diff --git a/configure.ac b/configure.ac
index 1d5d457..08fbf4e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -44,10 +44,10 @@ AC_TYPE_UINT8_T
 AC_FUNC_MKTIME
 AC_FUNC_MALLOC
 AC_FUNC_REALLOC
-AC_CHECK_FUNCS([memset mkdir strdup strrchr strstr strtoul utime])
+AC_CHECK_FUNCS([memmove memset mkdir strdup strpbrk strrchr strstr strtoul utime])
 
 # test for --with-zlib
-AC_MSG_CHECKING([if compile with zlib])
+AC_MSG_CHECKING([whether compile with zlib])
 AC_ARG_WITH(zlib,
             AC_HELP_STRING([--with-zlib],[Use zlib instead of included miniz @<:@default=yes@:>@]),
             [if test "$withval" = yes; then use_zlib=yes; else use_zlib=no; fi],
@@ -70,7 +70,7 @@ AC_SUBST(LIBZ_LDFLAGS)
 AC_SUBST(MINIZ_CFLAGS)
 
 # test for --with-libxml2
-AC_MSG_CHECKING([if compile with libxml2])
+AC_MSG_CHECKING([whether compile with libxml2])
 AC_ARG_WITH(libxml2,
             AC_HELP_STRING([--with-libxml2],[Compile with libxml2 @<:@default=yes@:>@]),
             [if test "$withval" = yes; then use_libxml2=yes; else use_libxml2=no; fi],
@@ -160,7 +160,7 @@ AC_DEFINE_UNQUOTED([MOBI_INLINE], [$def_inline],
                    [How to obtain function inlining.])
 
 # Check --enable-debug
-AC_MSG_CHECKING([if enable debugging])
+AC_MSG_CHECKING([whether enable debugging])
 AC_ARG_ENABLE([debug],
 AS_HELP_STRING([--enable-debug],
                [enable debugging @<:@default=no@:>@]),
@@ -188,7 +188,7 @@ fi
 AC_SUBST(DEBUG_CFLAGS)
 
 # Check --enable-debug-alloc
-AC_MSG_CHECKING([if enable alloc debugging])
+AC_MSG_CHECKING([whether enable alloc debugging])
 AC_ARG_ENABLE([debug_alloc],
 AS_HELP_STRING([--enable-debug-alloc],
                [enable memory allocation debugging @<:@default=no@:>@]),
@@ -204,7 +204,7 @@ if test x$debug_alloc = xyes; then
 fi
 
 # Check --enable-mobitool-static
-AC_MSG_CHECKING([if link mobitool against static libmobi])
+AC_MSG_CHECKING([whether link mobitool against static libmobi])
 AC_ARG_ENABLE([mobitool_static],
 AS_HELP_STRING([--enable-mobitool-static],
                [link mobitool against static libmobi @<:@default=no@:>@]),
diff --git a/libmobi.pc.in b/libmobi.pc.in
index fb6409c..ccfb623 100644
--- a/libmobi.pc.in
+++ b/libmobi.pc.in
@@ -8,5 +8,6 @@ Description: MOBI ebook format handling library
 URL: http://www.fabiszewski.net/libmobi
 Version: @VERSION@
 Requires:
-Libs: -L${libdir} -lmobi @LIBZ_LDFLAGS@
+Libs: -L${libdir} -lmobi
+Libs.private: @LIBZ_LDFLAGS@ @LIBXML2_LDFLAGS@
 Cflags: -I${includedir}
diff --git a/src/Makefile.am b/src/Makefile.am
index f19c447..a00c525 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,8 +1,8 @@
 # libmobi 
 
