comparison src/libid3tag-0.15.1b/file.c @ 85:545efbb81310

Import initial set of sources

+/*
+ * libid3tag - ID3 tag manipulation library
+ * Copyright (C) 2000-2004 Underbit Technologies, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * $Id: file.c,v 1.21 2004/01/23 09:41:32 rob Exp $
+ */
+
+# ifdef HAVE_CONFIG_H
+#  include "config.h"
+# endif
+
+# include "global.h"
+
+# include <stdio.h>
+# include <stdlib.h>
+# include <string.h>
+
+# ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+# endif
+
+# ifdef HAVE_ASSERT_H
+#  include <assert.h>
+# endif
+
+# include "id3tag.h"
+# include "file.h"
+# include "tag.h"
+# include "field.h"
+
+struct filetag {
+  struct id3_tag *tag;
+  unsigned long location;
+  id3_length_t length;
+};
+
+struct id3_file {
+  FILE *iofile;
+  enum id3_file_mode mode;
+  char *path;
+
+  int flags;
+
+  struct id3_tag *primary;
+
+  unsigned int ntags;
+  struct filetag *tags;
+};
+
+enum {
+  ID3_FILE_FLAG_ID3V1 = 0x0001
+};
+
+/*
+ * NAME:	query_tag()
+ * DESCRIPTION:	check for a tag at a file's current position
+ */
+static
+signed long query_tag(FILE *iofile)
+{
+  fpos_t save_position;
+  id3_byte_t query[ID3_TAG_QUERYSIZE];
+  signed long size;
+
+  if (fgetpos(iofile, &save_position) == -1)
+    return 0;
+
+  size = id3_tag_query(query, fread(query, 1, sizeof(query), iofile));
+
+  if (fsetpos(iofile, &save_position) == -1)
+    return 0;
+
+  return size;
+}
+
+/*
+ * NAME:	read_tag()
+ * DESCRIPTION:	read and parse a tag at a file's current position
+ */
+static
+struct id3_tag *read_tag(FILE *iofile, id3_length_t size)
+{
+  id3_byte_t *data;
+  struct id3_tag *tag = 0;
+
+  data = malloc(size);
+  if (data) {
+    if (fread(data, size, 1, iofile) == 1)
+      tag = id3_tag_parse(data, size);
+
+    free(data);
+  }
+
+  return tag;
+}
+
+/*
+ * NAME:	update_primary()
+ * DESCRIPTION:	update the primary tag with data from a new tag
+ */
+static
+int update_primary(struct id3_tag *tag, struct id3_tag const *new)
+{
+  unsigned int i;
+  struct id3_frame *frame;
+
+  if (new) {
+    if (!(new->extendedflags & ID3_TAG_EXTENDEDFLAG_TAGISANUPDATE))
+      id3_tag_clearframes(tag);
+
+    i = 0;
+    while ((frame = id3_tag_findframe(new, 0, i++))) {
+      if (id3_tag_attachframe(tag, frame) == -1)
+	return -1;
+    }
+  }
+
+  return 0;
+}
+
+/*
+ * NAME:	tag_compare()
+ * DESCRIPTION:	tag sort function for qsort()
+ */
+static
+int tag_compare(const void *a, const void *b)
+{
+  struct filetag const *tag1 = a, *tag2 = b;
+
+  if (tag1->location < tag2->location)
+    return -1;
+  else if (tag1->location > tag2->location)
+    return +1;
+
+  return 0;
+}
+
+/*
+ * NAME:	add_filetag()
+ * DESCRIPTION:	add a new file tag entry
+ */
+static
+int add_filetag(struct id3_file *file, struct filetag const *filetag)
+{
+  struct filetag *tags;
+
+  tags = realloc(file->tags, (file->ntags + 1) * sizeof(*tags));
+  if (tags == 0)
+    return -1;
+
+  file->tags = tags;
+  file->tags[file->ntags++] = *filetag;
+
+  /* sort tags by location */
+
+  if (file->ntags > 1)
+    qsort(file->tags, file->ntags, sizeof(file->tags[0]), tag_compare);
+
+  return 0;
+}
+
+/*
+ * NAME:	del_filetag()
+ * DESCRIPTION:	delete a file tag entry
+ */
+static
+void del_filetag(struct id3_file *file, unsigned int index)
+{
+  assert(index < file->ntags);
+
+  while (index < file->ntags - 1) {
+    file->tags[index] = file->tags[index + 1];
