szddd.c File Reference

#include <system.h>
#include <szdd.h>

Go to the source code of this file.

Functions
static struct msszddd_header *	szddd_open (struct msszdd_decompressor *base, const char *filename)
static void	szddd_close (struct msszdd_decompressor *base, struct msszddd_header *hdr)
static int	szddd_read_headers (struct mspack_system *sys, struct mspack_file *fh, struct msszddd_header *hdr)
static int	szddd_extract (struct msszdd_decompressor *base, struct msszddd_header *hdr, const char *filename)
static int	szddd_decompress (struct msszdd_decompressor *base, const char *input, const char *output)
static int	szddd_error (struct msszdd_decompressor *base)
struct msszdd_decompressor *	mspack_create_szdd_decompressor (struct mspack_system *sys)
void	mspack_destroy_szdd_decompressor (struct msszdd_decompressor *base)

Variables
static unsigned char	szdd_signature_expand [8]
static unsigned char	szdd_signature_qbasic [8]

Function Documentation

mspack_create_szdd_decompressor()

struct msszdd_decompressor* mspack_create_szdd_decompressor

(

struct mspack_system *

sys

)

Creates a new SZDD decompressor.

Parameters

sys	a custom mspack_system structure, or NULL to use the default

Returns

a msszdd_decompressor or NULL

Definition at line 41 of file szddd.c.

{
  struct msszdd_decompressor_p *self = NULL;
 
  if (!sys) sys = mspack_default_system;
  if (!mspack_valid_system(sys)) return NULL;
 
  if ((self = (struct msszdd_decompressor_p *) sys->alloc(sys, sizeof(struct msszdd_decompressor_p)))) {
    self->base.open       = &szddd_open;
    self->base.close      = &szddd_close;
    self->base.extract    = &szddd_extract;
    self->base.decompress = &szddd_decompress;
    self->base.last_error = &szddd_error;
    self->system          = sys;
    self->error           = MSPACK_ERR_OK;
  }
  return (struct msszdd_decompressor *) self;
}

References mspack_system::alloc, mspack_default_system, MSPACK_ERR_OK, mspack_valid_system(), NULL, szddd_close(), szddd_decompress(), szddd_error(), szddd_extract(), and szddd_open().

Referenced by main().

mspack_destroy_szdd_decompressor()

void mspack_destroy_szdd_decompressor

(

struct msszdd_decompressor *

self

)

Destroys an existing SZDD decompressor.

Parameters

self	the msszdd_decompressor to destroy

Definition at line 65 of file szddd.c.

{
    struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
    if (self) {
        struct mspack_system *sys = self->system;
        sys->free(self);
    }
}

References msszdd_decompressor_p::base, and mspack_system::free.

Referenced by main().

szddd_close()

static void szddd_close ( struct msszdd_decompressor *  base, struct msszddd_header *  hdr  )

static

Definition at line 115 of file szddd.c.

{
    struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
    struct msszddd_header_p *hdr_p = (struct msszddd_header_p *) hdr;
 
    if (!self || !self->system) return;
 
    /* close the file handle associated */
    self->system->close(hdr_p->fh);
 
    /* free the memory associated */
    self->system->free(hdr);
 
    self->error = MSPACK_ERR_OK;
}

References msszdd_decompressor_p::base, msszddd_header_p::fh, and MSPACK_ERR_OK.

Referenced by mspack_create_szdd_decompressor(), and szddd_decompress().

szddd_decompress()

static int szddd_decompress ( struct msszdd_decompressor *  base, const char *  input, const char *  output  )

static

Definition at line 223 of file szddd.c.

{
    struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
    struct msszddd_header *hdr;
    int error;
 
    if (!self) return MSPACK_ERR_ARGS;
 
    if (!(hdr = szddd_open(base, input))) return self->error;
    error = szddd_extract(base, hdr, output);
    szddd_close(base, hdr);
    return self->error = error;
}

References msszdd_decompressor_p::base, error(), input(), MSPACK_ERR_ARGS, output, szddd_close(), szddd_extract(), and szddd_open().

Referenced by mspack_create_szdd_decompressor().

szddd_error()

static int szddd_error ( struct msszdd_decompressor *  base )

static

Definition at line 243 of file szddd.c.

{
    struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
    return (self) ? self->error : MSPACK_ERR_ARGS;
}

References msszdd_decompressor_p::base, and MSPACK_ERR_ARGS.

Referenced by mspack_create_szdd_decompressor().

szddd_extract()

static int szddd_extract ( struct msszdd_decompressor *  base, struct msszddd_header *  hdr, const char *  filename  )

static

Definition at line 181 of file szddd.c.

