Quelle gzlib.c Sprache: C

/* gzlib.c -- zlib functions common to reading and writing gzip files
* Copyright (C) 2004-2024 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/

#include "gzguts.h"

#if defined(_WIN32) && !defined(__BORLANDC__)
#  define LSEEK _lseeki64
#else
#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
#  define LSEEK lseek64
#else
#  define LSEEK lseek
#endif
#endif

#if defined UNDER_CE

/* Map the Windows error number in ERROR to a locale-dependent error message
   string and return a pointer to it.  Typically, the values for ERROR come
   from GetLastError.

   The string pointed to shall not be modified by the application, but may be
   overwritten by a subsequent call to gz_strwinerror

   The gz_strwinerror function does not change the current setting of
   GetLastError. */
char ZLIB_INTERNAL *gz_strwinerror(DWORD error) {
    static char buf[1024];

    wchar_t *msgbuf;
    DWORD lasterr = GetLastError();
    DWORD chars = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM
        | FORMAT_MESSAGE_ALLOCATE_BUFFER,
        NULL,
        error,
        0, /* Default language */
        (LPVOID)&msgbuf,
        0,
        NULL);
    if (chars != 0) {
        /* If there is an \r\n appended, zap it.  */
        if (chars >= 2
            && msgbuf[chars - 2] == '\r' && msgbuf[chars - 1] == '\n') {
            chars -= 2;
            msgbuf[chars] = 0;
        }

        if (chars > sizeof (buf) - 1) {
            chars = sizeof (buf) - 1;
            msgbuf[chars] = 0;
        }

        wcstombs(buf, msgbuf, chars + 1);
        LocalFree(msgbuf);
    }
    else {
        sprintf(buf, "unknown win32 error (%ld)", error);
    }

    SetLastError(lasterr);
    return buf;
}

#endif /* UNDER_CE */

/* Reset gzip file state */
local void gz_reset(gz_statep state) {
    state->x.have = 0;              /* no output data available */
    if (state->mode == GZ_READ) {   /* for reading ... */
        state->eof = 0;             /* not at end of file */
        state->past = 0;            /* have not read past end yet */
        state->how = LOOK;          /* look for gzip header */
    }
    else                            /* for writing ... */
        state->reset = 0;           /* no deflateReset pending */
    state->seek = 0;                /* no seek request pending */
    gz_error(state, Z_OK, NULL);    /* clear error */
    state->x.pos = 0;               /* no uncompressed data yet */
    state->strm.avail_in = 0;       /* no input data yet */
}

/* Open a gzip file either by name or file descriptor. */
local gzFile gz_open(const void *path, int fd, const char *mode) {
    gz_statep state;
    z_size_t len;
    int oflag;
#ifdef O_CLOEXEC
    int cloexec = 0;
#endif
#ifdef O_EXCL
    int exclusive = 0;
#endif

    /* check input */
    if (path == NULL)
        return NULL;

    /* allocate gzFile structure to return */
    state = (gz_statep)malloc(sizeof(gz_state));
    if (state == NULL)
        return NULL;
    state->size = 0;            /* no buffers allocated yet */
    state->want = GZBUFSIZE;    /* requested buffer size */
    state->msg = NULL;          /* no error message yet */

    /* interpret mode */
    state->mode = GZ_NONE;
    state->level = Z_DEFAULT_COMPRESSION;
    state->strategy = Z_DEFAULT_STRATEGY;
    state->direct = 0;
    while (*mode) {
        if (*mode >= '0' && *mode <= '9')
            state->level = *mode - '0';
        else
            switch (*mode) {
            case 'r':
                state->mode = GZ_READ;
                break;
#ifndef NO_GZCOMPRESS
            case 'w':
                state->mode = GZ_WRITE;
                break;
            case 'a':
                state->mode = GZ_APPEND;
                break;
#endif
            case '+':       /* can't read and write at the same time */
                free(state);
                return NULL;
            case 'b':       /* ignore -- will request binary anyway */
                break;
#ifdef O_CLOEXEC
            case 'e':
                cloexec = 1;
                break;
#endif
#ifdef O_EXCL
            case 'x':
                exclusive = 1;
                break;
#endif
            case 'f':
                state->strategy = Z_FILTERED;
                break;
            case 'h':
                state->strategy = Z_HUFFMAN_ONLY;
                break;
            case 'R':
                state->strategy = Z_RLE;
                break;
            case 'F':
                state->strategy = Z_FIXED;
                break;
            case 'T':
                state->direct = 1;
                break;
            default:        /* could consider as an error, but just ignore */
                ;
            }
        mode++;
    }

