1 files changed, 459 insertions, 0 deletions

diff --git a/gzio.c b/gzio.c
new file mode 100644
index 0000000..b488e96
--- /dev/null
+++ b/gzio.c
@@ -0,0 +1,459 @@
+/* gzio.c -- IO on .gz files
+ * Copyright (C) 1995 Jean-loup Gailly.
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+/* $Id: gzio.c,v 1.4 1995/04/14 14:50:52 jloup Exp $ */
+
+#include <stdio.h>
+
+#include "zutil.h"
+
+struct internal_state {int dummy;}; /* for buggy compilers */
+
+#define Z_BUFSIZE 4096
+
+#define ALLOC(size) zcalloc((voidp)0, 1, size)
+#define TRYFREE(p) {if (p) zcfree((voidp)0, p);}
+
+#define GZ_MAGIC_1 0x1f
+#define GZ_MAGIC_2 0x8b
+
+/* 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 */
+
+#ifndef SEEK_CUR
+#  define SEEK_CUR 1
+#endif
+
+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' */
+} gz_stream;
+
+
+/* ===========================================================================
+ * Cleanup then free the given gz_stream. Return a zlib error code.
+ */
+local int destroy (s)
+    gz_stream *s;
+{
+    int err = Z_OK;
+
+    if (!s) return Z_STREAM_ERROR;
+
+    TRYFREE(s->inbuf);
+    TRYFREE(s->outbuf);
+    TRYFREE(s->path);
+    TRYFREE(s->msg);
+
+    if (s->stream.state != NULL) {
+       if (s->mode == 'w') {
+           err = deflateEnd(&(s->stream));
+       } else if (s->mode == 'r') {
+           err = inflateEnd(&(s->stream));
+       }
+    }
+    if (s->file != NULL && fclose(s->file)) {
+        err = Z_ERRNO;
+    }
+    zcfree((voidp)0, s);
+    return s->z_err < 0 ? s->z_err : err;
+}
+
+/* ===========================================================================
+     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 descritor
+   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 (path, mode, fd)
+    char *path;
+    char *mode;
+    int  fd;
+{
+    int err;
+    char *p = mode;
+    gz_stream *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.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->crc = crc32(0L, Z_NULL, 0);
+    s->msg = NULL;
+    s->transparent = 0;
+
+    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->mode = '\0';
+    do {
+        if (*p == 'r') s->mode = 'r';
+        if (*p == 'w') s->mode = 'w';
+    } while (*p++);
+    if (s->mode == '\0') return destroy(s), (gzFile)Z_NULL;
+    
+    if (s->mode == 'w') {
+        err = deflateInit2(&(s->stream), Z_DEFAULT_COMPRESSION,
+                           DEFLATED, -WBITS, MEM_LEVEL, 0);
+        /* windowBits is passed < 0 to suppress zlib header */
+
+        s->stream.next_out = s->outbuf = ALLOC(Z_BUFSIZE);
+
+        if (err != Z_OK || s->outbuf == Z_NULL) {
+            return destroy(s), (gzFile)Z_NULL;
+        }
+    } else {
+        err = inflateInit2(&(s->stream), -WBITS);
+        s->stream.next_in  = s->inbuf = ALLOC(Z_BUFSIZE);
+
+        if (err != Z_OK || s->inbuf == Z_NULL) {
+            return destroy(s), (gzFile)Z_NULL;
+        }
+    }
+    s->stream.avail_out = Z_BUFSIZE;
+
+    errno = 0;
+    s->file = fd < 0 ? FOPEN(path, mode) : fdopen(fd, mode);
+
+    if (s->file == NULL) {
+        return destroy(s), (gzFile)Z_NULL;
+    }
+    if (s->mode == 'w') {
+        /* Write a very simple .gz header:
+         */
+        fprintf(s->file, "%c%c%c%c%c%c%c%c%c%c", GZ_MAGIC_1, GZ_MAGIC_2,
+               DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE);
+    } else {
+        /* Check and skip the header:
+         */
+        Byte c1 = 0, c2 = 0;
+        Byte method = 0;
+        Byte flags = 0;
+        Byte xflags = 0;
+        Byte time[4];
+        Byte osCode;
+        int c;
+
+        s->stream.avail_in = fread(s->inbuf, 1, 2, s->file);
+        if (s->stream.avail_in != 2 || s->inbuf[0] != GZ_MAGIC_1
+            || s->inbuf[1] != GZ_MAGIC_2) {
+            s->transparent = 1;
+            return (gzFile)s;
+        }
