utf8.con commit sideband.c: small optimization of strbuf usage (c61b2af)
   1#include "git-compat-util.h"
   2#include "strbuf.h"
   3#include "utf8.h"
   4
   5/* This code is originally from http://www.cl.cam.ac.uk/~mgk25/ucs/ */
   6
   7struct interval {
   8        ucs_char_t first;
   9        ucs_char_t last;
  10};
  11
  12size_t display_mode_esc_sequence_len(const char *s)
  13{
  14        const char *p = s;
  15        if (*p++ != '\033')
  16                return 0;
  17        if (*p++ != '[')
  18                return 0;
  19        while (isdigit(*p) || *p == ';')
  20                p++;
  21        if (*p++ != 'm')
  22                return 0;
  23        return p - s;
  24}
  25
  26/* auxiliary function for binary search in interval table */
  27static int bisearch(ucs_char_t ucs, const struct interval *table, int max)
  28{
  29        int min = 0;
  30        int mid;
  31
  32        if (ucs < table[0].first || ucs > table[max].last)
  33                return 0;
  34        while (max >= min) {
  35                mid = (min + max) / 2;
  36                if (ucs > table[mid].last)
  37                        min = mid + 1;
  38                else if (ucs < table[mid].first)
  39                        max = mid - 1;
  40                else
  41                        return 1;
  42        }
  43
  44        return 0;
  45}
  46
  47/* The following two functions define the column width of an ISO 10646
  48 * character as follows:
  49 *
  50 *    - The null character (U+0000) has a column width of 0.
  51 *
  52 *    - Other C0/C1 control characters and DEL will lead to a return
  53 *      value of -1.
  54 *
  55 *    - Non-spacing and enclosing combining characters (general
  56 *      category code Mn or Me in the Unicode database) have a
  57 *      column width of 0.
  58 *
  59 *    - SOFT HYPHEN (U+00AD) has a column width of 1.
  60 *
  61 *    - Other format characters (general category code Cf in the Unicode
  62 *      database) and ZERO WIDTH SPACE (U+200B) have a column width of 0.
  63 *
  64 *    - Hangul Jamo medial vowels and final consonants (U+1160-U+11FF)
  65 *      have a column width of 0.
  66 *
  67 *    - Spacing characters in the East Asian Wide (W) or East Asian
  68 *      Full-width (F) category as defined in Unicode Technical
  69 *      Report #11 have a column width of 2.
  70 *
  71 *    - All remaining characters (including all printable
  72 *      ISO 8859-1 and WGL4 characters, Unicode control characters,
  73 *      etc.) have a column width of 1.
  74 *
  75 * This implementation assumes that ucs_char_t characters are encoded
  76 * in ISO 10646.
  77 */
  78
  79static int git_wcwidth(ucs_char_t ch)
  80{
  81        /*
  82         * Sorted list of non-overlapping intervals of non-spacing characters,
  83         */
  84#include "unicode_width.h"
  85
  86        /* test for 8-bit control characters */
  87        if (ch == 0)
  88                return 0;
  89        if (ch < 32 || (ch >= 0x7f && ch < 0xa0))
  90                return -1;
  91
  92        /* binary search in table of non-spacing characters */
  93        if (bisearch(ch, zero_width, sizeof(zero_width)
  94                                / sizeof(struct interval) - 1))
  95                return 0;
  96
  97        /* binary search in table of double width characters */
  98        if (bisearch(ch, double_width, sizeof(double_width)
  99                                / sizeof(struct interval) - 1))
 100                return 2;
 101
 102        return 1;
 103}
 104
 105/*
 106 * Pick one ucs character starting from the location *start points at,
 107 * and return it, while updating the *start pointer to point at the
 108 * end of that character.  When remainder_p is not NULL, the location
 109 * holds the number of bytes remaining in the string that we are allowed
 110 * to pick from.  Otherwise we are allowed to pick up to the NUL that
 111 * would eventually appear in the string.  *remainder_p is also reduced
 112 * by the number of bytes we have consumed.
 113 *
 114 * If the string was not a valid UTF-8, *start pointer is set to NULL
 115 * and the return value is undefined.
 116 */
 117static ucs_char_t pick_one_utf8_char(const char **start, size_t *remainder_p)
 118{
 119        unsigned char *s = (unsigned char *)*start;
 120        ucs_char_t ch;
 121        size_t remainder, incr;
 122
 123        /*
 124         * A caller that assumes NUL terminated text can choose
 125         * not to bother with the remainder length.  We will
 126         * stop at the first NUL.