    /* must provide an "r", "w", or "a" */
    if (state->mode == GZ_NONE) {
        free(state);
        return NULL;
    }

    /* can't force transparent read */
    if (state->mode == GZ_READ) {
        if (state->direct) {
            free(state);
            return NULL;
        }
        state->direct = 1;      /* for empty file */
    }

    /* save the path name for error messages */
#ifdef WIDECHAR
    if (fd == -2) {
        len = wcstombs(NULL, path, 0);
        if (len == (z_size_t)-1)
            len = 0;
    }
    else
#endif
        len = strlen((const char *)path);
    state->path = (char *)malloc(len + 1);
    if (state->path == NULL) {
        free(state);
        return NULL;
    }
#ifdef WIDECHAR
    if (fd == -2)
        if (len)
            wcstombs(state->path, path, len + 1);
        else
            *(state->path) = 0;
    else
#endif
#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
        (void)snprintf(state->path, len + 1, "%s", (const char *)path);
#else
        strcpy(state->path, path);
#endif

    /* compute the flags for open() */
    oflag =
#ifdef O_LARGEFILE
        O_LARGEFILE |
#endif
#ifdef O_BINARY
        O_BINARY |
#endif
#ifdef O_CLOEXEC
        (cloexec ? O_CLOEXEC : 0) |
#endif
        (state->mode == GZ_READ ?
         O_RDONLY :
         (O_WRONLY | O_CREAT |
#ifdef O_EXCL
          (exclusive ? O_EXCL : 0) |
#endif
          (state->mode == GZ_WRITE ?
           O_TRUNC :
           O_APPEND)));

    /* open the file with the appropriate flags (or just use fd) */
    state->fd = fd > -1 ? fd : (
#ifdef WIDECHAR
        fd == -2 ? _wopen(path, oflag, 0666) :
#endif
        open((const char *)path, oflag, 0666));
    if (state->fd == -1) {
        free(state->path);
        free(state);
        return NULL;
    }
    if (state->mode == GZ_APPEND) {
        LSEEK(state->fd, 0, SEEK_END);  /* so gzoffset() is correct */
        state->mode = GZ_WRITE;         /* simplify later checks */
    }

    /* save the current position for rewinding (only if reading) */
    if (state->mode == GZ_READ) {
        state->start = LSEEK(state->fd, 0, SEEK_CUR);
        if (state->start == -1) state->start = 0;
    }

    /* initialize stream */
    gz_reset(state);

    /* return stream */
    return (gzFile)state;
}

/* -- see zlib.h -- */
gzFile ZEXPORT gzopen(const char *path, const char *mode) {
    return gz_open(path, -1, mode);
}

/* -- see zlib.h -- */
gzFile ZEXPORT gzopen64(const char *path, const char *mode) {
    return gz_open(path, -1, mode);
}

/* -- see zlib.h -- */
gzFile ZEXPORT gzdopen(int fd, const char *mode) {
    char *path;         /* identifier for error messages */
    gzFile gz;

    if (fd == -1 || (path = (char *)malloc(7 + 3 * sizeof(int))) == NULL)
        return NULL;
#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
    (void)snprintf(path, 7 + 3 * sizeof(int), "", fd);
#else
    sprintf(path, "", fd);   /* for debugging */
#endif
    gz = gz_open(path, fd, mode);
    free(path);
    return gz;
}

