harfbuzz/src/hb-buffer-serialize.cc

/*
 * Copyright © 2012,2013  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Google Author(s): Behdad Esfahbod
 */

#include "hb-buffer.hh"


static const char *serialize_formats[] = {
  "text",
  "json",
  nullptr
};

/**
 * hb_buffer_serialize_list_formats:
 *
 * Returns a list of supported buffer serialization formats.
 *
 * Return value: (transfer none):
 * A string array of buffer serialization formats. Should not be freed.
 *
 * Since: 0.9.7
 **/
const char **
hb_buffer_serialize_list_formats (void)
{
  return serialize_formats;
}

/**
 * hb_buffer_serialize_format_from_string:
 * @str: (array length=len) (element-type uint8_t): a string to parse
 * @len: length of @str, or -1 if string is %NULL terminated
 *
 * Parses a string into an #hb_buffer_serialize_format_t. Does not check if
 * @str is a valid buffer serialization format, use
 * hb_buffer_serialize_list_formats() to get the list of supported formats.
 *
 * Return value:
 * The parsed #hb_buffer_serialize_format_t.
 *
 * Since: 0.9.7
 **/
hb_buffer_serialize_format_t
hb_buffer_serialize_format_from_string (const char *str, int len)
{
  /* Upper-case it. */
  return (hb_buffer_serialize_format_t) (hb_tag_from_string (str, len) & ~0x20202020u);
}

/**
 * hb_buffer_serialize_format_to_string:
 * @format: an #hb_buffer_serialize_format_t to convert.
 *
 * Converts @format to the string corresponding it, or %NULL if it is not a valid
 * #hb_buffer_serialize_format_t.
 *
 * Return value: (transfer none):
 * A %NULL terminated string corresponding to @format. Should not be freed.
 *
 * Since: 0.9.7
 **/
const char *
hb_buffer_serialize_format_to_string (hb_buffer_serialize_format_t format)
{
  switch (format)
  {
    case HB_BUFFER_SERIALIZE_FORMAT_TEXT:	return serialize_formats[0];
    case HB_BUFFER_SERIALIZE_FORMAT_JSON:	return serialize_formats[1];
    default:
    case HB_BUFFER_SERIALIZE_FORMAT_INVALID:	return nullptr;
  }
}

static unsigned int
_hb_buffer_serialize_glyphs_json (hb_buffer_t *buffer,
				  unsigned int start,
				  unsigned int end,
				  char *buf,
				  unsigned int buf_size,
				  unsigned int *buf_consumed,
				  hb_font_t *font,
				  hb_buffer_serialize_flags_t flags)
{
  hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
  hb_glyph_position_t *pos = (flags & HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS) ?
			     nullptr : hb_buffer_get_glyph_positions (buffer, nullptr);

  *buf_consumed = 0;
  hb_position_t x = 0, y = 0;
  for (unsigned int i = start; i < end; i++)
  {
    char b[1024];
    char *p = b;

    /* In the following code, we know b is large enough that no overflow can happen. */

#define APPEND(s) HB_STMT_START { strcpy (p, s); p += strlen (s); } HB_STMT_END

    if (i)
      *p++ = ',';

    *p++ = '{';

    APPEND ("\"g\":");
    if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES))
    {
      char g[128];
      hb_font_glyph_to_string (font, info[i].codepoint, g, sizeof (g));
      *p++ = '"';
      for (char *q = g; *q; q++) {
        if (*q == '"')
	  *p++ = '\\';
	*p++ = *q;
      }
      *p++ = '"';
    }
    else
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "%u", info[i].codepoint));

    if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS)) {
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",\"cl\":%u", info[i].cluster));
    }

    if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS))
    {
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",\"dx\":%d,\"dy\":%d",
			     x+pos[i].x_offset, y+pos[i].y_offset));
      if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES))
	p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",\"ax\":%d,\"ay\":%d",
			       pos[i].x_advance, pos[i].y_advance));
    }

    if (flags & HB_BUFFER_SERIALIZE_FLAG_GLYPH_FLAGS)
    {
      if (info[i].mask & HB_GLYPH_FLAG_DEFINED)
	p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",\"fl\":%u", info[i].mask & HB_GLYPH_FLAG_DEFINED));
    }

    if (flags & HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS)
    {
      hb_glyph_extents_t extents;
      hb_font_get_glyph_extents(font, info[i].codepoint, &extents);
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",\"xb\":%d,\"yb\":%d",
		extents.x_bearing, extents.y_bearing));
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",\"w\":%d,\"h\":%d",
		extents.width, extents.height));
    }

