X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flibpspp%2Fzip-reader.c;h=52d2b029e785a4c02d3084c6d8785768a56bacfd;hb=c336b3315deeafb2cffa66e1a52bcc645e6890b1;hp=13986cbeca21ac51ce6ef856cb37c1f70d6ff1e2;hpb=d4ff0e074d703dbeb8af5aa3ac470ddda5ebe301;p=pspp

diff --git a/src/libpspp/zip-reader.c b/src/libpspp/zip-reader.c
index 13986cbeca..52d2b029e7 100644
--- a/src/libpspp/zip-reader.c
+++ b/src/libpspp/zip-reader.c
@@ -16,7 +16,7 @@
 
 #include <config.h>
 
-
+#include <inttypes.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -28,9 +28,6 @@
 #include <libpspp/compiler.h>
 
 #include <byteswap.h>
-#include <crc.h>
-
-#include "inflate.h"
 
 #include "str.h"
 
@@ -41,81 +38,80 @@
 #define _(msgid) gettext (msgid)
 #define N_(msgid) (msgid)
 
-
-static bool find_eocd (FILE *fp, off_t *off);
-
-static int
-stored_read (struct zip_member *zm, void *buf, size_t n)
-{
-  return fread (buf, 1, n, zm->fp);
-}
-
-static bool
-stored_init (struct zip_member *zm UNUSED)
+struct zip_member
 {
-  return true;
-}
+  char *file_name;             /* File name. */
+  char *member_name;          /* Member name. */
+  FILE *fp;                   /* The stream from which the data is read */
+  uint32_t offset;            /* Starting offset in file. */
+  uint32_t comp_size;         /* Length of member file data, in bytes. */
+  uint32_t ucomp_size;        /* Uncompressed length of member file data, in bytes. */
+  const struct decompressor *decompressor;
+
+  size_t bytes_unread;       /* Number of bytes left in the member available for reading */
+  struct string *errmsgs;    /* A string to hold error messages.
+				This string is NOT owned by this object. */
+  void *aux;
+};
 
-static void
-stored_finish (struct zip_member *zm UNUSED)
+struct decompressor
 {
-  /* Nothing required */
-}
-
+  bool (*init) (struct zip_member *);
+  int  (*read) (struct zip_member *, void *, size_t);
+  void (*finish) (struct zip_member *);
+};
+static const struct decompressor stored_decompressor;
+static const struct decompressor inflate_decompressor;
 
-static struct decompressor decompressors[n_COMPRESSION] =
-  {
-    {stored_init, stored_read, stored_finish},
-    {inflate_init, inflate_read, inflate_finish}
-  };
+static bool find_eocd (FILE *fp, off_t *off);
 
-static enum compression
-comp_code (struct zip_member *zm, uint16_t c)
+static const struct decompressor *
+get_decompressor (uint16_t c)
 {
-  enum compression which;
-  assert (zm->errmsgs);
   switch (c)
     {
     case 0:
-      which = COMPRESSION_STORED;
-      break;
+      return &stored_decompressor;
+
     case 8:
-      which = COMPRESSION_INFLATE;
-      break;
+      return &inflate_decompressor;
+
     default:
-      ds_put_format (zm->errmsgs, _("Unsupported compression type (%d)"), c);
-      which = n_COMPRESSION;
-      break;
+      return NULL;
     }
-  return which;
 }
 
