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- /* seekable zip */
- #include "unzip.h"
- #include <stdlib.h>
- #include <string.h>
- #include <errno.h>
- #include "zlib/zlib.h"
- #define errormsg(str1,def,fname) printf("%s: " #def ": " str1 "\n", fname);
- /* from gzio.c . Be careful with binary compatibility */
- 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' */
- z_off_t start; /* start of compressed data in file (header skipped) */
- z_off_t in; /* bytes into deflate or inflate */
- z_off_t out; /* bytes out of deflate or inflate */
- int back; /* one character push-back */
- int last; /* true if push-back is last character */
- } gz_stream;
- #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)
- int destroy OF((gz_stream *s));
- gzFile zip2gz(ZIP* zip, struct zipent* ent)
- {
- int err;
- gz_stream *s;
- const char *path;
- int transparent = 0;
- uInt len;
- if (!zip || !ent)
- return NULL;
- /* zip stuff */
- if (ent->compression_method == 0x0000)
- {
- /* file is not compressed, simply stored */
- /* check if size are equal */
- if (ent->compressed_size != ent->uncompressed_size) {
- errormsg("Wrong uncompressed size in store compression", ERROR_CORRUPT,zip->zip);
- return NULL;
- }
- transparent = 1;
- }
- else if (ent->compression_method == 0x0008)
- {
- /* file is compressed using "Deflate" method */
- if (ent->version_needed_to_extract > 0x14) {
- errormsg("Version too new", ERROR_UNSUPPORTED,zip->zip);
- return NULL;
- }
- if (ent->os_needed_to_extract != 0x00) {
- errormsg("OS not supported", ERROR_UNSUPPORTED,zip->zip);
- return NULL;
- }
- if (ent->disk_number_start != zip->number_of_this_disk) {
- errormsg("Cannot span disks", ERROR_UNSUPPORTED,zip->zip);
- return NULL;
- }
- } else {
- errormsg("Compression method unsupported", ERROR_UNSUPPORTED, zip->zip);
- return NULL;
- }
- /* seek to compressed data */
- if (seekcompresszip(zip,ent) != 0) {
- return NULL;
- }
- path = zip->zip;
- /* normal gzip init for read */
- s = (gz_stream *)ALLOC(sizeof(gz_stream));
- if (!s) return Z_NULL;
- 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 = NULL;
- s->z_err = Z_OK;
- s->z_eof = 0;
- s->in = 0;
- s->out = 0;
- s->back = EOF;
- s->crc = crc32(0L, Z_NULL, 0);
- s->msg = NULL;
- s->transparent = transparent;
- s->mode = 'r';
- s->path = (char*)ALLOC(strlen(path)+1);
- if (s->path == NULL) {
- return destroy(s), (gzFile)Z_NULL;
- }
- strcpy(s->path, path); /* do this early for debugging */
- s->stream.next_in = s->inbuf = (Byte*)ALLOC(Z_BUFSIZE);
- err = inflateInit2(&(s->stream), -MAX_WBITS);
- /* windowBits is passed < 0 to tell that there is no zlib header.
- * Note that in this case inflate *requires* an extra "dummy" byte
- * after the compressed stream in order to complete decompression and
- * return Z_STREAM_END. Here the gzip CRC32 ensures that 4 bytes are
- * present after the compressed stream.
- */
- if (err != Z_OK || s->inbuf == Z_NULL) {
- return destroy(s), (gzFile)Z_NULL;
- }
- s->stream.avail_out = Z_BUFSIZE;
- errno = 0;
- s->file = zip->fp;
- if (s->file == NULL) {
- return destroy(s), (gzFile)Z_NULL;
- }
- /* check_header(s); */
- errno = 0;
- len = (uInt)fread(s->inbuf, 1, Z_BUFSIZE, s->file);
- if (len == 0 && ferror(s->file)) s->z_err = Z_ERRNO;
- s->stream.avail_in += len;
- s->stream.next_in = s->inbuf;
- if (s->stream.avail_in < 2) {
- return destroy(s), (gzFile)Z_NULL;
- }
- s->start = ftell(s->file) - s->stream.avail_in;
- return (gzFile)s;
- }
- int gzerror2(gzFile file)
- {
- gz_stream *s = (gz_stream*)file;
- if (s == NULL)
- return Z_STREAM_ERROR;
- return s->z_err;
- }
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