kc3-lang/md4c/md2html/render_html.c

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• Hash : dc3dde78
  Author :
  Date : 2017-08-28T16:14:04
  

  render_html: Add a new line after <ol>. This makes the behavior more consistent with <ul>.

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• md2html/render_html.c

• /*
   * MD4C: Markdown parser for C
   * (http://github.com/mity/md4c)
   *
   * Copyright (c) 2016-2017 Martin Mitas
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   */
  
  #include <stdio.h>
  #include <string.h>
  
  #include "render_html.h"
  #include "entity.h"
  
  
  #ifdef _MSC_VER
      /* MSVC does not understand "inline" when building as pure C (not C++).
       * However it understands "__inline" */
      #ifndef __cplusplus
          #define inline __inline
      #endif
  #endif
  
  #ifdef _WIN32
      #define snprintf _snprintf
  #endif
  
  
  
  typedef struct MD_RENDER_HTML_tag MD_RENDER_HTML;
  struct MD_RENDER_HTML_tag {
      void (*process_output)(const MD_CHAR*, MD_SIZE, void*);
      void* userdata;
      unsigned flags;
  };
  
  
  /*****************************************
   ***  HTML rendering helper functions  ***
   *****************************************/
  
  #define ISDIGIT(ch)     ('0' <= (ch) && (ch) <= '9')
  #define ISLOWER(ch)     ('a' <= (ch) && (ch) <= 'z')
  #define ISUPPER(ch)     ('A' <= (ch) && (ch) <= 'Z')
  #define ISALNUM(ch)     (ISLOWER(ch) || ISUPPER(ch) || ISDIGIT(ch))
  
  
  static inline void
  render_text(MD_RENDER_HTML* r, const MD_CHAR* text, MD_SIZE size)
  {
      r->process_output(text, size, r->userdata);
  }
  
  #define RENDER_LITERAL(r, literal)    render_text((r), (literal), strlen(literal))
  
  
  static void
  render_html_escaped(MD_RENDER_HTML* r, const MD_CHAR* data, MD_SIZE size)
  {
      MD_OFFSET beg = 0;
      MD_OFFSET off = 0;
  
      /* Some characters need to be escaped in normal HTML text. */
      #define HTML_NEED_ESCAPE(ch)                                            \
              ((ch) == '&' || (ch) == '<' || (ch) == '>' || (ch) == '"')
  
      while(1) {
          while(off < size  &&  !HTML_NEED_ESCAPE(data[off]))
              off++;
          if(off > beg)
              render_text(r, data + beg, off - beg);
  
          if(off < size) {
              switch(data[off]) {
                  case '&':   RENDER_LITERAL(r, "&amp;"); break;
                  case '<':   RENDER_LITERAL(r, "&lt;"); break;
                  case '>':   RENDER_LITERAL(r, "&gt;"); break;
                  case '"':   RENDER_LITERAL(r, "&quot;"); break;
              }
              off++;
          } else {
              break;
          }
          beg = off;
      }
  }
  
  static void
  render_url_escaped(MD_RENDER_HTML* r, const MD_CHAR* data, MD_SIZE size)
  {
      static const MD_CHAR hex_chars[] = "0123456789ABCDEF";
      MD_OFFSET beg = 0;
      MD_OFFSET off = 0;
  
      #define URL_NEED_ESCAPE(ch)                                             \
              (!ISALNUM(ch)  &&  strchr("-_.+!*'(),%#@?=;:/,+$", ch) == NULL)
  
      while(1) {
          while(off < size  &&  !URL_NEED_ESCAPE(data[off]))
              off++;
          if(off > beg)
              render_text(r, data + beg, off - beg);
  
          if(off < size) {
              char hex[3];
  
