/* gzio.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. */ /* memgzio.c - IO on .gz files in memory * Adapted from original gzio.c from zlib library by Forgotten */ /* @(#) $Id: memgzio.c,v 1.5 2006/06/06 21:04:20 spacy51 Exp $ */ #include #include #include #include #include #include "memgzio.h" #ifndef local #define local static #endif #ifndef DEF_MEM_LEVEL # define DEF_MEM_LEVEL 8 #endif #ifndef OS_CODE #define OS_CODE 3 #endif #ifndef zmemcpy #define zmemcpy memcpy #endif /*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 _MemFile { char *memory; char *next; int available; int error; char mode; } MEMFILE; typedef struct mem_stream { z_stream stream; int z_err; /* error code for last stream operation */ int z_eof; /* set if end of input file */ MEMFILE *file; /* memoru file */ Byte *inbuf; /* input buffer */ Byte *outbuf; /* output buffer */ uLong crc; /* crc32 of uncompressed data */ char *msg; /* error message */ 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) */ } mem_stream; local gzFile gz_open OF((char *memory, const int available, const char *mode)); local int do_flush OF((gzFile file, int flush)); local int get_byte OF((mem_stream *s)); local void check_header OF((mem_stream *s)); local int destroy OF((mem_stream *s)); local void putLong OF((MEMFILE *file, uLong x)); local uLong getLong OF((mem_stream *s)); local MEMFILE *memOpen(char *memory, int available, char mode) { MEMFILE *f; if(available <= 8) return NULL; if(mode != 'w' && mode != 'r') return NULL; f = (MEMFILE *)malloc(sizeof(MEMFILE)); f->memory = memory; f->mode = mode; f->error = 0; if(mode == 'w') { f->available = available - 8; f->next = memory + 8; memory[0] = 'V'; memory[1] = 'B'; memory[2] = 'A'; memory[3] = ' '; *((int *)(memory+4)) = 0; } else { if(memory[0] != 'V' || memory[1] != 'B' || memory[2] != 'A' || memory[3] != ' ') { free(f); return NULL; } f->available = *((int *)(memory+4)); f->next = memory+8; } return f; } local size_t memWrite(const void *buffer, size_t size, size_t count, MEMFILE *file) { size_t total = size*count; if(file->mode != 'w') { file->error = 1; return 0; } if(total > (size_t)file->available) { total = file->available; } memcpy(file->next, buffer, total); file->available -= (int)total; file->next += total; return total; } local size_t memRead(void *buffer, size_t size, size_t count, MEMFILE *file) { size_t total = size*count; if(file->mode != 'r') { file->error = 1; return 0; } if(file->available == 0) return -1; if(total > (size_t)file->available) { total = file->available; } memcpy(buffer, file->next, total); file->available -= (int)total; file->next += total; return total; } local int memPutc(int c, MEMFILE *file) { if(file->mode != 'w') { file->error = 1; return -1; } if(file->available >= 1) { *file->next++ = c; file->available--; } else return -1; return c; } local long memTell(MEMFILE *f) { return (long)(f->next - f->memory) - 8; } local int memError(MEMFILE *f) { return f->error; } local int memClose(MEMFILE *f) { if(f->mode == 'w') { *((int *)(f->memory+4)) = memTell(f); } free(f); return 0; } local int memPrintf(MEMFILE *f, const char *format, ...) { char buffer[80]; va_list list; int len; va_start(list, format); len = vsprintf(buffer, format, list); va_end(list); return (int)memWrite(buffer, 1, len, f); } /* =========================================================================== 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). */ local gzFile gz_open (memory, available, mode) char *memory; const int available; const char *mode; { int err; int level = Z_DEFAULT_COMPRESSION; /* compression level */ int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */ char *p = (char*)mode; mem_stream *s; char fmode[80]; /* copy of mode, without the compression level */ char *m = fmode; s = (mem_stream *)ALLOC(sizeof(mem_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->z_err = Z_OK; s->z_eof = 0; s->crc = crc32(0L, Z_NULL, 0); s->msg = NULL; s->transparent = 0; s->file = 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; } else { *m++ = *p; /* copy the mode */ } } while (*p++ && m != fmode + sizeof(fmode)); if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL; if (s->mode == 'w') { #ifdef NO_DEFLATE err = Z_STREAM_ERROR; #else 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 { 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 = memOpen(memory, available, s->mode); if (s->file == NULL) { return destroy(s), (gzFile)Z_NULL; } if (s->mode == 'w') { /* Write a very simple .gz header: */ memPrintf(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. */ } else { check_header(s); /* skip the .gz header */ s->startpos = (memTell(s->file) - s->stream.avail_in); } return (gzFile)s; } /* =========================================================================== Opens a gzip (.gz) file for reading or writing. */ gzFile ZEXPORT memgzopen (memory, available, mode) char *memory; int available; const char *mode; { return gz_open (memory, available, mode); } /* =========================================================================== Read a byte from a mem_stream; update next_in and avail_in. Return EOF for end of file. IN assertion: the stream s has been sucessfully opened for reading. */ local int get_byte(s) mem_stream *s; { if (s->z_eof) return EOF; if (s->stream.avail_in == 0) { errno = 0; s->stream.avail_in = (uInt)memRead(s->inbuf, 1, Z_BUFSIZE, s->file); if (s->stream.avail_in == 0) { s->z_eof = 1; if (memError(s->file)) s->z_err = Z_ERRNO; return EOF; } s->stream.next_in = s->inbuf; } s->stream.avail_in--; return *(s->stream.next_in)++; } /* =========================================================================== Check the gzip header of a mem_stream opened for reading. Set the stream mode to transparent if the gzip magic header is not present; set s->err to Z_DATA_ERROR if the magic header is present but the rest of the header is incorrect. IN assertion: the stream s has already been created sucessfully; s->stream.avail_in is zero for the first time, but may be non-zero for concatenated .gz files. */ local void check_header(s) mem_stream *s; { int method; /* method byte */ int flags; /* flags byte */ uInt len; int c; /* Check the gzip magic header */ for (len = 0; len < 2; len++) { c = get_byte(s); if (c != gz_magic[len]) { if (len != 0) s->stream.avail_in++, s->stream.next_in--; if (c != EOF) { s->stream.avail_in++, s->stream.next_in--; s->transparent = 1; } s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END; return; } } method = get_byte(s); flags = get_byte(s); if (method != Z_DEFLATED || (flags & RESERVED) != 0) { s->z_err = Z_DATA_ERROR; return; } /* Discard time, xflags and OS code: */ for (len = 0; len < 6; len++) (void)get_byte(s); if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ len = (uInt)get_byte(s); len += ((uInt)get_byte(s))<<8; /* len is garbage if EOF but the loop below will quit anyway */ while (len-- != 0 && get_byte(s) != EOF) ; } if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ while ((c = get_byte(s)) != 0 && c != EOF) ; } if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ while ((c = get_byte(s)) != 0 && c != EOF) ; } if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ for (len = 0; len < 2; len++) (void)get_byte(s); } s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK; } /* =========================================================================== * Cleanup then free the given mem_stream. Return a zlib error code. Try freeing in the reverse order of allocations. */ local int destroy (s) mem_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 } else if (s->mode == 'r') { err = inflateEnd(&(s->stream)); } } if (s->file != NULL && memClose(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); return err; } /* =========================================================================== Reads the given number of uncompressed bytes from the compressed file. gzread returns the number of bytes actually read (0 for end of file). */ int ZEXPORT memgzread (file, buf, len) gzFile