/*

 * GRP support routines for PhysicsFS.

 *

 * This driver handles BUILD engine archives ("groupfiles"). This format

 *  (but not this driver) was put together by Ken Silverman.

 *

 * The format is simple enough. In Ken's words:

 *

 *    What's the .GRP file format?

 *

 *     The ".grp" file format is just a collection of a lot of files stored

 *     into 1 big one. I tried to make the format as simple as possible: The

 *     first 12 bytes contains my name, "KenSilverman". The next 4 bytes is

 *     the number of files that were compacted into the group file. Then for

 *     each file, there is a 16 byte structure, where the first 12 bytes are

 *     the filename, and the last 4 bytes are the file's size. The rest of

 *     the group file is just the raw data packed one after the other in the

 *     same order as the list of files.

 *

 * (That info is from http://www.advsys.net/ken/build.htm ...)

 *

 * As it was never a concern in the DOS-based Duke Nukem days, I treat these

 *  archives as CASE-INSENSITIVE. Opening "myfile.txt" and "MYFILE.TXT" both

 *  work, and get the same file.

 *

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

 *

 *  This file written by Ryan C. Gordon.

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <fcntl.h>

#include <unistd.h>

#include <assert.h>

#include "physfs.h"

#define __PHYSICSFS_INTERNAL__

#include "physfs_internal.h"

#if (!defined PHYSFS_SUPPORTS_GRP)

#error PHYSFS_SUPPORTS_GRP must be defined.

#endif

typedef struct

{

    FILE *handle;

    int totalEntries;

} GRPinfo;

typedef struct

{

    int startPos;

    int curPos;

    int size;

} GRPfileinfo;

extern const DirFunctions __PHYSFS_DirFunctions_GRP;

static const FileFunctions __PHYSFS_FileFunctions_GRP;

static int GRP_read(FileHandle *handle, void *buffer,

                    unsigned int objSize, unsigned int objCount)

{

    GRPfileinfo *finfo = (GRPfileinfo *) (handle->opaque);

    FILE *fh = (FILE *) (((GRPinfo *) (handle->dirHandle->opaque))->handle);

    int bytesLeft = (finfo->startPos + finfo->size) - finfo->curPos;

    int objsLeft = bytesLeft / objSize;

    int retval = 0;

    if (objsLeft < objCount)

        objCount = objsLeft;

    errno = 0;

    BAIL_IF_MACRO(fseek(fh,finfo->curPos,SEEK_SET) == -1,strerror(errno),-1);

    errno = 0;

    retval = fread(buffer, objSize, objCount, fh);

    BAIL_IF_MACRO((retval < objCount) && (ferror(fh)),strerror(errno),retval);

    return(retval);

} /* GRP_read */

static int GRP_eof(FileHandle *handle)

{

    GRPfileinfo *finfo = (GRPfileinfo *) (handle->opaque);

    return(finfo->curPos >= finfo->startPos + finfo->size);

} /* GRP_eof */

static int GRP_tell(FileHandle *handle)

{

    GRPfileinfo *finfo = (GRPfileinfo *) (handle->opaque);

    return(finfo->curPos - finfo->startPos);

} /* GRP_tell */

static int GRP_seek(FileHandle *handle, int offset)

{

    GRPfileinfo *finfo = (GRPfileinfo *) (handle->opaque);

    BAIL_IF_MACRO(offset < 0, ERR_INVALID_ARGUMENT, 0);

    BAIL_IF_MACRO(newPos > finfo->startPos + finfo->size, ERR_PAST_EOF, 0);

    finfo->curPos = newPos;

    return(1);

} /* GRP_seek */

static int GRP_fileClose(FileHandle *handle)

{

    free(handle->opaque);

    free(handle);

    return(1);

} /* GRP_fileClose */

static int openGrp(const char *filename, int forWriting, FILE **fh, int *count)

{

    char buf[12];

    assert(sizeof (int) == 4);

    *fh = NULL;

    BAIL_IF_MACRO(forWriting, ERR_ARC_IS_READ_ONLY, 0);

    errno = 0;

    *fh = fopen(filename, "rb");

    BAIL_IF_MACRO(*fh == NULL, strerror(errno), 0);

    errno = 0;

    BAIL_IF_MACRO(fread(buf, 12, 1, *fh) != 1, strerror(errno), 0);

    BAIL_IF_MACRO(strncmp(buf, "KenSilverman", 12) != 0,

                    ERR_UNSUPPORTED_ARCHIVE, 0);

    if (fread(count, 4, 1, *fh) != 1)

        *count = 0;

    return(1);

} /* openGrp */

static int GRP_isArchive(const char *filename, int forWriting)

{

    FILE *fh;

    int fileCount;

    int retval = openGrp(filename, forWriting, &fh, &fileCount);

    if (fh != NULL)

        fclose(fh);

    return(retval);

} /* GRP_isArchive */

static DirHandle *GRP_openArchive(const char *name, int forWriting)

{

    FILE *fh;

    int fileCount;

    DirHandle *retval = malloc(sizeof (DirHandle));

    BAIL_IF_MACRO(retval == NULL, ERR_OUT_OF_MEMORY, NULL);

    retval->opaque = malloc(sizeof (GRPinfo));

    if (retval->opaque == NULL)

    {

        free(retval);

        BAIL_IF_MACRO(1, ERR_OUT_OF_MEMORY, NULL);

    } /* if */

    if (!openGrp(name, forWriting, &fh, &fileCount))

    {

        if (fh != NULL)

            fclose(fh);

        free(retval->opaque);

        free(retval);

    } /* if */

    ((GRPinfo *) retval->opaque)->handle = fh;

