1 files changed, 210 insertions, 159 deletions

diff --git a/gzio.c b/gzio.c
index 03a4674..6f6832b 100644
--- a/gzio.c
+++ b/gzio.c
@@ -1,9 +1,9 @@
 /* gzio.c -- IO on .gz files
- * Copyright (C) 1995 Jean-loup Gailly.
+ * Copyright (C) 1995-1996 Jean-loup Gailly.
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
-/* $Id: gzio.c,v 1.8 1995/05/03 17:27:09 jloup Exp $ */
+/* $Id: gzio.c,v 1.12 1996/01/30 21:59:14 me Exp $ */
 
 #include <stdio.h>
 
@@ -16,8 +16,7 @@ struct internal_state {int dummy;}; /* for buggy compilers */
 #define ALLOC(size) malloc(size)
 #define TRYFREE(p) {if (p) free(p);}
 
-#define GZ_MAGIC_1 0x1f
-#define GZ_MAGIC_2 0x8b
+static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
 
 /* gzip flag byte */
 #define ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
@@ -27,10 +26,6 @@ struct internal_state {int dummy;}; /* for buggy compilers */
 #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 */
@@ -46,40 +41,12 @@ typedef struct gz_stream {
 } gz_stream;
 
 
-local int    destroy OF((gz_stream *s));
-local gzFile gz_open OF((char *path, char *mode, int  fd));
-local void   putLong OF((FILE *file, uLong x));
-local uLong  getLong OF((Bytef *buf));
-
- /* ===========================================================================
- * 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;
-    }
-    if (s->z_err < 0) err = s->z_err;
-    TRYFREE(s);
-    return err;
-}
+local gzFile gz_open      OF((const char *path, const char *mode, int  fd));
+local int    get_byte     OF((gz_stream *s));
+local void   check_header OF((gz_stream *s));
+local int    destroy      OF((gz_stream *s));
+local void   putLong      OF((FILE *file, uLong x));
+local uLong  getLong      OF((gz_stream *s));
 
 /* ===========================================================================
      Opens a gzip (.gz) file for reading or writing. The mode parameter
@@ -91,15 +58,20 @@ local int destroy (s)
    zlib error is Z_MEM_ERROR).
 */
 local gzFile gz_open (path, mode, fd)
-    char *path;
-    char *mode;
+    const char *path;
+    const char *mode;
     int  fd;
 {
     int err;
     int level = Z_DEFAULT_COMPRESSION; /* compression level */
-    char *p = mode;
-    gz_stream *s = (gz_stream *)ALLOC(sizeof(gz_stream));
+    char *p = (char*)mode;
+    gz_stream *s;
+    char fmode[80]; /* copy of mode, without the compression level */
+    char *m = fmode;
+
+    if (!path || !mode) return Z_NULL;
 
+    s = (gz_stream *)ALLOC(sizeof(gz_stream));
     if (!s) return Z_NULL;
 
     s->stream.zalloc = (alloc_func)0;
@@ -124,9 +96,13 @@ local gzFile gz_open (path, mode, fd)
     s->mode = '\0';
     do {
         if (*p == 'r') s->mode = 'r';
-        if (*p == 'w') s->mode = 'w';
-        if (*p >= '1' && *p <= '9') level = *p - '0';
-    } while (*p++);
+        if (*p == 'w' || *p == 'a') s->mode = 'w';
+        if (*p >= '0' && *p <= '9') {
+            level = *p - '0';
+        } 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') {
@@ -150,7 +126,7 @@ local gzFile gz_open (path, mode, fd)
     s->stream.avail_out = Z_BUFSIZE;
 
     errno = 0;
-    s->file = fd < 0 ? FOPEN(path, mode) : (FILE*)fdopen(fd, mode);
+    s->file = fd < 0 ? FOPEN(path, fmode) : (FILE*)fdopen(fd, fmode);
 
     if (s->file == NULL) {
         return destroy(s), (gzFile)Z_NULL;
@@ -158,50 +134,10 @@ local gzFile gz_open (path, mode, fd)
     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,
+        fprintf(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);
     } 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 != Z_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;
-        }
+        check_header(s); /* skip the .gz header */
     }
     return (gzFile)s;
 }
@@ -210,26 +146,139 @@ local gzFile gz_open (path, mode, fd)
      Opens a gzip (.gz) file for reading or writing.
 */
 gzFile gzopen (path, mode)
-    char *path;
-    char *mode;
+    const char *path;
+    const char *mode;
 {
     return gz_open (path, mode, -1);
 }
 
