| /* gzread.c -- zlib functions for reading gzip files |
| * Copyright (C) 2004, 2005, 2010, 2011, 2012, 2013 Mark Adler |
| * For conditions of distribution and use, see copyright notice in zlib.h |
| */ |
| |
| #include "gzguts.h" |
| |
| /* Local functions */ |
| local int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *)); |
| local int gz_avail OF((gz_statep)); |
| local int gz_look OF((gz_statep)); |
| local int gz_decomp OF((gz_statep)); |
| local int gz_fetch OF((gz_statep)); |
| local int gz_skip OF((gz_statep, z_off64_t)); |
| |
| /* Use read() to load a buffer -- return -1 on error, otherwise 0. Read from |
| state->fd, and update state->eof, state->err, and state->msg as appropriate. |
| This function needs to loop on read(), since read() is not guaranteed to |
| read the number of bytes requested, depending on the type of descriptor. */ |
| local int gz_load( |
| gz_statep state, |
| unsigned char *buf, |
| unsigned len, |
| unsigned *have) |
| { |
| int ret; |
| |
| *have = 0; |
| do { |
| ret = read(state->fd, buf + *have, len - *have); |
| if (ret <= 0) |
| break; |
| *have += ret; |
| } while (*have < len); |
| if (ret < 0) { |
| gz_error(state, Z_ERRNO, zstrerror()); |
| return -1; |
| } |
| if (ret == 0) |
| state->eof = 1; |
| return 0; |
| } |
| |
| /* Load up input buffer and set eof flag if last data loaded -- return -1 on |
| error, 0 otherwise. Note that the eof flag is set when the end of the input |
| file is reached, even though there may be unused data in the buffer. Once |
| that data has been used, no more attempts will be made to read the file. |
| If strm->avail_in != 0, then the current data is moved to the beginning of |
| the input buffer, and then the remainder of the buffer is loaded with the |
| available data from the input file. */ |
| local int gz_avail( |
| gz_statep state) |
| { |
| unsigned got; |
| z_streamp strm = &(state->strm); |
| |
| if (state->err != Z_OK && state->err != Z_BUF_ERROR) |
| return -1; |
| if (state->eof == 0) { |
| if (strm->avail_in) { /* copy what's there to the start */ |
| unsigned char *p = state->in; |
| unsigned const char *q = strm->next_in; |
| unsigned n = strm->avail_in; |
| do { |
| *p++ = *q++; |
| } while (--n); |
| } |
| if (gz_load(state, state->in + strm->avail_in, |
| state->size - strm->avail_in, &got) == -1) |
| return -1; |
| strm->avail_in += got; |
| strm->next_in = state->in; |
| } |
| return 0; |
| } |
| |
| /* Look for gzip header, set up for inflate or copy. state->x.have must be 0. |
| If this is the first time in, allocate required memory. state->how will be |
| left unchanged if there is no more input data available, will be set to COPY |
| if there is no gzip header and direct copying will be performed, or it will |
| be set to GZIP for decompression. If direct copying, then leftover input |
| data from the input buffer will be copied to the output buffer. In that |
| case, all further file reads will be directly to either the output buffer or |
| a user buffer. If decompressing, the inflate state will be initialized. |
| gz_look() will return 0 on success or -1 on failure. */ |
| local int gz_look( |
| gz_statep state) |
| { |
| z_streamp strm = &(state->strm); |
| |
| /* allocate read buffers and inflate memory */ |
| if (state->size == 0) { |
| /* allocate buffers */ |
| state->in = (unsigned char *)malloc(state->want); |
| state->out = (unsigned char *)malloc(state->want << 1); |