    *p++ = '}';

    unsigned int l = p - b;
    if (buf_size > l)
    {
      memcpy (buf, b, l);
      buf += l;
      buf_size -= l;
      *buf_consumed += l;
      *buf = '\0';
    } else
      return i - start;

    if (pos && (flags & HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES))
    {
      x += pos[i].x_advance;
      y += pos[i].y_advance;
    }
  }

  return end - start;
}

static unsigned int
_hb_buffer_serialize_glyphs_text (hb_buffer_t *buffer,
				  unsigned int start,
				  unsigned int end,
				  char *buf,
				  unsigned int buf_size,
				  unsigned int *buf_consumed,
				  hb_font_t *font,
				  hb_buffer_serialize_flags_t flags)
{
  hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
  hb_glyph_position_t *pos = (flags & HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS) ?
			     nullptr : hb_buffer_get_glyph_positions (buffer, nullptr);

  *buf_consumed = 0;
  hb_position_t x = 0, y = 0;
  for (unsigned int i = start; i < end; i++)
  {
    char b[1024];
    char *p = b;

    /* In the following code, we know b is large enough that no overflow can happen. */

    if (i)
      *p++ = '|';

    if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES))
    {
      hb_font_glyph_to_string (font, info[i].codepoint, p, 128);
      p += strlen (p);
    }
    else
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "%u", info[i].codepoint));

    if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS)) {
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "=%u", info[i].cluster));
    }

    if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS))
    {
      if (x+pos[i].x_offset || y+pos[i].y_offset)
	p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "@%d,%d", x+pos[i].x_offset, y+pos[i].y_offset));

      if (!(flags & HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES))
      {
	*p++ = '+';
	p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "%d", pos[i].x_advance));
	if (pos[i].y_advance)
	  p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), ",%d", pos[i].y_advance));
      }
    }

    if (flags & HB_BUFFER_SERIALIZE_FLAG_GLYPH_FLAGS)
    {
      if (info[i].mask &HB_GLYPH_FLAG_DEFINED)
	p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "#%X", info[i].mask &HB_GLYPH_FLAG_DEFINED));
    }

    if (flags & HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS)
    {
      hb_glyph_extents_t extents;
      hb_font_get_glyph_extents(font, info[i].codepoint, &extents);
      p += MAX (0, snprintf (p, ARRAY_LENGTH (b) - (p - b), "<%d,%d,%d,%d>", extents.x_bearing, extents.y_bearing, extents.width, extents.height));
    }

    unsigned int l = p - b;
    if (buf_size > l)
    {
      memcpy (buf, b, l);
      buf += l;
      buf_size -= l;
      *buf_consumed += l;
      *buf = '\0';
    } else
      return i - start;

    if (pos && (flags & HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES))
    {
      x += pos[i].x_advance;
      y += pos[i].y_advance;
    }
  }

  return end - start;
}

/**
 * hb_buffer_serialize_glyphs:
 * @buffer: an #hb_buffer_t buffer.
 * @start: the first item in @buffer to serialize.
 * @end: the last item in @buffer to serialize.
 * @buf: (out) (array length=buf_size) (element-type uint8_t): output string to
 *       write serialized buffer into.
 * @buf_size: the size of @buf.
 * @buf_consumed: (out) (allow-none): if not %NULL, will be set to the number of byes written into @buf.
 * @font: (allow-none): the #hb_font_t used to shape this buffer, needed to
 *        read glyph names and extents. If %NULL, and empty font will be used.
 * @format: the #hb_buffer_serialize_format_t to use for formatting the output.
 * @flags: the #hb_buffer_serialize_flags_t that control what glyph properties
 *         to serialize.
 *
 * Serializes @buffer into a textual representation of its glyph content,
 * useful for showing the contents of the buffer, for example during debugging.
 * There are currently two supported serialization formats:
 *
 * ## text
 * A human-readable, plain text format.
 * The serialized glyphs will look something like:
 *
 * ```
 * [uni0651=0@518,0+0|uni0628=0+1897]
 * ```
 * - The serialized glyphs are delimited with `[` and `]`.
 * - Glyphs are separated with `|`
 * - Each glyph starts with glyph name, or glyph index if
 *   #HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES flag is set. Then,
 *   - If #HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS is not set, `=` then #hb_glyph_info_t.cluster.
 *   - If #HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS is not set, the #hb_glyph_position_t in the format:
 *     - If both #hb_glyph_position_t.x_offset and #hb_glyph_position_t.y_offset are not 0, `@x_offset,y_offset`. Then,
 *     - `+x_advance`, then `,y_advance` if #hb_glyph_position_t.y_advance is not 0. Then,
 *   - If #HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS is set, the
 *     #hb_glyph_extents_t in the format
 *     `&lt;x_bearing,y_bearing,width,height&gt;`
 *
 * ## json
 * TODO.
 *
 * Return value:
 * The number of serialized items.
 *
 * Since: 0.9.7
 **/
unsigned int
hb_buffer_serialize_glyphs (hb_buffer_t *buffer,
			    unsigned int start,
			    unsigned int end,
			    char *buf,
			    unsigned int buf_size,
			    unsigned int *buf_consumed,
			    hb_font_t *font,
			    hb_buffer_serialize_format_t format,
			    hb_buffer_serialize_flags_t flags)
{
  assert (start <= end && end <= buffer->len);

