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653 lines
20 KiB
653 lines
20 KiB
/* gzread.c -- zlib functions for reading gzip files |
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* Copyright (C) 2004, 2005, 2010 Mark Adler |
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* For conditions of distribution and use, see copyright notice in zlib.h |
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*/ |
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|
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#include "gzguts.h" |
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|
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/* Local functions */ |
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local int gz_load OF((gz_statep, unsigned char *, unsigned, unsigned *)); |
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local int gz_avail OF((gz_statep)); |
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local int gz_next4 OF((gz_statep, unsigned long *)); |
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local int gz_head OF((gz_statep)); |
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local int gz_decomp OF((gz_statep)); |
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local int gz_make OF((gz_statep)); |
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local int gz_skip OF((gz_statep, z_off64_t)); |
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|
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/* Use read() to load a buffer -- return -1 on error, otherwise 0. Read from |
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state->fd, and update state->eof, state->err, and state->msg as appropriate. |
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This function needs to loop on read(), since read() is not guaranteed to |
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read the number of bytes requested, depending on the type of descriptor. */ |
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local int gz_load(state, buf, len, have) |
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gz_statep state; |
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unsigned char *buf; |
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unsigned len; |
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unsigned *have; |
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{ |
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int ret; |
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|
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*have = 0; |
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do { |
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ret = read(state->fd, buf + *have, len - *have); |
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if (ret <= 0) |
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break; |
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*have += ret; |
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} while (*have < len); |
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if (ret < 0) { |
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gz_error(state, Z_ERRNO, zstrerror()); |
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return -1; |
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} |
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if (ret == 0) |
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state->eof = 1; |
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return 0; |
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} |
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|
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/* Load up input buffer and set eof flag if last data loaded -- return -1 on |
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error, 0 otherwise. Note that the eof flag is set when the end of the input |
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file is reached, even though there may be unused data in the buffer. Once |
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that data has been used, no more attempts will be made to read the file. |
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gz_avail() assumes that strm->avail_in == 0. */ |
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local int gz_avail(state) |
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gz_statep state; |
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{ |
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z_streamp strm = &(state->strm); |
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if (state->err != Z_OK) |
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return -1; |
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if (state->eof == 0) { |
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if (gz_load(state, state->in, state->size, |
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(unsigned *)&(strm->avail_in)) == -1) |
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return -1; |
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strm->next_in = state->in; |
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} |
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return 0; |
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} |
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|
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/* Get next byte from input, or -1 if end or error. */ |
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#define NEXT() ((strm->avail_in == 0 && gz_avail(state) == -1) ? -1 : \ |
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(strm->avail_in == 0 ? -1 : \ |
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(strm->avail_in--, *(strm->next_in)++))) |
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|
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/* Get a four-byte little-endian integer and return 0 on success and the value |
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in *ret. Otherwise -1 is returned and *ret is not modified. */ |
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local int gz_next4(state, ret) |
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gz_statep state; |
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unsigned long *ret; |
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{ |
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int ch; |
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unsigned long val; |
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z_streamp strm = &(state->strm); |
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val = NEXT(); |
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val += (unsigned)NEXT() << 8; |
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val += (unsigned long)NEXT() << 16; |
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ch = NEXT(); |
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if (ch == -1) |
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return -1; |
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val += (unsigned long)ch << 24; |
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*ret = val; |
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return 0; |
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} |
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/* Look for gzip header, set up for inflate or copy. state->have must be zero. |
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If this is the first time in, allocate required memory. state->how will be |
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left unchanged if there is no more input data available, will be set to COPY |
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if there is no gzip header and direct copying will be performed, or it will |
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be set to GZIP for decompression, and the gzip header will be skipped so |
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that the next available input data is the raw deflate stream. If direct |
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copying, then leftover input data from the input buffer will be copied to |
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the output buffer. In that case, all further file reads will be directly to |
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either the output buffer or a user buffer. If decompressing, the inflate |
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state and the check value will be initialized. gz_head() will return 0 on |
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success or -1 on failure. Failures may include read errors or gzip header |
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errors. */ |
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local int gz_head(state) |
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gz_statep state; |
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{ |
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z_streamp strm = &(state->strm); |
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int flags; |
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unsigned len; |
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|
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/* allocate read buffers and inflate memory */ |
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if (state->size == 0) { |