| if (state->in == NULL || state->out == NULL) { |
| if (state->out != NULL) |
| free(state->out); |
| if (state->in != NULL) |
| free(state->in); |
| gz_error(state, Z_MEM_ERROR, "out of memory"); |
| return -1; |
| } |
| state->size = state->want; |
| |
| /* allocate inflate memory */ |
| state->strm.zalloc = Z_NULL; |
| state->strm.zfree = Z_NULL; |
| state->strm.opaque = Z_NULL; |
| state->strm.avail_in = 0; |
| state->strm.next_in = Z_NULL; |
| if (inflateInit2(&(state->strm), 15 + 16) != Z_OK) { /* gunzip */ |
| free(state->out); |
| free(state->in); |
| state->size = 0; |
| gz_error(state, Z_MEM_ERROR, "out of memory"); |
| return -1; |
| } |
| } |
| |
| /* get at least the magic bytes in the input buffer */ |
| if (strm->avail_in < 2) { |
| if (gz_avail(state) == -1) |
| return -1; |
| if (strm->avail_in == 0) |
| return 0; |
| } |
| |
| /* look for gzip magic bytes -- if there, do gzip decoding (note: there is |
| a logical dilemma here when considering the case of a partially written |
| gzip file, to wit, if a single 31 byte is written, then we cannot tell |
| whether this is a single-byte file, or just a partially written gzip |
| file -- for here we assume that if a gzip file is being written, then |
| the header will be written in a single operation, so that reading a |
| single byte is sufficient indication that it is not a gzip file) */ |
| if (strm->avail_in > 1 && |
| strm->next_in[0] == 31 && strm->next_in[1] == 139) { |
| inflateReset(strm); |
| state->how = GZIP; |
| state->direct = 0; |
| return 0; |
| } |
| |
| /* no gzip header -- if we were decoding gzip before, then this is trailing |
| garbage. Ignore the trailing garbage and finish. */ |
| if (state->direct == 0) { |
| strm->avail_in = 0; |
| state->eof = 1; |
| state->x.have = 0; |
| return 0; |
| } |
| |
| /* doing raw i/o, copy any leftover input to output -- this assumes that |
| the output buffer is larger than the input buffer, which also assures |
| space for gzungetc() */ |
| state->x.next = state->out; |
| if (strm->avail_in) { |
| memcpy(state->x.next, strm->next_in, strm->avail_in); |
| state->x.have = strm->avail_in; |
| strm->avail_in = 0; |
| } |
| state->how = COPY; |
| state->direct = 1; |
| return 0; |
| } |
| |
| /* Decompress from input to the provided next_out and avail_out in the state. |
| On return, state->x.have and state->x.next point to the just decompressed |
| data. If the gzip stream completes, state->how is reset to LOOK to look for |
| the next gzip stream or raw data, once state->x.have is depleted. Returns 0 |
| on success, -1 on failure. */ |
| local int gz_decomp( |
| gz_statep state) |
| { |
| int ret = Z_OK; |
| unsigned had; |
| z_streamp strm = &(state->strm); |
| |
| /* fill output buffer up to end of deflate stream */ |
| had = strm->avail_out; |
| do { |
| /* get more input for inflate() */ |
| if (strm->avail_in == 0 && gz_avail(state) == -1) |
| return -1; |
| if (strm->avail_in == 0) { |
| gz_error(state, Z_BUF_ERROR, "unexpected end of file"); |
| break; |
| } |
| |
| /* decompress and handle errors */ |
| ret = inflate(strm, Z_NO_FLUSH); |
| if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) { |
| gz_error(state, Z_STREAM_ERROR, |
| "internal error: inflate stream corrupt"); |
| return -1; |
| } |
| if (ret == Z_MEM_ERROR) { |
| gz_error(state, Z_MEM_ERROR, "out of memory"); |
| return -1; |
| } |
| if (ret == Z_DATA_ERROR) { /* deflate stream invalid */ |
