diff options
| -rw-r--r-- | preconv.c | 133 |
1 files changed, 58 insertions, 75 deletions
@@ -19,6 +19,7 @@ #include <sys/types.h> +#include <assert.h> #include <stdio.h> #include <string.h> #include "mandoc.h" @@ -28,88 +29,70 @@ int preconv_encode(struct buf *ib, size_t *ii, struct buf *ob, size_t *oi, int *filenc) { - size_t i; - int state; + unsigned char *cu; + int nby; unsigned int accum; - unsigned char cu; + + cu = ib->buf + *ii; + assert(*cu & 0x80); if ( ! (*filenc & MPARSE_UTF8)) goto latin; - state = 0; - accum = 0U; - - for (i = *ii; i < ib->sz; i++) { - cu = ib->buf[i]; - if (state) { - if ( ! (cu & 128) || (cu & 64)) { - /* Bad sequence header. */ - break; - } - - /* Accept only legitimate bit patterns. */ - - if (cu > 191 || cu < 128) { - /* Bad in-sequence bits. */ - break; - } - - accum |= (cu & 63) << --state * 6; - - if (state) - continue; - - if (accum < 0x80) - ob->buf[(*oi)++] = accum; - else - *oi += snprintf(ob->buf + *oi, - 11, "\\[u%.4X]", accum); - *ii = i + 1; - *filenc &= ~MPARSE_LATIN1; - return(1); - } else { - /* - * Entering a UTF-8 state: if we encounter a - * UTF-8 bitmask, calculate the expected UTF-8 - * state from it. - */ - for (state = 0; state < 7; state++) - if ( ! (cu & (1 << (7 - state)))) - break; - - /* Accept only legitimate bit patterns. */ - - switch (state--) { - case (4): - if (cu <= 244 && cu >= 240) { - accum = (cu & 7) << 18; - continue; - } - /* Bad 4-sequence start bits. */ - break; - case (3): - if (cu <= 239 && cu >= 224) { - accum = (cu & 15) << 12; - continue; - } - /* Bad 3-sequence start bits. */ - break; - case (2): - if (cu <= 223 && cu >= 194) { - accum = (cu & 31) << 6; - continue; - } - /* Bad 2-sequence start bits. */ - break; - default: - /* Bad sequence bit mask. */ - break; - } - break; - } + nby = 1; + while (nby < 5 && *cu & (1 << (7 - nby))) + nby++; + + switch (nby) { + case 2: + accum = *cu & 0x1f; + if (accum < 0x02) /* Obfuscated ASCII. */ + goto latin; + break; + case 3: + accum = *cu & 0x0f; + break; + case 4: + accum = *cu & 0x07; + if (accum > 0x04) /* Beyond Unicode. */ + goto latin; + break; + default: /* Bad sequence header. */ + goto latin; + } + + cu++; + switch (nby) { + case 3: + if ((accum == 0x00 && ! (*cu & 0x20)) || /* Use 2-byte. */ + (accum == 0x0d && *cu & 0x20)) /* Surrogates. */ + goto latin; + break; + case 4: + if ((accum == 0x00 && ! (*cu & 0x30)) || /* Use 3-byte. */ + (accum == 0x04 && *cu & 0x30)) /* Beyond Unicode. */ + goto latin; + break; + default: + break; + } + + while (--nby) { + if ((*cu & 0xc0) != 0x80) /* Invalid continuation. */ + goto latin; + accum <<= 6; + accum += *cu & 0x3f; + cu++; } - /* FALLTHROUGH: Invalid or incomplete UTF-8 sequence. */ + assert(accum > 0x7f); + assert(accum < 0x110000); + assert(accum < 0xd800 || accum > 0xdfff); + + *oi += snprintf(ob->buf + *oi, 11, "\\[u%.4X]", accum); + *ii = (char *)cu - ib->buf; + *filenc &= ~MPARSE_LATIN1; + return(1); latin: if ( ! (*filenc & MPARSE_LATIN1)) |