/*

 * hbuf.c       -- History buffer implementation

 * 

 * Copyright (C) 2005 Mikael Berthe <bmikael@lists.lilotux.net>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or (at

 * your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307

 * USA

 */

#include <string.h>

#include "hbuf.h"

/* This is a private structure type */

#define PREFIX_LENGTH 32

typedef struct {

  char *ptr;

  char *ptr_end;

  guchar flags;

  // XXX This should certainly be a pointer, and be allocated only when needed

  // (for ex. when HBB_FLAG_PERSISTENT is set).

  struct { // hbuf_line_info

    char *ptr_end_alloc;

    char prefix[PREFIX_LENGTH];

  } persist;

} hbuf_block;

//  hbuf_add_line(p_hbuf, text, prefix, width)

// Add a line to the given buffer.  If width is not null, then lines are

// wrapped at this length.

//

// Note 1: Splitting according to width won't work if there are tabs; they

//         should be expanded before.

// Note 2: width does not include the ending \0.

void hbuf_add_line(GList **p_hbuf, const char *text, const char *prefix,

        unsigned int width)

{

  GList *hbuf = *p_hbuf;

  char *line, *cr, *end;

  hbuf_block *hbuf_block_elt;

  if (!text) return;

  hbuf_block_elt = g_new0(hbuf_block, 1);

  if (prefix)

    strncpy(hbuf_block_elt->persist.prefix, prefix, PREFIX_LENGTH-1);

  if (!hbuf) {

    hbuf_block_elt->ptr    = g_new(char, HBB_BLOCKSIZE);

    hbuf_block_elt->flags  = HBB_FLAG_ALLOC | HBB_FLAG_PERSISTENT;

    hbuf_block_elt->persist.ptr_end_alloc = hbuf_block_elt->ptr + HBB_BLOCKSIZE;

    *p_hbuf = g_list_append(*p_hbuf, hbuf_block_elt);

  } else {

    hbuf_block *hbuf_b_prev = g_list_last(hbuf)->data;

    hbuf_block_elt->ptr    = hbuf_b_prev->ptr_end;

    hbuf_block_elt->flags  = HBB_FLAG_PERSISTENT;

    hbuf_block_elt->persist.ptr_end_alloc = hbuf_b_prev->persist.ptr_end_alloc;

    *p_hbuf = g_list_append(*p_hbuf, hbuf_block_elt);

  }

  if (strlen(text) >= HBB_BLOCKSIZE) {

    // Too long

    text = "[ERR:LINE_TOO_LONG]";

  }

  if (hbuf_block_elt->ptr + strlen(text) >= hbuf_block_elt->persist.ptr_end_alloc) {

    // Too long for the current allocated bloc, we need another one

    hbuf_block_elt->ptr    = g_new0(char, HBB_BLOCKSIZE);

    hbuf_block_elt->flags  = HBB_FLAG_ALLOC | HBB_FLAG_PERSISTENT;

    hbuf_block_elt->persist.ptr_end_alloc = hbuf_block_elt->ptr + HBB_BLOCKSIZE;

  }

  line = hbuf_block_elt->ptr;

  // Ok, now we can copy the text..

  strcpy(line, text);

  hbuf_block_elt->ptr_end = line + strlen(line) + 1;

  end = hbuf_block_elt->ptr_end;

  // Let's add non-persistent blocs if necessary

  // - If there are '\n' in the string

  // - If length > width (and width != 0)

  cr = strchr(line, '\n');

  while (cr || (width && strlen(line) > width)) {

    hbuf_block *hbuf_b_prev = hbuf_block_elt;

    if (!width || (cr && (cr - line <= (int)width))) {

      // Carriage return

      *cr = 0;

      hbuf_block_elt->ptr_end = cr;

      // Create another persistent block

      hbuf_block_elt = g_new0(hbuf_block, 1);

      hbuf_block_elt->ptr      = hbuf_b_prev->ptr_end + 1; // == cr+1

      hbuf_block_elt->ptr_end  = end;

      hbuf_block_elt->flags    = HBB_FLAG_PERSISTENT;

      hbuf_block_elt->persist.ptr_end_alloc = hbuf_b_prev->persist.ptr_end_alloc;

      *p_hbuf = g_list_append(*p_hbuf, hbuf_block_elt);

      line = hbuf_block_elt->ptr;

    } else {

      // We need to break where we can find a space char

      char *br; // break pointer

      for (br = line + width; br > line && *br != 32 && *br != 9; br--)

