Initial revision

svn path=/trunk/; revision=1768

1 files changed, 383 insertions, 0 deletions

diff --git a/libibex/file.c b/libibex/file.c
new file mode 100644
index 0000000000..e9eaab7f51
--- /dev/null
+++ b/libibex/file.c
@@ -0,0 +1,383 @@
+/*
+	Copyright 2000 Helix Code Inc.
+*/
+
+/* file.c: index file read/write ops */
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "ibex_internal.h"
+
+static unsigned long read_number(FILE *f);
+static void write_number(FILE *f, unsigned long n);
+static char *get_compressed_word(FILE *f, char **lastword);
+
+static gint free_file(gpointer key, gpointer value, gpointer data);
+static void free_word(gpointer key, gpointer value, gpointer data);
+
+/* The file format is:
+ *
+ * version string (currently "ibex1")
+ * file count
+ * list of compressed filenames, separated by \0
+ * word count
+ * list of compressed words, each followed by \0, a count, and that
+ *   many references.
+ *
+ * All numbers are stored 7-bit big-endian, with the high bit telling
+ * whether or not the number continues to the next byte.
+ *
+ * compressed text consists of a byte telling how many characters the
+ * line has in common with the line before it, followed by the rest of
+ * the string. Obviously this only really works if the lists are sorted.
+ */
+ibex *
+ibex_open(char *file, gboolean create)
+{
+  ibex *ib;
+  FILE *f;
+  char vbuf[sizeof(IBEX_VERSION) - 1];
+  char *word, *lastword;
+  unsigned long nfiles, nwords, nrefs, ref;
+  ibex_file **ibfs = NULL;
+  int i;
+  GPtrArray *refs;
+
+  f = fopen(file, "r");
+  if (!f && (errno != ENOENT || !create))
+    {
+      if (errno == 0)
+	errno = ENOMEM;
+      return NULL;
+    }
+
+  ib = g_malloc(sizeof(ibex));
+  ib->dirty = FALSE;
+  ib->path = g_strdup(file);
+  ib->files = g_tree_new(strcmp);
+  ib->words = g_hash_table_new(g_str_hash, g_str_equal);
+  ib->oldfiles = g_ptr_array_new();
+
+  if (!f)
+    return ib;
+
+  /* Check version. */
+  if (fread(vbuf, 1, sizeof(vbuf), f) != sizeof(vbuf))
+    {
+      if (feof(f))
+	errno = EINVAL;
+      goto errout;
+    }
+  if (strncmp(vbuf, IBEX_VERSION, sizeof(vbuf) != 0))
+    {
+      errno = EINVAL;
+      goto errout;
+    }
+
+  /* Read list of files. */
+  nfiles = read_number(f);
+  ibfs = g_malloc(nfiles * sizeof(ibex_file *));
+  lastword = NULL;
+  for (i = 0; i < nfiles; i++)
+    {
+      ibfs[i] = g_malloc(sizeof(ibex_file));
+      ibfs[i]->name = get_compressed_word(f, &lastword);
+      if (!ibfs[i]->name)
+	goto errout;
+      ibfs[i]->index = 0;
+      g_tree_insert(ib->files, ibfs[i]->name, ibfs[i]);
+    }
+
+  /* Read list of words. */
+  nwords = read_number(f);
+  lastword = NULL;
+  for (i = 0; i < nwords; i++)
+    {
+      word = get_compressed_word(f, &lastword);
+      if (!word)
+	goto errout;
+
+      nrefs = read_number(f);
+      refs = g_ptr_array_new();
+      g_ptr_array_set_size(refs, nrefs);
+      while (nrefs--)
+	{
+	  ref = read_number(f);
+	  if (ref >= nfiles)
+	    goto errout;
+	  refs->pdata[nrefs] = ibfs[ref];
+	}
+
+      g_hash_table_insert(ib->words, word, refs);
+    }
+
+  g_free(ibfs);
+  fclose(f);
+  return ib;
+
+errout:
+  fclose(f);
+  g_tree_traverse(ib->files, free_file, G_IN_ORDER, NULL);
+  g_tree_destroy(ib->files);
+  g_hash_table_foreach(ib->words, free_word, NULL);
+  g_hash_table_destroy(ib->words);
+  g_ptr_array_free(ib->oldfiles, TRUE);
+  if (ibfs)
+    g_free(ibfs);
+  g_free(ib->path);
+  g_free(ib);
+
+  return NULL;
+}
+
+struct ibex_write_data {
+  unsigned long index;
+  FILE *f;
+  char *lastname;
+};
+
+static int
+get_prefix(struct ibex_write_data *iwd, char *name)
+{
+  int i = 0;
+  if (iwd->lastname)
+    {
+      while (!strncmp(iwd->lastname, name, i + 1))
+	i++;
+    }
+  iwd->lastname = name;
+  return i;
+}
+
+static gint
+write_file(gpointer key, gpointer value, gpointer data)
+{
+  char *file = key;
+  ibex_file *ibf = value;
+  struct ibex_write_data *iwd = data;
+  int prefix;
+
+  ibf->index = iwd->index++;