 lib_LTLIBRARIES = libmobi.la
-libmobi_la_SOURCES = buffer.c compression.c debug.c index.c memory.c parse_rawml.c read.c util.c write.c  \
-                  buffer.h compression.h config.h debug.h index.h memory.h mobi.h parse_rawml.h read.h util.h write.h
+libmobi_la_SOURCES = buffer.c compression.c debug.c index.c memory.c parse_rawml.c read.c structure.c util.c write.c  \
+                  buffer.h compression.h config.h debug.h index.h memory.h mobi.h parse_rawml.h read.h structure.h util.h write.h
 if USE_LIBXML2
 libmobi_la_SOURCES += opf.c opf.h
 endif
diff --git a/src/buffer.c b/src/buffer.c
index 7948866..15b1e2c 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -567,124 +567,3 @@ void buffer_free_null(MOBIBuffer *buf) {
 	if (buf == NULL) { return; }
 	free(buf);
 }
-
-/**
- @brief Initializer for MOBIArray structure
- 
- It allocates memory for structure and for data: array of uint32_t variables.
- Memory should be freed with array_free().
- 
- @param[in] len Initial size of the array
- @return MOBIArray on success, NULL otherwise
- */
-MOBIArray * array_init(const size_t len) {
-    MOBIArray *arr = NULL;
-    arr = malloc(sizeof(MOBIArray));
-    if (arr == NULL) {
-        debug_print("%s", "Array allocation failed\n");
-        return NULL;
-    }
-    arr->data = malloc(len * sizeof(*arr->data));
-	if (arr->data == NULL) {
-		free(arr);
-        debug_print("%s", "Array data allocation failed\n");
-		return NULL;
-	}
-    arr->maxsize = arr->step = len;
-    arr->size = 0;
-    return arr;
-}
-
-/**
- @brief Inserts value into MOBIArray array
- 
- @param[in,out] arr MOBIArray array
- @param[in] value Value to be inserted
- @return MOBI_RET status code (on success MOBI_SUCCESS)
- */
-MOBI_RET array_insert(MOBIArray *arr, const uint32_t value) {
-    if (!arr || arr->maxsize == 0) {
-        return MOBI_INIT_FAILED;
-    }
-    if (arr->maxsize == arr->size) {
-        arr->maxsize += arr->step;
-        uint32_t *tmp = realloc(arr->data, arr->maxsize * sizeof(*arr->data));
-        if (!tmp) {
-            free(arr->data);
-            arr->data = NULL;
-            debug_print("%s\n", "Memory allocation failed");
-            return MOBI_MALLOC_FAILED;
-        }
-        arr->data = tmp;
-    }
-    arr->data[arr->size] = value;
-    arr->size++;
-    return MOBI_SUCCESS;
-}
-
-/**
- @brief Helper for qsort in array_sort() function.
- 
- @param[in] a First element to compare
- @param[in] b Second element to compare
- @return -1 if a < b; 1 if a > b; 0 if a = b
- */
-static int array_compare(const void *a, const void *b) {
-    if (*(uint32_t *) a < *(uint32_t *) b) {
-        return -1;
-    };
-    if (*(uint32_t *) a > *(uint32_t *) b) {
-        return 1;
-    };
-    return 0;
-}
-
-/**
- @brief Sort MOBIArray in ascending order.
- 
- When unique is set to true, duplicate values are discarded.
- 
- @param[in,out] arr MOBIArray array
- @param[in] unique Discard duplicate values if true
- */
-void array_sort(MOBIArray *arr, const bool unique) {
-    if (!arr || !arr->data || arr->size == 0) {
-        return;
-    }
-    qsort(arr->data, arr->size, sizeof(*arr->data), array_compare);
-    if (unique) {
-        size_t i = 1, j = 1;
-        while (i < arr->size) {
-            if (arr->data[j - 1] == arr->data[i]) {
-                i++;
-                continue;
-            }
-            arr->data[j++] = arr->data[i++];
-        }
-        arr->size = j;
-    }
-}
-
-/**
- @brief Get size of the array
- 
- @param[in] arr MOBIArray structure
- */
-size_t array_size(MOBIArray *arr) {
-    return arr->size;
-}
-
-/**
- @brief Free MOBIArray structure and contained data
- 
- Free data initialized with array_init();
- 
- @param[in] arr MOBIArray structure
- */
-void array_free(MOBIArray *arr) {
-    if (!arr) { return; }
-    if (arr->data) {
-        free(arr->data);
-    }
-    free(arr);
-}
diff --git a/src/buffer.h b/src/buffer.h
index dd6409e..cfe089c 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -52,20 +52,4 @@ void buffer_setpos(MOBIBuffer *buf, size_t pos);
 void buffer_free(MOBIBuffer *buf);
 void buffer_free_null(MOBIBuffer *buf);
 
