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      1 /*
      2  **********************************************************************
      3  *   Copyright (C) 2005-2008, International Business Machines
      4  *   Corporation and others.  All Rights Reserved.
      5  **********************************************************************
      6  */
      7 
      8 #include "unicode/utypes.h"
      9 
     10 #if !UCONFIG_NO_CONVERSION
     11 
     12 #include "inputext.h"
     13 
     14 #include "cmemory.h"
     15 #include "cstring.h"
     16 
     17 #include <string.h>
     18 
     19 U_NAMESPACE_BEGIN
     20 
     21 #define BUFFER_SIZE 8192
     22 
     23 #define ARRAY_SIZE(array) (sizeof array / sizeof array[0])
     24 
     25 #define NEW_ARRAY(type,count) (type *) uprv_malloc((count) * sizeof(type))
     26 #define DELETE_ARRAY(array) uprv_free((void *) (array))
     27 
     28 InputText::InputText(UErrorCode &status)
     29     : fInputBytes(NEW_ARRAY(uint8_t, BUFFER_SIZE)), // The text to be checked.  Markup will have been
     30                                                  //   removed if appropriate.
     31       fByteStats(NEW_ARRAY(int16_t, 256)),       // byte frequency statistics for the input text.
     32                                                  //   Value is percent, not absolute.
     33       fDeclaredEncoding(0),
     34       fRawInput(0),
     35       fRawLength(0)
     36 {
     37     if (fInputBytes == NULL || fByteStats == NULL) {
     38         status = U_MEMORY_ALLOCATION_ERROR;
     39     }
     40 }
     41 
     42 InputText::~InputText()
     43 {
     44     DELETE_ARRAY(fDeclaredEncoding);
     45     DELETE_ARRAY(fByteStats);
     46     DELETE_ARRAY(fInputBytes);
     47 }
     48 
     49 void InputText::setText(const char *in, int32_t len)
     50 {
     51     fInputLen  = 0;
     52     fC1Bytes   = FALSE;
     53     fRawInput  = (const uint8_t *) in;
     54     fRawLength = len == -1? uprv_strlen(in) : len;
     55 }
     56 
     57 void InputText::setDeclaredEncoding(const char* encoding, int32_t len)
     58 {
     59     if(encoding) {
     60         if (len == -1) {
     61             len = uprv_strlen(encoding);
     62         }
     63 
     64         len += 1;     // to make place for the \0 at the end.
     65         uprv_free(fDeclaredEncoding);
     66         fDeclaredEncoding = NEW_ARRAY(char, len);
     67         uprv_strncpy(fDeclaredEncoding, encoding, len);
     68     }
     69 }
     70 
     71 UBool InputText::isSet() const
     72 {
     73     return fRawInput != NULL;
     74 }
     75 
     76 /**
     77 *  MungeInput - after getting a set of raw input data to be analyzed, preprocess
     78 *               it by removing what appears to be html markup.
     79 *
     80 * @internal
     81 */
     82 void InputText::MungeInput(UBool fStripTags) {
     83     int     srci = 0;
     84     int     dsti = 0;
     85     uint8_t b;
     86     bool    inMarkup = FALSE;
     87     int32_t openTags = 0;
     88     int32_t badTags  = 0;
     89 
     90     //
     91     //  html / xml markup stripping.
     92     //     quick and dirty, not 100% accurate, but hopefully good enough, statistically.
     93     //     discard everything within < brackets >
     94     //     Count how many total '<' and illegal (nested) '<' occur, so we can make some
     95     //     guess as to whether the input was actually marked up at all.
     96     // TODO: Think about how this interacts with EBCDIC charsets that are detected.
     97     if (fStripTags) {
     98         for (srci = 0; srci < fRawLength && dsti < BUFFER_SIZE; srci += 1) {
     99             b = fRawInput[srci];
    100 
    101             if (b == (uint8_t)0x3C) { /* Check for the ASCII '<' */
    102                 if (inMarkup) {
    103                     badTags += 1;
    104                 }
    105 
    106                 inMarkup = TRUE;
    107                 openTags += 1;
    108             }
    109 
    110             if (! inMarkup) {
    111                 fInputBytes[dsti++] = b;
    112             }
    113 
    114             if (b == (uint8_t)0x3E) { /* Check for the ASCII '>' */
    115                 inMarkup = FALSE;
    116             }
    117         }
    118 
    119         fInputLen = dsti;
    120     }
    121 
    122     //
    123     //  If it looks like this input wasn't marked up, or if it looks like it's
    124     //    essentially nothing but markup abandon the markup stripping.
    125     //    Detection will have to work on the unstripped input.
    126     //
    127     if (openTags<5 || openTags/5 < badTags ||
    128         (fInputLen < 100 && fRawLength>600))
    129     {
    130         int32_t limit = fRawLength;
    131 
    132         if (limit > BUFFER_SIZE) {
    133             limit = BUFFER_SIZE;
    134         }
    135 
    136         for (srci=0; srci<limit; srci++) {
    137             fInputBytes[srci] = fRawInput[srci];
    138         }
    139 
    140         fInputLen = srci;
    141     }
    142 
    143     //
    144     // Tally up the byte occurence statistics.
    145     // These are available for use by the various detectors.
    146     //
    147 
    148     uprv_memset(fByteStats, 0, (sizeof fByteStats[0]) * 256);
    149 
    150     for (srci = 0; srci < fInputLen; srci += 1) {
    151         fByteStats[fInputBytes[srci]] += 1;
    152     }
    153 
    154     for (int32_t i = 0x80; i <= 0x9F; i += 1) {
    155         if (fByteStats[i] != 0) {
    156             fC1Bytes = TRUE;
    157             break;
    158         }
    159     }
    160 }
    161 
    162 U_NAMESPACE_END
    163 #endif
    164 
    165