+        s->stream.avail_in = 0;
+        fscanf(s->file,"%c%c%4c%c%c", &method, &flags, time, &xflags, &osCode);
+
+        if (method != DEFLATED || feof(s->file) || (flags & RESERVED) != 0) {
+            s->z_err = Z_DATA_ERROR;
+            return (gzFile)s;
+        }
+        if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
+            long len;
+            fscanf(s->file, "%c%c", &c1, &c2);
+            len = c1 + ((long)c2<<8);
+            fseek(s->file, len, SEEK_CUR);
+        }
+        if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
+            while ((c = getc(s->file)) != 0 && c != EOF) ;
+        }
+        if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
+            while ((c = getc(s->file)) != 0 && c != EOF) ;
+        }
+        if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
+            fscanf(s->file, "%c%c", &c1, &c2);
+        }
+        if (feof(s->file)) {
+            s->z_err = Z_DATA_ERROR;
+        }
+    }
+    return (gzFile)s;
+}
+
+/* ===========================================================================
+     Opens a gzip (.gz) file for reading or writing.
+*/
+gzFile gzopen (path, mode)
+    char *path;
+    char *mode;
+{
+    return gz_open (path, mode, -1);
+}
+
+/* ===========================================================================
+     Associate a gzFile with the file descriptor fd.
+*/
+gzFile gzdopen (fd, mode)
+    int fd;
+    char *mode;
+{
+    char name[20];
+    sprintf(name, "_fd:%d_", fd); /* for debugging */
+
+    return gz_open (name, mode, fd);
+}
+
+/* ===========================================================================
+     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 gzread (file, buf, len)
+    gzFile file;
+    voidp buf;
+    unsigned len;
+{
+    gz_stream *s = (gz_stream*)file;
+
+    if (s == NULL || s->mode != 'r') return Z_STREAM_ERROR;
+
+    if (s->transparent) {
+        unsigned n = 0;
+        /* Copy the first two (non-magic) bytes if not done already */
+        while (s->stream.avail_in > 0 && len > 0) {
+            *((Byte*)buf)++ = *s->stream.next_in++;
+            s->stream.avail_in--;
+            len--; n++;
+        }
+        if (len == 0) return n;
+        return n + fread(buf, 1, len, s->file);
+    }
+    if (s->z_err == Z_DATA_ERROR) return -1; /* bad .gz file */
+    if (s->z_err == Z_STREAM_END) return 0;  /* don't read crc as data */
+
+    s->stream.next_out = buf;
+    s->stream.avail_out = len;
+
+    while (s->stream.avail_out != 0) {
+
+        if (s->stream.avail_in == 0 && !s->z_eof) {
+
+            errno = 0;
+            s->stream.avail_in =
+                fread(s->inbuf, 1, Z_BUFSIZE, s->file);
+            if (s->stream.avail_in == 0) {
+                s->z_eof = 1;
+            } else if (s->stream.avail_in == (uInt)EOF) {
+                s->stream.avail_in = 0;
+                s->z_eof = 1;
+                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 ||
+            s->z_err != Z_OK  || s->z_eof) break;
+    }
+    len -= s->stream.avail_out;
+    s->crc = crc32(s->crc, buf, len);
+    return len;
+}
+
+/* ===========================================================================
+     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 gzwrite (file, buf, len)
+    gzFile file;
+    voidp buf;
+    unsigned len;
+{
+    gz_stream *s = (gz_stream*)file;
+
+    if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR;
+
+    s->stream.next_in = 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 (fwrite(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, buf, len);
+
+    return len - s->stream.avail_in;
+}
+
+/* ===========================================================================
+     Flushes all pending output into the compressed file. The parameter
+   flush is as in the deflate() function.
