squilu/gumbo/tag.c

// Copyright 2011 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Author: [email protected] (Jonathan Tang)

#include "gumbo.h"

#include <assert.h>
#include <ctype.h>
#include <string.h>

const char* kGumboTagNames[] = {
#include "tag_strings.h"
    "",  // TAG_UNKNOWN
    "",  // TAG_LAST
};

static const unsigned char kGumboTagSizes[] = {
#include "tag_sizes.h"
    0,  // TAG_UNKNOWN
    0,  // TAG_LAST
};

const char* gumbo_normalized_tagname(GumboTag tag) {
  assert(tag <= GUMBO_TAG_LAST);
  return kGumboTagNames[tag];
}

void gumbo_tag_from_original_text(GumboStringPiece* text) {
  if (text->data == NULL) {
    return;
  }

  assert(text->length >= 2);
  assert(text->data[0] == '<');
  assert(text->data[text->length - 1] == '>');
  if (text->data[1] == '/') {
    // End tag.
    assert(text->length >= 3);
    text->data += 2;  // Move past </
    text->length -= 3;
  } else {
    // Start tag.
    text->data += 1;  // Move past <
    text->length -= 2;
    // strnchr is apparently not a standard C library function, so I loop
    // explicitly looking for whitespace or other illegal tag characters.
    for (const char* c = text->data; c != text->data + text->length; ++c) {
      if (isspace(*c) || *c == '/') {
        text->length = c - text->data;
        break;
      }
    }
  }
}

static int case_memcmp(const char* s1, const char* s2, unsigned int n) {
  while (n--) {
    unsigned char c1 = tolower(*s1++);
    unsigned char c2 = tolower(*s2++);
    if (c1 != c2) return (int) c1 - (int) c2;
  }
  return 0;
}

#include "tag_gperf.h"
#define TAG_MAP_SIZE (sizeof(kGumboTagMap) / sizeof(kGumboTagMap[0]))

GumboTag gumbo_tagn_enum(const char* tagname, unsigned int length) {
  if (length) {
    unsigned int key = tag_hash(tagname, length);
    if (key < TAG_MAP_SIZE) {
      GumboTag tag = kGumboTagMap[key];
      if (length == kGumboTagSizes[(int) tag] &&
          !case_memcmp(tagname, kGumboTagNames[(int) tag], length))
        return tag;
    }
  }
  return GUMBO_TAG_UNKNOWN;
}

GumboTag gumbo_tag_enum(const char* tagname) {
  return gumbo_tagn_enum(tagname, strlen(tagname));
}