feat: Enhance x52 character map bin file

Prior to this change, the char_map.bin file was only used for testing.
However, with the upcoming support for profiles, we need to enhance it
and have it installed in the data directory for use by the (future)
compiler.

libx52util/char_map_test.c

@@ -13,13 +13,69 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
 
 #include <libx52/libx52util.h>
 
-// Fix this if we ever hit longer sequences
+#define CHAR_MAP_MAGIC "X52M"
-#define RECORD_SIZE 8
+#define CHAR_MAP_HEADER_V1_BYTES 16
+
+static uint16_t read_be16(const uint8_t *p)
+{
+    return (uint16_t)((uint16_t)p[0] << 8) | p[1];
+}
+
+static uint32_t read_be32(const uint8_t *p)
+{
+    return (uint32_t)p[0] << 24 | (uint32_t)p[1] << 16 |
+            (uint32_t)p[2] << 8 | p[3];
+}
+
+static int parse_char_map_header(const uint8_t *base, size_t filesize,
+                                 size_t *data_offset, uint32_t *num_entries,
+                                 uint16_t *record_size)
+{
+    uint16_t version;
+    uint16_t rec_sz;
+    uint32_t nent;
+    uint32_t off;
+
+    if (filesize < CHAR_MAP_HEADER_V1_BYTES) {
+        puts("# char_map.bin smaller than header");
+        return -1;
+    }
+    if (memcmp(base, CHAR_MAP_MAGIC, 4) != 0) {
+        puts("# char_map.bin missing X52M magic");
+        return -1;
+    }
+    version = read_be16(base + 4);
+    rec_sz = read_be16(base + 6);
+    nent = read_be32(base + 8);
+    off = read_be32(base + 12);
+    if (version != 1) {
+        printf("# char_map.bin unsupported version %u\n", version);
+        return -1;
+    }
+    if (rec_sz < 2 || rec_sz > 256) {
+        printf("# char_map.bin invalid record_size %u\n", rec_sz);
+        return -1;
+    }
+    if (off < CHAR_MAP_HEADER_V1_BYTES || off > filesize) {
+        puts("# char_map.bin invalid data_offset");
+        return -1;
+    }
+    if (off + (size_t)nent * rec_sz > filesize) {
+        puts("# char_map.bin truncated payload");
+        return -1;
+    }
+
+    *data_offset = off;
+    *num_entries = nent;
+    *record_size = rec_sz;
+    return 0;
+}
 
 // Blindly encode a string into it's smallest UTF8 representation
 static void encode_utf8(uint32_t cp, uint8_t *out)
@@ -70,15 +126,21 @@ static double get_time_diff(struct timespec start, struct timespec end)
 int main(int argc, char *argv[])
 {
     uint8_t input[8] = {0};
-    uint8_t output[RECORD_SIZE];
+    uint8_t output[256];
     size_t len;
     int result;
 
     int fd;
-    uint8_t *expected_blob;
+    uint8_t *mapped;
+    size_t filesize;
+    size_t data_offset;
+    uint32_t num_entries;
+    uint16_t record_size;
+    const uint8_t *expected_blob;
     bool smp_pages_ok;
 
     struct timespec start, end;
+    struct stat st;
 
     // Argument check
     if (argc != 2) {
@@ -94,13 +156,38 @@ int main(int argc, char *argv[])
         return 1;
     }
 
-    expected_blob = mmap(NULL, 0x10000 * RECORD_SIZE,
+    if (fstat(fd, &st) != 0) {
-                         PROT_READ, MAP_SHARED, fd, 0);
+        printf("Bail out! fstat failed %d: %s\n", errno, strerror(errno));
-    if (expected_blob == MAP_FAILED) {
+        close(fd);
+        return 1;
+    }
+
+    filesize = (size_t)st.st_size;
+    mapped = mmap(NULL, filesize, PROT_READ, MAP_SHARED, fd, 0);
+    if (mapped == MAP_FAILED) {
         printf("Bail out! MMAP failed with error %d: %s\n",
                 errno, strerror(errno));
+        close(fd);
+        return 1;
     }
 
