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+/*
+ * Copyright © 2009 Red Hat, Inc.
+ * Copyright © 2012 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.
+ *
+ * Red Hat Author(s): Behdad Esfahbod
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include "hb-private.hh"
+
+#include "hb-shaper-private.hh"
+#include "hb-shape-plan-private.hh"
+#include "hb-buffer-private.hh"
+#include "hb-font-private.hh"
+
+/**
+ * SECTION:hb-shape
+ * @title: Shaping
+ * @short_description: Conversion of text strings into positioned glyphs
+ * @include: hb.h
+ *
+ * Shaping is the central operation of HarfBuzz. Shaping operates on buffers,
+ * which are sequences of Unicode characters that use the same font and have
+ * the same text direction, script and language. After shaping the buffer
+ * contains the output glyphs and their positions.
+ **/
+
+static bool
+parse_space (const char **pp, const char *end)
+{
+ while (*pp < end && ISSPACE (**pp))
+ (*pp)++;
+ return true;
+}
+
+static bool
+parse_char (const char **pp, const char *end, char c)
+{
+ parse_space (pp, end);
+
+ if (*pp == end || **pp != c)
+ return false;
+
+ (*pp)++;
+ return true;
+}
+
+static bool
+parse_uint (const char **pp, const char *end, unsigned int *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;
+ unsigned int v;
+
+ /* Intentionally use strtol instead of strtoul, such that
+ * -1 turns into "big number"... */
+ errno = 0;
+ v = strtol (p, &pend, 0);
+ if (errno || p == pend)
+ return false;
+
+ *pv = v;
+ *pp += pend - p;
+ return true;
+}
+
+static bool
+parse_bool (const char **pp, const char *end, unsigned int *pv)
+{
+ parse_space (pp, end);
+
+ const char *p = *pp;
+ while (*pp < end && ISALPHA(**pp))
+ (*pp)++;
+
+ /* CSS allows on/off as aliases 1/0. */
+ if (*pp - p == 2 || 0 == strncmp (p, "on", 2))
+ *pv = 1;
+ else if (*pp - p == 3 || 0 == strncmp (p, "off", 2))
+ *pv = 0;
+ else
+ return false;
+
+ return true;
+}
+
+static bool
+parse_feature_value_prefix (const char **pp, const char *end, hb_feature_t *feature)
+{
+ if (parse_char (pp, end, '-'))
+ feature->value = 0;
+ else {
+ parse_char (pp, end, '+');
+ feature->value = 1;
+ }
+
+ return true;
+}
+
+static bool
+parse_feature_tag (const char **pp, const char *end, hb_feature_t *feature)
+{
+ parse_space (pp, end);
+
+ char quote = 0;
+
+ if (*pp < end && (**pp == '\'' || **pp == '"'))
+ {
+ quote = **pp;
+ (*pp)++;
+ }
+
+ const char *p = *pp;
+ while (*pp < end && ISALNUM(**pp))
+ (*pp)++;
+
+ if (p == *pp || *pp - p > 4)
+ return false;
+
+ feature->tag = hb_tag_from_string (p, *pp - p);
+
+ if (quote)
+ {
+ /* CSS expects exactly four bytes. And we only allow quotations for
+ * CSS compatibility. So, enforce the length. */
+ if (*pp - p != 4)
+ return false;
+ if (*pp == end || **pp != quote)
+ return false;
+ (*pp)++;
+ }
+
+ return true;
+}
+
+static bool
+parse_feature_indices (const char **pp, const char *end, hb_feature_t *feature)
+{
+ parse_space (pp, end);
+
+ bool has_start;
+
+ feature->start = 0;
+ feature->end = (unsigned int) -1;
+
+ if (!parse_char (pp, end, '['))
+ return true;
+
+ has_start = parse_uint (pp, end, &feature->start);
+
+ if (parse_char (pp, end, ':')) {
+ parse_uint (pp, end, &feature->end);
+ } else {
+ if (has_start)
+ feature->end = feature->start + 1;
+ }
+
+ return parse_char (pp, end, ']');
+}
+
+static bool
+parse_feature_value_postfix (const char **pp, const char *end, hb_feature_t *feature)
+{
+ bool had_equal = parse_char (pp, end, '=');
+ bool had_value = parse_uint (pp, end, &feature->value) ||
+ parse_bool (pp, end, &feature->value);
+ /* CSS doesn't use equal-sign between tag and value.
+ * If there was an equal-sign, then there *must* be a value.
+ * A value without an eqaul-sign is ok, but not required. */
+ return !had_equal || had_value;
+}
+
+
+static bool
+parse_one_feature (const char **pp, const char *end, hb_feature_t *feature)
+{
+ return parse_feature_value_prefix (pp, end, feature) &&
+ parse_feature_tag (pp, end, feature) &&
+ parse_feature_indices (pp, end, feature) &&
+ parse_feature_value_postfix (pp, end, feature) &&
+ parse_space (pp, end) &&
+ *pp == end;
+}
+
+/**
+ * hb_feature_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
+ * @feature: (out): the #hb_feature_t to initialize with the parsed values
+ *
+ * Parses a string into a #hb_feature_t.
+ *
+ * TODO: document the syntax here.
+ *
+ * Return value:
+ * %true if @str is successfully parsed, %false otherwise.
