misc/libphysfs/archiver_hog.c
author nemo
Mon, 10 Apr 2017 12:06:43 -0400
changeset 12218 bb5522e88ab2
parent 8524 a65e9bcf0a03
permissions -rw-r--r--
bulk copy of latest physfs to our misc/libphysfs since this seems to fix an off-by-1 error reliably hit in readln read of 1 byte probably introduced in the addition of the buffered read. Whether this is excessive or whether libphysfs should even be maintained by us is another matter. But at least we shouldn't crash

/*
 * HOG support routines for PhysicsFS.
 *
 * This driver handles Descent I/II HOG archives.
 *
 * The format is very simple:
 *
 *   The file always starts with the 3-byte signature "DHF" (Descent
 *   HOG file). After that the files of a HOG are just attached after
 *   another, divided by a 17 bytes header, which specifies the name
 *   and length (in bytes) of the forthcoming file! So you just read
 *   the header with its information of how big the following file is,
 *   and then skip exact that number of bytes to get to the next file
 *   in that HOG.
 *
 *    char sig[3] = {'D', 'H', 'F'}; // "DHF"=Descent HOG File
 *
 *    struct {
 *     char file_name[13]; // Filename, padded to 13 bytes with 0s
 *     int file_size; // filesize in bytes
 *     char data[file_size]; // The file data
 *    } FILE_STRUCT; // Repeated until the end of the file.
 *
 * (That info is from http://www.descent2.com/ddn/specs/hog/)
 *
 * Please see the file LICENSE.txt in the source's root directory.
 *
 *  This file written by Bradley Bell.
 *  Based on grp.c by Ryan C. Gordon.
 */

#define __PHYSICSFS_INTERNAL__
#include "physfs_internal.h"

#if PHYSFS_SUPPORTS_HOG

static UNPKentry *hogLoadEntries(PHYSFS_Io *io, PHYSFS_uint32 *_entCount)
{
    const PHYSFS_uint64 iolen = io->length(io);
    PHYSFS_uint32 entCount = 0;
    void *ptr = NULL;
    UNPKentry *entries = NULL;
    UNPKentry *entry = NULL;
    PHYSFS_uint32 size = 0;
    PHYSFS_uint32 pos = 3;

    while (pos < iolen)
    {
        entCount++;
        ptr = allocator.Realloc(ptr, sizeof (UNPKentry) * entCount);
        GOTO_IF_MACRO(ptr == NULL, PHYSFS_ERR_OUT_OF_MEMORY, failed);
        entries = (UNPKentry *) ptr;
        entry = &entries[entCount-1];

        GOTO_IF_MACRO(!__PHYSFS_readAll(io, &entry->name, 13), ERRPASS, failed);
        pos += 13;
        GOTO_IF_MACRO(!__PHYSFS_readAll(io, &size, 4), ERRPASS, failed);
        pos += 4;

        entry->size = PHYSFS_swapULE32(size);
        entry->startPos = pos;
        pos += size;

        /* skip over entry */
        GOTO_IF_MACRO(!io->seek(io, pos), ERRPASS, failed);
    } /* while */

    *_entCount = entCount;
    return entries;

failed:
    allocator.Free(entries);
    return NULL;
} /* hogLoadEntries */


static void *HOG_openArchive(PHYSFS_Io *io, const char *name, int forWriting)
{
    PHYSFS_uint8 buf[3];
    PHYSFS_uint32 count = 0;
    UNPKentry *entries = NULL;

    assert(io != NULL);  /* shouldn't ever happen. */
    BAIL_IF_MACRO(forWriting, PHYSFS_ERR_READ_ONLY, NULL);
    BAIL_IF_MACRO(!__PHYSFS_readAll(io, buf, 3), ERRPASS, NULL);
    BAIL_IF_MACRO(memcmp(buf, "DHF", 3) != 0, PHYSFS_ERR_UNSUPPORTED, NULL);

    entries = hogLoadEntries(io, &count);
    BAIL_IF_MACRO(!entries, ERRPASS, NULL);
    return UNPK_openArchive(io, entries, count);
} /* HOG_openArchive */


const PHYSFS_Archiver __PHYSFS_Archiver_HOG =
{
    CURRENT_PHYSFS_ARCHIVER_API_VERSION,
    {
        "HOG",
        "Descent I/II HOG file format",
        "Bradley Bell <btb@icculus.org>",
        "https://icculus.org/physfs/",
        0,  /* supportsSymlinks */
    },
    HOG_openArchive,
    UNPK_enumerateFiles,
    UNPK_openRead,
    UNPK_openWrite,
    UNPK_openAppend,
    UNPK_remove,
    UNPK_mkdir,
    UNPK_stat,
    UNPK_closeArchive
};

#endif  /* defined PHYSFS_SUPPORTS_HOG */

/* end of archiver_hog.c ... */