-/**
- @brief Dynamic array of uint32_t values structure
- */
-typedef struct {
-    uint32_t *data; /**< Array */
-    size_t maxsize; /**< Allocated size */
-    size_t step; /**< Step by which array will be enlarged if out of memory */
-    size_t size; /**< Current size */
-} MOBIArray;
-
-MOBIArray * array_init(const size_t len);
-MOBI_RET array_insert(MOBIArray *arr, uint32_t value);
-void array_sort(MOBIArray *arr, bool unique);
-size_t array_size(MOBIArray *arr);
-void array_free(MOBIArray *arr);
-
 #endif
diff --git a/src/index.h b/src/index.h
index 045fa61..2601e1d 100644
--- a/src/index.h
+++ b/src/index.h
@@ -12,7 +12,7 @@
 #define mobi_index_h
 
 #include "config.h"
-#include "buffer.h"
+#include "structure.h"
 #include "mobi.h"
 
 /**
diff --git a/src/mobi.h b/src/mobi.h
index 2ab636d..55c7bde 100644
--- a/src/mobi.h
+++ b/src/mobi.h
@@ -400,11 +400,6 @@ extern "C"
         uint32_t *fdst_section_ends; /**< Array of section end offsets */
     } MOBIFdst;
 
-    /**
-     @brief Maximum value of tag values in index entry (MOBIIndexTag) 
-     FIXME: is 2 enough?
-     */
-#define MOBI_INDX_MAXTAGVALUES 100
     