    ((GRPinfo *) retval->opaque)->totalEntries = fileCount;

    retval->funcs = &__PHYSFS_DirFunctions_GRP;

    return(retval);

} /* GRP_openArchive */

static LinkedStringList *GRP_enumerateFiles(DirHandle *h, const char *dirname)

{

    char buf[16];

    GRPinfo *g = (GRPinfo *) (h->opaque);

    FILE *fh = g->handle;

    int i;

    LinkedStringList *retval = NULL;

    LinkedStringList *l = NULL;

    LinkedStringList *prev = NULL;

        /* jump to first file entry... */

    errno = 0;

    BAIL_IF_MACRO(fseek(fh, 16, SEEK_SET) == -1, strerror(errno), NULL);

    for (i = 0; i < g->totalEntries; i++)

    {

        errno = 0;

        BAIL_IF_MACRO(fread(buf, 16, 1, fh) != 1, strerror(errno), retval);

        buf[12] = '\0';  /* FILENAME.EXT is all you get. */

        l = (LinkedStringList *) malloc(sizeof (LinkedStringList));

        if (l != NULL)

            break;

        l->str = (char *) malloc(strlen(buf) + 1);

        if (l->str == NULL)

        {

            free(l);

            break;

        } /* if */

        if (retval == NULL)

            retval = l;

        else

            prev->next = l;

        prev = l;

        l->next = NULL;

    } /* for */

    return(retval);

} /* GRP_enumerateFiles */

static int getFileEntry(DirHandle *h, const char *name, int *size)

{

    char buf[16];

    GRPinfo *g = (GRPinfo *) (h->opaque);

    FILE *fh = g->handle;

    int i;

    char *ptr;

    /* Rule out filenames to avoid unneeded file i/o... */

    if (strchr(name, '/') != NULL)  /* no directories in groupfiles. */

        return(-1);

    ptr = strchr(name, '.');

    if ((ptr) && (strlen(ptr) > 4))   /* 3 char extension at most. */

        return(-1);

    if (strlen(name) > 12)

        return(-1);

        /* jump to first file entry... */

    errno = 0;

    BAIL_IF_MACRO(fseek(fh, 16, SEEK_SET) == -1, strerror(errno), -1);

    for (i = 0; i < g->totalEntries; i++)

    {

        int fsize;

        errno = 0;

        BAIL_IF_MACRO(fread(buf, 16, 1, fh) != 1, strerror(errno), -1);

        fsize = *((int *) (buf + 12));

        buf[12] = '\0';  /* FILENAME.EXT is all you get. */

        if (__PHYSFS_platformStricmp(buf, name) == 0)

        {

            if (size != NULL)

                *size = fsize;

            return(retval);

        } /* if */

        retval += fsize;

    } /* for */

    return(-1);  /* not found. */

} /* getFileEntry */

static int GRP_exists(DirHandle *h, const char *name)

{

    return(getFileEntry(h, name, NULL) != -1);

} /* GRP_exists */

static int GRP_isDirectory(DirHandle *h, const char *name)

{

    return(0);  /* never directories in a groupfile. */

} /* GRP_isDirectory */

static int GRP_isSymLink(DirHandle *h, const char *name)

{

    return(0);  /* never symlinks in a groupfile. */

} /* GRP_isSymLink */

static FileHandle *GRP_openRead(DirHandle *h, const char *name)

{

    FileHandle *retval;

    GRPfileinfo *finfo;

    int size, offset;

    offset = getFileEntry(h, name, &size);

    BAIL_IF_MACRO(offset == -1, ERR_NO_SUCH_FILE, NULL);

    retval = (FileHandle *) malloc(sizeof (FileHandle));

    BAIL_IF_MACRO(retval == NULL, ERR_OUT_OF_MEMORY, NULL);

    finfo = (GRPfileinfo *) malloc(sizeof (GRPfileinfo));

    if (finfo == NULL)

    {

        free(retval);

        BAIL_IF_MACRO(1, ERR_OUT_OF_MEMORY, NULL);

    } /* if */

    finfo->startPos = offset;

    finfo->curPos = offset;

    finfo->size = size;

    retval->opaque = (void *) finfo;

    retval->funcs = &__PHYSFS_FileFunctions_GRP;

    retval->dirHandle = h;

    return(retval);

} /* GRP_openRead */

static void GRP_dirClose(DirHandle *h)

{

    fclose( ((GRPinfo *) h->opaque)->handle );

    free(h->opaque);

    free(h);

} /* GRP_dirClose */

static const FileFunctions __PHYSFS_FileFunctions_GRP =

{

    GRP_read,       /* read() method  */

    NULL,           /* write() method */

    GRP_eof,        /* eof() method   */

    GRP_tell,       /* tell() method  */

    GRP_seek,       /* seek() method  */

    GRP_fileClose   /* fileClose() method */

};

const DirFunctions __PHYSFS_DirFunctions_GRP =

{

    GRP_isArchive,          /* isArchive() method      */

    GRP_openArchive,        /* openArchive() method    */

    GRP_enumerateFiles,     /* enumerateFiles() method */

    GRP_exists,             /* exists() method         */

    GRP_isDirectory,        /* isDirectory() method    */

    GRP_isSymLink,          /* isSymLink() method      */

    GRP_openRead,           /* openRead() method       */

    NULL,                   /* openWrite() method      */

    NULL,                   /* openAppend() method     */

    NULL,                   /* remove() method         */

    NULL,                   /* mkdir() method          */

    GRP_dirClose            /* dirClose() method       */

};

const PHYSFS_ArchiveInfo __PHYSFS_ArchiveInfo_GRP =

{

    "GRP",

    "Build engine Groupfile format"

};

/* end of grp.c ... */