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/* allocate buffers */ |
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state->in = malloc(state->want); |
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state->out = malloc(state->want << 1); |
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if (state->in == NULL || state->out == NULL) { |
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if (state->out != NULL) |
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free(state->out); |
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if (state->in != NULL) |
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free(state->in); |
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gz_error(state, Z_MEM_ERROR, "out of memory"); |
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return -1; |
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} |
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state->size = state->want; |
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|
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/* allocate inflate memory */ |
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state->strm.zalloc = Z_NULL; |
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state->strm.zfree = Z_NULL; |
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state->strm.opaque = Z_NULL; |
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state->strm.avail_in = 0; |
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state->strm.next_in = Z_NULL; |
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if (inflateInit2(&(state->strm), -15) != Z_OK) { /* raw inflate */ |
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free(state->out); |
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free(state->in); |
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state->size = 0; |
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gz_error(state, Z_MEM_ERROR, "out of memory"); |
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return -1; |
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} |
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} |
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|
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/* get some data in the input buffer */ |
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if (strm->avail_in == 0) { |
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if (gz_avail(state) == -1) |
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return -1; |
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if (strm->avail_in == 0) |
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return 0; |
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} |
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/* look for the gzip magic header bytes 31 and 139 */ |
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if (strm->next_in[0] == 31) { |
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strm->avail_in--; |
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strm->next_in++; |
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if (strm->avail_in == 0 && gz_avail(state) == -1) |
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return -1; |
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if (strm->avail_in && strm->next_in[0] == 139) { |
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/* we have a gzip header, woo hoo! */ |
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strm->avail_in--; |
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strm->next_in++; |
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|
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/* skip rest of header */ |
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if (NEXT() != 8) { /* compression method */ |
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gz_error(state, Z_DATA_ERROR, "unknown compression method"); |
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return -1; |
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} |
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flags = NEXT(); |
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if (flags & 0xe0) { /* reserved flag bits */ |
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gz_error(state, Z_DATA_ERROR, "unknown header flags set"); |
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return -1; |
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} |
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NEXT(); /* modification time */ |
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NEXT(); |
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NEXT(); |
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NEXT(); |
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NEXT(); /* extra flags */ |
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NEXT(); /* operating system */ |
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if (flags & 4) { /* extra field */ |
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len = (unsigned)NEXT(); |
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len += (unsigned)NEXT() << 8; |
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while (len--) |
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if (NEXT() < 0) |
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break; |
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} |
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if (flags & 8) /* file name */ |
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while (NEXT() > 0) |
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; |
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if (flags & 16) /* comment */ |
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while (NEXT() > 0) |
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; |
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if (flags & 2) { /* header crc */ |
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NEXT(); |
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NEXT(); |
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} |
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/* an unexpected end of file is not checked for here -- it will be |
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noticed on the first request for uncompressed data */ |
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/* set up for decompression */ |
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inflateReset(strm); |
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strm->adler = crc32(0L, Z_NULL, 0); |
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state->how = GZIP; |
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state->direct = 0; |
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return 0; |
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} |
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else { |
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/* not a gzip file -- save first byte (31) and fall to raw i/o */ |
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state->out[0] = 31; |
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state->have = 1; |
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} |
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} |
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/* doing raw i/o, save start of raw data for seeking, copy any leftover |
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input to output -- this assumes that the output buffer is larger than |
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the input buffer, which also assures space for gzungetc() */ |
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state->raw = state->pos; |
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state->next = state->out; |
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if (strm->avail_in) { |
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memcpy(state->next + state->have, strm->next_in, strm->avail_in); |
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state->have += strm->avail_in; |
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strm->avail_in = 0; |
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} |
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state->how = COPY; |
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state->direct = 1; |
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return 0; |
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} |
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/* Decompress from input to the provided next_out and avail_out in the state. |
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If the end of the compressed data is reached, then verify the gzip trailer |
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check value and length (modulo 2^32). state->have and state->next are set |
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to point to the just decompressed data, and the crc is updated. If the |
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trailer is verified, state->how is reset to LOOK to look for the next gzip |
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stream or raw data, once state->have is depleted. Returns 0 on success, -1 |
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on failure. Failures may include invalid compressed data or a failed gzip |
