X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fdata%2Fsys-file-reader.c;h=07471e8831990ae4d757b2e5a424e3182e5ef013;hb=refs%2Fbuilds%2F20120402030503%2Fpspp;hp=336549b7614248bee9ebaf7077dbcd1b0f2add1d;hpb=261869b71aa60b8974c4a6b98e35b74af5d11de5;p=pspp

diff --git a/src/data/sys-file-reader.c b/src/data/sys-file-reader.c
index 336549b761..07471e8831 100644
--- a/src/data/sys-file-reader.c
+++ b/src/data/sys-file-reader.c
@@ -88,6 +88,7 @@ enum
 /* Fields from the top-level header record. */
 struct sfm_header_record
   {
+    char magic[5];              /* First 4 bytes of file, then null. */
     int weight_idx;             /* 0 if unweighted, otherwise a var index. */
     int nominal_case_size;      /* Number of var positions. */
 
@@ -213,6 +214,7 @@ static void skip_extension_record (struct sfm_reader *, int subtype);
 
 static const char *choose_encoding (
   struct sfm_reader *,
+  const struct sfm_header_record *,
   const struct sfm_extension_record *ext_integer,
   const struct sfm_extension_record *ext_encoding);
 
@@ -310,12 +312,17 @@ sfm_read_info_destroy (struct sfm_read_info *info)
 /* Opens the system file designated by file handle FH for reading.  Reads the
    system file's dictionary into *DICT.
 
+   Ordinarily the reader attempts to automatically detect the character
+   encoding based on the file's contents.  This isn't always possible,
+   especially for files written by old versions of SPSS or PSPP, so specifying
+   a nonnull ENCODING overrides the choice of character encoding.
+
    If INFO is non-null, then it receives additional info about the system file,
    which the caller must eventually free with sfm_read_info_destroy() when it
    is no longer needed. */
 struct casereader *
-sfm_open_reader (struct file_handle *fh, struct dictionary **dictp,
-                 struct sfm_read_info *infop)
+sfm_open_reader (struct file_handle *fh, const char *volatile encoding,
+                 struct dictionary **dictp, struct sfm_read_info *infop)
 {
   struct sfm_reader *volatile r = NULL;
   struct sfm_read_info info;
@@ -452,8 +459,10 @@ sfm_open_reader (struct file_handle *fh, struct dictionary **dictp,
 
      First, figure out the correct character encoding, because this determines
      how the rest of the header data is to be interpreted. */
-  dict = dict_create (choose_encoding (r, extensions[EXT_INTEGER],
-                                       extensions[EXT_ENCODING]));
+  dict = dict_create (encoding
+                      ? encoding
+                      : choose_encoding (r, &header, extensions[EXT_INTEGER],
+                                         extensions[EXT_ENCODING]));
   r->encoding = dict_get_encoding (dict);
 
   /* These records don't use variables at all. */
@@ -598,13 +607,13 @@ sys_file_casereader_destroy (struct casereader *reader UNUSED, void *r_)
 bool
 sfm_detect (FILE *file)
 {
-  char rec_type[5];
+  char magic[5];
 
-  if (fread (rec_type, 4, 1, file) != 1)
+  if (fread (magic, 4, 1, file) != 1)
     return false;
-  rec_type[4] = '\0';
+  magic[4] = '\0';
 
-  return !strcmp ("$FL2", rec_type);
+  return !strcmp (ASCII_MAGIC, magic) || !strcmp (EBCDIC_MAGIC, magic);
 }
 
 /* Reads the global header of the system file.  Initializes *HEADER and *INFO,
@@ -614,14 +623,14 @@ static void
 read_header (struct sfm_reader *r, struct sfm_read_info *info,
              struct sfm_header_record *header)
 {
-  char rec_type[5];
   uint8_t raw_layout_code[4];
   uint8_t raw_bias[8];
 
-  read_string (r, rec_type, sizeof rec_type);
+  read_string (r, header->magic, sizeof header->magic);
   read_string (r, header->eye_catcher, sizeof header->eye_catcher);
 
-  if (strcmp ("$FL2", rec_type) != 0)
+  if (strcmp (ASCII_MAGIC, header->magic)
+      && strcmp (EBCDIC_MAGIC, header->magic))
     sys_error (r, 0, _("This is not an SPSS system file."));
 
   /* Identify integer format. */
@@ -1185,6 +1194,7 @@ parse_machine_integer_info (struct sfm_reader *r,
 
 static const char *
 choose_encoding (struct sfm_reader *r,
+                 const struct sfm_header_record *header,
                  const struct sfm_extension_record *ext_integer,
                  const struct sfm_extension_record *ext_encoding)
 {
@@ -1223,6 +1233,10 @@ choose_encoding (struct sfm_reader *r,
         }
     }
 
+  /* If the file magic number is EBCDIC then its character data is too. */
+  if (!strcmp (header->magic, EBCDIC_MAGIC))
+    return "EBCDIC-US";
+
   return locale_charset ();
 }
 
@@ -2425,7 +2439,7 @@ text_parse_counted_string (struct sfm_reader *r, struct text_record *text)
 
   start = text->pos;
   n = 0;
-  for (;;)
+  while (text->pos < text->buffer.length)
     {
       int c = text->buffer.string[text->pos];
       if (c < '0' || c > '9')
@@ -2433,7 +2447,7 @@ text_parse_counted_string (struct sfm_reader *r, struct text_record *text)
       n = (n * 10) + (c - '0');
       text->pos++;
     }
-  if (start == text->pos)
+  if (text->pos >= text->buffer.length || start == text->pos)
     {
       sys_warn (r, text->start,
                 _("Expecting digit at offset %zu in MRSETS record."),