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libcitadel  8.12
Functions
html_to_ascii.c File Reference
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <ctype.h>
#include <string.h>
#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <time.h>
#include "libcitadel.h"

Go to the source code of this file.

Functions

char * html_to_ascii (const char *inputmsg, int msglen, int screenwidth, int do_citaformat)

Function Documentation

char* html_to_ascii ( const char *  inputmsg,
int  msglen,
int  screenwidth,
int  do_citaformat 
)

Definition at line 52 of file html_to_ascii.c.

                                                                                          {
       char inbuf[SIZ];
       int inbuf_len = 0;
       char outbuf[SIZ];
       char tag[1024];
       int done_reading = 0;
       const char *inptr;
       char *outptr;
       size_t outptr_buffer_size;
       size_t output_len = 0;
       int i, j, ch, did_out, rb, scanch;
       int nest = 0;        /* Bracket nesting level */
       int blockquote = 0;  /* BLOCKQUOTE nesting level */
       int styletag = 0;    /* STYLE tag nesting level */
       int styletag_start = 0;
       int bytes_processed = 0;
       char nl[128];

       tag[0] = '\0';
       strcpy(nl, "\n");
       inptr = inputmsg;
       strcpy(inbuf, "");
       strcpy(outbuf, "");
       if (msglen == 0) msglen = strlen(inputmsg);

       outptr_buffer_size = strlen(inptr) + SIZ;
       outptr = malloc(outptr_buffer_size);
       if (outptr == NULL) return NULL;
       strcpy(outptr, "");
       output_len = 0;

       do {
              /* Fill the input buffer */
              inbuf_len = strlen(inbuf);
              if ( (done_reading == 0) && (inbuf_len < (SIZ-128)) ) {

                     ch = *inptr++;
                     if (ch != 0) {
                            inbuf[inbuf_len++] = ch;
                            inbuf[inbuf_len] = 0;
                     } 
                     else {
                            done_reading = 1;
                     }

                     ++bytes_processed;
                     if (bytes_processed > msglen) {
                            done_reading = 1;
                     }

              }

              /* Do some parsing */
              if (!IsEmptyStr(inbuf)) {


                  /* Fold in all the spacing */
                  for (i=0; !IsEmptyStr(&inbuf[i]); ++i) {
                     if (inbuf[i]==10) inbuf[i]=32;
                     if (inbuf[i]==13) inbuf[i]=32;
                     if (inbuf[i]==9) inbuf[i]=32;
                  }
                  for (i=0; !IsEmptyStr(&inbuf[i]); ++i) {
                     while ((inbuf[i]==32)&&(inbuf[i+1]==32)) {
                            strcpy(&inbuf[i], &inbuf[i+1]);
                     }
                  }

                  for (i=0; !IsEmptyStr(&inbuf[i]); ++i) {

                     ch = inbuf[i];

                     if (ch == '<') {
                            ++nest;
                            strcpy(tag, "");
                     }

                     else if (ch == '>') {       /* We have a tag. */
                            if (nest > 0) --nest;

                            /* Unqualify the tag (truncate at first space) */
                            if (strchr(tag, ' ') != NULL) {
                                   strcpy(strchr(tag, ' '), "");
                            }
                            
                            if (!strcasecmp(tag, "P")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            if (!strcasecmp(tag, "/DIV")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            if (!strcasecmp(tag, "LI")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, " * ");
                            }

                            else if (!strcasecmp(tag, "/UL")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "H1")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "H2")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "H3")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "H4")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "/H1")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "/H2")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "/H3")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "/H4")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "HR")) {
                                   strcat(outbuf, nl);
                                   strcat(outbuf, " ");
                                   for (j=0; j<screenwidth-2; ++j)
                                          strcat(outbuf, "-");
                                   strcat(outbuf, nl);
                            }

