[ORC-1034] The search byte array algorithm is incorrectly implemented in FileDump.java

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.0, 1.6.11
• Fix Version/s: 1.7.1, 1.6.12
• Component/s: Java, tools
• Assignee: Yiqun Zhang
• Reporter: Yiqun Zhang
• Created: 20/Oct/21 08:21
• Updated: 02/Feb/22 23:52
• Resolved: 20/Oct/21 20:35

Description

  private static int indexOf(final byte[] data, final byte[] pattern, final int index) {
    if (data == null || data.length == 0 || pattern == null || pattern.length == 0 ||
        index > data.length || index < 0) {
      return -1;
    }

    int j = 0;
    for (int i = index; i < data.length; i++) {
      if (pattern[j] == data[i]) {
        j++;
      } else {
        j = 0;
      }

      if (j == pattern.length) {
        return i - pattern.length + 1;
      }
    }

    return -1;
  }

This matching algorithm is wrong when i does not backtrack after a failed match in the middle. As a simple example data = OOORC, pattern= ORC, index = 1, this algorithm will return -1.

Issue Links

• links to: GitHub Pull Request #943