-
 struct zip_reader
 {
-  char *filename;                  /* The name of the file from which the data is read */
-  FILE *fr;                        /* The stream from which the meta data is read */
-  uint16_t n_members;              /* The number of members in this archive */
-  struct zip_member **members;     /* The members (may be null pointers until the headers have been read */
-  int nm;
-  struct string *errs;
+  char *file_name;                  /* The name of the file from which the data is read */
+  uint16_t n_entries;              /* Number of directory entries. */
+  struct zip_entry *entries;       /* Directory entries. */
+  struct string *errs;             /* A string to hold error messages.  This
+                                      string is NOT owned by this object. */
+};
+
+struct zip_entry
+{
+  uint32_t offset;            /* Starting offset in file. */
+  uint32_t comp_size;         /* Length of member file data, in bytes. */
+  uint32_t ucomp_size;        /* Uncompressed length of member file data, in bytes. */
+  char *name;                 /* Name of member file. */
 };
 
 void
 zip_member_finish (struct zip_member *zm)
 {
-  ds_clear (zm->errmsgs);
-  /*  Probably not useful, because we would have to read right to the end of the member
-  if (zm->expected_crc != zm->crc)
+  if (zm)
     {
-      ds_put_cstr (zm->errs, _("CRC error reading zip"));
+      free (zm->file_name);
+      free (zm->member_name);
+      ds_clear (zm->errmsgs);
+      zm->decompressor->finish (zm);
+      fclose (zm->fp);
+      free (zm);
     }
-  */
-  zip_member_unref (zm);
 }
 
-
-
 /* Destroy the zip reader */
 void
 zip_reader_destroy (struct zip_reader *zr)
@@ -124,25 +120,18 @@ zip_reader_destroy (struct zip_reader *zr)
   if (zr == NULL)
     return;
 
-  fclose (zr->fr);
-  free (zr->filename);
+  free (zr->file_name);
 
-  for (i = 0; i < zr->n_members; ++i)
+  for (i = 0; i < zr->n_entries; ++i)
     {
-      zip_member_unref (zr->members[i]);
+      struct zip_entry *ze = &zr->entries[i];
+      free (ze->name);
     }
-  free (zr->members);
+  free (zr->entries);
   free (zr);
 }
 
 
-void
-zm_dump (const struct zip_member *zm)
-{
-  printf ("%d\t%08x\t %s\n", zm->ucomp_size, zm->expected_crc, zm->name);
-}
-
-
 /* Skip N bytes in F */
 static void
 skip_bytes (FILE *f, size_t n)
@@ -200,7 +189,8 @@ get_u16 (FILE *f, uint16_t *v)
 /* Read 32 bit integer and compare it with EXPECTED.
    place an error string in ERR if necessary. */
 static bool
-check_magic (FILE *f, uint32_t expected, struct string *err)
+check_magic (FILE *f, const char *file_name,
+             uint32_t expected, struct string *err)
 {
   uint32_t magic;
 
@@ -209,8 +199,11 @@ check_magic (FILE *f, uint32_t expected, struct string *err)
   if ((expected != magic))
     {
       ds_put_format (err,
-		     _("Corrupt file at 0x%llx: Expected %"PRIx32"; got %"PRIx32),
-		     (long long int) ftello (f) - sizeof (uint32_t), expected, magic);
+		     _("%s: corrupt archive at 0x%llx: "
+                       "expected %#"PRIx32" but got %#"PRIx32),
+                     file_name,
+		     (long long int) ftello (f) - sizeof (uint32_t),
+                     expected, magic);
 
       return false;
     }
@@ -230,83 +223,65 @@ zip_member_read (struct zip_member *zm, void *buf, size_t bytes)
   if ( bytes > zm->bytes_unread)
     bytes = zm->bytes_unread;
 
-  bytes_read  = decompressors[zm->compression].read (zm, buf, bytes);
+  bytes_read  = zm->decompressor->read (zm, buf, bytes);
   if ( bytes_read < 0)
     return bytes_read;
 