 127         */
 128        remainder = (remainder_p ? *remainder_p : 999);
 129
 130        if (remainder < 1) {
 131                goto invalid;
 132        } else if (*s < 0x80) {
 133                /* 0xxxxxxx */
 134                ch = *s;
 135                incr = 1;
 136        } else if ((s[0] & 0xe0) == 0xc0) {
 137                /* 110XXXXx 10xxxxxx */
 138                if (remainder < 2 ||
 139                    (s[1] & 0xc0) != 0x80 ||
 140                    (s[0] & 0xfe) == 0xc0)
 141                        goto invalid;
 142                ch = ((s[0] & 0x1f) << 6) | (s[1] & 0x3f);
 143                incr = 2;
 144        } else if ((s[0] & 0xf0) == 0xe0) {
 145                /* 1110XXXX 10Xxxxxx 10xxxxxx */
 146                if (remainder < 3 ||
 147                    (s[1] & 0xc0) != 0x80 ||
 148                    (s[2] & 0xc0) != 0x80 ||
 149                    /* overlong? */
 150                    (s[0] == 0xe0 && (s[1] & 0xe0) == 0x80) ||
 151                    /* surrogate? */
 152                    (s[0] == 0xed && (s[1] & 0xe0) == 0xa0) ||
 153                    /* U+FFFE or U+FFFF? */
 154                    (s[0] == 0xef && s[1] == 0xbf &&
 155                     (s[2] & 0xfe) == 0xbe))
 156                        goto invalid;
 157                ch = ((s[0] & 0x0f) << 12) |
 158                        ((s[1] & 0x3f) << 6) | (s[2] & 0x3f);
 159                incr = 3;
 160        } else if ((s[0] & 0xf8) == 0xf0) {
 161                /* 11110XXX 10XXxxxx 10xxxxxx 10xxxxxx */
 162                if (remainder < 4 ||
 163                    (s[1] & 0xc0) != 0x80 ||
 164                    (s[2] & 0xc0) != 0x80 ||
 165                    (s[3] & 0xc0) != 0x80 ||
 166                    /* overlong? */
 167                    (s[0] == 0xf0 && (s[1] & 0xf0) == 0x80) ||
 168                    /* > U+10FFFF? */
 169                    (s[0] == 0xf4 && s[1] > 0x8f) || s[0] > 0xf4)
 170                        goto invalid;
 171                ch = ((s[0] & 0x07) << 18) | ((s[1] & 0x3f) << 12) |
 172                        ((s[2] & 0x3f) << 6) | (s[3] & 0x3f);
 173                incr = 4;
 174        } else {
 175invalid:
 176                *start = NULL;
 177                return 0;
 178        }
 179
 180        *start += incr;
 181        if (remainder_p)
 182                *remainder_p = remainder - incr;
 183        return ch;
 184}
 185
 186/*
 187 * This function returns the number of columns occupied by the character
 188 * pointed to by the variable start. The pointer is updated to point at
 189 * the next character. When remainder_p is not NULL, it points at the
 190 * location that stores the number of remaining bytes we can use to pick
 191 * a character (see pick_one_utf8_char() above).
 192 */
 193int utf8_width(const char **start, size_t *remainder_p)
 194{
 195        ucs_char_t ch = pick_one_utf8_char(start, remainder_p);
 196        if (!*start)
 197                return 0;
 198        return git_wcwidth(ch);
 199}
 200
 201/*
 202 * Returns the total number of columns required by a null-terminated
 203 * string, assuming that the string is utf8.  Returns strlen() instead
 204 * if the string does not look like a valid utf8 string.
 205 */
 206int utf8_strnwidth(const char *string, int len, int skip_ansi)
 207{
 208        int width = 0;
 209        const char *orig = string;
 210
 211        if (len == -1)
 212                len = strlen(string);
 213        while (string && string < orig + len) {
 214                int skip;
 215                while (skip_ansi &&
 216                       (skip = display_mode_esc_sequence_len(string)) != 0)
 217                        string += skip;
 218                width += utf8_width(&string, NULL);
 219        }
 220        return string ? width : len;
 221}
 222
 223int utf8_strwidth(const char *string)
 224{
 225        return utf8_strnwidth(string, -1, 0);
 226}
 227
 228int is_utf8(const char *text)
 229{
 230        while (*text) {
 231                if (*text == '\n' || *text == '\t' || *text == '\r') {
 232                        text++;
 233                        continue;
 234                }
 235                utf8_width(&text, NULL);
 236                if (!text)
 237                        return 0;
 238        }
 239        return 1;
 240}
 241
 242static void strbuf_add_indented_text(struct strbuf *buf, const char *text,
 243                                     int indent, int indent2)
 244{
 245        if (indent < 0)
 246                indent = 0;
 247        while (*text) {
 248                const char *eol = strchrnul(text, '\n');
 249                if (*eol == '\n')
 250                        eol++;
 251                strbuf_addchars(buf, ' ', indent);
 252                strbuf_add(buf, text, eol - text);
 253                text = eol;
 254                indent = indent2;
 255        }
 256}
 257
 258/*
 259 * Wrap the text, if necessary. The variable indent is the indent for the
 260 * first line, indent2 is the indent for all other lines.