              switch(data[off]) {
                  case '&':   RENDER_LITERAL(r, "&amp;"); break;
                  case '\'':  RENDER_LITERAL(r, "&#x27;"); break;
                  default:
                      hex[0] = '%';
                      hex[1] = hex_chars[((unsigned)data[off] >> 4) & 0xf];
                      hex[2] = hex_chars[((unsigned)data[off] >> 0) & 0xf];
                      render_text(r, hex, 3);
                      break;
              }
              off++;
          } else {
              break;
          }
  
          beg = off;
      }
  }
  
  static unsigned
  hex_val(char ch)
  {
      if('0' <= ch && ch <= '9')
          return ch - '0';
      if('A' <= ch && ch <= 'Z')
          return ch - 'A' + 10;
      else
          return ch - 'a' + 10;
  }
  
  static void
  render_utf8_codepoint(MD_RENDER_HTML* r, unsigned codepoint,
                        void (*fn_append)(MD_RENDER_HTML*, const MD_CHAR*, MD_SIZE))
  {
      static const MD_CHAR utf8_replacement_char[] = { 0xef, 0xbf, 0xbd };
  
      unsigned char utf8[4];
      size_t n;
  
      if(codepoint <= 0x7f) {
          n = 1;
          utf8[0] = codepoint;
      } else if(codepoint <= 0x7ff) {
          n = 2;
          utf8[0] = 0xc0 | ((codepoint >>  6) & 0x1f);
          utf8[1] = 0x80 + ((codepoint >>  0) & 0x3f);
      } else if(codepoint <= 0xffff) {
          n = 3;
          utf8[0] = 0xe0 | ((codepoint >> 12) & 0xf);
          utf8[1] = 0x80 + ((codepoint >>  6) & 0x3f);
          utf8[2] = 0x80 + ((codepoint >>  0) & 0x3f);
      } else {
          n = 4;
          utf8[0] = 0xf0 | ((codepoint >> 18) & 0x7);
          utf8[1] = 0x80 + ((codepoint >> 12) & 0x3f);
          utf8[2] = 0x80 + ((codepoint >>  6) & 0x3f);
          utf8[3] = 0x80 + ((codepoint >>  0) & 0x3f);
      }
  
      if(0 < codepoint  &&  codepoint <= 0x10ffff)
          fn_append(r, (char*)utf8, n);
      else
          fn_append(r, utf8_replacement_char, 3);
  }
  
  /* Translate entity to its UTF-8 equivalent, or output the verbatim one
   * if such entity is unknown (or if the translation is disabled). */
  static void
  render_entity(MD_RENDER_HTML* r, const MD_CHAR* text, MD_SIZE size,
                void (*fn_append)(MD_RENDER_HTML*, const MD_CHAR*, MD_SIZE))
  {
      if(r->flags & MD_RENDER_FLAG_VERBATIM_ENTITIES) {
          fn_append(r, text, size);
          return;
      }
  
      /* We assume UTF-8 output is what is desired. */
      if(size > 3 && text[1] == '#') {
          unsigned codepoint = 0;
  
          if(text[2] == 'x' || text[2] == 'X') {
              /* Hexadecimal entity (e.g. "&#x1234abcd;")). */
              MD_SIZE i;
              for(i = 3; i < size-1; i++)
                  codepoint = 16 * codepoint + hex_val(text[i]);
          } else {
              /* Decimal entity (e.g. "&1234;") */
              MD_SIZE i;
              for(i = 2; i < size-1; i++)
                  codepoint = 10 * codepoint + (text[i] - '0');
          }
  
          render_utf8_codepoint(r, codepoint, fn_append);
          return;
      } else {
          /* Named entity (e.g. "&nbsp;"). */
          const struct entity* ent;
  
          ent = entity_lookup(text, size);
          if(ent != NULL) {
              render_utf8_codepoint(r, ent->codepoints[0], fn_append);
              if(ent->codepoints[1])
                  render_utf8_codepoint(r, ent->codepoints[1], fn_append);
              return;
          }
      }
  