+    ++index;
+  }
+
+  --file->ntags;
+}
+
+/*
+ * NAME:	add_tag()
+ * DESCRIPTION:	read, parse, and add a tag to a file structure
+ */
+static
+struct id3_tag *add_tag(struct id3_file *file, id3_length_t length)
+{
+  long location;
+  unsigned int i;
+  struct filetag filetag;
+  struct id3_tag *tag;
+
+  location = ftell(file->iofile);
+  if (location == -1)
+    return 0;
+
+  /* check for duplication/overlap */
+  {
+    unsigned long begin1, end1, begin2, end2;
+
+    begin1 = location;
+    end1   = begin1 + length;
+
+    for (i = 0; i < file->ntags; ++i) {
+      begin2 = file->tags[i].location;
+      end2   = begin2 + file->tags[i].length;
+
+      if (begin1 == begin2 && end1 == end2)
+	return file->tags[i].tag;  /* duplicate */
+
+      if (begin1 < end2 && end1 > begin2)
+	return 0;  /* overlap */
+    }
+  }
+
+  tag = read_tag(file->iofile, length);
+
+  filetag.tag      = tag;
+  filetag.location = location;
+  filetag.length   = length;
+
+  if (add_filetag(file, &filetag) == -1 ||
+      update_primary(file->primary, tag) == -1) {
+    if (tag)
+      id3_tag_delete(tag);
+    return 0;
+  }
+
+  if (tag)
+    id3_tag_addref(tag);
+
+  return tag;
+}
+
+/*
+ * NAME:	search_tags()
+ * DESCRIPTION:	search for tags in a file
+ */
+static
+int search_tags(struct id3_file *file)
+{
+  fpos_t save_position;
+  signed long size;
+
+  /*
+   * save the current seek position
+   *
+   * We also verify the stream is seekable by calling fsetpos(), since
+   * fgetpos() alone is not reliable enough for this purpose.
+   *
+   * [Apparently not even fsetpos() is sufficient under Win32.]
+   */
+
+  if (fgetpos(file->iofile, &save_position) == -1 ||
+      fsetpos(file->iofile, &save_position) == -1)
+    return -1;
+
+  /* look for an ID3v1 tag */
+
+  if (fseek(file->iofile, -128, SEEK_END) == 0) {
+    size = query_tag(file->iofile);
+    if (size > 0) {
+      struct id3_tag const *tag;
+
+      tag = add_tag(file, size);
+
+      /* if this is indeed an ID3v1 tag, mark the file so */
+
+      if (tag && (ID3_TAG_VERSION_MAJOR(id3_tag_version(tag)) == 1))
+	file->flags |= ID3_FILE_FLAG_ID3V1;
+    }
+  }
+
+  /* look for a tag at the beginning of the file */
+
+  rewind(file->iofile);
+
+  size = query_tag(file->iofile);
+  if (size > 0) {
+    struct id3_tag const *tag;
+    struct id3_frame const *frame;
+
+    tag = add_tag(file, size);
+
+    /* locate tags indicated by SEEK frames */
+
+    while (tag && (frame = id3_tag_findframe(tag, "SEEK", 0))) {
+      long seek;
+
+      seek = id3_field_getint(id3_frame_field(frame, 0));
+      if (seek < 0 || fseek(file->iofile, seek, SEEK_CUR) == -1)
+	break;
+
+      size = query_tag(file->iofile);
+      tag  = (size > 0) ? add_tag(file, size) : 0;
+    }
+  }
+
+  /* look for a tag at the end of the file (before any ID3v1 tag) */
+
+  if (fseek(file->iofile, ((file->flags & ID3_FILE_FLAG_ID3V1) ? -128 : 0) +
+	    -10, SEEK_END) == 0) {
+    size = query_tag(file->iofile);
+    if (size < 0 && fseek(file->iofile, size, SEEK_CUR) == 0) {
+      size = query_tag(file->iofile);
+      if (size > 0)
+	add_tag(file, size);
+    }
+  }
+
+  clearerr(file->iofile);
+
+  /* restore seek position */
+
+  if (fsetpos(file->iofile, &save_position) == -1)
+    return -1;
+
+  /* set primary tag options and target padded length for convenience */
+
+  if ((file->ntags > 0 && !(file->flags & ID3_FILE_FLAG_ID3V1)) ||