 261 * If indent is negative, assume that already -indent columns have been
 262 * consumed (and no extra indent is necessary for the first line).
 263 */
 264void strbuf_add_wrapped_text(struct strbuf *buf,
 265                const char *text, int indent1, int indent2, int width)
 266{
 267        int indent, w, assume_utf8 = 1;
 268        const char *bol, *space, *start = text;
 269        size_t orig_len = buf->len;
 270
 271        if (width <= 0) {
 272                strbuf_add_indented_text(buf, text, indent1, indent2);
 273                return;
 274        }
 275
 276retry:
 277        bol = text;
 278        w = indent = indent1;
 279        space = NULL;
 280        if (indent < 0) {
 281                w = -indent;
 282                space = text;
 283        }
 284
 285        for (;;) {
 286                char c;
 287                size_t skip;
 288
 289                while ((skip = display_mode_esc_sequence_len(text)))
 290                        text += skip;
 291
 292                c = *text;
 293                if (!c || isspace(c)) {
 294                        if (w <= width || !space) {
 295                                const char *start = bol;
 296                                if (!c && text == start)
 297                                        return;
 298                                if (space)
 299                                        start = space;
 300                                else
 301                                        strbuf_addchars(buf, ' ', indent);
 302                                strbuf_add(buf, start, text - start);
 303                                if (!c)
 304                                        return;
 305                                space = text;
 306                                if (c == '\t')
 307                                        w |= 0x07;
 308                                else if (c == '\n') {
 309                                        space++;
 310                                        if (*space == '\n') {
 311                                                strbuf_addch(buf, '\n');
 312                                                goto new_line;
 313                                        }
 314                                        else if (!isalnum(*space))
 315                                                goto new_line;
 316                                        else
 317                                                strbuf_addch(buf, ' ');
 318                                }
 319                                w++;
 320                                text++;
 321                        }
 322                        else {
 323new_line:
 324                                strbuf_addch(buf, '\n');
 325                                text = bol = space + isspace(*space);
 326                                space = NULL;
 327                                w = indent = indent2;
 328                        }
 329                        continue;
 330                }
 331                if (assume_utf8) {
 332                        w += utf8_width(&text, NULL);
 333                        if (!text) {
 334                                assume_utf8 = 0;
 335                                text = start;
 336                                strbuf_setlen(buf, orig_len);
 337                                goto retry;
 338                        }
 339                } else {
 340                        w++;
 341                        text++;
 342                }
 343        }
 344}
 345
 346void strbuf_add_wrapped_bytes(struct strbuf *buf, const char *data, int len,
 347                             int indent, int indent2, int width)
 348{
 349        char *tmp = xstrndup(data, len);
 350        strbuf_add_wrapped_text(buf, tmp, indent, indent2, width);
 351        free(tmp);
 352}
 353
 354void strbuf_utf8_replace(struct strbuf *sb_src, int pos, int width,
 355                         const char *subst)
 356{
 357        struct strbuf sb_dst = STRBUF_INIT;
 358        char *src = sb_src->buf;
 359        char *end = src + sb_src->len;
 360        char *dst;
 361        int w = 0, subst_len = 0;
 362
 363        if (subst)
 364                subst_len = strlen(subst);
 365        strbuf_grow(&sb_dst, sb_src->len + subst_len);
 366        dst = sb_dst.buf;
 367
 368        while (src < end) {
 369                char *old;
 370                size_t n;
 371
 372                while ((n = display_mode_esc_sequence_len(src))) {
 373                        memcpy(dst, src, n);
 374                        src += n;
 375                        dst += n;
 376                }
 377
 378                if (src >= end)
 379                        break;
 380
 381                old = src;
 382                n = utf8_width((const char**)&src, NULL);
 383                if (!src)       /* broken utf-8, do nothing */
 384                        return;
 385                if (n && w >= pos && w < pos + width) {
 386                        if (subst) {
 387                                memcpy(dst, subst, subst_len);
 388                                dst += subst_len;
 389                                subst = NULL;
 390                        }
 391                        w += n;
 392                        continue;
 393                }
 394                memcpy(dst, old, src - old);
 395                dst += src - old;
 396                w += n;
 397        }
 398        strbuf_setlen(&sb_dst, dst - sb_dst.buf);
 399        strbuf_swap(sb_src, &sb_dst);
 400        strbuf_release(&sb_dst);
 401}
 402
 403int is_encoding_utf8(const char *name)
 404{
 405        if (!name)
 406                return 1;
 407        if (!strcasecmp(name, "utf-8") || !strcasecmp(name, "utf8"))
 408                return 1;
 409        return 0;
 410}
 411
 412int same_encoding(const char *src, const char *dst)
 413{
 414        if (is_encoding_utf8(src) && is_encoding_utf8(dst))
 415                return 1;
 416        return !strcasecmp(src, dst);
 417}
 418
 419/*
 420 * Wrapper for fprintf and returns the total number of columns required
 421 * for the printed string, assuming that the string is utf8.