      fn_append(r, text, size);
  }
  
  static void
  render_attribute(MD_RENDER_HTML* r, const MD_ATTRIBUTE* attr,
                   void (*fn_append)(MD_RENDER_HTML*, const MD_CHAR*, MD_SIZE))
  {
      int i;
  
      for(i = 0; attr->substr_offsets[i] < attr->size; i++) {
          MD_TEXTTYPE type = attr->substr_types[i];
          MD_OFFSET off = attr->substr_offsets[i];
          MD_SIZE size = attr->substr_offsets[i+1] - off;
          const MD_CHAR* text = attr->text + off;
  
          switch(type) {
              case MD_TEXT_ENTITY:    render_entity(r, text, size, fn_append); break;
              default:                fn_append(r, text, size); break;
          }
      }
  }
  
  
  static int image_nesting_level = 0;
  
  static void
  render_open_ol_block(MD_RENDER_HTML* r, const MD_BLOCK_OL_DETAIL* det)
  {
      char buf[64];
  
      if(det->start == 1) {
          RENDER_LITERAL(r, "<ol>\n");
          return;
      }
  
      snprintf(buf, sizeof(buf), "<ol start=\"%u\">\n", det->start);
      RENDER_LITERAL(r, buf);
  }
  
  static void
  render_open_code_block(MD_RENDER_HTML* r, const MD_BLOCK_CODE_DETAIL* det)
  {
      RENDER_LITERAL(r, "<pre><code");
  
      /* If known, output the HTML 5 attribute class="language-LANGNAME". */
      if(det->lang.text != NULL) {
          RENDER_LITERAL(r, " class=\"language-");
          render_attribute(r, &det->lang, render_html_escaped);
          RENDER_LITERAL(r, "\"");
      }
  
      RENDER_LITERAL(r, ">");
  }
  
  static void
  render_open_td_block(MD_RENDER_HTML* r, const MD_CHAR* cell_type, const MD_BLOCK_TD_DETAIL* det)
  {
      RENDER_LITERAL(r, "<");
      RENDER_LITERAL(r, cell_type);
  
      switch(det->align) {
          case MD_ALIGN_LEFT:     RENDER_LITERAL(r, " align=\"left\">"); break;
          case MD_ALIGN_CENTER:   RENDER_LITERAL(r, " align=\"center\">"); break;
          case MD_ALIGN_RIGHT:    RENDER_LITERAL(r, " align=\"right\">"); break;
          default:                RENDER_LITERAL(r, ">"); break;
      }
  }
  
  static void
  render_open_a_span(MD_RENDER_HTML* r, const MD_SPAN_A_DETAIL* det)
  {
      RENDER_LITERAL(r, "<a href=\"");
      render_attribute(r, &det->href, render_url_escaped);
  
      if(det->title.text != NULL) {
          RENDER_LITERAL(r, "\" title=\"");
          render_attribute(r, &det->title, render_html_escaped);
      }
  
      RENDER_LITERAL(r, "\">");
  }
  
  static void
  render_open_img_span(MD_RENDER_HTML* r, const MD_SPAN_IMG_DETAIL* det)
  {
      RENDER_LITERAL(r, "<img src=\"");
      render_attribute(r, &det->src, render_url_escaped);
  
      RENDER_LITERAL(r, "\" alt=\"");
  
      image_nesting_level++;
  }
  
  static void
  render_close_img_span(MD_RENDER_HTML* r, const MD_SPAN_IMG_DETAIL* det)
  {
      if(det->title.text != NULL) {
          RENDER_LITERAL(r, "\" title=\"");
          render_attribute(r, &det->title, render_html_escaped);
      }
  
