apps/ccam/gzio_compress.c

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/* gzio_compress.c -- IO on .gz files
 * Copyright (C) 1995-2002 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h
 *
 * Compile this file with -DNO_DEFLATE to avoid the compression code.
 */

/* @(#) $Id: gzio_compress.c,v 1.1.1.1 2007/06/25 18:20:19 elphel Exp $ */

#include <stdio.h>

#include "zlib/zutil.h"
#include "gzio_compress.h"

struct internal_state {int dummy;}; /* for buggy compilers */

#ifndef Z_BUFSIZE
#  ifdef MAXSEG_64K
#    define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */
#  else
#    define Z_BUFSIZE 16384
#  endif
#endif
#ifndef Z_PRINTF_BUFSIZE
#  define Z_PRINTF_BUFSIZE 4096
#endif

#define ALLOC(size) malloc(size)
#define TRYFREE(p) {if (p) free(p);}

static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */

/* gzip flag byte */
#define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
#define HEAD_CRC     0x02 /* bit 1 set: header CRC present */
#define EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
#define ORIG_NAME    0x08 /* bit 3 set: original file name present */
#define COMMENT      0x10 /* bit 4 set: file comment present */
#define RESERVED     0xE0 /* bits 5..7: reserved */

typedef struct gz_stream {
    z_stream stream;
    int      z_err;   /* error code for last stream operation */
    int      z_eof;   /* set if end of input file */
    FILE     *file;   /* .gz file */
    Byte     *inbuf;  /* input buffer */
    Byte     *outbuf; /* output buffer */
    uLong    crc;     /* crc32 of uncompressed data */
    char     *msg;    /* error message */
    char     *path;   /* path name for debugging only */
    int      transparent; /* 1 if input file is not a .gz file */
    char     mode;    /* 'w' or 'r' */
    long     startpos; /* start of compressed data in file (header skipped) */
} gz_stream;

gzFile gz_useFile (FILE *file, const char *mode); // compressor mode only

local gzFile gz_open      OF((const char *path, const char *mode, int  fd));
local int do_flush        OF((gzFile file, int flush));
local int    destroy      OF((gz_stream *s));
local void   putLong      OF((FILE *file, uLong x));

/* ===========================================================================
     Opens a gzip (.gz) file for reading or writing. The mode parameter
   is as in fopen ("rb" or "wb"). The file is given either by file descriptor
   or path name (if fd == -1).
     gz_open return NULL if the file could not be opened or if there was
   insufficient memory to allocate the (de)compression state; errno
   can be checked to distinguish the two cases (if errno is zero, the
   zlib error is Z_MEM_ERROR).
*/
gzFile gz_useFile (file,mode) // compressor mode only
    FILE *file;
    const char *mode;
{
    int err;
    int level = Z_DEFAULT_COMPRESSION; /* compression level */
    int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */
    char *p = (char*)mode;
    gz_stream *s;
    if (!mode) return Z_NULL;

    s = (gz_stream *)ALLOC(sizeof(gz_stream));
    if (!s) return Z_NULL;
    s->startpos = 0L;
    s->stream.zalloc = (alloc_func)0;
    s->stream.zfree = (free_func)0;
    s->stream.opaque = (voidpf)0;
    s->stream.next_in = s->inbuf = Z_NULL;
    s->stream.next_out = s->outbuf = Z_NULL;
    s->stream.avail_in = s->stream.avail_out = 0;
    s->file = file;
    s->z_err = Z_OK;
    s->z_eof = 0;
    s->crc = crc32(0L, Z_NULL, 0);
    s->msg = NULL;
    s->transparent = 0;

    s->path = NULL;

    s->mode = '\0';
    do {
        if (*p == 'r') s->mode = 'r';
        if (*p == 'w' || *p == 'a') s->mode = 'w';
        if (*p >= '0' && *p <= '9') {
            level = *p - '0';
        } else if (*p == 'f') {
          strategy = Z_FILTERED;
        } else if (*p == 'h') {
          strategy = Z_HUFFMAN_ONLY;
        }
    } while (*p++);
    if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
    
    if (s->mode == 'w') {
       if (level==0) s->transparent = 1; // to speedup gzprintf

#ifdef NO_DEFLATE
        err = Z_STREAM_ERROR;
#else
        if (!s->transparent) {
          err = deflateInit2(&(s->stream), level,
                           Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy);
          /* windowBits is passed < 0 to suppress zlib header */

          s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE);
#endif
          if (err != Z_OK || s->outbuf == Z_NULL) {
            return destroy(s), (gzFile)Z_NULL;
          }
        }
    } else {
        err = Z_STREAM_ERROR;
        return destroy(s), (gzFile)Z_NULL;
    }
    s->stream.avail_out = Z_BUFSIZE;

    errno = 0;
    if (s->file == NULL) {
        return destroy(s), (gzFile)Z_NULL;
    }
    if ((s->mode == 'w') && !s->transparent) { // no header if level=0 !!!
        /* Write a very simple .gz header:
         */
        fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1],
             Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
        s->startpos = 10L;
        /* We use 10L instead of ftell(s->file) to because ftell causes an
         * fflush on some systems. This version of the library doesn't use
         * startpos anyway in write mode, so this initialization is not
         * necessary.
         */
    }
    return (gzFile)s;
}