-  zm->crc = crc32_update (zm->crc, buf, bytes_read);
-
   zm->bytes_unread -= bytes_read;
 
   return bytes_read;
 }
 
 
-/*
-  Read a local file header from ZR and add it to ZR's internal array.
-  Returns a pointer to the member read.  This pointer belongs to ZR.
-  If the caller wishes to control it, she should ref it with
-  zip_member_ref.
-*/
-static struct zip_member *
-zip_header_read_next (struct zip_reader *zr)
+/* Read a central directory header from FILE and initializes ZE with it.
+   Returns true if successful, false otherwise.  On error, appends error
+   messages to ERRS. */
+static bool
+zip_header_read_next (FILE *file, const char *file_name,
+                      struct zip_entry *ze, struct string *errs)
 {
-  struct zip_member *zm = xzalloc (sizeof *zm);
-
   uint16_t v, nlen, extralen;
   uint16_t gp, time, date;
+  uint32_t expected_crc;
 
   uint16_t clen, diskstart, iattr;
   uint32_t eattr;
   uint16_t comp_type;
 
-  ds_clear (zr->errs);
-  zm->errmsgs = zr->errs;
-
-  if ( ! check_magic (zr->fr, MAGIC_SOCD, zr->errs))
-    return NULL;
-
-  if (! get_u16 (zr->fr, &v)) return NULL;
-
-  if (! get_u16 (zr->fr, &v)) return NULL;
-  if (! get_u16 (zr->fr, &gp)) return NULL;
-  if (! get_u16 (zr->fr, &comp_type)) return NULL;
-
-  zm->compression = comp_code (zm, comp_type);
-
-  if (! get_u16 (zr->fr, &time)) return NULL;
-  if (! get_u16 (zr->fr, &date)) return NULL;
-  if (! get_u32 (zr->fr, &zm->expected_crc)) return NULL;
-  if (! get_u32 (zr->fr, &zm->comp_size)) return NULL;
-  if (! get_u32 (zr->fr, &zm->ucomp_size)) return NULL;
-  if (! get_u16 (zr->fr, &nlen)) return NULL;
-  if (! get_u16 (zr->fr, &extralen)) return NULL;
-  if (! get_u16 (zr->fr, &clen)) return NULL;
-  if (! get_u16 (zr->fr, &diskstart)) return NULL;
-  if (! get_u16 (zr->fr, &iattr)) return NULL;
-  if (! get_u32 (zr->fr, &eattr)) return NULL;
-  if (! get_u32 (zr->fr, &zm->offset)) return NULL;
-
-  zm->name = xzalloc (nlen + 1);
-  if (! get_bytes (zr->fr, zm->name, nlen)) return NULL;
-
-  skip_bytes (zr->fr, extralen);
-
-  zr->members[zr->nm++] = zm;
-
-  zm->fp = fopen (zr->filename, "rb");
-  zm->ref_cnt = 1;
+  if ( ! check_magic (file, file_name, MAGIC_SOCD, errs))
+    return false;
 
+  if (! get_u16 (file, &v)) return false;
+  if (! get_u16 (file, &v)) return false;
+  if (! get_u16 (file, &gp)) return false;
+  if (! get_u16 (file, &comp_type)) return false;
+  if (! get_u16 (file, &time)) return false;
+  if (! get_u16 (file, &date)) return false;
+  if (! get_u32 (file, &expected_crc)) return false;
+  if (! get_u32 (file, &ze->comp_size)) return false;
+  if (! get_u32 (file, &ze->ucomp_size)) return false;
+  if (! get_u16 (file, &nlen)) return false;
+  if (! get_u16 (file, &extralen)) return false;
+  if (! get_u16 (file, &clen)) return false;
+  if (! get_u16 (file, &diskstart)) return false;
+  if (! get_u16 (file, &iattr)) return false;
+  if (! get_u32 (file, &eattr)) return false;
+  if (! get_u32 (file, &ze->offset)) return false;
+
+  ze->name = xzalloc (nlen + 1);
+  if (! get_bytes (file, ze->name, nlen)) return false;
+
+  skip_bytes (file, extralen);
 
-  return zm;
+  return true;
 }
 
 
-/* Create a reader from the zip called FILENAME */
+/* Create a reader from the zip called FILE_NAME */
 struct zip_reader *
-zip_reader_create (const char *filename, struct string *errs)
+zip_reader_create (const char *file_name, struct string *errs)
 {
-  uint16_t disknum, total_members;
+  uint16_t disknum, n_members, total_members;
   off_t offset = 0;
   uint32_t central_dir_start, central_dir_length;
 