+  prefix = get_prefix(iwd, file);
+  fprintf(iwd->f, "%c%s", prefix, file + prefix);
+  fputc(0, iwd->f);
+  return FALSE;
+}
+
+static void
+store_word(gpointer key, gpointer value, gpointer data)
+{
+  GTree *wtree = data;
+
+  g_tree_insert(wtree, key, value);
+}
+
+static gint
+write_word(gpointer key, gpointer value, gpointer data)
+{
+  char *word = key;
+  GPtrArray *refs = value;
+  struct ibex_write_data *iwd = data;
+  ibex_file *ibf;
+  int i, ind, prefix;
+
+  for (i = ind = 0; i < refs->len; i++)
+    {
+      ibf = g_ptr_array_index(refs, i);
+      if (ibf->index == -1)
+	{
+	  g_ptr_array_remove_index_fast(refs, i);
+	  i--;
+	}
+      else
+	ind++;
+    }
+
+  if (ind != 0)
+    {
+      prefix = get_prefix(iwd, word);
+      fprintf(iwd->f, "%c%s", prefix, word + prefix);
+      fputc(0, iwd->f);
+
+      write_number(iwd->f, ind);
+
+      for (i = 0; i < refs->len; i++)
+	{
+	  ibf = g_ptr_array_index(refs, i);
+	  write_number(iwd->f, ibf->index);
+	}
+    }
+  return FALSE;
+}      
+
+int
+ibex_write(ibex *ib)
+{
+  struct ibex_write_data iwd;
+  GTree *wtree;
+  char *tmpfile;
+
+  tmpfile = g_strdup_printf("%s~", ib->path);
+  iwd.f = fopen(tmpfile, "w");
+  if (!iwd.f)
+    {
+      if (errno == 0)
+	errno = ENOMEM;
+      g_free(tmpfile);
+      return -1;
+    }
+
+  fputs(IBEX_VERSION, iwd.f);
+  if (ferror(iwd.f))
+    goto lose;
+
+  iwd.index = 0;
+  iwd.lastname = NULL;
+  write_number(iwd.f, g_tree_nnodes(ib->files));
+  if (ferror(iwd.f))
+    goto lose;
+  g_tree_traverse(ib->files, write_file, G_IN_ORDER, &iwd);
+  if (ferror(iwd.f))
+    goto lose;
+
+  iwd.lastname = NULL;
+  write_number(iwd.f, g_hash_table_size(ib->words));
+  if (ferror(iwd.f))
+    goto lose;
+  wtree = g_tree_new(strcmp);
+  g_hash_table_foreach(ib->words, store_word, wtree);
+  g_tree_traverse(wtree, write_word, G_IN_ORDER, &iwd);
+  g_tree_destroy(wtree);
+  if (ferror(iwd.f))
+    goto lose;
+
+  if (fclose(iwd.f) == 0 && rename(tmpfile, ib->path) == 0)
+    {
+      g_free(tmpfile);
+      ib->dirty = FALSE;
+      return 0;
+    }
+
+lose:
+  unlink(tmpfile);
+  g_free(tmpfile);
+  return -1;
+}
+
+int
+ibex_close(ibex *ib)
+{
+  ibex_file *ibf;
+
+  if (ib->dirty && ibex_write(ib) == -1)
+    return -1;
+
+  g_tree_traverse(ib->files, free_file, G_IN_ORDER, NULL);
+  g_tree_destroy(ib->files);
+  g_hash_table_foreach(ib->words, free_word, NULL);
+  g_hash_table_destroy(ib->words);
+
+  while (ib->oldfiles->len)
+    {
+      ibf = g_ptr_array_remove_index(ib->oldfiles, 0);
+      g_free(ibf->name);
+      g_free(ibf);
+    }
+  g_ptr_array_free(ib->oldfiles, TRUE);
+  g_free(ib->path);
+  g_free(ib);
+
+  return 0;
+}
+
+static gint
+free_file(gpointer key, gpointer value, gpointer data)
+{
+  ibex_file *ibf = value;
+
+  g_free(ibf->name);
+  g_free(ibf);
+  return FALSE;
+}
+
+static void
+free_word(gpointer key, gpointer value, gpointer data)
+{
+  g_free(key);
+  g_ptr_array_free(value, TRUE);
+}
+
+static char *
+get_compressed_word(FILE *f, char **lastword)
+{
+  char *buf, *p;
+  int c, size;
+
+  c = getc(f);
+  if (c == EOF)
+    return NULL;
+
+  size = c + 10;
+  buf = g_malloc(size);
+  if (*lastword)
+    strncpy(buf, *lastword, c);
+  p = buf + c;
+  do
+    {
+      c = getc(f);
+      if (c == EOF)
+	return NULL;
+      if (p == buf + size)
+	{
+	  buf = g_realloc(buf, size + 10);
+	  p = buf + size;
+	  size += 10;
+	}
+      *p++ = c;
+    }
+  while (c != 0);
+
+  *lastword = buf;
+  return buf;
+}
+
+static void
+write_number(FILE *f, unsigned long number)
+{
+  int i, flag = 0;
+  char buf[4];
+
+  i = 4;
+  do
+    {
+      buf[--i] = (number & 0x7F) | flag;
+      number = number >> 7;
+      flag = 0x80;
+    }
+  while (number != 0);
+
+  fwrite(buf + i, 1, 4 - i, f);
+}
+
+static unsigned long
+read_number(FILE *f)
+{
+  int byte;
+  unsigned long num;
+
+  num = 0;
+  do
+    {
+      byte = getc(f);
+      num = num << 7 | (byte & 0x7F);
+    }
+  while (byte & 0x80);
+  
+  return num;
+}
+