Start to sketch APIs for subsetting

src/Makefile.am

@@ -27,7 +27,9 @@ HBNONPCLIBS =
 HBDEPS =
 HBSOURCES =  $(HB_BASE_sources)
 HBSOURCES += $(HB_BASE_RAGEL_GENERATED_sources)
+HBSOURCES += $(HB_SUBSET_sources)
 HBHEADERS = $(HB_BASE_headers)
+HBHEADERS += $(HB_SUBSET_headers)
 HBNODISTHEADERS = $(HB_NODIST_headers)
 
 if HAVE_OT

src/Makefile.sources

@@ -181,6 +181,10 @@ HB_UCDN_sources  = hb-ucdn.cc
 HB_ICU_sources = hb-icu.cc
 HB_ICU_headers = hb-icu.h
 
+# Sources for libharfbuzz-subset
+HB_SUBSET_sources = hb-subset.cc
+HB_SUBSET_headers = hb-subset.h
+
 HB_GOBJECT_sources = hb-gobject-structs.cc
 HB_GOBJECT_STRUCTS_headers = hb-gobject-structs.h
 HB_GOBJECT_headers = hb-gobject.h $(HB_GOBJECT_STRUCTS_headers)

src/hb-subset.h

@@ -0,0 +1,88 @@
+/*
+ * Copyright © 2018  Google
+ *
+ *  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): Rod Sheeter
+ */
+
+#ifndef HB_H_IN
+#error "Include <hb.h> instead."
+#endif
+
+#ifndef HB_SUBSET_H
+#define HB_SUBSET_H
+
+#include "hb-common.h"
+#include "hb-face.h"
+
+HB_BEGIN_DECLS
+
+/*
+ * hb_subset_profile_t
+ * Things that change based on target environment, e.g. OS
+ */
+
+typedef struct hb_subset_profile_t hb_subset_profile_t;
+
+HB_EXTERN hb_subset_profile_t *
+hb_subset_profile_create();
+
+HB_EXTERN void
+hb_subset_profile_destroy(hb_subset_profile_t *profile);
+
+/*
+ * hb_subset_input_t
+ * Things that change based on the input. Characters to keep, etc.
+ */
+
+typedef struct hb_subset_input_t hb_subset_input_t;
+
+HB_EXTERN hb_subset_input_t *
+hb_subset_input_create();
+
+HB_EXTERN void
+hb_subset_input_destroy(hb_subset_input_t *subset_input);
+
+/*
+ * hb_subset_face_t
+ * Reusable subset-ready plan for a given face. Threadsafe for multiple
+ * concurrent subset operations.
+ */
+
+typedef struct hb_subset_face_t hb_subset_face_t;
+
+HB_EXTERN hb_subset_face_t *
+hb_subset_face_create(hb_face_t *face);
+
+HB_EXTERN void
+hb_subset_face_destroy(hb_subset_face_t *face);
+
+
+HB_EXTERN hb_bool_t
+hb_subset(hb_subset_profile_t *profile,
+          hb_subset_input_t *input,
+          hb_subset_face_t *face
+          hb_blob_t *result /* OUT */);
+
+HB_END_DECLS
+
+#endif /* HB_SUBSET_H */

util/Makefile.am

@@ -46,6 +46,9 @@ endif # HAVE_FREETYPE
 hb_shape_SOURCES = $(HB_SHAPE_sources)
 bin_PROGRAMS += hb-shape
 
+hb_subset_SOURCES = $(HB_SUBSET_sources)
+bin_PROGRAMS += hb-subset
+
 if HAVE_OT
 hb_ot_shape_closure_SOURCES = $(HB_OT_SHAPE_CLOSURE_sources)
 bin_PROGRAMS += hb-ot-shape-closure

util/Makefile.sources

@@ -28,3 +28,7 @@ HB_OT_SHAPE_CLOSURE_sources = \
 	options.hh \
 	main-font-text.hh \
 	$(NULL)
+
+HB_SUBSET_sources = \
+	hb-subset.cc \
+	$(NULL)

util/hb-subset.cc

@@ -0,0 +1,61 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "hb-private.hh"
+#include "hb-blob.h"
+
+int
+main (int argc, char **argv)
+{
+  int exit_code = 0;
+  int fd = open("/tmp/Lobster-Regular.ttf", O_RDONLY);
+  if (fd == -1) {
+    perror("Unable to open file");
+    exit(1);
+  }
+
+  void *mapped_file = MAP_FAILED;
+  char *raw_font = nullptr;
+
+  struct stat stat;
+  if (fstat(fd, &stat) != -1) {
+    printf("File is %zu bytes\n", stat.st_size);
+
+    void *mapped_file = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (mapped_file != MAP_FAILED) {
+      raw_font = static_cast<char*>(mapped_file);
+    } else {
+      perror("Failed to map file");
+    }
+  } else {
+    perror("Unable to fstat");
+  }
+
+  if (raw_font) {
+      printf("Mapped file\n");      
+      for (int i = 0; i < 4; i++) {
+        printf("%02x", *(raw_font + i));
+      }
+      printf("\n");
+
+      hb_blob_t *font_blob = hb_blob_create(raw_font, stat.st_size, HB_MEMORY_MODE_READONLY, nullptr, nullptr);
+  }
+
+  if (mapped_file != MAP_FAILED) {
+    if (munmap(mapped_file, stat.st_size) == -1) {
+      perror("Unable to unmap file");
+      exit_code = 1;
+    }
+  }
+
+  if (close(fd) == -1) {
+    perror("Unable to close file");
+    exit_code = 1;
+  }
+  return exit_code;
+}