@@ -315,192 +290,199 @@ zip_reader_create (const char *filename, struct string *errs)
   if ( zr->errs)
     ds_init_empty (zr->errs);
 
-  zr->nm = 0;
-
-  zr->fr = fopen (filename, "rb");
-  if (NULL == zr->fr)
+  FILE *file = fopen (file_name, "rb");
+  if (!file)
     {
-      ds_put_cstr (zr->errs, strerror (errno));
+      ds_put_format (zr->errs, _("%s: open failed (%s)"),
+                     file_name, strerror (errno));
       free (zr);
       return NULL;
     }
 
-  if ( ! check_magic (zr->fr, MAGIC_LHDR, zr->errs))
+  if ( ! check_magic (file, file_name, MAGIC_LHDR, zr->errs))
     {
-      fclose (zr->fr);
+      fclose (file);
       free (zr);
       return NULL;
     }
 
-  if ( ! find_eocd (zr->fr, &offset))
+  if ( ! find_eocd (file, &offset))
     {
-      ds_put_format (zr->errs, _("Cannot find central directory"));
-      fclose (zr->fr);
+      ds_put_format (zr->errs, _("%s: cannot find central directory"),
+                     file_name);
+      fclose (file);
       free (zr);
       return NULL;
     }
 
-  if ( 0 != fseeko (zr->fr, offset, SEEK_SET))
+  if ( 0 != fseeko (file, offset, SEEK_SET))
     {
-      const char *mm = strerror (errno);
-      ds_put_format (zr->errs, _("Failed to seek to end of central directory record: %s"), mm);
-      fclose (zr->fr);
+      ds_put_format (zr->errs, _("%s: seek failed (%s)"),
+                     file_name, strerror (errno));
+      fclose (file);
       free (zr);
       return NULL;
     }
 
 
-  if ( ! check_magic (zr->fr, MAGIC_EOCD, zr->errs))
+  if ( ! check_magic (file, file_name, MAGIC_EOCD, zr->errs))
     {
-      fclose (zr->fr);
+      fclose (file);
       free (zr);
       return NULL;
     }
 
-  if (! get_u16 (zr->fr, &disknum)) return NULL;
-  if (! get_u16 (zr->fr, &disknum)) return NULL;
+  if (! get_u16 (file, &disknum)
+      || ! get_u16 (file, &disknum)
 
-  if (! get_u16 (zr->fr, &zr->n_members)) return NULL;
-  if (! get_u16 (zr->fr, &total_members)) return NULL;
+      || ! get_u16 (file, &n_members)
+      || ! get_u16 (file, &total_members)
 
-  if (! get_u32 (zr->fr, &central_dir_length)) return NULL;
-  if (! get_u32 (zr->fr, &central_dir_start)) return NULL;
+      || ! get_u32 (file, &central_dir_length)
+      || ! get_u32 (file, &central_dir_start))
+    {
+      fclose (file);
+      free (zr);
+      return NULL;
+    }
 
-  if ( 0 != fseeko (zr->fr, central_dir_start, SEEK_SET))
+  if ( 0 != fseeko (file, central_dir_start, SEEK_SET))
     {
-      const char *mm = strerror (errno);
-      ds_put_format (zr->errs, _("Failed to seek to central directory: %s"), mm);
-      fclose (zr->fr);
+      ds_put_format (zr->errs, _("%s: seek failed (%s)"),
+                     file_name, strerror (errno));
+      fclose (file);
       free (zr);
       return NULL;
     }
 
-  zr->members = xcalloc (zr->n_members, sizeof (*zr->members));
-  memset (zr->members, 0, zr->n_members * sizeof (*zr->members));
+  zr->file_name = xstrdup (file_name);
 