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trailer verification. */ |
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local int gz_decomp(state) |
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gz_statep state; |
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{ |
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int ret; |
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unsigned had; |
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unsigned long crc, len; |
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z_streamp strm = &(state->strm); |
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/* fill output buffer up to end of deflate stream */ |
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had = strm->avail_out; |
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do { |
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/* get more input for inflate() */ |
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if (strm->avail_in == 0 && gz_avail(state) == -1) |
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return -1; |
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if (strm->avail_in == 0) { |
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gz_error(state, Z_DATA_ERROR, "unexpected end of file"); |
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return -1; |
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} |
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/* decompress and handle errors */ |
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ret = inflate(strm, Z_NO_FLUSH); |
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if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) { |
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gz_error(state, Z_STREAM_ERROR, |
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"internal error: inflate stream corrupt"); |
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return -1; |
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} |
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if (ret == Z_MEM_ERROR) { |
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gz_error(state, Z_MEM_ERROR, "out of memory"); |
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return -1; |
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} |
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if (ret == Z_DATA_ERROR) { /* deflate stream invalid */ |
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gz_error(state, Z_DATA_ERROR, |
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strm->msg == NULL ? "compressed data error" : strm->msg); |
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return -1; |
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} |
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} while (strm->avail_out && ret != Z_STREAM_END); |
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|
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/* update available output and crc check value */ |
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state->have = had - strm->avail_out; |
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state->next = strm->next_out - state->have; |
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strm->adler = crc32(strm->adler, state->next, state->have); |
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/* check gzip trailer if at end of deflate stream */ |
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if (ret == Z_STREAM_END) { |
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if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) { |
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gz_error(state, Z_DATA_ERROR, "unexpected end of file"); |
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return -1; |
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} |
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if (crc != strm->adler) { |
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gz_error(state, Z_DATA_ERROR, "incorrect data check"); |
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return -1; |
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} |
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if (len != (strm->total_out & 0xffffffffL)) { |
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gz_error(state, Z_DATA_ERROR, "incorrect length check"); |
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return -1; |
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} |
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state->how = LOOK; /* ready for next stream, once have is 0 (leave |
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state->direct unchanged to remember how) */ |
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} |
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/* good decompression */ |
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return 0; |
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} |
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/* Make data and put in the output buffer. Assumes that state->have == 0. |
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Data is either copied from the input file or decompressed from the input |
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file depending on state->how. If state->how is LOOK, then a gzip header is |
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looked for (and skipped if found) to determine wither to copy or decompress. |
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Returns -1 on error, otherwise 0. gz_make() will leave state->have as COPY |
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or GZIP unless the end of the input file has been reached and all data has |
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been processed. */ |
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local int gz_make(state) |
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gz_statep state; |
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{ |
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z_streamp strm = &(state->strm); |
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if (state->how == LOOK) { /* look for gzip header */ |
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if (gz_head(state) == -1) |
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return -1; |
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if (state->have) /* got some data from gz_head() */ |
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return 0; |
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} |
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if (state->how == COPY) { /* straight copy */ |
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if (gz_load(state, state->out, state->size << 1, &(state->have)) == -1) |
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return -1; |
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state->next = state->out; |
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} |
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else if (state->how == GZIP) { /* decompress */ |
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strm->avail_out = state->size << 1; |
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strm->next_out = state->out; |
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if (gz_decomp(state) == -1) |
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return -1; |
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} |
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return 0; |
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} |
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|
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/* Skip len uncompressed bytes of output. Return -1 on error, 0 on success. */ |
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local int gz_skip(state, len) |
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gz_statep state; |
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z_off64_t len; |
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{ |
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unsigned n; |
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|
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/* skip over len bytes or reach end-of-file, whichever comes first */ |
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while (len) |
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/* skip over whatever is in output buffer */ |
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if (state->have) { |
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n = GT_OFF(state->have) || (z_off64_t)state->have > len ? |
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(unsigned)len : state->have; |
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state->have -= n; |
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state->next += n; |
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state->pos += n; |
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len -= n; |
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} |
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|
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/* output buffer empty -- return if we're at the end of the input */ |
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else if (state->eof && state->strm.avail_in == 0) |