     /**
      @brief Parsed tag for an index entry
diff --git a/src/structure.c b/src/structure.c
new file mode 100644
index 0000000..505757c
--- /dev/null
+++ b/src/structure.c
@@ -0,0 +1,360 @@
+/** @file structure.c
+ *  @brief Data structures
+ *
+ * Copyright (c) 2014 Bartek Fabiszewski
+ * http://www.fabiszewski.net
+ *
+ * This file is part of libmobi.
+ * Licensed under LGPL, either version 3, or any later.
+ * See <http://www.gnu.org/licenses/>
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "structure.h"
+#include "debug.h"
+
+/**
+ @brief Initializer for MOBIArray structure
+ 
+ It allocates memory for structure and for data: array of uint32_t variables.
+ Memory should be freed with array_free().
+ 
+ @param[in] len Initial size of the array
+ @return MOBIArray on success, NULL otherwise
+ */
+MOBIArray * array_init(const size_t len) {
+    MOBIArray *arr = NULL;
+    arr = malloc(sizeof(MOBIArray));
+    if (arr == NULL) {
+        debug_print("%s", "Array allocation failed\n");
+        return NULL;
+    }
+    arr->data = malloc(len * sizeof(*arr->data));
+    if (arr->data == NULL) {
+        free(arr);
+        debug_print("%s", "Array data allocation failed\n");
+        return NULL;
+    }
+    arr->maxsize = arr->step = len;
+    arr->size = 0;
+    return arr;
+}
+
+/**
+ @brief Inserts value into MOBIArray array
+ 
+ @param[in,out] arr MOBIArray array
+ @param[in] value Value to be inserted
+ @return MOBI_RET status code (on success MOBI_SUCCESS)
+ */
+MOBI_RET array_insert(MOBIArray *arr, const uint32_t value) {
+    if (!arr || arr->maxsize == 0) {
+        return MOBI_INIT_FAILED;
+    }
+    if (arr->maxsize == arr->size) {
+        arr->maxsize += arr->step;
+        uint32_t *tmp = realloc(arr->data, arr->maxsize * sizeof(*arr->data));
+        if (!tmp) {
+            free(arr->data);
+            arr->data = NULL;
+            debug_print("%s\n", "Memory allocation failed");
+            return MOBI_MALLOC_FAILED;
+        }
+        arr->data = tmp;
+    }
+    arr->data[arr->size] = value;
+    arr->size++;
+    return MOBI_SUCCESS;
+}
+
+/**
+ @brief Helper for qsort in array_sort() function.
+ 
+ @param[in] a First element to compare
+ @param[in] b Second element to compare
+ @return -1 if a < b; 1 if a > b; 0 if a = b
+ */
+static int array_compare(const void *a, const void *b) {
+    if (*(uint32_t *) a < *(uint32_t *) b) {
+        return -1;
+    };
+    if (*(uint32_t *) a > *(uint32_t *) b) {
+        return 1;
+    };
+    return 0;
+}
+
+/**
+ @brief Sort MOBIArray in ascending order.
+ 
+ When unique is set to true, duplicate values are discarded.
+ 
+ @param[in,out] arr MOBIArray array
+ @param[in] unique Discard duplicate values if true
+ */
+void array_sort(MOBIArray *arr, const bool unique) {
+    if (!arr || !arr->data || arr->size == 0) {
+        return;
+    }
+    qsort(arr->data, arr->size, sizeof(*arr->data), array_compare);
+    if (unique) {
+        size_t i = 1, j = 1;
+        while (i < arr->size) {
+            if (arr->data[j - 1] == arr->data[i]) {
+                i++;
+                continue;
+            }
+            arr->data[j++] = arr->data[i++];
+        }
+        arr->size = j;
+    }
+}
+
+/**
+ @brief Get size of the array
+ 
+ @param[in] arr MOBIArray structure
+ */
+size_t array_size(MOBIArray *arr) {
+    return arr->size;
+}
+
+/**
+ @brief Free MOBIArray structure and contained data
+ 
+ Free data initialized with array_init();
+ 
+ @param[in] arr MOBIArray structure
+ */
+void array_free(MOBIArray *arr) {
+    if (!arr) { return; }
+    if (arr->data) {
+        free(arr->data);
+    }
+    free(arr);
+}
+
+
+/**
+ @brief Create and return MOBITrie structure
+ 
+ @return MOBITrie stucture initialized with zeroes
+ */
+static MOBITrie * mobi_trie_mknode(void) {
+    MOBITrie *node = calloc(1, sizeof(MOBITrie));
+    if (node == NULL) {
+        debug_print("Memory allocation failed%s", "\n");
+    }
+    return node;