+     gzflush should be called only when strictly necessary because it can
+   degrade compression.
+*/
+int gzflush (file, flush)
+    gzFile file;
+    int flush;
+{
+    uInt len;
+    int done = 0;
+    gz_stream *s = (gz_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 (fwrite(s->outbuf, 1, len, s->file) != len) {
+                s->z_err = Z_ERRNO;
+                break;
+            }
+            s->stream.next_out = s->outbuf;
+            s->stream.avail_out = Z_BUFSIZE;
+        }
+        if (done) break;
+        s->z_err = deflate(&(s->stream), flush);
+
+        if (s->z_err != Z_OK) break;
+
+        /* 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);
+    }
+    return s->z_err;
+}
+
+/* ===========================================================================
+   Outputs a long in LSB order to the given file
+*/
+local void putLong (file, x)
+    FILE *file;
+    uLong x;
+{
+    int n;
+    for (n = 0; n < 4; n++) {
+        fputc(x & 0xff, file);
+        x >>= 8;
+    }
+}
+
+/* ===========================================================================
+   Reads a long in LSB order from the given buffer
+*/
+local uLong getLong (buf)
+    Byte *buf;
+{
+    uLong x = 0;
+    Byte *p = buf+4;
+
+    do {
+        x <<= 8;
+        x |= *--p; 
+    } while (p != buf);
+    return x;
+}
+
+/* ===========================================================================
+     Flushes all pending output if necessary, closes the compressed file
+   and deallocates all the (de)compression state.
+*/
+int gzclose (file)
+    gzFile file;
+{
+    uInt n;
+    gz_stream *s = (gz_stream*)file;
+
+    if (s == NULL) return Z_STREAM_ERROR;
+
+    if (s->mode == 'w') {
+        gzflush (file, Z_FINISH);
+        putLong (s->file, s->crc);
+        putLong (s->file, s->stream.total_in);
+
+    } else if (s->mode == 'r' && s->z_err == Z_STREAM_END) {
+
+        /* slide CRC and original size if they are at the end of inbuf */
+        if ((n = s->stream.avail_in) < 8  && !s->z_eof) {
+            Byte *p = s->inbuf;
+            Byte *q = s->stream.next_in;
+            while (n--) { *p++ = *q++; };
+
+            n = s->stream.avail_in;
+            n += fread(p, 1, 8, s->file);
+            s->stream.next_in = s->inbuf;
+        }
+        /* check CRC and original size */
+        if (n < 8 ||
+            getLong(s->stream.next_in) != s->crc ||
+            getLong(s->stream.next_in + 4) != s->stream.total_out) {
+
+            s->z_err = Z_DATA_ERROR;
+        }
+    }
+    return destroy(file);
+}
+
+/* ===========================================================================
+     Returns the error message for the last error which occured on the
+   given compressed file. errnum is set to zlib error number. If an
+   error occured in the file system and not in the compression library,
+   errnum is set to Z_ERRNO and the application may consult errno
+   to get the exact error code.
+*/
+char*  gzerror (file, errnum)
+    gzFile file;
+    int *errnum;
+{
+    char *m;
+    gz_stream *s = (gz_stream*)file;
+
+    if (s == NULL) {
+        *errnum = Z_STREAM_ERROR;
+        return z_errmsg[1-Z_STREAM_ERROR];
+    }
+    *errnum = s->z_err;
+    if (*errnum == Z_OK) return "";
+
+    m =  *errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg;
+
+    if (m == NULL || *m == '\0') m = z_errmsg[1-s->z_err];
+
+    TRYFREE(s->msg);
+    s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);
+    strcpy(s->msg, s->path);
+    strcat(s->msg, ": ");
+    strcat(s->msg, m);
+    return s->msg;
+}