-  zr->filename = strdup (filename);
+  zr->entries = xcalloc (n_members, sizeof *zr->entries);
+  for (int i = 0; i < n_members; i++)
+    {
+      if (!zip_header_read_next (file, file_name,
+                                 &zr->entries[zr->n_entries], errs))
+        {
+          fclose (file);
+          zip_reader_destroy (zr);
+          return NULL;
+        }
+      zr->n_entries++;
+    }
 
   return zr;
 }
 
+static struct zip_entry *
+zip_entry_find (struct zip_reader *zr, const char *member)
+{
+  for (int i = 0; i < zr->n_entries; ++i)
+    {
+      struct zip_entry *ze = &zr->entries[i];
+      if (0 == strcmp (ze->name, member))
+        return ze;
+    }
+  return NULL;
+}
 
+const char *
+zip_reader_get_member_name(const struct zip_reader *zr, size_t idx)
+{
+  return idx < zr->n_entries ? zr->entries[idx].name : NULL;
+}
 
 /* Return the member called MEMBER from the reader ZR  */
 struct zip_member *
 zip_member_open (struct zip_reader *zr, const char *member)
 {
-  uint16_t v, nlen, extra_len;
-  uint16_t gp, comp_type, time, date;
-  uint32_t ucomp_size, comp_size;
-
-  uint32_t crc;
-  bool new_member = false;
-  char *name = NULL;
-
-  int i;
-  struct zip_member *zm = NULL;
-
-  if ( zr == NULL)
-    return NULL;
-
-  for (i = 0; i < zr->n_members; ++i)
-  {
-    zm = zr->members[i];
-
-    if (zm == NULL)
-      {
-	zm = zr->members[i] = zip_header_read_next (zr);
-	new_member = true;
-      }
-    if (zm && 0 == strcmp (zm->name, member))
-      break;
-    else
-      zm = NULL;
-  }
-
-  if ( zm == NULL)
-    return NULL;
-
-  if ( 0 != fseeko (zm->fp, zm->offset, SEEK_SET))
+  struct zip_entry *ze = zip_entry_find (zr, member);
+  if ( ze == NULL)
     {
-      const char *mm = strerror (errno);
-      ds_put_format (zm->errmsgs, _("Failed to seek to start of member `%s': %s"), zm->name, mm);
+      ds_put_format (zr->errs, _("%s: unknown member \"%s\""),
+                     zr->file_name, member);
       return NULL;
     }
 
-  if ( ! check_magic (zm->fp, MAGIC_LHDR, zr->errs))
+  FILE *fp = fopen (zr->file_name, "rb");
+  if (!fp)
     {
+      ds_put_format (zr->errs, _("%s: open failed (%s)"),
+                     zr->file_name, strerror (errno));
       return NULL;
     }
 
-  if (! get_u16 (zm->fp, &v)) return NULL;
-  if (! get_u16 (zm->fp, &gp)) return NULL;
-  if (! get_u16 (zm->fp, &comp_type)) return NULL;
-  zm->compression = comp_code (zm, comp_type);
-  if (! get_u16 (zm->fp, &time)) return NULL;
-  if (! get_u16 (zm->fp, &date)) return NULL;
-  if (! get_u32 (zm->fp, &crc)) return NULL;
-  if (! get_u32 (zm->fp, &comp_size)) return NULL;
-
-  if (! get_u32 (zm->fp, &ucomp_size)) return NULL;
-  if (! get_u16 (zm->fp, &nlen)) return NULL;
-  if (! get_u16 (zm->fp, &extra_len)) return NULL;
-
-  name = xzalloc (nlen + 1);
+  struct zip_member *zm = xmalloc (sizeof *zm);
+  zm->file_name = xstrdup (zr->file_name);
+  zm->member_name = xstrdup (member);
+  zm->fp = fp;
+  zm->offset = ze->offset;
+  zm->comp_size = ze->comp_size;
+  zm->ucomp_size = ze->ucomp_size;
+  zm->decompressor = NULL;
+  zm->bytes_unread = ze->ucomp_size;
+  zm->errmsgs = zr->errs;
+  zm->aux = NULL;
 