+}
+
+/**
+ @brief Recursively free MOBITrie trie starting from node
+ 
+ @param[in] node Starting node
+ */
+void mobi_trie_free(MOBITrie *node) {
+    if (node) {
+        mobi_trie_free(node->next);
+        mobi_trie_free(node->children);
+        free(node->values);
+        free(node);
+    }
+}
+
+/**
+ @brief Insert value into array at given MOBITrie node
+ 
+ @param[in,out] node Starting node
+ @param[in] value Value to be inserted
+ @return MOBI_RET status code (on success MOBI_SUCCESS)
+ */
+static MOBI_RET mobi_trie_addvalue(MOBITrie *node, char *value) {
+    if (node->values) {
+        size_t cnt = ++node->values_count;
+        void *new_values = realloc(node->values, cnt * sizeof(*node->values));
+        if (new_values == NULL) {
+            debug_print("Memory allocation failed%s", "\n");
+            return MOBI_MALLOC_FAILED;
+        }
+        node->values = new_values;
+        node->values[cnt - 1] = value;
+    } else {
+        node->values = malloc(sizeof(*node->values));
+        if (node->values == NULL) {
+            debug_print("Memory allocation failed%s", "\n");
+            return MOBI_MALLOC_FAILED;
+        }
+        node->values[0] = value;
+        node->values_count = 1;
+    }
+    return MOBI_SUCCESS;
+}
+
+/**
+ @brief Insert key character and value (if given) at MOBITrie node
+ 
+ @param[in,out] node Starting node
+ @param[in] c Key character
+ @param[in] value Value to be inserted at terminal node, or NULL if not terminal
+ @return MOBITrie node: current node if value inserted (terminal), 
+         children node (if transitional) or NULL on error
+ */
+static MOBITrie * mobi_trie_insert_char(MOBITrie *node, char c, char *value) {
+    if (!node) { return NULL; }
+    while (true) {
+        if (node->c == c) {
+            break;
+        }
+        if (node->next == NULL) {
+            node->next = mobi_trie_mknode();
+            node = node->next;
+            break;
+        }
+        node = node->next;
+    }
+    if (node->c == 0) {
+        node->c = c;
+    }
+    if (value) {
+        /* terminal node */
+        if (mobi_trie_addvalue(node, value) == MOBI_SUCCESS) {
+            return node;
+        } else {
+            return NULL;
+        }
+    }
+    if (node->children == NULL) {
+        node->children = mobi_trie_mknode();
+    }
+    return node->children;
+}
+
+/**
+ @brief Insert reversed string into MOBITrie trie
+ 
+ @param[in,out] root Root node
+ @param[in] string String to be inserted
+ @param[in] value Value associated with the string
+ @return MOBI_RET status code (on success MOBI_SUCCESS)
+ */
+MOBI_RET mobi_trie_insert_reversed(MOBITrie **root, char *string, char *value) {
+    if (*root == NULL) {
+        *root = mobi_trie_mknode();
+        if (*root == NULL) {
+            return MOBI_MALLOC_FAILED;
+        }
+    }
+    size_t length = strlen(string);
+    MOBITrie *node = *root;
+    while (length > 1) {
+        node = mobi_trie_insert_char(node, string[length - 1], NULL);
+        if (node == NULL) {
+            return MOBI_MALLOC_FAILED;
+        }
+        length--;
+    }
+    node = mobi_trie_insert_char(node, string[length - 1], value);
+    if (node == NULL) {
+        return MOBI_MALLOC_FAILED;
+    }
+    return MOBI_SUCCESS;
+}
+
+/**
+ @brief Fetch values for key c from MOBITrie trie's current level starting at node
+ 
+ @param[in,out] values Array of values to be fetched
+ @param[in,out] values_count Array size
+ @param[in] node MOBITrie node to start search
+ @param[in] c Key character
+ @return MOBITrie children node of the node with c key or NULL if not found
+ */
+MOBITrie * mobi_trie_get_next(char ***values, size_t *values_count, const MOBITrie *node, const char c) {
+    if (!node) { return NULL; }
+    while (node) {
+        if (node->c == c) {
+            *values = (char**) node->values;
+            *values_count = node->values_count;
+            return node->children;
+        }