 /* ===========================================================================
 * Cleanup then free the given gz_stream. Return a zlib error code.
   Try freeing in the reverse order of allocations.
 */
local int destroy (s)
    gz_stream *s;
{
    int err = Z_OK;

    if (!s) return Z_STREAM_ERROR;

    TRYFREE(s->msg);

    if (s->stream.state != NULL) {
        if (s->mode == 'w') {
#ifdef NO_DEFLATE
            err = Z_STREAM_ERROR;
#else
            err = deflateEnd(&(s->stream));
#endif
        }
    }
    if (s->file != NULL && fclose(s->file)) {
#ifdef ESPIPE
        if (errno != ESPIPE) /* fclose is broken for pipes in HP/UX */
#endif
            err = Z_ERRNO;
    }
    if (s->z_err < 0) err = s->z_err;

    TRYFREE(s->inbuf);
    TRYFREE(s->outbuf);
    TRYFREE(s->path);
    TRYFREE(s);
    return err;
}

#ifndef NO_DEFLATE
/* ===========================================================================
     Writes the given number of uncompressed bytes into the compressed file.
   gzwrite returns the number of bytes actually written (0 in case of error).
*/
int ZEXPORT gzwrite (file, buf, len)
    gzFile file;
    const voidp buf;
    unsigned len;
{
    gz_stream *s = (gz_stream*)file;

    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;

    s->stream.next_in = (Bytef*)buf;
    s->stream.avail_in = len;

    while (s->stream.avail_in != 0) {

        if (s->stream.avail_out == 0) {

            s->stream.next_out = s->outbuf;
            if (fwrite(s->outbuf, 1, Z_BUFSIZE, s->file) != Z_BUFSIZE) {
                s->z_err = Z_ERRNO;
                break;
            }
            s->stream.avail_out = Z_BUFSIZE;
        }
        s->z_err = deflate(&(s->stream), Z_NO_FLUSH);
        if (s->z_err != Z_OK) break;
    }
    s->crc = crc32(s->crc, (const Bytef *)buf, len);

    return (int)(len - s->stream.avail_in);
}

/* ===========================================================================
     Converts, formats, and writes the args to the compressed file under
   control of the format string, as in fprintf. gzprintf returns the number of
   uncompressed bytes actually written (0 in case of error).
*/
#ifdef STDC
#include <stdarg.h>

int ZEXPORTVA gzprintf (gzFile file, const char *format, /* args */ ...)
{   
    gz_stream *s = (gz_stream*)file;
    char buf[Z_PRINTF_BUFSIZE];
    va_list va;
    int len;

    va_start(va, format);
/*
    if (s->transparent) { // speedup non-compressed mode
      len=fprintf(s->file, format, va);
      va_end(va);
      return len;
    }
*/
#ifdef HAS_vsnprintf
    (void)vsnprintf(buf, sizeof(buf), format, va);
#else
    (void)vsprintf(buf, format, va);
#endif
    va_end(va);
    len = strlen(buf); /* some *sprintf don't return the nb of bytes written */
    if (len <= 0) return 0;
    if (s->transparent) { // speedup non-compressed mode
      return fwrite(buf, (size_t) len, 1, s->file);
    }

    return gzwrite(file, buf, (unsigned)len);
}
#else /* not ANSI C */
#error  not ANSI C!
int ZEXPORTVA gzprintf (file, format, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
                       a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)
    gzFile file;
    const char *format;
    int a1, a2, a3, a4, a5, a6, a7, a8, a9, a10,
        a11, a12, a13, a14, a15, a16, a17, a18, a19, a20;
{
    char buf[Z_PRINTF_BUFSIZE];
    int len;

#ifdef HAS_snprintf
    snprintf(buf, sizeof(buf), format, a1, a2, a3, a4, a5, a6, a7, a8,
             a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
#else
    sprintf(buf, format, a1, a2, a3, a4, a5, a6, a7, a8,
            a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20);
#endif
    len = strlen(buf); /* old sprintf doesn't return the nb of bytes written */
    if (len <= 0) return 0;

    return gzwrite(file, buf, len);
}
#endif

/* ===========================================================================
     Flushes all pending output into the compressed file. The parameter
   flush is as in the deflate() function.
*/
local int do_flush (file, flush)
    gzFile file;
    int flush;
{
    uInt len;
    int done = 0;
    gz_stream *s = (gz_stream*)file;