      RENDER_LITERAL(r, "\">");
  
      image_nesting_level--;
  }
  
  
  /**************************************
   ***  HTML renderer implementation  ***
   **************************************/
  
  static int
  enter_block_callback(MD_BLOCKTYPE type, void* detail, void* userdata)
  {
      static const MD_CHAR* head[6] = { "<h1>", "<h2>", "<h3>", "<h4>", "<h5>", "<h6>" };
      MD_RENDER_HTML* r = (MD_RENDER_HTML*) userdata;
  
      switch(type) {
          case MD_BLOCK_DOC:      /* noop */ break;
          case MD_BLOCK_QUOTE:    RENDER_LITERAL(r, "<blockquote>\n"); break;
          case MD_BLOCK_UL:       RENDER_LITERAL(r, "<ul>\n"); break;
          case MD_BLOCK_OL:       render_open_ol_block(r, (const MD_BLOCK_OL_DETAIL*)detail); break;
          case MD_BLOCK_LI:       RENDER_LITERAL(r, "<li>"); break;
          case MD_BLOCK_HR:       RENDER_LITERAL(r, "<hr>\n"); break;
          case MD_BLOCK_H:        RENDER_LITERAL(r, head[((MD_BLOCK_H_DETAIL*)detail)->level - 1]); break;
          case MD_BLOCK_CODE:     render_open_code_block(r, (const MD_BLOCK_CODE_DETAIL*) detail); break;
          case MD_BLOCK_HTML:     /* noop */ break;
          case MD_BLOCK_P:        RENDER_LITERAL(r, "<p>"); break;
          case MD_BLOCK_TABLE:    RENDER_LITERAL(r, "<table>\n"); break;
          case MD_BLOCK_THEAD:    RENDER_LITERAL(r, "<thead>\n"); break;
          case MD_BLOCK_TBODY:    RENDER_LITERAL(r, "<tbody>\n"); break;
          case MD_BLOCK_TR:       RENDER_LITERAL(r, "<tr>\n"); break;
          case MD_BLOCK_TH:       render_open_td_block(r, "th", (MD_BLOCK_TD_DETAIL*)detail); break;
          case MD_BLOCK_TD:       render_open_td_block(r, "td", (MD_BLOCK_TD_DETAIL*)detail); break;
      }
  
      return 0;
  }
  
  static int
  leave_block_callback(MD_BLOCKTYPE type, void* detail, void* userdata)
  {
      static const MD_CHAR* head[6] = { "</h1>\n", "</h2>\n", "</h3>\n", "</h4>\n", "</h5>\n", "</h6>\n" };
      MD_RENDER_HTML* r = (MD_RENDER_HTML*) userdata;
  
      switch(type) {
          case MD_BLOCK_DOC:      /*noop*/ break;
          case MD_BLOCK_QUOTE:    RENDER_LITERAL(r, "</blockquote>\n"); break;
          case MD_BLOCK_UL:       RENDER_LITERAL(r, "</ul>\n"); break;
          case MD_BLOCK_OL:       RENDER_LITERAL(r, "</ol>\n"); break;
          case MD_BLOCK_LI:       RENDER_LITERAL(r, "</li>\n"); break;
          case MD_BLOCK_HR:       /*noop*/ break;
          case MD_BLOCK_H:        RENDER_LITERAL(r, head[((MD_BLOCK_H_DETAIL*)detail)->level - 1]); break;
          case MD_BLOCK_CODE:     RENDER_LITERAL(r, "</code></pre>\n"); break;
          case MD_BLOCK_HTML:     /* noop */ break;
          case MD_BLOCK_P:        RENDER_LITERAL(r, "</p>\n"); break;
          case MD_BLOCK_TABLE:    RENDER_LITERAL(r, "</table>\n"); break;
          case MD_BLOCK_THEAD:    RENDER_LITERAL(r, "</thead>\n"); break;
          case MD_BLOCK_TBODY:    RENDER_LITERAL(r, "</tbody>\n"); break;
          case MD_BLOCK_TR:       RENDER_LITERAL(r, "</tr>\n"); break;
          case MD_BLOCK_TH:       RENDER_LITERAL(r, "</th>\n"); break;
          case MD_BLOCK_TD:       RENDER_LITERAL(r, "</td>\n"); break;
      }
  
