1 files changed, 124 insertions, 0 deletions
diff --git a/libfonts_create_transcoding_table.c b/libfonts_create_transcoding_table.c
new file mode 100644
index 0000000..ee75bf4
--- /dev/null
+++ b/libfonts_create_transcoding_table.c
@@ -0,0 +1,124 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+static int
+set_range(uint32_t low, uint32_t high, uint32_t target, uint32_t target_inc, struct libfonts_transcoding_table *table)
+{
+	uint32_t i;
+
+	if (low < table->first_valid) {
+		if (target != LIBFONTS_UNDEFINED_CHAR)
+			return -1;
+		low = table->first_valid;
+	}
+
+	if (high > table->last_valid) {
+		if (target != LIBFONTS_UNDEFINED_CHAR)
+			return -1;
+		high = table->last_valid;
+	}
+
+	i = low;
+	do {
+		LIBFONTS_LOOKUP_TRANSCODING_TABLE(table, i) = target;
+		target += target_inc;
+	} while (i++ < high);
+
+	return 0;
+}
+
+struct libfonts_transcoding_table *
+libfonts_create_transcoding_table(const struct libfonts_encoding *encoding, size_t mapping)
+{
+	const struct libfonts_encoding_mapping *map;
+	size_t size, entry;
+	uint16_t size_rows, size_cols;
+	uint8_t first_row, first_col;
+	struct libfonts_transcoding_table *ret;
+	uint32_t i;
+	int r;
+
+	if (!encoding ||
+	    mapping > encoding->nmappings ||
+	    !encoding->mappings ||
+	    (encoding->mappings[mapping].nentries && !encoding->mappings[mapping].entries) ||
+	    !encoding->size_rows)
+		goto einvalid;
+
+	map = &encoding->mappings[mapping];
+	size_rows = encoding->size_rows;
+	size_cols = encoding->size_cols;
+	first_row = encoding->first_index_row;
+	first_col = encoding->first_index_col;
+
+#if SIZE_MAX <= UINT32_MAX
+	if ((size_t)size_rows - (size_t)first_row > SIZE_MAX / (size_cols ? (size_t)size_cols : 1))
+		goto enomem;
+#endif
+	size = ((size_t)size_rows - (size_t)first_row) * (size_cols ? (size_t)size_cols : 1);
+	if (size > (SIZE_MAX - offsetof(struct libfonts_transcoding_table, table)) / sizeof(uint32_t))
+		goto enomem;
+	ret = malloc(size * sizeof(uint32_t) + offsetof(struct libfonts_transcoding_table, table));
+	if (!ret)
+		goto enomem;
+
+	ret->first_valid = (uint32_t)first_row;
+	ret->last_valid = (uint32_t)size_rows - 1;
+	if (size_cols) {
+		ret->first_valid <<= 8;
+		ret->first_valid |= (uint32_t)first_col;
+		ret->last_valid <<= 8;
+		ret->last_valid |= (uint32_t)size_cols - 1;
+	}
+
+	ret->offset = encoding->size_cols ? (uint32_t)first_row << 8 : (uint32_t)first_col;
+	ret->multiplier = (uint32_t)size_cols;
+
+	for (i = ret->first_valid; i <= ret->last_valid; i++)
+		LIBFONTS_LOOKUP_TRANSCODING_TABLE(ret, i) = i;
+
+	for (entry = 0; entry < map->nentries; entry++) {
+		if (map->entries[entry].type == LIBFONTS_ENCODING_MAPPING_ENTRY_UNDEFINED_RANGE) {
+			set_range(map->entries[entry].undefined_range.low_source,
+			          map->entries[entry].undefined_range.high_source,
+			          LIBFONTS_UNDEFINED_CHAR, 0, ret);
+
+		} else if (map->entries[entry].type == LIBFONTS_ENCODING_MAPPING_ENTRY_REMAPPED_RANGE) {
+			r = set_range(map->entries[entry].remapped_range.low_source,
+			              map->entries[entry].remapped_range.high_source,
+			              map->entries[entry].remapped_range.low_target, 0, ret);
+			if (r)
+				goto invalid;
+
+		} else {
+			goto invalid;
+		}
+	}
+
+	return ret;
+
+enomem:
+	errno = ENOMEM;
+	return NULL;
+
+invalid:
+	free(ret);
+einvalid:
+	errno = EINVAL;
+	return NULL;
+}
+
+
+#else
+
+
+int
+main(void)
+{
+	return 0; /* XXX add test */
+}
+
+
+#endif