+    if (parse_char_map_header(mapped, filesize,
+            &data_offset, &num_entries, &record_size) != 0) {
+        puts("Bail out! Invalid char_map.bin header");
+        munmap(mapped, filesize);
+        close(fd);
+        return 1;
+    }
+
+    if (num_entries < 0x10000) {
+        printf("Bail out! num_entries %u < 0x10000\n", num_entries);
+        munmap(mapped, filesize);
+        close(fd);
+        return 1;
+    }
+
+    expected_blob = mapped + data_offset;
+
     puts("TAP version 13");
     // Check the 256 BMP Pages, plus the supplementary pages
     puts("1..257");
@@ -112,7 +199,7 @@ int main(int argc, char *argv[])
 
         for (uint32_t offset = 0; offset < 256; offset++) {
             uint32_t cp = page * 256 + offset;
-            const uint8_t *rec = &expected_blob[cp * RECORD_SIZE];
+            const uint8_t *rec = &expected_blob[cp * record_size];
 
             memset(input, 0, sizeof(input));
             memset(output, 0, sizeof(output));
@@ -164,14 +251,14 @@ int main(int argc, char *argv[])
     // Handle the supplementary pages
     smp_pages_ok = true;
     for (uint32_t smp = 0x1; smp <= 0x10; smp++) {
-        const uint8_t *rec = &expected_blob[0xFFFD * RECORD_SIZE];
+        const uint8_t *rec = &expected_blob[0xFFFD * record_size];
         for (uint32_t offset = 0; offset < 0x100; offset += 0xFF) {
             uint32_t cp = smp * 0x10000 + offset;
 
             memset(input, 0, sizeof(input));
             memset(output, 0, sizeof(output));
-            len = sizeof(output);
             encode_utf8(cp, input);
+            len = sizeof(output);
 
             result = libx52util_convert_utf8_string(input, output, &len);
             if (result != 0) {
@@ -209,7 +296,7 @@ int main(int argc, char *argv[])
     printf("%sok - 257 SMP tests\n", smp_pages_ok ? "" : "not ");
 
     // Cleanup
-    munmap(expected_blob, 0x10000 * RECORD_SIZE);
+    munmap(mapped, filesize);
     close(fd);
     return 0;
 }

libx52util/meson.build

@@ -7,7 +7,9 @@ util_char_map = custom_target('util-char-map',
   depend_files: ['x52_char_map_gen.py', 'x52_char_map.cfg'],
   command: [python, gen_script, '@INPUT@', '@OUTPUT0@', '@OUTPUT1@'],
   input: 'x52_char_map.cfg',
-  output: ['char_map.c', 'char_map.bin'])
+  output: ['char_map.c', 'char_map.bin'],
+  install: true,
+  install_dir: [false, get_option('datadir') / 'x52d'])
 
 lib_libx52util = library('x52util', util_char_map, 'char_map_lookup.c',
   install: true,

libx52util/x52_char_map_gen.py

@@ -11,9 +11,18 @@ for the X52/X52 Pro MFD
 
 import sys
 import re
-import json
+import struct
 import unicodedata
 
+# Binary blob written to char_map.bin (shared by libx52util tests and Python tools).
+# v1 header: magic (4) then big-endian version, record_size, num_entries, data_offset.
+# Payload: one fixed record per Unicode code point U+0000..U+FFFF
+# (length byte + payload + zero padding to record_size; see generate_test_tables).
+CHAR_MAP_MAGIC = b"X52M"
+CHAR_MAP_VERSION = 1
+CHAR_MAP_HEADER_STRUCT = struct.Struct(">4sHHII")  # magic, version, record_size, num_entries, data_offset
+
+
 class LineFormatError(ValueError):
     """
     Error class for parser
@@ -263,7 +272,20 @@ class BMPTable:
         else:
             record_length = 1 << longest.bit_length()
 
+        num_entries = 0x10000
+        header_bytes = CHAR_MAP_HEADER_STRUCT.size
+        data_offset = header_bytes
+
         with open(self.output_map, 'wb') as output_map:
+            output_map.write(
+                CHAR_MAP_HEADER_STRUCT.pack(
+                    CHAR_MAP_MAGIC,
+                    CHAR_MAP_VERSION,
+                    record_length,
+                    num_entries,
+                    data_offset,
+                )
+            )
             pad = [0] * record_length
             for seq in output:
                 record = [len(seq)] + list(seq) + pad
@@ -271,7 +293,9 @@ class BMPTable:
 
 if __name__ == "__main__":
     if len(sys.argv) != 4:
-        sys.stderr.write(f"Usage: {sys.argv[0]} <input-map> <output-c-file> <output-json-map>\n")
+        sys.stderr.write(
+            f"Usage: {sys.argv[0]} <input-map> <output-c-file> <output-char-map.bin>\n"
+        )
         sys.exit(1)
 
     BMPTable(sys.argv[1], sys.argv[2], sys.argv[3])