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break; |
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|
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/* need more data to skip -- load up output buffer */ |
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else { |
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/* get more output, looking for header if required */ |
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if (gz_make(state) == -1) |
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return -1; |
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} |
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return 0; |
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} |
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|
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/* -- see zlib.h -- */ |
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int ZEXPORT gzread(file, buf, len) |
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gzFile file; |
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voidp buf; |
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unsigned len; |
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{ |
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unsigned got, n; |
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gz_statep state; |
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z_streamp strm; |
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/* get internal structure */ |
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if (file == NULL) |
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return -1; |
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state = (gz_statep)file; |
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strm = &(state->strm); |
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|
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/* check that we're reading and that there's no error */ |
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if (state->mode != GZ_READ || state->err != Z_OK) |
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return -1; |
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|
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/* since an int is returned, make sure len fits in one, otherwise return |
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with an error (this avoids the flaw in the interface) */ |
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if ((int)len < 0) { |
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gz_error(state, Z_BUF_ERROR, "requested length does not fit in int"); |
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return -1; |
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} |
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|
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/* if len is zero, avoid unnecessary operations */ |
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if (len == 0) |
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return 0; |
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|
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/* process a skip request */ |
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if (state->seek) { |
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state->seek = 0; |
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if (gz_skip(state, state->skip) == -1) |
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return -1; |
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} |
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|
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/* get len bytes to buf, or less than len if at the end */ |
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got = 0; |
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do { |
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/* first just try copying data from the output buffer */ |
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if (state->have) { |
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n = state->have > len ? len : state->have; |
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memcpy(buf, state->next, n); |
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state->next += n; |
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state->have -= n; |
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} |
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|
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/* output buffer empty -- return if we're at the end of the input */ |
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else if (state->eof && strm->avail_in == 0) |
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break; |
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|
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/* need output data -- for small len or new stream load up our output |
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buffer */ |
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else if (state->how == LOOK || len < (state->size << 1)) { |
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/* get more output, looking for header if required */ |
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if (gz_make(state) == -1) |
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return -1; |
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continue; /* no progress yet -- go back to memcpy() above */ |
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/* the copy above assures that we will leave with space in the |
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output buffer, allowing at least one gzungetc() to succeed */ |
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} |
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|
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/* large len -- read directly into user buffer */ |
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else if (state->how == COPY) { /* read directly */ |
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if (gz_load(state, buf, len, &n) == -1) |
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return -1; |
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} |
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|
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/* large len -- decompress directly into user buffer */ |
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else { /* state->how == GZIP */ |
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strm->avail_out = len; |
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strm->next_out = buf; |
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if (gz_decomp(state) == -1) |
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return -1; |
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n = state->have; |
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state->have = 0; |
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} |
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|
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/* update progress */ |
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len -= n; |
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buf = (char *)buf + n; |
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got += n; |
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state->pos += n; |
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} while (len); |
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|
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/* return number of bytes read into user buffer (will fit in int) */ |
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return (int)got; |
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} |
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|
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/* -- see zlib.h -- */ |
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int ZEXPORT gzgetc(file) |
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gzFile file; |
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{ |
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int ret; |
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unsigned char buf[1]; |
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gz_statep state; |
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|
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/* get internal structure */ |
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if (file == NULL) |
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return -1; |
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state = (gz_statep)file; |
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|
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/* check that we're reading and that there's no error */ |
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if (state->mode != GZ_READ || state->err != Z_OK) |
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return -1; |
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|
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/* try output buffer (no need to check for skip request) */ |
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if (state->have) { |
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state->have--; |
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state->pos++; |