-  if (! get_bytes (zm->fp, name, nlen)) return NULL;
+  if ( 0 != fseeko (zm->fp, zm->offset, SEEK_SET))
+    {
+      ds_put_format (zr->errs, _("%s: seek failed (%s)"),
+                     ze->name, strerror (errno));
+      goto error;
+    }
 
-  skip_bytes (zm->fp, extra_len);
+  if ( ! check_magic (zm->fp, zr->file_name, MAGIC_LHDR, zr->errs))
+    goto error;
 
-  if (strcmp (name, zm->name) != 0)
+  uint16_t v, nlen, extra_len;
+  uint16_t gp, comp_type, time, date;
+  uint32_t ucomp_size, comp_size;
+  uint32_t crc;
+  if (! get_u16 (zm->fp, &v)) goto error;
+  if (! get_u16 (zm->fp, &gp)) goto error;
+  if (! get_u16 (zm->fp, &comp_type)) goto error;
+  zm->decompressor = get_decompressor (comp_type);
+  if (! zm->decompressor) goto error;
+  if (! get_u16 (zm->fp, &time)) goto error;
+  if (! get_u16 (zm->fp, &date)) goto error;
+  if (! get_u32 (zm->fp, &crc)) goto error;
+  if (! get_u32 (zm->fp, &comp_size)) goto error;
+
+  if (! get_u32 (zm->fp, &ucomp_size)) goto error;
+  if (! get_u16 (zm->fp, &nlen)) goto error;
+  if (! get_u16 (zm->fp, &extra_len)) goto error;
+
+  char *name = xzalloc (nlen + 1);
+  if (! get_bytes (zm->fp, name, nlen))
+    {
+      free (name);
+      goto error;
+    }
+  if (strcmp (name, ze->name) != 0)
     {
       ds_put_format (zm->errmsgs,
-		     _("Name mismatch in zip archive. Central directory says `%s'; local file header says `%s'"),
-		     zm->name, name);
+		     _("%s: name mismatch betwen central directory (%s) "
+                       "and local file header (%s)"),
+                     zm->file_name, ze->name, name);
       free (name);
-      free (zm);
-      return NULL;
+      goto error;
     }
-
   free (name);
 
-  zm->bytes_unread = zm->ucomp_size;
-
-  if ( !new_member)
-    decompressors[zm->compression].finish (zm);
+  skip_bytes (zm->fp, extra_len);
 
-  if (!decompressors[zm->compression].init (zm) )
-    return NULL;
+  if (!zm->decompressor->init (zm) )
+    goto error;
 
   return zm;
-}
-
-void
-zip_member_ref (struct zip_member *zm)
-{
-  zm->ref_cnt++;
-}
-
 
-
-
-void
-zip_member_unref (struct zip_member *zm)
-{
-  if ( zm == NULL)
-    return;
-
-  if (--zm->ref_cnt == 0)
-    {
-      decompressors[zm->compression].finish (zm);
-      if (zm->fp)
-	fclose (zm->fp);
-      free (zm->name);
-      free (zm);
-    }
+error:
+  fclose (zm->fp);
+  free (zm->file_name);
+  free (zm->member_name);
+  free (zm);
+  return NULL;
 }
 