 /* ===========================================================================
-     Associate a gzFile with the file descriptor fd.
+     Associate a gzFile with the file descriptor fd. fd is not dup'ed here
+   to mimic the behavio(u)r of fdopen.
 */
 gzFile gzdopen (fd, mode)
     int fd;
-    char *mode;
+    const char *mode;
 {
     char name[20];
+
+    if (fd < 0) return (gzFile)Z_NULL;
     sprintf(name, "<fd:%d>", fd); /* for debugging */
 
     return gz_open (name, mode, fd);
 }
 
 /* ===========================================================================
+     Read a byte from a gz_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)
+    gz_stream *s;
+{
+    if (s->z_eof) return EOF;
+    if (s->stream.avail_in == 0) {
+        errno = 0;
+        s->stream.avail_in = fread(s->inbuf, 1, Z_BUFSIZE, s->file);
+        if (s->stream.avail_in == 0) {
+            s->z_eof = 1;
+            if (ferror(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 gz_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)
+    gz_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]) {
+            s->transparent = 1;
+            if (c != EOF) s->stream.avail_in++, s->stream.next_in--;
+            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 gz_stream. Return a zlib error code.
+   Try freeing in the reverse order of allocations.
+ */
+local int destroy (s)
+    gz_stream *s;
+{
+    int err = Z_OK;
+
+    if (!s) return Z_STREAM_ERROR;
+
+    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;
+    }
+    if (s->z_err < 0) err = s->z_err;
+
+    TRYFREE(s->inbuf);
+    TRYFREE(s->outbuf);
+    TRYFREE(s->path);
+    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).
 */
@@ -239,52 +288,73 @@ int gzread (file, buf, len)
     unsigned len;
 {
     gz_stream *s = (gz_stream*)file;
+    Bytef *start = 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->transparent) {
-        int n = 0;
-        Byte *b = (Byte*)buf;
-        /* Copy the first two (non-magic) bytes if not done already */
-        while (s->stream.avail_in > 0 && len > 0) {
-            *b++ = *s->stream.next_in++;
-            s->stream.avail_in--;
-            len--; n++;
-        }
-        if (len == 0) return n;
-        return n + fread(b, 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 */
+    if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO) return -1;
+    if (s->z_err == Z_STREAM_END) return 0;  /* EOF */
 
-    s->stream.next_out = buf;
+    s->stream.next_out = next_out = 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 -= fread(next_out, 1, s->stream.avail_out,
+                                             s->file);
+            }
+            return (int)(len - s->stream.avail_out);
+        }
         if (s->stream.avail_in == 0 && !s->z_eof) {
 
             errno = 0;
-            s->stream.avail_in =
-                fread(s->inbuf, 1, Z_BUFSIZE, s->file);
+            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;
+                if (ferror(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 ||
-            s->z_err != Z_OK  || s->z_eof) break;
+        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 || getLong(s) != s->stream.total_out) {
+                s->z_err = Z_DATA_ERROR;
+            } else {
+                /* Check for concatenated .gz files: */
+                check_header(s);
+                if (s->z_err == Z_OK) {
+                    inflateReset(&(s->stream));
+                    s->crc = crc32(0L, Z_NULL, 0);
+                }
+            }
+        }
+        if (s->z_err != Z_OK || s->z_eof) break;
     }
-    len -= s->stream.avail_out;
-    s->crc = crc32(s->crc, buf, len);
-    return (int)len;
+    s->crc = crc32(s->crc, start, (uInt)(s->stream.next_out - start));
+
+    return (int)(len - s->stream.avail_out);
 }
 
 /* ===========================================================================
@@ -293,7 +363,7 @@ int gzread (file, buf, len)
 */
 int gzwrite (file, buf, len)
     gzFile file;
-    voidp buf;
+    const voidp buf;
     unsigned len;
 {
     gz_stream *s = (gz_stream*)file;
@@ -344,7 +414,7 @@ int gzflush (file, flush)
         len = Z_BUFSIZE - s->stream.avail_out;
 
         if (len != 0) {
-            if (fwrite(s->outbuf, 1, len, s->file) != len) {
+            if ((uInt)fwrite(s->outbuf, 1, len, s->file) != len) {
                 s->z_err = Z_ERRNO;
                 return Z_ERRNO;
             }
@@ -380,18 +450,19 @@ local void putLong (file, x)
 }
 
 /* ===========================================================================
-   Reads a long in LSB order from the given buffer
+   Reads a long in LSB order from the given gz_stream. Sets 
 */
-local uLong getLong (buf)
-    Bytef *buf;
+local uLong getLong (s)
+    gz_stream *s;
 {
-    uLong x = 0;
-    Bytef *p = buf+4;
-
-    do {
-        x <<= 8;
-        x |= *--p; 
-    } while (p != buf);
+    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;
 }
 
@@ -402,7 +473,6 @@ local uLong getLong (buf)
 int gzclose (file)
     gzFile file;
 {
-    uInt n;
     int err;
     gz_stream *s = (gz_stream*)file;
 
@@ -415,25 +485,6 @@ int gzclose (file)
         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;
-            Bytef *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);
 }
@@ -454,14 +505,14 @@ char*  gzerror (file, errnum)
 
     if (s == NULL) {
         *errnum = Z_STREAM_ERROR;
-        return z_errmsg[1-Z_STREAM_ERROR];
+        return ERR_MSG(Z_STREAM_ERROR);
     }
     *errnum = s->z_err;
-    if (*errnum == Z_OK) return "";
+    if (*errnum == Z_OK) return (char*)"";
 
-    m =  *errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg;
+    m =  (char*)(*errnum == Z_ERRNO ? zstrerror(errno) : s->stream.msg);
 
-    if (m == NULL || *m == '\0') m = z_errmsg[1-s->z_err];
+    if (m == NULL || *m == '\0') m = ERR_MSG(s->z_err);
 
     TRYFREE(s->msg);
     s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);