      return 0;
  }
  
  static int
  enter_span_callback(MD_SPANTYPE type, void* detail, void* userdata)
  {
      MD_RENDER_HTML* r = (MD_RENDER_HTML*) userdata;
  
      if(image_nesting_level > 0) {
          /* We are inside an image, i.e. rendering the ALT attribute of
           * <IMG> tag. */
          return 0;
      }
  
      switch(type) {
          case MD_SPAN_EM:        RENDER_LITERAL(r, "<em>"); break;
          case MD_SPAN_STRONG:    RENDER_LITERAL(r, "<strong>"); break;
          case MD_SPAN_A:         render_open_a_span(r, (MD_SPAN_A_DETAIL*) detail); break;
          case MD_SPAN_IMG:       render_open_img_span(r, (MD_SPAN_IMG_DETAIL*) detail); break;
          case MD_SPAN_CODE:      RENDER_LITERAL(r, "<code>"); break;
          case MD_SPAN_DEL:       RENDER_LITERAL(r, "<del>"); break;
      }
  
      return 0;
  }
  
  static int
  leave_span_callback(MD_SPANTYPE type, void* detail, void* userdata)
  {
      MD_RENDER_HTML* r = (MD_RENDER_HTML*) userdata;
  
      if(image_nesting_level > 0) {
          /* We are inside an image, i.e. rendering the ALT attribute of
           * <IMG> tag. */
          if(image_nesting_level == 1  &&  type == MD_SPAN_IMG)
              render_close_img_span(r, (MD_SPAN_IMG_DETAIL*) detail);
          return 0;
      }
  
      switch(type) {
          case MD_SPAN_EM:        RENDER_LITERAL(r, "</em>"); break;
          case MD_SPAN_STRONG:    RENDER_LITERAL(r, "</strong>"); break;
          case MD_SPAN_A:         RENDER_LITERAL(r, "</a>"); break;
          case MD_SPAN_IMG:       /*noop, handled above*/ break;
          case MD_SPAN_CODE:      RENDER_LITERAL(r, "</code>"); break;
          case MD_SPAN_DEL:       RENDER_LITERAL(r, "</del>"); break;
      }
  
      return 0;
  }
  
  static int
  text_callback(MD_TEXTTYPE type, const MD_CHAR* text, MD_SIZE size, void* userdata)
  {
      MD_RENDER_HTML* r = (MD_RENDER_HTML*) userdata;
  
      switch(type) {
          case MD_TEXT_NULLCHAR:  render_utf8_codepoint(r, 0x0000, render_text); break;
          case MD_TEXT_BR:        RENDER_LITERAL(r, (image_nesting_level == 0 ? "<br>\n" : " ")); break;
          case MD_TEXT_SOFTBR:    RENDER_LITERAL(r, (image_nesting_level == 0 ? "\n" : " ")); break;
          case MD_TEXT_HTML:      render_text(r, text, size); break;
          case MD_TEXT_ENTITY:    render_entity(r, text, size, render_html_escaped); break;
          default:                render_html_escaped(r, text, size); break;
      }
  
      return 0;
  }
  
  static void
  debug_log_callback(const char* msg, void* userdata)
  {
      MD_RENDER_HTML* r = (MD_RENDER_HTML*) userdata;
      if(r->flags & MD_RENDER_FLAG_DEBUG)
          fprintf(stderr, "MD4C: %s\n", msg);
  }
  
  int
  md_render_html(const MD_CHAR* input, MD_SIZE input_size,
                 void (*process_output)(const MD_CHAR*, MD_SIZE, void*),
                 void* userdata, unsigned parser_flags, unsigned renderer_flags)
  {
      MD_RENDER_HTML render = { process_output, userdata, renderer_flags };
  
      MD_RENDERER renderer = {
          enter_block_callback,
          leave_block_callback,
          enter_span_callback,
          leave_span_callback,
          text_callback,
          debug_log_callback,
          parser_flags
      };
  
      return md_parse(input, input_size, &renderer, (void*) &render);
  }
  
  

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