  unsigned int sconsumed;
  if (!buf_consumed)
    buf_consumed = &sconsumed;
  *buf_consumed = 0;
  if (buf_size)
    *buf = '\0';

  assert ((!buffer->len && buffer->content_type == HB_BUFFER_CONTENT_TYPE_INVALID) ||
	  buffer->content_type == HB_BUFFER_CONTENT_TYPE_GLYPHS);

  if (!buffer->have_positions)
    flags |= HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS;

  if (unlikely (start == end))
    return 0;

  if (!font)
    font = hb_font_get_empty ();

  switch (format)
  {
    case HB_BUFFER_SERIALIZE_FORMAT_TEXT:
      return _hb_buffer_serialize_glyphs_text (buffer, start, end,
					       buf, buf_size, buf_consumed,
					       font, flags);

    case HB_BUFFER_SERIALIZE_FORMAT_JSON:
      return _hb_buffer_serialize_glyphs_json (buffer, start, end,
					       buf, buf_size, buf_consumed,
					       font, flags);

    default:
    case HB_BUFFER_SERIALIZE_FORMAT_INVALID:
      return 0;

  }
}


static hb_bool_t
parse_uint (const char *pp, const char *end, uint32_t *pv)
{
  char buf[32];
  unsigned int len = MIN (ARRAY_LENGTH (buf) - 1, (unsigned int) (end - pp));
  strncpy (buf, pp, len);
  buf[len] = '\0';

  char *p = buf;
  char *pend = p;
  uint32_t v;

  errno = 0;
  v = strtol (p, &pend, 10);
  if (errno || p == pend || pend - p != end - pp)
    return false;

  *pv = v;
  return true;
}

static hb_bool_t
parse_int (const char *pp, const char *end, int32_t *pv)
{
  char buf[32];
  unsigned int len = MIN (ARRAY_LENGTH (buf) - 1, (unsigned int) (end - pp));
  strncpy (buf, pp, len);
  buf[len] = '\0';

  char *p = buf;
  char *pend = p;
  int32_t v;

  errno = 0;
  v = strtol (p, &pend, 10);
  if (errno || p == pend || pend - p != end - pp)
    return false;

  *pv = v;
  return true;
}

#include "hb-buffer-deserialize-json.hh"
#include "hb-buffer-deserialize-text.hh"

/**
 * hb_buffer_deserialize_glyphs:
 * @buffer: an #hb_buffer_t buffer.
 * @buf: (array length=buf_len):
 * @buf_len:
 * @end_ptr: (out):
 * @font:
 * @format:
 *
 *
 *
 * Return value:
 *
 * Since: 0.9.7
 **/
hb_bool_t
hb_buffer_deserialize_glyphs (hb_buffer_t *buffer,
			      const char *buf,
			      int buf_len, /* -1 means nul-terminated */
			      const char **end_ptr, /* May be NULL */
			      hb_font_t *font, /* May be NULL */
			      hb_buffer_serialize_format_t format)
{
  const char *end;
  if (!end_ptr)
    end_ptr = &end;
  *end_ptr = buf;

  assert ((!buffer->len && buffer->content_type == HB_BUFFER_CONTENT_TYPE_INVALID) ||
	  buffer->content_type == HB_BUFFER_CONTENT_TYPE_GLYPHS);

  if (buf_len == -1)
    buf_len = strlen (buf);

  if (!buf_len)
  {
    *end_ptr = buf;
    return false;
  }

  hb_buffer_set_content_type (buffer, HB_BUFFER_CONTENT_TYPE_GLYPHS);

  if (!font)
    font = hb_font_get_empty ();

  switch (format)
  {
    case HB_BUFFER_SERIALIZE_FORMAT_TEXT:
      return _hb_buffer_deserialize_glyphs_text (buffer,
						 buf, buf_len, end_ptr,
						 font);

    case HB_BUFFER_SERIALIZE_FORMAT_JSON:
      return _hb_buffer_deserialize_glyphs_json (buffer,
						 buf, buf_len, end_ptr,
						 font);

    default:
    case HB_BUFFER_SERIALIZE_FORMAT_INVALID:
      return false;

  }
}