                            else if (
                                   (!strcasecmp(tag, "B"))
                                   || (!strcasecmp(tag, "/B"))
                                   || (!strcasecmp(tag, "STRONG"))
                                   || (!strcasecmp(tag, "/STRONG"))
                            ) {
                                   strcat(outbuf, "*");
                                   
                            }

                            else if (
                                   (!strcasecmp(tag, "I"))
                                   || (!strcasecmp(tag, "/I"))
                                   || (!strcasecmp(tag, "EM"))
                                   || (!strcasecmp(tag, "/EM"))
                            ) {
                                   strcat(outbuf, "/");
                                   
                            }

                            else if (
                                   (!strcasecmp(tag, "U"))
                                   || (!strcasecmp(tag, "/U"))
                            ) {
                                   strcat(outbuf, "_");
                                   
                            }

                            else if (!strcasecmp(tag, "BR")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "TR")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "/TABLE")) {
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "BLOCKQUOTE")) {
                                   ++blockquote;
                                   strcpy(nl, "\n");
                                   for (j=0; j<blockquote; ++j) strcat(nl, ">");
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "/BLOCKQUOTE")) {
                                   strcat(outbuf, "\n");
                                   --blockquote;
                                   strcpy(nl, "\n");
                                   for (j=0; j<blockquote; ++j) strcat(nl, ">");
                                   strcat(outbuf, nl);
                            }

                            else if (!strcasecmp(tag, "STYLE")) {
                                   ++styletag;
                                   if (styletag == 1) {
                                          styletag_start = strlen(outbuf);
                                   }
                            }

                            else if (!strcasecmp(tag, "/STYLE")) {
                                   --styletag;
                                   if (styletag == 0) {
                                          outbuf[styletag_start] = 0;
                                   }
                            }

                     }

                     else if ((nest > 0) && (strlen(tag)<(sizeof(tag)-1))) {
                            tag[strlen(tag)+1] = 0;
                            tag[strlen(tag)] = ch;
                     }
                            
                     else if (!nest) {
                            outbuf[strlen(outbuf)+1] = 0;
                            outbuf[strlen(outbuf)] = ch;
                     }
                  }
                  strcpy(inbuf, &inbuf[i]);
              }

              /* Convert &; tags to the forbidden characters */
              if (!IsEmptyStr(outbuf)) for (i=0; !IsEmptyStr(&outbuf[i]); ++i) {

                     /* Character entity references */
                     if (!strncasecmp(&outbuf[i], "&nbsp;", 6)) {
                            outbuf[i] = ' ';
                            strcpy(&outbuf[i+1], &outbuf[i+6]);
                     }

                     if (!strncasecmp(&outbuf[i], "&ensp;", 6)) {
                            outbuf[i] = ' ';
                            strcpy(&outbuf[i+1], &outbuf[i+6]);
                     }

                     if (!strncasecmp(&outbuf[i], "&emsp;", 6)) {
                            outbuf[i] = ' ';
                            strcpy(&outbuf[i+1], &outbuf[i+6]);
                     }