| gz_error(state, Z_DATA_ERROR, |
| strm->msg == NULL ? "compressed data error" : strm->msg); |
| return -1; |
| } |
| } while (strm->avail_out && ret != Z_STREAM_END); |
| |
| /* update available output */ |
| state->x.have = had - strm->avail_out; |
| state->x.next = strm->next_out - state->x.have; |
| |
| /* if the gzip stream completed successfully, look for another */ |
| if (ret == Z_STREAM_END) |
| state->how = LOOK; |
| |
| /* good decompression */ |
| return 0; |
| } |
| |
| /* Fetch data and put it in the output buffer. Assumes state->x.have is 0. |
| Data is either copied from the input file or decompressed from the input |
| file depending on state->how. If state->how is LOOK, then a gzip header is |
| looked for to determine whether to copy or decompress. Returns -1 on error, |
| otherwise 0. gz_fetch() will leave state->how as COPY or GZIP unless the |
| end of the input file has been reached and all data has been processed. */ |
| local int gz_fetch( |
| gz_statep state) |
| { |
| z_streamp strm = &(state->strm); |
| |
| do { |
| switch(state->how) { |
| case LOOK: /* -> LOOK, COPY (only if never GZIP), or GZIP */ |
| if (gz_look(state) == -1) |
| return -1; |
| if (state->how == LOOK) |
| return 0; |
| break; |
| case COPY: /* -> COPY */ |
| if (gz_load(state, state->out, state->size << 1, &(state->x.have)) |
| == -1) |
| return -1; |
| state->x.next = state->out; |
| return 0; |
| case GZIP: /* -> GZIP or LOOK (if end of gzip stream) */ |
| strm->avail_out = state->size << 1; |
| strm->next_out = state->out; |
| if (gz_decomp(state) == -1) |
| return -1; |
| } |
| } while (state->x.have == 0 && (!state->eof || strm->avail_in)); |
| return 0; |
| } |
| |
| /* Skip len uncompressed bytes of output. Return -1 on error, 0 on success. */ |
| local int gz_skip( |
| gz_statep state, |
| z_off64_t len) |
| { |
| unsigned n; |
| |
| /* skip over len bytes or reach end-of-file, whichever comes first */ |
| while (len) |
| /* skip over whatever is in output buffer */ |
| if (state->x.have) { |
| n = GT_OFF(state->x.have) || (z_off64_t)state->x.have > len ? |
| (unsigned)len : state->x.have; |
| state->x.have -= n; |
| state->x.next += n; |
| state->x.pos += n; |
| len -= n; |
| } |
| |
| /* output buffer empty -- return if we're at the end of the input */ |
| else if (state->eof && state->strm.avail_in == 0) |
| break; |
| |
| /* need more data to skip -- load up output buffer */ |
| else { |
| /* get more output, looking for header if required */ |
| if (gz_fetch(state) == -1) |
| return -1; |
| } |
| return 0; |
| } |
| |
| /* -- see zlib.h -- */ |
| int ZEXPORT gzread( |
| gzFile file, |
| voidp buf, |
| unsigned len) |
| { |
| unsigned got, n; |
| gz_statep state; |
| z_streamp strm; |
| |
| /* get internal structure */ |
| if (file == NULL) |
| return -1; |
| state = (gz_statep)file; |
| strm = &(state->strm); |
| |
| /* check that we're reading and that there's no (serious) error */ |
| if (state->mode != GZ_READ || |
| (state->err != Z_OK && state->err != Z_BUF_ERROR)) |
| return -1; |
| |
| /* since an int is returned, make sure len fits in one, otherwise return |
| with an error (this avoids the flaw in the interface) */ |
| if ((int)len < 0) { |
| gz_error(state, Z_DATA_ERROR, "requested length does not fit in int"); |
| return -1; |
| } |
| |
| /* if len is zero, avoid unnecessary operations */ |
| if (len == 0) |
| return 0; |
| |
| /* process a skip request */ |
| if (state->seek) { |
