 ln)

{

    char *newstr = __PHYSFS_smallAlloc(ln + 1);

    if (newstr == NULL)

        return;

    memcpy(newstr, str, ln);

    newstr[ln] = '\0';

    cb(callbackdata, odir, newstr);

    __PHYSFS_smallFree(newstr);

} /* doEnumCallback */

void UNPK_enumerateFiles(PHYSFS_Dir *opaque, const char *dname,

                         int omitSymLinks, PHYSFS_EnumFilesCallback cb,

                         const char *origdir, void *callbackdata)

{

    UNPKinfo *info = ((UNPKinfo *) opaque);

    PHYSFS_sint32 dlen, dlen_inc, max, i;

    i = findStartOfDir(info, dname, 0);

    if (i == -1)  /* no such directory. */

        return;

    dlen = (PHYSFS_sint32) strlen(dname);

    if ((dlen > 0) && (dname[dlen - 1] == '/')) /* ignore trailing slash. */

        dlen--;

    dlen_inc = ((dlen > 0) ? 1 : 0) + dlen;

    max = (PHYSFS_sint32) info->entryCount;

    while (i < max)

    {

        char *add;

        char *ptr;

        PHYSFS_sint32 ln;

        char *e = info->entries[i].name;

        if ((dlen) &&

            ((__PHYSFS_strnicmpASCII(e, dname, dlen)) || (e[dlen] != '/')))

        {

            break;  /* past end of this dir; we're done. */

        } /* if */

        add = e + dlen_inc;

        ptr = strchr(add, '/');

        ln = (PHYSFS_sint32) ((ptr) ? ptr-add : strlen(add));

        doEnumCallback(cb, callbackdata, origdir, add, ln);

        ln += dlen_inc;  /* point past entry to children... */

        /* increment counter and skip children of subdirs... */

        while ((++i < max) && (ptr != NULL))

        {

            char *e_new = info->entries[i].name;

            if ((__PHYSFS_strnicmpASCII(e, e_new, ln) != 0) ||

                (e_new[ln] != '/'))

            {

                break;

            } /* if */

        } /* while */

    } /* while */

} /* UNPK_enumerateFiles */

/*

 * This will find the UNPKentry associated with a path in platform-independent

 *  notation. Directories don't have UNPKentries associated with them, but

 *  (*isDir) will be set to non-zero if a dir was hit.

 */

static UNPKentry *findEntry(const UNPKinfo *info, const char *path, int *isDir)

{

    UNPKentry *a = info->entries;

    PHYSFS_sint32 pathlen = (PHYSFS_sint32) strlen(path);

    PHYSFS_sint32 lo = 0;

    PHYSFS_sint32 hi = (PHYSFS_sint32) (info->entryCount - 1);

    PHYSFS_sint32 middle;

    const char *thispath = NULL;

    int rc;

    while (lo <= hi)

    {

        middle = lo + ((hi - lo) / 2);

        thispath = a[middle].name;

        rc = __PHYSFS_strnicmpASCII(path, thispath, pathlen);

        if (rc > 0)

            lo = middle + 1;

        else if (rc < 0)

            hi = middle - 1;

        else /* substring match...might be dir or entry or nothing. */

        {

            if (isDir != NULL)

            {

                *isDir = (thispath[pathlen] == '/');

                if (*isDir)

                    return NULL;

            } /* if */

            if (thispath[pathlen] == '\0') /* found entry? */

                return &a[middle];

            /* adjust search params, try again. */

            else if (thispath[pathlen] > '/')

                hi = middle - 1;

            else

                lo = middle + 1;

        } /* if */

    } /* while */

    if (isDir != NULL)

        *isDir = 0;

    BAIL_MACRO(PHYSFS_ERR_NO_SUCH_PATH, NULL);

} /* findEntry */

PHYSFS_Io *UNPK_openRead(PHYSFS_Dir *opaque, const char *fnm, int *fileExists)

{

    PHYSFS_Io *retval = NULL;

    UNPKinfo *info = (UNPKinfo *) opaque;

    UNPKfileinfo *finfo = NULL;

    int isdir = 0;

    UNPKentry *entry = findEntry(info, fnm, &isdir);

    *fileExists = (entry != NULL);

    GOTO_IF_MACRO(isdir, PHYSFS_ERR_NOT_A_FILE, UNPK_openRead_failed);

    GOTO_IF_MACRO(!entry, ERRPASS, UNPK_openRead_failed);

    retval = (PHYSFS_Io *) allocator.Malloc(sizeof (PHYSFS_Io));

    GOTO_IF_MACRO(!retval, PHYSFS_ERR_OUT_OF_MEMORY, UNPK_openRead_failed);

    finfo = (UNPKfileinfo *) allocator.Malloc(sizeof (UNPKfileinfo));

    GOTO_IF_MACRO(!finfo, PHYSFS_ERR_OUT_OF_MEMORY, UNPK_openRead_failed);

    finfo->io = info->io->duplicate(info->io);

    GOTO_IF_MACRO(!finfo->io, ERRPASS, UNPK_openRead_failed);

    if (!finfo->io->seek(finfo->io, entry->startPos))

        goto UNPK_openRead_failed;

    finfo->curPos = 0;

    finfo->entry = entry;

    memcpy(retval, &UNPK_Io, sizeof (*retval));

    retval->opaque = finfo;

    return retval;

UNPK_openRead_failed:

    if (finfo != NULL)

    {

        if (finfo->io != NULL)

            finfo->io->destroy(finfo->io);

        allocator.Free(finfo);

    } /* if */

    if (retval != NULL)

        allocator.Free(retval);

    return NULL;

} /* UNPK_openRead */

PHYSFS_Io *UNPK_openWrite(PHYSFS_Dir *opaque, const char *name)

{

    BAIL_MACRO(PHYSFS_ERR_READ_ONLY, NULL);

} /* UNPK_openWrite */

PHYSFS_Io *UNPK_openAppend(PHYSFS_Dir *opaque, const char *name)

{

    BAIL_MACRO(PHYSFS_ERR_READ_ONLY, NULL);

} /* UNPK_openAppend */

int UNPK_remove(PHYSFS_Dir *opaque, const char *name)

{

    BAIL_MACRO(PHYSFS_ERR_READ_ONLY, 0);

} /* UNPK_remove */

int UNPK_mkdir(PHYSFS_Dir *opaque, const char *name)

{

    BAIL_MACRO(PHYSFS_ERR_READ_ONLY, 0);

} /* UNPK_mkdir */

int UNPK_stat(PHYSFS_Dir *opaque, const char *filename,