                     if (!strncasecmp(&outbuf[i], "&thinsp;", 8)) {
                            outbuf[i] = ' ';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&lt;", 4)) {
                            outbuf[i] = '<';
                            strcpy(&outbuf[i+1], &outbuf[i+4]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&gt;", 4)) {
                            outbuf[i] = '>';
                            strcpy(&outbuf[i+1], &outbuf[i+4]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&amp;", 5)) {
                            strcpy(&outbuf[i+1], &outbuf[i+5]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&quot;", 6)) {
                            outbuf[i] = '\"';
                            strcpy(&outbuf[i+1], &outbuf[i+6]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&lsquo;", 7)) {
                            outbuf[i] = '`';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&rsquo;", 7)) {
                            outbuf[i] = '\'';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&copy;", 6)) {
                            outbuf[i] = '(';
                            outbuf[i+1] = 'c';
                            outbuf[i+2] = ')';
                            strcpy(&outbuf[i+3], &outbuf[i+6]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&bull;", 6)) {
                            outbuf[i] = ' ';
                            outbuf[i+1] = '*';
                            outbuf[i+2] = ' ';
                            strcpy(&outbuf[i+3], &outbuf[i+6]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&hellip;", 8)) {
                            outbuf[i] = '.';
                            outbuf[i+1] = '.';
                            outbuf[i+2] = '.';
                            strcpy(&outbuf[i+3], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&trade;", 7)) {
                            outbuf[i] = '(';
                            outbuf[i+1] = 't';
                            outbuf[i+2] = 'm';
                            outbuf[i+3] = ')';
                            strcpy(&outbuf[i+4], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&reg;", 5)) {
                            outbuf[i] = '(';
                            outbuf[i+1] = 'r';
                            outbuf[i+2] = ')';
                            strcpy(&outbuf[i+3], &outbuf[i+5]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&frac14;", 8)) {
                            outbuf[i] = '1';
                            outbuf[i+1] = '/';
                            outbuf[i+2] = '4';
                            strcpy(&outbuf[i+3], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&frac12;", 8)) {
                            outbuf[i] = '1';
                            outbuf[i+1] = '/';
                            outbuf[i+2] = '2';
                            strcpy(&outbuf[i+3], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&frac34;", 8)) {
                            outbuf[i] = '3';
                            outbuf[i+1] = '/';
                            outbuf[i+2] = '4';
                            strcpy(&outbuf[i+3], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&ndash;", 7)) {
                            outbuf[i] = '-';
                            outbuf[i+1] = '-';
                            strcpy(&outbuf[i+2], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&mdash;", 7)) {
                            outbuf[i] = '-';
                            outbuf[i+1] = '-';
                            outbuf[i+2] = '-';
                            strcpy(&outbuf[i+3], &outbuf[i+7]);
                     }

                     else if (!strncmp(&outbuf[i], "&Ccedil;", 8)) {
                            outbuf[i] = 'C';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&ccedil;", 8)) {
                            outbuf[i] = 'c';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncmp(&outbuf[i], "&Egrave;", 8)) {
                            outbuf[i] = 'E';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&egrave;", 8)) {
                            outbuf[i] = 'e';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncmp(&outbuf[i], "&Ecirc;", 7)) {
                            outbuf[i] = 'E';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&ecirc;", 7)) {
                            outbuf[i] = 'e';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncmp(&outbuf[i], "&Eacute;", 8)) {
                            outbuf[i] = 'E';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&eacute;", 8)) {
                            outbuf[i] = 'e';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncmp(&outbuf[i], "&Agrave;", 8)) {
                            outbuf[i] = 'A';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&agrave;", 8)) {
                            outbuf[i] = 'a';
                            strcpy(&outbuf[i+1], &outbuf[i+8]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&ldquo;", 7)) {
                            outbuf[i] = '\"';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&rdquo;", 7)) {
                            outbuf[i] = '\"';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&acute;", 7)) {
                            outbuf[i] = '\'';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&#8217;", 7)) {
                            outbuf[i] = '\'';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     else if (!strncasecmp(&outbuf[i], "&#8211;", 7)) {
                            outbuf[i] = '-';
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

                     /* two-digit decimal equivalents */
                     else if (outbuf[i] == '&'       &&
                             outbuf[i + 1] == '#'   &&
                             isdigit(outbuf[i + 2]) && 
                             isdigit(outbuf[i + 3]) &&
                             (outbuf[i+4] == ';') ) 
                     {
                            scanch = 0;
                            sscanf(&outbuf[i+2], "%02d", &scanch);
                            outbuf[i] = scanch;
                            strcpy(&outbuf[i+1], &outbuf[i+5]);
                     }