| state->seek = 0; |
| if (gz_skip(state, state->skip) == -1) |
| return -1; |
| } |
| |
| /* get len bytes to buf, or less than len if at the end */ |
| got = 0; |
| do { |
| /* first just try copying data from the output buffer */ |
| if (state->x.have) { |
| n = state->x.have > len ? len : state->x.have; |
| memcpy(buf, state->x.next, n); |
| state->x.next += n; |
| state->x.have -= n; |
| } |
| |
| /* output buffer empty -- return if we're at the end of the input */ |
| else if (state->eof && strm->avail_in == 0) { |
| state->past = 1; /* tried to read past end */ |
| break; |
| } |
| |
| /* need output data -- for small len or new stream load up our output |
| buffer */ |
| else if (state->how == LOOK || len < (state->size << 1)) { |
| /* get more output, looking for header if required */ |
| if (gz_fetch(state) == -1) |
| return -1; |
| continue; /* no progress yet -- go back to copy above */ |
| /* the copy above assures that we will leave with space in the |
| output buffer, allowing at least one gzungetc() to succeed */ |
| } |
| |
| /* large len -- read directly into user buffer */ |
| else if (state->how == COPY) { /* read directly */ |
| if (gz_load(state, (unsigned char *)buf, len, &n) == -1) |
| return -1; |
| } |
| |
| /* large len -- decompress directly into user buffer */ |
| else { /* state->how == GZIP */ |
| strm->avail_out = len; |
| strm->next_out = (unsigned char *)buf; |
| if (gz_decomp(state) == -1) |
| return -1; |
| n = state->x.have; |
| state->x.have = 0; |
| } |
| |
| /* update progress */ |
| len -= n; |
| buf = (char *)buf + n; |
| got += n; |
| state->x.pos += n; |
| } while (len); |
| |
| /* return number of bytes read into user buffer (will fit in int) */ |
| return (int)got; |
| } |
| |
| /* -- see zlib.h -- */ |
| #ifdef Z_PREFIX_SET |
| # undef z_gzgetc |
| #else |
| # undef gzgetc |
| #endif |
| int ZEXPORT gzgetc( |
| gzFile file) |
| { |
| int ret; |
| unsigned char buf[1]; |
| 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 (serious) error */ |
| if (state->mode != GZ_READ || |
| (state->err != Z_OK && state->err != Z_BUF_ERROR)) |
| return -1; |
| |
| /* try output buffer (no need to check for skip request) */ |
| if (state->x.have) { |
| state->x.have--; |
| state->x.pos++; |
| return *(state->x.next)++; |
| } |
| |
| /* nothing there -- try gzread() */ |
| ret = gzread(file, buf, 1); |
| return ret < 1 ? -1 : buf[0]; |
| } |
| |
| int ZEXPORT gzgetc_( |
| gzFile file) |
| { |
| return gzgetc(file); |
| } |
| |
| /* -- see zlib.h -- */ |
| int ZEXPORT gzungetc( |
| int c, |
| 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 (serious) error */ |
| if (state->mode != GZ_READ || |
| (state->err != Z_OK && state->err != Z_BUF_ERROR)) |
| return -1; |
| |
| /* process a skip request */ |
| if (state->seek) { |
| state->seek = 0; |
| if (gz_skip(state, state->skip) == -1) |
| return -1; |
| } |
| |
| /* can't push EOF */ |
| if (c < 0) |
| return -1; |
| |
| /* if output buffer empty, put byte at end (allows more pushing) */ |
| if (state->x.have == 0) { |
| state->x.have = 1; |
| state->x.next = state->out + (state->size << 1) - 1; |
| state->x.next[0] = c; |
| state->x.pos--; |
| state->past = 0; |
| return c; |
| } |
| |
| /* if no room, give up (must have already done a gzungetc()) */ |
| if (state->x.have == (state->size << 1)) { |
| gz_error(state, Z_DATA_ERROR, "out of room to push characters"); |
| return -1; |
| } |
| |