 422 */
 423int utf8_fprintf(FILE *stream, const char *format, ...)
 424{
 425        struct strbuf buf = STRBUF_INIT;
 426        va_list arg;
 427        int columns;
 428
 429        va_start(arg, format);
 430        strbuf_vaddf(&buf, format, arg);
 431        va_end(arg);
 432
 433        columns = fputs(buf.buf, stream);
 434        if (0 <= columns) /* keep the error from the I/O */
 435                columns = utf8_strwidth(buf.buf);
 436        strbuf_release(&buf);
 437        return columns;
 438}
 439
 440/*
 441 * Given a buffer and its encoding, return it re-encoded
 442 * with iconv.  If the conversion fails, returns NULL.
 443 */
 444#ifndef NO_ICONV
 445#if defined(OLD_ICONV) || (defined(__sun__) && !defined(_XPG6))
 446        typedef const char * iconv_ibp;
 447#else
 448        typedef char * iconv_ibp;
 449#endif
 450char *reencode_string_iconv(const char *in, size_t insz, iconv_t conv, int *outsz_p)
 451{
 452        size_t outsz, outalloc;
 453        char *out, *outpos;
 454        iconv_ibp cp;
 455
 456        outsz = insz;
 457        outalloc = outsz + 1; /* for terminating NUL */
 458        out = xmalloc(outalloc);
 459        outpos = out;
 460        cp = (iconv_ibp)in;
 461
 462        while (1) {
 463                size_t cnt = iconv(conv, &cp, &insz, &outpos, &outsz);
 464
 465                if (cnt == (size_t) -1) {
 466                        size_t sofar;
 467                        if (errno != E2BIG) {
 468                                free(out);
 469                                return NULL;
 470                        }
 471                        /* insz has remaining number of bytes.
 472                         * since we started outsz the same as insz,
 473                         * it is likely that insz is not enough for
 474                         * converting the rest.
 475                         */
 476                        sofar = outpos - out;
 477                        outalloc = sofar + insz * 2 + 32;
 478                        out = xrealloc(out, outalloc);
 479                        outpos = out + sofar;
 480                        outsz = outalloc - sofar - 1;
 481                }
 482                else {
 483                        *outpos = '\0';
 484                        if (outsz_p)
 485                                *outsz_p = outpos - out;
 486                        break;
 487                }
 488        }
 489        return out;
 490}
 491
 492char *reencode_string_len(const char *in, int insz,
 493                          const char *out_encoding, const char *in_encoding,
 494                          int *outsz)
 495{
 496        iconv_t conv;
 497        char *out;
 498
 499        if (!in_encoding)
 500                return NULL;
 501
 502        conv = iconv_open(out_encoding, in_encoding);
 503        if (conv == (iconv_t) -1) {
 504                /*
 505                 * Some platforms do not have the variously spelled variants of
 506                 * UTF-8, so let's fall back to trying the most official
 507                 * spelling. We do so only as a fallback in case the platform
 508                 * does understand the user's spelling, but not our official
 509                 * one.
 510                 */
 511                if (is_encoding_utf8(in_encoding))
 512                        in_encoding = "UTF-8";
 513                if (is_encoding_utf8(out_encoding))
 514                        out_encoding = "UTF-8";
 515                conv = iconv_open(out_encoding, in_encoding);
 516                if (conv == (iconv_t) -1)
 517                        return NULL;
 518        }
 519
 520        out = reencode_string_iconv(in, insz, conv, outsz);
 521        iconv_close(conv);
 522        return out;
 523}
 524#endif
 525
 526/*
 527 * Returns first character length in bytes for multi-byte `text` according to
 528 * `encoding`.