+        node = node->next;
+    }
+    return NULL;
+}
+
+#if 0
+/* Simple imprementation of binary tree, storing key strings 
+ and associated arrays of values
+ currently not used, save for later */
+
+typedef struct MOBIBtree {
+    char *key; /**< key */
+    char **array; /**< array of strings */
+    size_t value_count; /**< strings count */
+    struct MOBIBtree *left; /**< left child */
+    struct MOBIBtree *right; /**< right child */
+} MOBIBtree;
+
+/**
+ @brief Search MOBIBtree tree for string key
+ 
+ @param[in] node MOBIBtree node to start search
+ @param[in] key Key string
+ @return MOBIBtree node or NULL if not found
+ */
+MOBIBtree *mobi_btree_search(MOBIBtree *node, const char *key) {
+    MOBIBtree *found = NULL;
+    int compare = strcmp(key, node->key);
+    if (compare < 0) {
+        found = mobi_btree_search(node->left, key);
+    } else if (compare > 0) {
+        found = mobi_btree_search(node->right, key);
+    } else {
+        found = node;
+    }
+    return found;
+}
+
+/**
+ @brief Insert key and value (into array) into MOBIBtree tree
+ 
+ @param[in] node MOBIBtree root node
+ @param[in] key Key string
+ @param[in] value Value string will be inserted into array
+ @return MOBI_RET status code (on success MOBI_SUCCESS)
+ */
+MOBI_RET mobi_btree_insert(MOBIBtree **node, char *key, char *value) {
+    MOBI_RET ret = MOBI_SUCCESS;
+    if (*node == NULL) {
+        *node = malloc(sizeof(MOBIBtree));
+        if (*node == NULL) {
+            return MOBI_MALLOC_FAILED;
+        }
+        (*node)->key = key;
+        (*node)->value_count = 1;
+        (*node)->array = malloc(sizeof(*(*node)->array));
+        (*node)->array[0] = value;
+        (*node)->left = NULL;
+        (*node)->right = NULL;
+        return MOBI_SUCCESS;
+    }
+    int compare = strcmp(key, (*node)->key);
+    if (compare < 0) {
+        ret = mobi_btree_insert(&(*node)->left, key, value);
+    } else if (compare > 0) {
+        ret = mobi_btree_insert(&(*node)->right, key, value);
+    } else {
+        size_t cnt = ++(*node)->value_count;
+        char **new_array = realloc((*node)->array, cnt * sizeof(*(*node)->array));
+        if (new_array) {
+            (*node)->array = new_array;
+            (*node)->array[cnt - 1] = value;
+        } else {
+            return MOBI_MALLOC_FAILED;
+        }
+    }
+    return ret;
+}
+#endif
diff --git a/src/structure.h b/src/structure.h
new file mode 100644
index 0000000..b2793ba
--- /dev/null
+++ b/src/structure.h
@@ -0,0 +1,48 @@
+/** @file structure.h
+ *
+ * Copyright (c) 2014 Bartek Fabiszewski
+ * http://www.fabiszewski.net
+ *
+ * This file is part of libmobi.
+ * Licensed under LGPL, either version 3, or any later.
+ * See <http://www.gnu.org/licenses/>
+ */
+
+#ifndef mobi_structure_h
+#define mobi_structure_h
+
+#include "config.h"
+#include "mobi.h"
+
+/**
+ @brief Dynamic array of uint32_t values structure
+ */
+typedef struct {
+    uint32_t *data; /**< Array */
+    size_t maxsize; /**< Allocated size */
+    size_t step; /**< Step by which array will be enlarged if out of memory */
+    size_t size; /**< Current size */
+} MOBIArray;
+
+MOBIArray * array_init(const size_t len);
+MOBI_RET array_insert(MOBIArray *arr, uint32_t value);
+void array_sort(MOBIArray *arr, bool unique);
+size_t array_size(MOBIArray *arr);
+void array_free(MOBIArray *arr);
+
+/**
+ @brief Trie storing arrays of values for character keys
+ */
+typedef struct MOBITrie {
+    char c; /**< Key character */
+    void **values; /**< Array of values */
+    size_t values_count; /**< Array size */
+    struct MOBITrie *next; /**< Next node at the same level */
+    struct MOBITrie *children; /**< Link to children nodes, lower level */
+} MOBITrie;
+
+MOBI_RET mobi_trie_insert_reversed(MOBITrie **root, char *string, char *value);
+MOBITrie * mobi_trie_get_next(char ***values, size_t *values_count, const MOBITrie *node, const char c);
+void mobi_trie_free(MOBITrie *node);
+
+#endif