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return *(state->next)++; |
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} |
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|
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/* nothing there -- try gzread() */ |
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ret = gzread(file, buf, 1); |
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return ret < 1 ? -1 : buf[0]; |
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} |
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|
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/* -- see zlib.h -- */ |
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int ZEXPORT gzungetc(c, file) |
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int c; |
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gzFile file; |
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{ |
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gz_statep state; |
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|
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/* get internal structure */ |
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if (file == NULL) |
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return -1; |
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state = (gz_statep)file; |
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|
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/* check that we're reading and that there's no error */ |
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if (state->mode != GZ_READ || state->err != Z_OK) |
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return -1; |
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|
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/* process a skip request */ |
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if (state->seek) { |
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state->seek = 0; |
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if (gz_skip(state, state->skip) == -1) |
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return -1; |
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} |
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|
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/* can't push EOF */ |
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if (c < 0) |
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return -1; |
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|
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/* if output buffer empty, put byte at end (allows more pushing) */ |
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if (state->have == 0) { |
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state->have = 1; |
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state->next = state->out + (state->size << 1) - 1; |
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state->next[0] = c; |
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state->pos--; |
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return c; |
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} |
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|
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/* if no room, give up (must have already done a gzungetc()) */ |
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if (state->have == (state->size << 1)) { |
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gz_error(state, Z_BUF_ERROR, "out of room to push characters"); |
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return -1; |
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} |
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|
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/* slide output data if needed and insert byte before existing data */ |
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if (state->next == state->out) { |
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unsigned char *src = state->out + state->have; |
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unsigned char *dest = state->out + (state->size << 1); |
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while (src > state->out) |
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*--dest = *--src; |
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state->next = dest; |
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} |
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state->have++; |
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state->next--; |
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state->next[0] = c; |
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state->pos--; |
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return c; |
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} |
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|
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/* -- see zlib.h -- */ |
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char * ZEXPORT gzgets(file, buf, len) |
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gzFile file; |
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char *buf; |
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int len; |
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{ |
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unsigned left, n; |
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char *str; |
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unsigned char *eol; |
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gz_statep state; |
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|
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/* check parameters and get internal structure */ |
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if (file == NULL || buf == NULL || len < 1) |
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return NULL; |
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state = (gz_statep)file; |
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|
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/* check that we're reading and that there's no error */ |
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if (state->mode != GZ_READ || state->err != Z_OK) |
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return NULL; |
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|
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/* process a skip request */ |
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if (state->seek) { |
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state->seek = 0; |
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if (gz_skip(state, state->skip) == -1) |
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return NULL; |
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} |
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|
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/* copy output bytes up to new line or len - 1, whichever comes first -- |
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append a terminating zero to the string (we don't check for a zero in |
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the contents, let the user worry about that) */ |
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str = buf; |
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left = (unsigned)len - 1; |
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if (left) do { |
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/* assure that something is in the output buffer */ |
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if (state->have == 0) { |
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if (gz_make(state) == -1) |
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return NULL; /* error */ |
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if (state->have == 0) { /* end of file */ |
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if (buf == str) /* got bupkus */ |
|
return NULL; |
|
break; /* got something -- return it */ |
|
} |
|
} |
|
|
|
/* look for end-of-line in current output buffer */ |
|
n = state->have > left ? left : state->have; |
|
eol = memchr(state->next, '\n', n); |
|
if (eol != NULL) |
|
n = (unsigned)(eol - state->next) + 1; |
|
|
|
/* copy through end-of-line, or remainder if not found */ |
|
memcpy(buf, state->next, n); |
|
state->have -= n; |
|
state->next += n; |
|
state->pos += n; |
|
left -= n; |
|
buf += n; |
|
} while (left && eol == NULL); |
|
|
|
/* found end-of-line or out of space -- terminate string and return it */ |
|
buf[0] = 0; |
|
return str; |
|
} |
|
|
|
/* -- see zlib.h -- */ |
|
int ZEXPORT gzdirect(file) |
|
gzFile file; |
|
{ |
|
gz_statep state; |
|
|
|
/* get internal structure */ |
|
if (file == NULL) |
|
return 0; |
|
state = (gz_statep)file; |
|
|
|
/* check that we're reading */ |
|
if (state->mode != GZ_READ) |
|
return 0; |
|
|
|
/* 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->how == LOOK && state->have == 0) |
|
(void)gz_head(state); |
|
|
|
/* return 1 if reading direct, 0 if decompressing a gzip stream */ |
|
return state->direct; |
|
} |
|
|
|
/* -- see zlib.h -- */ |
|
int ZEXPORT gzclose_r(file) |
|
gzFile file; |
|
{ |
|
int ret; |
|
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); |
|
} |
|
gz_error(state, Z_OK, NULL); |
|
free(state->path); |
|
ret = close(state->fd); |
|
free(state); |
|
return ret ? Z_ERRNO : Z_OK; |
|
}
|
|
|