{
    struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
    struct mspack_file *fh, *outfh;
    struct mspack_system *sys;
    off_t data_offset;
 
    if (!self) return MSPACK_ERR_ARGS;
    if (!hdr)  return self->error = MSPACK_ERR_ARGS;
    sys = self->system;
 
    fh = ((struct msszddd_header_p *) hdr)->fh;
 
    /* seek to the compressed data */
    data_offset = (hdr->format == MSSZDD_FMT_NORMAL) ? 14 : 12;
    if (sys->seek(fh, data_offset, MSPACK_SYS_SEEK_START)) {
        return self->error = MSPACK_ERR_SEEK;
    }
 
    /* open file for output */
    if (!(outfh = sys->open(sys, filename, MSPACK_SYS_OPEN_WRITE))) {
        return self->error = MSPACK_ERR_OPEN;
    }
 
    /* decompress the data */
    self->error = lzss_decompress(sys, fh, outfh, SZDD_INPUT_SIZE,
                                  hdr->format == MSSZDD_FMT_NORMAL
                                  ? LZSS_MODE_EXPAND
                                  : LZSS_MODE_QBASIC);
 
    /* close output file */
    sys->close(outfh);
 
    return self->error;
}

References msszdd_decompressor_p::base, mspack_system::close, fh, msszddd_header::format, lzss_decompress(), LZSS_MODE_EXPAND, LZSS_MODE_QBASIC, MSPACK_ERR_ARGS, MSPACK_ERR_OPEN, MSPACK_ERR_SEEK, MSPACK_SYS_OPEN_WRITE, MSPACK_SYS_SEEK_START, MSSZDD_FMT_NORMAL, mspack_system::open, mspack_system::seek, and SZDD_INPUT_SIZE.

Referenced by mspack_create_szdd_decompressor(), and szddd_decompress().

szddd_open()

static struct msszddd_header * szddd_open ( struct msszdd_decompressor *  base, const char *  filename  )

static

Definition at line 79 of file szddd.c.

{
    struct msszdd_decompressor_p *self = (struct msszdd_decompressor_p *) base;
    struct msszddd_header *hdr;
    struct mspack_system *sys;
    struct mspack_file *fh;
 
    if (!self) return NULL;
    sys = self->system;
 
    fh  = sys->open(sys, filename, MSPACK_SYS_OPEN_READ);
    hdr = (struct msszddd_header *) sys->alloc(sys, sizeof(struct msszddd_header_p));
    if (fh && hdr) {
        ((struct msszddd_header_p *) hdr)->fh = fh;
        self->error = szddd_read_headers(sys, fh, hdr);
    }
    else {
        if (!fh)  self->error = MSPACK_ERR_OPEN;
        if (!hdr) self->error = MSPACK_ERR_NOMEMORY;
    }
    
    if (self->error) {
        if (fh) sys->close(fh);
        sys->free(hdr);
        hdr = NULL;
    }
 
    return hdr;
}

References mspack_system::alloc, msszdd_decompressor_p::base, mspack_system::close, fh, mspack_system::free, MSPACK_ERR_NOMEMORY, MSPACK_ERR_OPEN, MSPACK_SYS_OPEN_READ, NULL, mspack_system::open, and szddd_read_headers().

Referenced by mspack_create_szdd_decompressor(), and szddd_decompress().

szddd_read_headers()

static int szddd_read_headers ( struct mspack_system *  sys, struct mspack_file *  fh, struct msszddd_header *  hdr  )

static

Definition at line 144 of file szddd.c.

{
    unsigned char buf[8];
 
    /* read and check signature */
    if (sys->read(fh, buf, 8) != 8) return MSPACK_ERR_READ;
 
    if ((memcmp(buf, szdd_signature_expand, 8) == 0)) {
        /* common SZDD */
        hdr->format = MSSZDD_FMT_NORMAL;
 
        /* read the rest of the header */
        if (sys->read(fh, buf, 6) != 6) return MSPACK_ERR_READ;
        if (buf[0] != 0x41) return MSPACK_ERR_DATAFORMAT;
        hdr->missing_char = buf[1];
        hdr->length = EndGetI32(&buf[2]);
    }
    else if ((memcmp(buf, szdd_signature_qbasic, 8) == 0)) {
        /* special QBasic SZDD */
        hdr->format = MSSZDD_FMT_QBASIC;
        if (sys->read(fh, buf, 4) != 4) return MSPACK_ERR_READ;
        hdr->missing_char = '\0';
        hdr->length = EndGetI32(buf);
    }
    else {
        return MSPACK_ERR_SIGNATURE;
    }
    return MSPACK_ERR_OK;
}

References EndGetI32, fh, msszddd_header::format, msszddd_header::length, msszddd_header::missing_char, MSPACK_ERR_DATAFORMAT, MSPACK_ERR_OK, MSPACK_ERR_READ, MSPACK_ERR_SIGNATURE, MSSZDD_FMT_NORMAL, MSSZDD_FMT_QBASIC, mspack_system::read, szdd_signature_expand, and szdd_signature_qbasic.

Referenced by szddd_open().

Variable Documentation

szdd_signature_expand

unsigned char szdd_signature_expand[8]

static

Initial value:

= {
    0x53, 0x5A, 0x44, 0x44, 0x88, 0xF0, 0x27, 0x33
}

Definition at line 137 of file szddd.c.

Referenced by szddd_read_headers().

szdd_signature_qbasic

unsigned char szdd_signature_qbasic[8]

static

Initial value:

= {
    0x53, 0x5A, 0x20, 0x88, 0xF0, 0x27, 0x33, 0xD1
}

Definition at line 140 of file szddd.c.

Referenced by szddd_read_headers().