212 lines
5.7 KiB
C
212 lines
5.7 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright (C) 2014 David Herrmann <dh.herrmann@gmail.com>
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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/*
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* Unifont
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* This implements the unifont glyph-array parser and provides it via a simple
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* API to the caller. No heavy transformations are performed so glyph-lookups
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* stay as fast as possible.
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*/
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#include <endian.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "macro.h"
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#include "unifont-def.h"
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#include "unifont-internal.h"
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#include "util.h"
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struct unifont {
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unsigned long ref;
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int fd;
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const uint8_t *map;
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size_t size;
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unifont_header header;
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const void *glyphs; /* unaligned! */
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size_t n_glyphs;
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size_t glyphsize;
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};
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static int unifont_fetch_header(unifont *u) {
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unifont_header h = { };
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uint64_t glyphsize;
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if (u->size < UNIFONT_HEADER_SIZE_MIN)
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return -EBFONT;
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assert_cc(sizeof(h) >= UNIFONT_HEADER_SIZE_MIN);
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memcpy(&h, u->map, UNIFONT_HEADER_SIZE_MIN);
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h.compatible_flags = le32toh(h.compatible_flags);
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h.incompatible_flags = le32toh(h.incompatible_flags);
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h.header_size = le32toh(h.header_size);
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h.glyph_header_size = le16toh(h.glyph_header_size);
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h.glyph_stride = le16toh(h.glyph_stride);
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h.glyph_body_size = le64toh(h.glyph_body_size);
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if (memcmp(h.signature, "DVDHRMUF", 8))
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return -EBFONT;
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if (h.incompatible_flags != 0)
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return -EBFONT;
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if (h.header_size < UNIFONT_HEADER_SIZE_MIN || h.header_size > u->size)
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return -EBFONT;
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if (h.glyph_header_size + h.glyph_body_size < h.glyph_header_size)
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return -EBFONT;
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if (h.glyph_stride * 16ULL > h.glyph_body_size)
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return -EBFONT;
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glyphsize = h.glyph_header_size + h.glyph_body_size;
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if (glyphsize == 0 || glyphsize > u->size - h.header_size) {
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u->n_glyphs = 0;
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} else {
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u->glyphs = u->map + h.header_size;
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u->n_glyphs = (u->size - h.header_size) / glyphsize;
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u->glyphsize = glyphsize;
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}
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memcpy(&u->header, &h, sizeof(h));
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return 0;
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}
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static int unifont_fetch_glyph(unifont *u, unifont_glyph_header *out_header, const void **out_body, uint32_t ucs4) {
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unifont_glyph_header glyph_header = { };
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const void *glyph_body = NULL;
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const uint8_t *p;
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if (ucs4 >= u->n_glyphs)
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return -ENOENT;
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p = u->glyphs;
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/* copy glyph-header data */
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p += ucs4 * u->glyphsize;
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memcpy(&glyph_header, p, MIN(sizeof(glyph_header), u->header.glyph_header_size));
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/* copy glyph-body pointer */
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p += u->header.glyph_header_size;
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glyph_body = p;
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if (glyph_header.width < 1)
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return -ENOENT;
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if (glyph_header.width > u->header.glyph_stride)
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return -EBFONT;
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memcpy(out_header, &glyph_header, sizeof(glyph_header));
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*out_body = glyph_body;
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return 0;
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}
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int unifont_new(unifont **out) {
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_cleanup_(unifont_unrefp) unifont *u = NULL;
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struct stat st;
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int r;
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assert_return(out, -EINVAL);
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u = new0(unifont, 1);
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if (!u)
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return -ENOMEM;
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u->ref = 1;
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u->fd = -1;
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u->map = MAP_FAILED;
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u->fd = open(UNIFONT_PATH, O_RDONLY | O_CLOEXEC | O_NOCTTY);
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if (u->fd < 0)
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return -errno;
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r = fstat(u->fd, &st);
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if (r < 0)
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return -errno;
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u->size = st.st_size;
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u->map = mmap(NULL, u->size, PROT_READ, MAP_PRIVATE, u->fd, 0);
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if (u->map == MAP_FAILED)
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return -errno;
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r = unifont_fetch_header(u);
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if (r < 0)
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return r;
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*out = u;
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u = NULL;
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return 0;
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}
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unifont *unifont_ref(unifont *u) {
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if (!u || !u->ref)
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return NULL;
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++u->ref;
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return u;
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}
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unifont *unifont_unref(unifont *u) {
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if (!u || !u->ref || --u->ref)
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return NULL;
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if (u->map != MAP_FAILED)
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munmap((void*)u->map, u->size);
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u->fd = safe_close(u->fd);
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free(u);
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return NULL;
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}
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unsigned int unifont_get_stride(unifont *u) {
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assert(u);
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return u->header.glyph_stride;
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}
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int unifont_lookup(unifont *u, unifont_glyph *out, uint32_t ucs4) {
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unifont_glyph_header h = { };
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const void *b = NULL;
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unifont_glyph g = { };
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int r;
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assert_return(u, -EINVAL);
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r = unifont_fetch_glyph(u, &h, &b, ucs4);
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if (r < 0)
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return r;
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g.width = h.width * 8U;
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g.height = 16U;
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g.stride = u->header.glyph_stride;
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g.cwidth = h.width;
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g.data = b;
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if (out)
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memcpy(out, &g, sizeof(g));
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return 0;
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}
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