diff options
Diffstat (limited to 'src/vterm/encoding.c')
| -rw-r--r-- | src/vterm/encoding.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/src/vterm/encoding.c b/src/vterm/encoding.c new file mode 100644 index 0000000000..434ac3f99b --- /dev/null +++ b/src/vterm/encoding.c @@ -0,0 +1,230 @@ +#include "vterm_internal.h" + +#define UNICODE_INVALID 0xFFFD + +#if defined(DEBUG) && DEBUG > 1 +# define DEBUG_PRINT_UTF8 +#endif + +struct UTF8DecoderData { + // number of bytes remaining in this codepoint + int bytes_remaining; + + // number of bytes total in this codepoint once it's finished + // (for detecting overlongs) + int bytes_total; + + int this_cp; +}; + +static void init_utf8(VTermEncoding *enc, void *data_) +{ + struct UTF8DecoderData *data = data_; + + data->bytes_remaining = 0; + data->bytes_total = 0; +} + +static void decode_utf8(VTermEncoding *enc, void *data_, + uint32_t cp[], int *cpi, int cplen, + const char bytes[], size_t *pos, size_t bytelen) +{ + struct UTF8DecoderData *data = data_; + +#ifdef DEBUG_PRINT_UTF8 + printf("BEGIN UTF-8\n"); +#endif + + for(; *pos < bytelen && *cpi < cplen; (*pos)++) { + unsigned char c = bytes[*pos]; + +#ifdef DEBUG_PRINT_UTF8 + printf(" pos=%zd c=%02x rem=%d\n", *pos, c, data->bytes_remaining); +#endif + + if(c < 0x20) // C0 + return; + + else if(c >= 0x20 && c < 0x7f) { + if(data->bytes_remaining) + cp[(*cpi)++] = UNICODE_INVALID; + + cp[(*cpi)++] = c; +#ifdef DEBUG_PRINT_UTF8 + printf(" UTF-8 char: U+%04x\n", c); +#endif + data->bytes_remaining = 0; + } + + else if(c == 0x7f) // DEL + return; + + else if(c >= 0x80 && c < 0xc0) { + if(!data->bytes_remaining) { + cp[(*cpi)++] = UNICODE_INVALID; + continue; + } + + data->this_cp <<= 6; + data->this_cp |= c & 0x3f; + data->bytes_remaining--; + + if(!data->bytes_remaining) { +#ifdef DEBUG_PRINT_UTF8 + printf(" UTF-8 raw char U+%04x bytelen=%d ", data->this_cp, data->bytes_total); +#endif + // Check for overlong sequences + switch(data->bytes_total) { + case 2: + if(data->this_cp < 0x0080) data->this_cp = UNICODE_INVALID; + break; + case 3: + if(data->this_cp < 0x0800) data->this_cp = UNICODE_INVALID; + break; + case 4: + if(data->this_cp < 0x10000) data->this_cp = UNICODE_INVALID; + break; + case 5: + if(data->this_cp < 0x200000) data->this_cp = UNICODE_INVALID; + break; + case 6: + if(data->this_cp < 0x4000000) data->this_cp = UNICODE_INVALID; + break; + } + // Now look for plain invalid ones + if((data->this_cp >= 0xD800 && data->this_cp <= 0xDFFF) || + data->this_cp == 0xFFFE || + data->this_cp == 0xFFFF) + data->this_cp = UNICODE_INVALID; +#ifdef DEBUG_PRINT_UTF8 + printf(" char: U+%04x\n", data->this_cp); +#endif + cp[(*cpi)++] = data->this_cp; + } + } + + else if(c >= 0xc0 && c < 0xe0) { + if(data->bytes_remaining) + cp[(*cpi)++] = UNICODE_INVALID; + + data->this_cp = c & 0x1f; + data->bytes_total = 2; + data->bytes_remaining = 1; + } + + else if(c >= 0xe0 && c < 0xf0) { + if(data->bytes_remaining) + cp[(*cpi)++] = UNICODE_INVALID; + + data->this_cp = c & 0x0f; + data->bytes_total = 3; + data->bytes_remaining = 2; + } + + else if(c >= 0xf0 && c < 0xf8) { + if(data->bytes_remaining) + cp[(*cpi)++] = UNICODE_INVALID; + + data->this_cp = c & 0x07; + data->bytes_total = 4; + data->bytes_remaining = 3; + } + + else if(c >= 0xf8 && c < 0xfc) { + if(data->bytes_remaining) + cp[(*cpi)++] = UNICODE_INVALID; + + data->this_cp = c & 0x03; + data->bytes_total = 5; + data->bytes_remaining = 4; + } + + else if(c >= 0xfc && c < 0xfe) { + if(data->bytes_remaining) + cp[(*cpi)++] = UNICODE_INVALID; + + data->this_cp = c & 0x01; + data->bytes_total = 6; + data->bytes_remaining = 5; + } + + else { + cp[(*cpi)++] = UNICODE_INVALID; + } + } +} + +static VTermEncoding encoding_utf8 = { + .init = &init_utf8, + .decode = &decode_utf8, +}; + +static void decode_usascii(VTermEncoding *enc, void *data, + uint32_t cp[], int *cpi, int cplen, + const char bytes[], size_t *pos, size_t bytelen) +{ + int is_gr = bytes[*pos] & 0x80; + + for(; *pos < bytelen && *cpi < cplen; (*pos)++) { + unsigned char c = bytes[*pos] ^ is_gr; + + if(c < 0x20 || c == 0x7f || c >= 0x80) + return; + + cp[(*cpi)++] = c; + } +} + +static VTermEncoding encoding_usascii = { + .decode = &decode_usascii, +}; + +struct StaticTableEncoding { + const VTermEncoding enc; + const uint32_t chars[128]; +}; + +static void decode_table(VTermEncoding *enc, void *data, + uint32_t cp[], int *cpi, int cplen, + const char bytes[], size_t *pos, size_t bytelen) +{ + struct StaticTableEncoding *table = (struct StaticTableEncoding *)enc; + int is_gr = bytes[*pos] & 0x80; + + for(; *pos < bytelen && *cpi < cplen; (*pos)++) { + unsigned char c = bytes[*pos] ^ is_gr; + + if(c < 0x20 || c == 0x7f || c >= 0x80) + return; + + if(table->chars[c]) + cp[(*cpi)++] = table->chars[c]; + else + cp[(*cpi)++] = c; + } +} + +#include "encoding/DECdrawing.inc" +#include "encoding/uk.inc" + +static struct { + VTermEncodingType type; + char designation; + VTermEncoding *enc; +} +encodings[] = { + { ENC_UTF8, 'u', &encoding_utf8 }, + { ENC_SINGLE_94, '0', (VTermEncoding*)&encoding_DECdrawing }, + { ENC_SINGLE_94, 'A', (VTermEncoding*)&encoding_uk }, + { ENC_SINGLE_94, 'B', &encoding_usascii }, + { 0 }, +}; + +/* This ought to be INTERNAL but isn't because it's used by unit testing */ +VTermEncoding *vterm_lookup_encoding(VTermEncodingType type, char designation) +{ + for(int i = 0; encodings[i].designation; i++) + if(encodings[i].type == type && encodings[i].designation == designation) + return encodings[i].enc; + return NULL; +} |