/* -- see zlib.h -- */
#ifdef WIDECHAR
gzFile ZEXPORT gzopen_w(const wchar_t *path, const char *mode) {
    return gz_open(path, -2, mode);
}
#endif

/* -- see zlib.h -- */
int ZEXPORT gzbuffer(gzFile file, unsigned size) {
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return -1;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return -1;

    /* make sure we haven't already allocated memory */
    if (state->size != 0)
        return -1;

    /* check and set requested size */
    if ((size << 1) < size)
        return -1;              /* need to be able to double it */
    if (size < 8)
        size = 8;               /* needed to behave well with flushing */
    state->want = size;
    return 0;
}

/* -- see zlib.h -- */
int ZEXPORT gzrewind(gzFile file) {
    gz_statep state;

    /* get internal structure */
    if (file == NULL)
        return -1;
    state = (gz_statep)file;

    /* check that we're reading and that there's no error */
    if (state->mode != GZ_READ ||
            (state->err != Z_OK && state->err != Z_BUF_ERROR))
        return -1;

    /* back up and start over */
    if (LSEEK(state->fd, state->start, SEEK_SET) == -1)
        return -1;
    gz_reset(state);
    return 0;
}

/* -- see zlib.h -- */
z_off64_t ZEXPORT gzseek64(gzFile file, z_off64_t offset, int whence) {
    unsigned n;
    z_off64_t ret;
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return -1;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return -1;

    /* check that there's no error */
    if (state->err != Z_OK && state->err != Z_BUF_ERROR)
        return -1;

    /* can only seek from start or relative to current position */
    if (whence != SEEK_SET && whence != SEEK_CUR)
        return -1;

    /* normalize offset to a SEEK_CUR specification */
    if (whence == SEEK_SET)
        offset -= state->x.pos;
    else if (state->seek)
        offset += state->skip;
    state->seek = 0;

    /* if within raw area while reading, just go there */
    if (state->mode == GZ_READ && state->how == COPY &&
            state->x.pos + offset >= 0) {
        ret = LSEEK(state->fd, offset - (z_off64_t)state->x.have, SEEK_CUR);
        if (ret == -1)
            return -1;
        state->x.have = 0;
        state->eof = 0;
        state->past = 0;
        state->seek = 0;
        gz_error(state, Z_OK, NULL);
        state->strm.avail_in = 0;
        state->x.pos += offset;
        return state->x.pos;
    }

    /* calculate skip amount, rewinding if needed for back seek when reading */
    if (offset < 0) {
        if (state->mode != GZ_READ)         /* writing -- can't go backwards */
            return -1;
        offset += state->x.pos;
        if (offset < 0)                     /* before start of file! */
            return -1;
        if (gzrewind(file) == -1)           /* rewind, then skip to offset */
            return -1;
    }

    /* if reading, skip what's in output buffer (one less gzgetc() check) */
    if (state->mode == GZ_READ) {
        n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > offset ?
            (unsigned)offset : state->x.have;
        state->x.have -= n;
        state->x.next += n;
        state->x.pos += n;
        offset -= n;
    }

    /* request skip (if not zero) */
    if (offset) {
        state->seek = 1;
        state->skip = offset;
    }
    return state->x.pos + offset;
}

/* -- see zlib.h -- */
z_off_t ZEXPORT gzseek(gzFile file, z_off_t offset, int whence) {
    z_off64_t ret;

    ret = gzseek64(file, (z_off64_t)offset, whence);
    return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}

/* -- see zlib.h -- */
z_off64_t ZEXPORT gztell64(gzFile file) {
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return -1;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return -1;

    /* return position */
    return state->x.pos + (state->seek ? state->skip : 0);
}

/* -- see zlib.h -- */
z_off_t ZEXPORT gztell(gzFile file) {
    z_off64_t ret;

    ret = gztell64(file);
    return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}