        ;

      if (br <= line)

        br = line + width;

      else

        br++;

      hbuf_block_elt->ptr_end = br;

      // Create another block, non-persistent

      hbuf_block_elt = g_new0(hbuf_block, 1);

      hbuf_block_elt->ptr      = hbuf_b_prev->ptr_end; // == br

      hbuf_block_elt->ptr_end  = end;

      hbuf_block_elt->flags    = 0;

      hbuf_block_elt->persist.ptr_end_alloc = hbuf_b_prev->persist.ptr_end_alloc;

      *p_hbuf = g_list_append(*p_hbuf, hbuf_block_elt);

      line = hbuf_block_elt->ptr;

    }

    cr = strchr(line, '\n');

  }

}

//  hbuf_free()

// Destroys all hbuf list.

void hbuf_free(GList **p_hbuf)

{

  hbuf_block *hbuf_b_elt;

  GList *hbuf_elt;

  GList *first_elt = g_list_first(*p_hbuf);

  for (hbuf_elt = first_elt; hbuf_elt; hbuf_elt = g_list_next(hbuf_elt)) {

    hbuf_b_elt = (hbuf_block*)(hbuf_elt->data);

    if (hbuf_b_elt->flags & HBB_FLAG_ALLOC) {

      g_free(hbuf_b_elt->ptr);

    }

  }

  g_list_free(*p_hbuf);

  *p_hbuf = NULL;

}

//  hbuf_rebuild()

// Rebuild all hbuf list, with the new width.

// If width == 0, lines are not wrapped.

void hbuf_rebuild(GList **p_hbuf, unsigned int width)

{

  GList *first_elt, *curr_elt, *next_elt;

  hbuf_block *hbuf_b_curr, *hbuf_b_next;

  // #1 Remove non-persistent blocks (ptr_end should be updated!)

  curr_elt = first_elt;

  while (curr_elt) {

    next_elt = g_list_next(curr_elt);

    // Last element?

    if (!next_elt)

      break;

    hbuf_b_curr = (hbuf_block*)(curr_elt->data);

    hbuf_b_next = (hbuf_block*)(next_elt->data);

    // Is next line not-persistent?

    if (!(hbuf_b_next->flags & HBB_FLAG_PERSISTENT)) {

      hbuf_b_curr->ptr_end = hbuf_b_next->ptr_end;

      g_list_delete_link(curr_elt, next_elt);

    } else 

      curr_elt = next_elt;

  }

  // #2 Go back to head and create non-persistent blocks when needed

  if (width) {

    char *line, *end;

    curr_elt = first_elt;

    while (curr_elt) {

      hbuf_b_curr = (hbuf_block*)(curr_elt->data);

      line = hbuf_b_curr->ptr;

      if (strlen(line) > width) {

        hbuf_block *hbuf_b_prev = hbuf_b_curr;

        // We need to break where we can find a space char

        char *br; // break pointer

        for (br = line + width; br > line && *br != 32 && *br != 9; br--)

          ;

        if (br <= line)

          br = line + width;

        else

          br++;

        end = hbuf_b_curr->ptr_end;

        hbuf_b_curr->ptr_end = br;

        // Create another block, non-persistent

        hbuf_b_curr = g_new0(hbuf_block, 1);

        hbuf_b_curr->ptr      = hbuf_b_prev->ptr_end; // == br

        hbuf_b_curr->ptr_end  = end;

        hbuf_b_curr->flags    = 0;

        hbuf_b_curr->persist.ptr_end_alloc = hbuf_b_prev->persist.ptr_end_alloc;

      }

      curr_elt = g_list_next(curr_elt);

    }

  }

}

//  hbuf_get_lines(hbuf, n, where)

// Returns an array of 2*n pointers (for n prefixes + n lines from hbuf)

// (prefix line 1, line 1, prefix line 2, line 2, etc.)

// (The first line will be the line currently pointed by hbuf)

// Note:The caller should free the array after use.

char **hbuf_get_lines(GList *hbuf, unsigned int n)

{

  unsigned int i;

  char **array = g_new0(char*, n*2);

  char **array_elt = array;

  for (i=0 ; i < n ; i++) {

    if (hbuf) {

      hbuf_block *blk = (hbuf_block*)(hbuf->data);

      int maxlen;

      maxlen = blk->ptr_end - blk->ptr;

      *array_elt++ = blk->persist.prefix;

      *array_elt++ = g_strndup(blk->ptr, maxlen);

      hbuf = g_list_next(hbuf);

    } else

      *array_elt++ = NULL;

  }

  return array;

}