+      (file->ntags > 1 &&  (file->flags & ID3_FILE_FLAG_ID3V1))) {
+    if (file->tags[0].location == 0)
+      id3_tag_setlength(file->primary, file->tags[0].length);
+    else
+      id3_tag_options(file->primary, ID3_TAG_OPTION_APPENDEDTAG, ~0);
+  }
+
+  return 0;
+}
+
+/*
+ * NAME:	finish_file()
+ * DESCRIPTION:	release memory associated with a file
+ */
+static
+void finish_file(struct id3_file *file)
+{
+  unsigned int i;
+
+  if (file->path)
+    free(file->path);
+
+  if (file->primary) {
+    id3_tag_delref(file->primary);
+    id3_tag_delete(file->primary);
+  }
+
+  for (i = 0; i < file->ntags; ++i) {
+    struct id3_tag *tag;
+
+    tag = file->tags[i].tag;
+    if (tag) {
+      id3_tag_delref(tag);
+      id3_tag_delete(tag);
+    }
+  }
+
+  if (file->tags)
+    free(file->tags);
+
+  free(file);
+}
+
+/*
+ * NAME:	new_file()
+ * DESCRIPTION:	create a new file structure and load tags
+ */
+static
+struct id3_file *new_file(FILE *iofile, enum id3_file_mode mode,
+			  char const *path)
+{
+  struct id3_file *file;
+
+  file = malloc(sizeof(*file));
+  if (file == 0)
+    goto fail;
+
+  file->iofile  = iofile;
+  file->mode    = mode;
+  file->path    = path ? strdup(path) : 0;
+
+  file->flags   = 0;
+
+  file->ntags   = 0;
+  file->tags    = 0;
+
+  file->primary = id3_tag_new();
+  if (file->primary == 0)
+    goto fail;
+
+  id3_tag_addref(file->primary);
+
+  /* load tags from the file */
+
+  if (search_tags(file) == -1)
+    goto fail;
+
+  id3_tag_options(file->primary, ID3_TAG_OPTION_ID3V1,
+		  (file->flags & ID3_FILE_FLAG_ID3V1) ? ~0 : 0);
+
+  if (0) {
+  fail:
+    if (file) {
+      finish_file(file);
+      file = 0;
+    }
+  }
+
+  return file;
+}
+
+/*
+ * NAME:	file->open()
+ * DESCRIPTION:	open a file given its pathname
+ */
+struct id3_file *id3_file_open(char const *path, enum id3_file_mode mode)
+{
+  FILE *iofile;
+  struct id3_file *file;
+
+  assert(path);
+
+  iofile = fopen(path, (mode == ID3_FILE_MODE_READWRITE) ? "r+b" : "rb");
+  if (iofile == 0)
+    return 0;
+
+  file = new_file(iofile, mode, path);
+  if (file == 0)
+    fclose(iofile);
+
+  return file;
+}
+
+/*
+ * NAME:	file->fdopen()
+ * DESCRIPTION:	open a file using an existing file descriptor
+ */
+struct id3_file *id3_file_fdopen(int fd, enum id3_file_mode mode)
+{
+# if 1 || defined(HAVE_UNISTD_H)
+  FILE *iofile;
+  struct id3_file *file;
+
+  iofile = fdopen(fd, (mode == ID3_FILE_MODE_READWRITE) ? "r+b" : "rb");
+  if (iofile == 0)
+    return 0;
+
+  file = new_file(iofile, mode, 0);
+  if (file == 0) {
+    int save_fd;
+
+    /* close iofile without closing fd */
+
+    save_fd = dup(fd);
+
+    fclose(iofile);
+
+    dup2(save_fd, fd);
+    close(save_fd);
+  }
+
+  return file;
+# else
+  return 0;
+# endif
+}
+
+/*
+ * NAME:	file->close()
+ * DESCRIPTION:	close a file and delete its associated tags
+ */
+int id3_file_close(struct id3_file *file)
+{
+  int result = 0;
+
+  assert(file);
+
+  if (fclose(file->iofile) == EOF)
+    result = -1;
+
+  finish_file(file);
+
+  return result;
+}
+
+/*
+ * NAME:	file->tag()
+ * DESCRIPTION:	return the primary tag structure for a file
+ */
+struct id3_tag *id3_file_tag(struct id3_file const *file)
+{
+  assert(file);
+
+  return file->primary;
+}
+
+/*
+ * NAME:	v1_write()
+ * DESCRIPTION:	write ID3v1 tag modifications to a file
+ */
+static
+int v1_write(struct id3_file *file,
+	     id3_byte_t const *data, id3_length_t length)