| /* slide output data if needed and insert byte before existing data */ |
| if (state->x.next == state->out) { |
| unsigned char *src = state->out + state->x.have; |
| unsigned char *dest = state->out + (state->size << 1); |
| while (src > state->out) |
| *--dest = *--src; |
| state->x.next = dest; |
| } |
| state->x.have++; |
| state->x.next--; |
| state->x.next[0] = c; |
| state->x.pos--; |
| state->past = 0; |
| return c; |
| } |
| |
| /* -- see zlib.h -- */ |
| char * ZEXPORT gzgets( |
| gzFile file, |
| char *buf, |
| int len) |
| { |
| unsigned left, n; |
| char *str; |
| unsigned char *eol; |
| gz_statep state; |
| |
| /* check parameters and get internal structure */ |
| if (file == NULL || buf == NULL || len < 1) |
| return NULL; |
| state = (gz_statep)file; |
| |
| /* check that we're reading and that there's no (serious) error */ |
| if (state->mode != GZ_READ || |
| (state->err != Z_OK && state->err != Z_BUF_ERROR)) |
| return NULL; |
| |
| /* process a skip request */ |
| if (state->seek) { |
| state->seek = 0; |
| if (gz_skip(state, state->skip) == -1) |
| return NULL; |
| } |
| |
| /* copy output bytes up to new line or len - 1, whichever comes first -- |
| append a terminating zero to the string (we don't check for a zero in |
| the contents, let the user worry about that) */ |
| str = buf; |
| left = (unsigned)len - 1; |
| if (left) do { |
| /* assure that something is in the output buffer */ |
| if (state->x.have == 0 && gz_fetch(state) == -1) |
| return NULL; /* error */ |
| if (state->x.have == 0) { /* end of file */ |
| state->past = 1; /* read past end */ |
| break; /* return what we have */ |
| } |
| |
| /* look for end-of-line in current output buffer */ |
| n = state->x.have > left ? left : state->x.have; |
| eol = (unsigned char *)memchr(state->x.next, '\n', n); |
| if (eol != NULL) |
| n = (unsigned)(eol - state->x.next) + 1; |
| |
| /* copy through end-of-line, or remainder if not found */ |
| memcpy(buf, state->x.next, n); |
| state->x.have -= n; |
| state->x.next += n; |
| state->x.pos += n; |
| left -= n; |
| buf += n; |
| } while (left && eol == NULL); |
| |
| /* return terminated string, or if nothing, end of file */ |
| if (buf == str) |
| return NULL; |
| buf[0] = 0; |
| return str; |
| } |
| |
| /* -- see zlib.h -- */ |
| int ZEXPORT gzdirect( |
| gzFile file) |
| { |
| gz_statep state; |
| |
| /* get internal structure */ |
| if (file == NULL) |
| return 0; |
| state = (gz_statep)file; |
| |
| /* if the state is not known, but we can find out, then do so (this is |
| mainly for right after a gzopen() or gzdopen()) */ |
| if (state->mode == GZ_READ && state->how == LOOK && state->x.have == 0) |
| (void)gz_look(state); |
| |
| /* return 1 if transparent, 0 if processing a gzip stream */ |
| return state->direct; |
| } |
| |
| /* -- see zlib.h -- */ |
| int ZEXPORT gzclose_r( |
| gzFile file) |
| { |
| int ret, err; |
| gz_statep state; |
| |
| /* get internal structure */ |
| if (file == NULL) |
| return Z_STREAM_ERROR; |
| state = (gz_statep)file; |
| |
| /* check that we're reading */ |
| if (state->mode != GZ_READ) |
| return Z_STREAM_ERROR; |
| |
| /* free memory and close file */ |
| if (state->size) { |
| inflateEnd(&(state->strm)); |
| free(state->out); |
| free(state->in); |
| } |
| err = state->err == Z_BUF_ERROR ? Z_BUF_ERROR : Z_OK; |
| gz_error(state, Z_OK, NULL); |
| free(state->path); |
| ret = close(state->fd); |
| free(state); |
| return ret ? Z_ERRNO : err; |
| } |