+ *
+ * Since: 0.9.5
+ **/
+hb_bool_t
+hb_feature_from_string (const char *str, int len,
+ hb_feature_t *feature)
+{
+ hb_feature_t feat;
+
+ if (len < 0)
+ len = strlen (str);
+
+ if (likely (parse_one_feature (&str, str + len, &feat)))
+ {
+ if (feature)
+ *feature = feat;
+ return true;
+ }
+
+ if (feature)
+ memset (feature, 0, sizeof (*feature));
+ return false;
+}
+
+/**
+ * hb_feature_to_string:
+ * @feature: an #hb_feature_t to convert
+ * @buf: (array length=size) (out): output string
+ * @size: the allocated size of @buf
+ *
+ * Converts a #hb_feature_t into a %NULL-terminated string in the format
+ * understood by hb_feature_from_string(). The client in responsible for
+ * allocating big enough size for @buf, 128 bytes is more than enough.
+ *
+ * Since: 0.9.5
+ **/
+void
+hb_feature_to_string (hb_feature_t *feature,
+ char *buf, unsigned int size)
+{
+ if (unlikely (!size)) return;
+
+ char s[128];
+ unsigned int len = 0;
+ if (feature->value == 0)
+ s[len++] = '-';
+ hb_tag_to_string (feature->tag, s + len);
+ len += 4;
+ while (len && s[len - 1] == ' ')
+ len--;
+ if (feature->start != 0 || feature->end != (unsigned int) -1)
+ {
+ s[len++] = '[';
+ if (feature->start)
+ len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%u", feature->start));
+ if (feature->end != feature->start + 1) {
+ s[len++] = ':';
+ if (feature->end != (unsigned int) -1)
+ len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%u", feature->end));
+ }
+ s[len++] = ']';
+ }
+ if (feature->value > 1)
+ {
+ s[len++] = '=';
+ len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%u", feature->value));
+ }
+ assert (len < ARRAY_LENGTH (s));
+ len = MIN (len, size - 1);
+ memcpy (buf, s, len);
+ buf[len] = '\0';
+}
+
+
+static const char **static_shaper_list;
+
+#ifdef HB_USE_ATEXIT
+static
+void free_static_shaper_list (void)
+{
+ free (static_shaper_list);
+}
+#endif
+
+/**
+ * hb_shape_list_shapers:
+ *
+ * Retrieves the list of shapers supported by HarfBuzz.
+ *
+ * Return value: (transfer none) (array zero-terminated=1): an array of
+ * constant strings
+ *
+ * Since: 0.9.2
+ **/
+const char **
+hb_shape_list_shapers (void)
+{
+retry:
+ const char **shaper_list = (const char **) hb_atomic_ptr_get (&static_shaper_list);
+
+ if (unlikely (!shaper_list))
+ {
+ /* Not found; allocate one. */
+ shaper_list = (const char **) calloc (1 + HB_SHAPERS_COUNT, sizeof (const char *));
+ if (unlikely (!shaper_list)) {
+ static const char *nil_shaper_list[] = {NULL};
+ return nil_shaper_list;
+ }
+
+ const hb_shaper_pair_t *shapers = _hb_shapers_get ();
+ unsigned int i;
+ for (i = 0; i < HB_SHAPERS_COUNT; i++)
+ shaper_list[i] = shapers[i].name;
+ shaper_list[i] = NULL;
+
+ if (!hb_atomic_ptr_cmpexch (&static_shaper_list, NULL, shaper_list)) {
+ free (shaper_list);
+ goto retry;
+ }
+
+#ifdef HB_USE_ATEXIT
+ atexit (free_static_shaper_list); /* First person registers atexit() callback. */
+#endif
+ }
+
+ return shaper_list;
+}
+
+
+/**
+ * hb_shape_full:
+ * @font: an #hb_font_t to use for shaping
+ * @buffer: an #hb_buffer_t to shape
+ * @features: (array length=num_features) (allow-none): an array of user
+ * specified #hb_feature_t or %NULL
+ * @num_features: the length of @features array
+ * @shaper_list: (array zero-terminated=1) (allow-none): a %NULL-terminated
+ * array of shapers to use or %NULL
+ *
+ * See hb_shape() for details. If @shaper_list is not %NULL, the specified
+ * shapers will be used in the given order, otherwise the default shapers list
+ * will be used.
+ *
+ * Return value: %FALSE if all shapers failed, %TRUE otherwise
+ *
+ * Since: 0.9.2
+ **/
+hb_bool_t
+hb_shape_full (hb_font_t *font,
+ hb_buffer_t *buffer,
+ const hb_feature_t *features,
+ unsigned int num_features,
+ const char * const *shaper_list)
+{
+ hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached2 (font->face, &buffer->props,
+ features, num_features,
+ font->coords, font->num_coords,
+ shaper_list);
+ hb_bool_t res = hb_shape_plan_execute (shape_plan, font, buffer, features, num_features);
+ hb_shape_plan_destroy (shape_plan);
+
+ if (res)
+ buffer->content_type = HB_BUFFER_CONTENT_TYPE_GLYPHS;
+ return res;
+}
+
+/**
+ * hb_shape:
+ * @font: an #hb_font_t to use for shaping
+ * @buffer: an #hb_buffer_t to shape
+ * @features: (array length=num_features) (allow-none): an array of user
+ * specified #hb_feature_t or %NULL
+ * @num_features: the length of @features array
+ *
+ * Shapes @buffer using @font turning its Unicode characters content to
+ * positioned glyphs. If @features is not %NULL, it will be used to control the
+ * features applied during shaping.
+ *
+ * Since: 0.9.2
+ **/
+void
+hb_shape (hb_font_t *font,
+ hb_buffer_t *buffer,
+ const hb_feature_t *features,
+ unsigned int num_features)
+{
+ hb_shape_full (font, buffer, features, num_features, NULL);
+}
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