+{
+  assert(!data || length == 128);
+
+  if (data) {
+    long location;
+
+    if (fseek(file->iofile, (file->flags & ID3_FILE_FLAG_ID3V1) ? -128 : 0,
+	      SEEK_END) == -1 ||
+	(location = ftell(file->iofile)) == -1 ||
+	fwrite(data, 128, 1, file->iofile) != 1 ||
+	fflush(file->iofile) == EOF)
+      return -1;
+
+    /* add file tag reference */
+
+    if (!(file->flags & ID3_FILE_FLAG_ID3V1)) {
+      struct filetag filetag;
+
+      filetag.tag      = 0;
+      filetag.location = location;
+      filetag.length   = 128;
+
+      if (add_filetag(file, &filetag) == -1)
+	return -1;
+
+      file->flags |= ID3_FILE_FLAG_ID3V1;
+    }
+  }
+# if defined(HAVE_FTRUNCATE)
+  else if (file->flags & ID3_FILE_FLAG_ID3V1) {
+    long length;
+
+    if (fseek(file->iofile, 0, SEEK_END) == -1)
+      return -1;
+
+    length = ftell(file->iofile);
+    if (length == -1 ||
+	(length >= 0 && length < 128))
+      return -1;
+
+    if (ftruncate(fileno(file->iofile), length - 128) == -1)
+      return -1;
+
+    /* delete file tag reference */
+
+    del_filetag(file, file->ntags - 1);
+
+    file->flags &= ~ID3_FILE_FLAG_ID3V1;
+  }
+# endif
+
+  return 0;
+}
+
+/*
+ * NAME:	v2_write()
+ * DESCRIPTION:	write ID3v2 tag modifications to a file
+ */
+static
+int v2_write(struct id3_file *file,
+	     id3_byte_t const *data, id3_length_t length)
+{
+  assert(!data || length > 0);
+
+  if (data &&
+      ((file->ntags == 1 && !(file->flags & ID3_FILE_FLAG_ID3V1)) ||
+       (file->ntags == 2 &&  (file->flags & ID3_FILE_FLAG_ID3V1))) &&
+      file->tags[0].length == length) {
+    /* easy special case: rewrite existing tag in-place */
+
+    if (fseek(file->iofile, file->tags[0].location, SEEK_SET) == -1 ||
+	fwrite(data, length, 1, file->iofile) != 1 ||
+	fflush(file->iofile) == EOF)
+      return -1;
+
+    goto done;
+  }
+
+  /* hard general case: rewrite entire file */
+
+  /* ... */
+
+ done:
+  return 0;
+}
+
+/*
+ * NAME:	file->update()
+ * DESCRIPTION:	rewrite tag(s) to a file
+ */
+int id3_file_update(struct id3_file *file)
+{
+  int options, result = 0;
+  id3_length_t v1size = 0, v2size = 0;
+  id3_byte_t id3v1_data[128], *id3v1 = 0, *id3v2 = 0;
+
+  assert(file);
+
+  if (file->mode != ID3_FILE_MODE_READWRITE)
+    return -1;
+
+  options = id3_tag_options(file->primary, 0, 0);
+
+  /* render ID3v1 */
+
+  if (options & ID3_TAG_OPTION_ID3V1) {
+    v1size = id3_tag_render(file->primary, 0);
+    if (v1size) {
+      assert(v1size == sizeof(id3v1_data));
+
+      v1size = id3_tag_render(file->primary, id3v1_data);
+      if (v1size) {
+	assert(v1size == sizeof(id3v1_data));
+	id3v1 = id3v1_data;
+      }
+    }
+  }
+
+  /* render ID3v2 */
+
+  id3_tag_options(file->primary, ID3_TAG_OPTION_ID3V1, 0);
+
+  v2size = id3_tag_render(file->primary, 0);
+  if (v2size) {
+    id3v2 = malloc(v2size);
+    if (id3v2 == 0)
+      goto fail;
+
+    v2size = id3_tag_render(file->primary, id3v2);
+    if (v2size == 0) {
+      free(id3v2);
+      id3v2 = 0;
+    }
+  }
+
+  /* write tags */
+
+  if (v2_write(file, id3v2, v2size) == -1 ||
+      v1_write(file, id3v1, v1size) == -1)
+    goto fail;
+
+  rewind(file->iofile);
+
+  /* update file tags array? ... */
+
+  if (0) {
+  fail:
+    result = -1;
+  }
+
+  /* clean up; restore tag options */
+
+  if (id3v2)
+    free(id3v2);
+
+  id3_tag_options(file->primary, ~0, options);
+
+  return result;
+}