    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;

    s->stream.avail_in = 0; /* should be zero already anyway */

    for (;;) {
        len = Z_BUFSIZE - s->stream.avail_out;

        if (len != 0) {
            if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
                s->z_err = Z_ERRNO;
                return Z_ERRNO;
            }
            s->stream.next_out = s->outbuf;
            s->stream.avail_out = Z_BUFSIZE;
        }
        if (done) break;
        s->z_err = deflate(&(s->stream), flush);

        /* Ignore the second of two consecutive flushes: */
        if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK;

        /* deflate has finished flushing only when it hasn't used up
         * all the available space in the output buffer: 
         */
        done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END);
 
        if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break;
    }
    return  s->z_err == Z_STREAM_END ? Z_OK : s->z_err;
}

#endif /* NO_DEFLATE */

/* ===========================================================================
      Sets the starting position for the next gzread or gzwrite on the given
   compressed file. The offset represents a number of bytes in the
      gzseek returns the resulting offset location as measured in bytes from
   the beginning of the uncompressed stream, or -1 in case of error.
      SEEK_END is not implemented, returns error.
      In this version of the library, gzseek can be extremely slow.
*/
z_off_t ZEXPORT gzseek (file, offset, whence)
    gzFile file;
    z_off_t offset;
    int whence;
{
    gz_stream *s = (gz_stream*)file;

    if (s == NULL || whence == SEEK_END ||
        s->z_err == Z_ERRNO || s->z_err == Z_DATA_ERROR) {
        return -1L;
    }
    
    if (s->mode == 'w') {
#ifdef NO_DEFLATE
        return -1L;
#else
        if (whence == SEEK_SET) {
            offset -= s->stream.total_in;
        }
        if (offset < 0) return -1L;

        /* At this point, offset is the number of zero bytes to write. */
        if (s->inbuf == Z_NULL) {
            s->inbuf = (Byte*)ALLOC(Z_BUFSIZE); /* for seeking */
            zmemzero(s->inbuf, Z_BUFSIZE);
        }
        while (offset > 0)  {
            uInt size = Z_BUFSIZE;
            if (offset < Z_BUFSIZE) size = (uInt)offset;

            size = gzwrite(file, s->inbuf, size);
            if (size == 0) return -1L;

            offset -= size;
        }
        return (z_off_t)s->stream.total_in;
#endif
    }
        return 0;
}


/* ===========================================================================
     Returns the starting position for the next gzread or gzwrite on the
   given compressed file. This position represents a number of bytes in the
   uncompressed data stream.
*/
z_off_t ZEXPORT gztell (file)
    gzFile file;
{
    return gzseek(file, 0L, SEEK_CUR);
}

/* ===========================================================================
     Returns 1 when EOF has previously been detected reading the given
   input stream, otherwise zero.
*/
int ZEXPORT gzeof (file)
    gzFile file;
{
    gz_stream *s = (gz_stream*)file;
    
    return (s == NULL || s->mode != 'r') ? 0 : s->z_eof;
}

/* ===========================================================================
   Outputs a long in LSB order to the given file
*/
local void putLong (file, x)
    FILE *file;
    uLong x;
{
    int n;
    for (n = 0; n < 4; n++) {
        fputc((int)(x & 0xff), file);
        x >>= 8;
    }
}


/* ===========================================================================
     Flushes all pending output if necessary, closes the compressed file
   and deallocates all the (de)compression state.
*/
int ZEXPORT gzclose (file)
    gzFile file;
{
    int err;
    gz_stream *s = (gz_stream*)file;

    if (s == NULL) return Z_STREAM_ERROR;

    if (s->mode == 'w') {
#ifdef NO_DEFLATE
        return Z_STREAM_ERROR;
#else
        if (!s->transparent) {// no header/trailer in transparent mode !!!
          err = do_flush (file, Z_FINISH);
          if (err != Z_OK) return destroy((gz_stream*)file);
          putLong (s->file, s->crc);
          putLong (s->file, s->stream.total_in);
        }
#endif
    }
    return destroy((gz_stream*)file);
}

/* ===========================================================================
     Returns the error message for the last error which occured on the
   given compressed file. errnum is set to zlib error number. If an
   error occured in the file system and not in the compression library,
   errnum is set to Z_ERRNO and the application may consult errno
   to get the exact error code.
*/
const char*  ZEXPORT gzerror (file, errnum)
    gzFile file;
    int *errnum;
{
    char *m;
    gz_stream *s = (gz_stream*)file;

    if (s == NULL) {
        *errnum = Z_STREAM_ERROR;
        return (const char*)ERR_MSG(Z_STREAM_ERROR);
    }
    *errnum = s->z_err;
    if (*errnum == Z_OK) return (const char*)"";

    m =  (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);

    if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err);

    TRYFREE(s->msg);
    s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
    strcpy(s->msg, s->path);
    strcat(s->msg, ": ");
    strcat(s->msg, m);
    return (const char*)s->msg;
}

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