-
 
 
 static bool probe_magic (FILE *fp, uint32_t magic, off_t start, off_t stop, off_t *off);
@@ -588,4 +570,150 @@ probe_magic (FILE *fp, uint32_t magic, off_t start, off_t stop, off_t *off)
 
   return false;
 }
+
+/* Null decompressor. */
+
+static int
+stored_read (struct zip_member *zm, void *buf, size_t n)
+{
+  return fread (buf, 1, n, zm->fp);
+}
+
+static bool
+stored_init (struct zip_member *zm UNUSED)
+{
+  return true;
+}
+
+static void
+stored_finish (struct zip_member *zm UNUSED)
+{
+  /* Nothing required */
+}
+
+static const struct decompressor stored_decompressor =
+  {stored_init, stored_read, stored_finish};
+
+/* Inflate decompressor. */
+
+#undef crc32
+#include <zlib.h>
+
+#define UCOMPSIZE 4096
+
+struct inflator
+{
+  z_stream zss;
+  int state;
+  unsigned char ucomp[UCOMPSIZE];
+  size_t bytes_uncomp;
+  size_t ucomp_bytes_read;
+
+  /* Two bitfields as defined by RFC1950 */
+  uint16_t cmf_flg ;
+};
+
+static void
+inflate_finish (struct zip_member *zm)
+{
+  struct inflator *inf = zm->aux;
+
+  inflateEnd (&inf->zss);
+
+  free (inf);
+}
+
+static bool
+inflate_init (struct zip_member *zm)
+{
+  int r;
+  struct inflator *inf = xzalloc (sizeof *inf);
+
+  uint16_t flg = 0 ;
+  uint16_t cmf = 0x8; /* Always 8 for inflate */
+
+  const uint16_t cinfo = 7;  /* log_2(Window size) - 8 */
+
+  cmf |= cinfo << 4;     /* Put cinfo into the high nibble */
+
+  /* make these into a 16 bit word */
+  inf->cmf_flg = (cmf << 8 ) | flg;
+
+  /* Set the check bits */
+  inf->cmf_flg += 31 - (inf->cmf_flg % 31);
+  assert (inf->cmf_flg % 31 == 0);
+
+  inf->zss.next_in = Z_NULL;
+  inf->zss.avail_in = 0;
+  inf->zss.zalloc = Z_NULL;
+  inf->zss.zfree  = Z_NULL;
+  inf->zss.opaque = Z_NULL;
+  r = inflateInit (&inf->zss);
+
+  if ( Z_OK != r)
+    {
+      ds_put_format (zm->errmsgs,
+                     _("%s: cannot initialize inflator (%s)"),
+                     zm->file_name, zError (r));
+      return false;
+    }
+
+  zm->aux = inf;
+
+  return true;
+}
+
+static int
+inflate_read (struct zip_member *zm, void *buf, size_t n)
+{
+  int r;
+  struct inflator *inf = zm->aux;
+
+  if (inf->zss.avail_in == 0)
+    {
+      int bytes_read;
+      int bytes_to_read;
+      int pad = 0;
+
+      if ( inf->state == 0)
+	{
+	  inf->ucomp[1] = inf->cmf_flg ;
+      	  inf->ucomp[0] = inf->cmf_flg >> 8 ;
+
+	  pad = 2;
+	  inf->state++;
+	}
+
+      bytes_to_read = zm->comp_size - inf->ucomp_bytes_read;
+
+      if (bytes_to_read == 0)
+	return 0;
+
+      if (bytes_to_read > UCOMPSIZE)
+	bytes_to_read = UCOMPSIZE;
+
+      bytes_read = fread (inf->ucomp + pad, 1, bytes_to_read - pad, zm->fp);
+
+      inf->ucomp_bytes_read += bytes_read;
+
+      inf->zss.avail_in = bytes_read + pad;
+      inf->zss.next_in = inf->ucomp;
+    }
+  inf->zss.avail_out = n;
+  inf->zss.next_out = buf;
+
+  r = inflate (&inf->zss, Z_NO_FLUSH);
+  if ( Z_OK == r)
+    {
+      return n - inf->zss.avail_out;
+    }
+
+  ds_put_format (zm->errmsgs, _("%s: error inflating \"%s\" (%s)"),
+                 zm->file_name, zm->member_name, zError (r));
+
+  return -1;
+}
+
+static const struct decompressor inflate_decompressor =
+  {inflate_init, inflate_read, inflate_finish};