file; voidp buf; unsigned len; { mem_stream *s = (mem_stream*)file; Bytef *start = (Bytef*)buf; /* starting point for crc computation */ Byte *next_out; /* == stream.next_out but not forced far (for MSDOS) */ if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR; if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1; if (s->z_err == Z_STREAM_END) return 0; /* EOF */ next_out = (Byte*)buf; s->stream.next_out = (Bytef*)buf; s->stream.avail_out = len; while (s->stream.avail_out != 0) { if (s->transparent) { /* Copy first the lookahead bytes: */ uInt n = s->stream.avail_in; if (n > s->stream.avail_out) n = s->stream.avail_out; if (n > 0) { zmemcpy(s->stream.next_out, s->stream.next_in, n); next_out += n; s->stream.next_out = next_out; s->stream.next_in += n; s->stream.avail_out -= n; s->stream.avail_in -= n; } if (s->stream.avail_out > 0) { s->stream.avail_out -= (uInt)memRead(next_out, 1, s->stream.avail_out, s->file); } len -= s->stream.avail_out; s->stream.total_in += (uLong)len; s->stream.total_out += (uLong)len; if (len == 0) s->z_eof = 1; return (int)len; } if (s->stream.avail_in == 0 && !s->z_eof) { errno = 0; s->stream.avail_in = (uInt)memRead(s->inbuf, 1, Z_BUFSIZE, s->file); if (s->stream.avail_in == 0) { s->z_eof = 1; if (memError(s->file)) { s->z_err = Z_ERRNO; break; } } s->stream.next_in = s->inbuf; } s->z_err = inflate(&(s->stream), Z_NO_FLUSH); if (s->z_err == Z_STREAM_END) { /* Check CRC and original size */ s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); start = s->stream.next_out; if (getLong(s) != s->crc) { s->z_err = Z_DATA_ERROR; } else { (void)getLong(s); /* The uncompressed length returned by above getlong() may * be different from s->stream.total_out) in case of * concatenated .gz files. Check for such files: */ check_header(s); if (s->z_err == Z_OK) { uLong total_in = s->stream.total_in; uLong total_out = s->stream.total_out; inflateReset(&(s->stream)); s->stream.total_in = total_in; s->stream.total_out = total_out; s->crc = crc32(0L, Z_NULL, 0); } } } if (s->z_err != Z_OK || s->z_eof) break; } s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start)); return (int)(len - s->stream.avail_out); } #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 memgzwrite (file, buf, len) gzFile file; const voidp buf; unsigned len; { mem_stream *s = (mem_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 (memWrite(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); } #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; mem_stream *s = (mem_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)memWrite(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; } /* =========================================================================== Outputs a long in LSB order to the given file */ local void putLong (file, x) MEMFILE *file; uLong x; { int n; for (n = 0; n < 4; n++) { memPutc((int)(x & 0xff), file); x >>= 8; } } /* =========================================================================== Reads a long in LSB order from the given mem_stream. Sets z_err in case of error. */ local uLong getLong (s) mem_stream *s; { uLong x = (uLong)get_byte(s); int c; x += ((uLong)get_byte(s))<<8; x += ((uLong)get_byte(s))<<16; c = get_byte(s); if (c == EOF) s->z_err = Z_DATA_ERROR; x += ((uLong)c)<<24; return x; } /* =========================================================================== Flushes all pending output if necessary, closes the compressed file and deallocates all the (de)compression state. */ int ZEXPORT memgzclose (file) gzFile file; { int err; mem_stream *s = (mem_stream*)file; if (s == NULL) return Z_STREAM_ERROR; if (s->mode == 'w') { #ifdef NO_DEFLATE return Z_STREAM_ERROR; #else err = do_flush (file, Z_FINISH); if (err != Z_OK) return destroy((mem_stream*)file); putLong (s->file, s->crc); putLong (s->file, s->stream.total_in); #endif } return destroy((mem_stream*)file); } long ZEXPORT memtell(file) gzFile file; { mem_stream *s = (mem_stream*)file; if (s == NULL) return Z_STREAM_ERROR; return memTell(s->file); }