/* -- see zlib.h -- */
z_off64_t ZEXPORT gzoffset64(gzFile file) {
    z_off64_t offset;
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return -1;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return -1;

    /* compute and return effective offset in file */
    offset = LSEEK(state->fd, 0, SEEK_CUR);
    if (offset == -1)
        return -1;
    if (state->mode == GZ_READ)             /* reading */
        offset -= state->strm.avail_in;     /* don't count buffered input */
    return offset;
}

/* -- see zlib.h -- */
z_off_t ZEXPORT gzoffset(gzFile file) {
    z_off64_t ret;

    ret = gzoffset64(file);
    return ret == (z_off_t)ret ? (z_off_t)ret : -1;
}

/* -- see zlib.h -- */
int ZEXPORT gzeof(gzFile file) {
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return 0;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return 0;

    /* return end-of-file state */
    return state->mode == GZ_READ ? state->past : 0;
}

/* -- see zlib.h -- */
const char * ZEXPORT gzerror(gzFile file, int *errnum) {
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return NULL;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return NULL;

    /* return error information */
    if (errnum != NULL)
        *errnum = state->err;
    return state->err == Z_MEM_ERROR ? "out of memory" :
                                       (state->msg == NULL ? "" : state->msg);
}

/* -- see zlib.h -- */
void ZEXPORT gzclearerr(gzFile file) {
    gz_statep state;

    /* get internal structure and check integrity */
    if (file == NULL)
        return;
    state = (gz_statep)file;
    if (state->mode != GZ_READ && state->mode != GZ_WRITE)
        return;

    /* clear error and end-of-file */
    if (state->mode == GZ_READ) {
        state->eof = 0;
        state->past = 0;
    }
    gz_error(state, Z_OK, NULL);
}

/* Create an error message in allocated memory and set state->err and
   state->msg accordingly.  Free any previous error message already there.  Do
   not try to free or allocate space if the error is Z_MEM_ERROR (out of
   memory).  Simply save the error message as a static string.  If there is an
   allocation failure constructing the error message, then convert the error to
   out of memory. */
void ZLIB_INTERNAL gz_error(gz_statep state, int err, const char *msg) {
    /* free previously allocated message and clear */
    if (state->msg != NULL) {
        if (state->err != Z_MEM_ERROR)
            free(state->msg);
        state->msg = NULL;
    }

    /* if fatal, set state->x.have to 0 so that the gzgetc() macro fails */
    if (err != Z_OK && err != Z_BUF_ERROR)
        state->x.have = 0;

    /* set error code, and if no message, then done */
    state->err = err;
    if (msg == NULL)
        return;

    /* for an out of memory error, return literal string when requested */
    if (err == Z_MEM_ERROR)
        return;

    /* construct error message with path */
    if ((state->msg = (char *)malloc(strlen(state->path) + strlen(msg) + 3)) ==
            NULL) {
        state->err = Z_MEM_ERROR;
        return;
    }
#if !defined(NO_snprintf) && !defined(NO_vsnprintf)
    (void)snprintf(state->msg, strlen(state->path) + strlen(msg) + 3,
                   "%s%s%s", state->path, ": ", msg);
#else
    strcpy(state->msg, state->path);
    strcat(state->msg, ": ");
    strcat(state->msg, msg);
#endif
}

/* portably return maximum value for an int (when limits.h presumed not
   available) -- we need to do this to cover cases where 2's complement not
   used, since C standard permits 1's complement and sign-bit representations,
   otherwise we could just use ((unsigned)-1) >> 1 */
unsigned ZLIB_INTERNAL gz_intmax(void) {
#ifdef INT_MAX
    return INT_MAX;
#else
    unsigned p = 1, q;
    do {
        q = p;
        p <<= 1;
        p++;
    } while (p > q);
    return q >> 1;
#endif
}

quality98%

¤ Dauer der Verarbeitung: 0.29 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.