 529 *
 530 * - The `text` pointer is updated to point at the next character.
 531 * - When `remainder_p` is not NULL, on entry `*remainder_p` is how much bytes
 532 *   we can consume from text, and on exit `*remainder_p` is reduced by returned
 533 *   character length. Otherwise `text` is treated as limited by NUL.
 534 */
 535int mbs_chrlen(const char **text, size_t *remainder_p, const char *encoding)
 536{
 537        int chrlen;
 538        const char *p = *text;
 539        size_t r = (remainder_p ? *remainder_p : SIZE_MAX);
 540
 541        if (r < 1)
 542                return 0;
 543
 544        if (is_encoding_utf8(encoding)) {
 545                pick_one_utf8_char(&p, &r);
 546
 547                chrlen = p ? (p - *text)
 548                           : 1 /* not valid UTF-8 -> raw byte sequence */;
 549        }
 550        else {
 551                /*
 552                 * TODO use iconv to decode one char and obtain its chrlen
 553                 * for now, let's treat encodings != UTF-8 as one-byte
 554                 */
 555                chrlen = 1;
 556        }
 557
 558        *text += chrlen;
 559        if (remainder_p)
 560                *remainder_p -= chrlen;
 561
 562        return chrlen;
 563}
 564
 565/*
 566 * Pick the next char from the stream, ignoring codepoints an HFS+ would.
 567 * Note that this is _not_ complete by any means. It's just enough
 568 * to make is_hfs_dotgit() work, and should not be used otherwise.
 569 */
 570static ucs_char_t next_hfs_char(const char **in)
 571{
 572        while (1) {
 573                ucs_char_t out = pick_one_utf8_char(in, NULL);
 574                /*
 575                 * check for malformed utf8. Technically this
 576                 * gets converted to a percent-sequence, but
 577                 * returning 0 is good enough for is_hfs_dotgit
 578                 * to realize it cannot be .git
 579                 */
 580                if (!*in)
 581                        return 0;
 582
 583                /* these code points are ignored completely */
 584                switch (out) {
 585                case 0x200c: /* ZERO WIDTH NON-JOINER */
 586                case 0x200d: /* ZERO WIDTH JOINER */
 587                case 0x200e: /* LEFT-TO-RIGHT MARK */
 588                case 0x200f: /* RIGHT-TO-LEFT MARK */
 589                case 0x202a: /* LEFT-TO-RIGHT EMBEDDING */
 590                case 0x202b: /* RIGHT-TO-LEFT EMBEDDING */
 591                case 0x202c: /* POP DIRECTIONAL FORMATTING */
 592                case 0x202d: /* LEFT-TO-RIGHT OVERRIDE */
 593                case 0x202e: /* RIGHT-TO-LEFT OVERRIDE */
 594                case 0x206a: /* INHIBIT SYMMETRIC SWAPPING */
 595                case 0x206b: /* ACTIVATE SYMMETRIC SWAPPING */
 596                case 0x206c: /* INHIBIT ARABIC FORM SHAPING */
 597                case 0x206d: /* ACTIVATE ARABIC FORM SHAPING */
 598                case 0x206e: /* NATIONAL DIGIT SHAPES */
 599                case 0x206f: /* NOMINAL DIGIT SHAPES */
 600                case 0xfeff: /* ZERO WIDTH NO-BREAK SPACE */
 601                        continue;
 602                }
 603
 604                return out;
 605        }
 606}
 607
 608int is_hfs_dotgit(const char *path)
 609{
 610        ucs_char_t c;
 611
 612        c = next_hfs_char(&path);
 613        if (c != '.')
 614                return 0;
 615        c = next_hfs_char(&path);
 616
 617        /*
 618         * there's a great deal of other case-folding that occurs
 619         * in HFS+, but this is enough to catch anything that will
 620         * convert to ".git"
 621         */
 622        if (c != 'g' && c != 'G')
 623                return 0;
 624        c = next_hfs_char(&path);
 625        if (c != 'i' && c != 'I')
 626                return 0;
 627        c = next_hfs_char(&path);
 628        if (c != 't' && c != 'T')
 629                return 0;
 630        c = next_hfs_char(&path);
 631        if (c && !is_dir_sep(c))
 632                return 0;
 633
 634        return 1;
 635}
 636
 637const char utf8_bom[] = "\357\273\277";
 638
 639int skip_utf8_bom(char **text, size_t len)
 640{
 641        if (len < strlen(utf8_bom) ||
 642            memcmp(*text, utf8_bom, strlen(utf8_bom)))
 643                return 0;
 644        *text += strlen(utf8_bom);
 645        return 1;
 646}