                     /* three-digit decimal equivalents */
                     else if (outbuf[i] == '&'       &&
                             outbuf[i + 1] == '#'   &&
                             isdigit(outbuf[i + 2]) && 
                             isdigit(outbuf[i + 3]) && 
                             isdigit(outbuf[i + 4]) &&
                             (outbuf[i + 5] == ';') ) 
                     {
                            scanch = 0;
                            sscanf(&outbuf[i+2], "%03d", &scanch);
                            outbuf[i] = scanch;
                            strcpy(&outbuf[i+1], &outbuf[i+6]);
                     }

                     /* four-digit decimal equivalents */
                     else if (outbuf[i] == '&'       &&
                             outbuf[i + 1] == '#'   &&
                             isdigit(outbuf[i + 2]) && 
                             isdigit(outbuf[i + 3]) && 
                             isdigit(outbuf[i + 4]) &&
                             isdigit(outbuf[i + 5]) &&
                             (outbuf[i + 6] == ';') ) 
                     {
                            scanch = 0;
                            sscanf(&outbuf[i+2], "%04d", &scanch);
                            outbuf[i] = scanch;
                            strcpy(&outbuf[i+1], &outbuf[i+7]);
                     }

              }

              /* Make sure the output buffer is big enough */
              if ((output_len + strlen(outbuf) + SIZ) > outptr_buffer_size) {
                     outptr_buffer_size += SIZ;
                     outptr = realloc(outptr, outptr_buffer_size);
                     if (outptr == NULL) {
                            abort();
                     }
              }

              /* Output any lines terminated with hard line breaks */
              do {
                     did_out = 0;
                     if (strlen(outbuf) > 0) {
                         for (i = 0; i<strlen(outbuf); ++i) {
                            if ( (i<(screenwidth-2)) && (outbuf[i]=='\n')) {

                                   strncpy(&outptr[output_len], outbuf, i+1);
                                   output_len += (i+1);

                                   if (do_citaformat) {
                                          strcpy(&outptr[output_len], " ");
                                          ++output_len;
                                   }

                                   strcpy(outbuf, &outbuf[i+1]);
                                   i = 0;
                                   did_out = 1;
                            }
                     }
                  }
              } while (did_out);

              /* Add soft line breaks */
              if (strlen(outbuf) > (screenwidth - 2 )) {
                     rb = (-1);
                     for (i=0; i<(screenwidth-2); ++i) {
                            if (outbuf[i]==32) rb = i;
                     }
                     if (rb>=0) {
                            strncpy(&outptr[output_len], outbuf, rb);
                            output_len += rb;
                            strcpy(&outptr[output_len], nl);
                            output_len += strlen(nl);
                            if (do_citaformat) {
                                   strcpy(&outptr[output_len], " ");
                                   ++output_len;
                            }
                            strcpy(outbuf, &outbuf[rb+1]);
                     } else {
                            strncpy(&outptr[output_len], outbuf,
                                   screenwidth-2);
                            output_len += (screenwidth-2);
                            strcpy(&outptr[output_len], nl);
                            output_len += strlen(nl);
                            if (do_citaformat) {
                                   strcpy(&outptr[output_len], " ");
                                   ++output_len;
                            }
                            strcpy(outbuf, &outbuf[screenwidth-2]);
                     }
              }

       } while (done_reading == 0);

       strcpy(&outptr[output_len], outbuf);
       output_len += strlen(outbuf);

       /* Strip leading/trailing whitespace.  We can't do this with
        * striplt() because it uses too many strlen()'s
        */
       while ((output_len > 0) && (isspace(outptr[0]))) {
              strcpy(outptr, &outptr[1]);
              --output_len;
       }
       while ((output_len > 0) && (isspace(outptr[output_len-1]))) {
              outptr[output_len-1] = 0;
              --output_len;
       }

       if ((output_len > 0) && (outptr[output_len-1] != '\n')) {
              strcat(outptr, "\n");
              ++output_len;
       }

       return outptr;

}

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