X-Git-Url: https://git.street.me.uk/andy/viking.git/blobdiff_plain/119ada4c560795285edd8902fd4854a0792bcd64..0c0b650b11ab46ec0ce0dc68e7c81b6936b7c2e6:/src/file.c diff --git a/src/file.c b/src/file.c index f185a467..d2692a35 100644 --- a/src/file.c +++ b/src/file.c @@ -3,6 +3,7 @@ * * Copyright (C) 2003-2005, Evan Battaglia * Copyright (C) 2012, Guilhem Bonnefille + * Copyright (C) 2012-2013, Rob Norris * * 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 @@ -25,7 +26,9 @@ #endif #include "viking.h" +#include "jpg.h" #include "gpx.h" +#include "geojson.h" #include "babel.h" #include @@ -34,26 +37,22 @@ #ifdef HAVE_UNISTD_H #include #endif +#ifdef WINDOWS +#define realpath(X,Y) _fullpath(Y,X,MAX_PATH) +#endif #include #include #include -/* Relax some dependencies */ -#if ! GLIB_CHECK_VERSION(2,12,0) -static gboolean return_true (gpointer a, gpointer b, gpointer c) { return TRUE; } -static g_hash_table_remove_all (GHashTable *ght) { g_hash_table_foreach_remove ( ght, (GHRFunc) return_true, FALSE ); } -#endif +#include "file.h" +#include "misc/strtod.h" #define TEST_BOOLEAN(str) (! ((str)[0] == '\0' || (str)[0] == '0' || (str)[0] == 'n' || (str)[0] == 'N' || (str)[0] == 'f' || (str)[0] == 'F') ) #define VIK_MAGIC "#VIK" #define GPX_MAGIC "name ) == 0 ) - return i; - return -1; -} - -void file_write_layer_param ( FILE *f, const gchar *name, guint8 type, VikLayerParamData data ) { +void file_write_layer_param ( FILE *f, const gchar *name, VikLayerParamType type, VikLayerParamData data ) { /* string lists are handled differently. We get a GList (that shouldn't * be freed) back for get_param and if it is null we shouldn't write * anything at all (otherwise we'd read in a list with an empty string, @@ -133,8 +123,9 @@ void file_write_layer_param ( FILE *f, const gchar *name, guint8 type, VikLayerP case VIK_LAYER_PARAM_UINT: fprintf ( f, "%d\n", data.u ); break; case VIK_LAYER_PARAM_INT: fprintf ( f, "%d\n", data.i ); break; case VIK_LAYER_PARAM_BOOLEAN: fprintf ( f, "%c\n", data.b ? 't' : 'f' ); break; - case VIK_LAYER_PARAM_STRING: fprintf ( f, "%s\n", data.s ); break; + case VIK_LAYER_PARAM_STRING: fprintf ( f, "%s\n", data.s ? data.s : "" ); break; case VIK_LAYER_PARAM_COLOR: fprintf ( f, "#%.2x%.2x%.2x\n", (int)(data.c.red/256),(int)(data.c.green/256),(int)(data.c.blue/256)); break; + default: break; } } } @@ -195,7 +186,9 @@ static void file_write ( VikAggregateLayer *top, FILE *f, gpointer vp ) g_critical("Houston, we've had a problem. mode=%d", mode); } - fprintf ( f, "#VIKING GPS Data file " VIKING_URL "\n\nxmpp=%f\nympp=%f\nlat=%f\nlon=%f\nmode=%s\ncolor=%s\nhighlightcolor=%s\ndrawscale=%s\ndrawcentermark=%s\ndrawhighlight=%s\n", + fprintf ( f, "#VIKING GPS Data file " VIKING_URL "\n" ); + fprintf ( f, "FILE_VERSION=%d\n", VIKING_FILE_VERSION ); + fprintf ( f, "\nxmpp=%f\nympp=%f\nlat=%f\nlon=%f\nmode=%s\ncolor=%s\nhighlightcolor=%s\ndrawscale=%s\ndrawcentermark=%s\ndrawhighlight=%s\n", vik_viewport_get_xmpp ( VIK_VIEWPORT(vp) ), vik_viewport_get_ympp ( VIK_VIEWPORT(vp) ), ll.lat, ll.lon, modestring, vik_viewport_get_background_color(VIK_VIEWPORT(vp)), vik_viewport_get_highlight_color(VIK_VIEWPORT(vp)), @@ -209,7 +202,7 @@ static void file_write ( VikAggregateLayer *top, FILE *f, gpointer vp ) while (stack && stack->data) { current_layer = VIK_LAYER(((GList *)stack->data)->data); - fprintf ( f, "\n~Layer %s\n", vik_layer_get_interface(current_layer->type)->name ); + fprintf ( f, "\n~Layer %s\n", vik_layer_get_interface(current_layer->type)->fixed_layer_name ); write_layer_params_and_data ( current_layer, f ); if ( current_layer->type == VIK_LAYER_AGGREGATE && !vik_aggregate_layer_is_empty(VIK_AGGREGATE_LAYER(current_layer)) ) { @@ -275,7 +268,7 @@ static void string_list_set_param (gint i, GList *list, gpointer *layer_and_vp) * TODO flow up line number(s) / error messages of problems encountered... * */ -static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) +static gboolean file_read ( VikAggregateLayer *top, FILE *f, const gchar *dirpath, VikViewport *vp ) { Stack *stack; struct LatLon ll = { 0.0, 0.0 }; @@ -335,9 +328,9 @@ static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) } else { - gint16 type = layer_type_from_string ( line+6 ); + VikLayerTypeEnum type = vik_layer_type_from_string ( line+6 ); push(&stack); - if ( type == -1 ) + if ( type == VIK_LAYER_NUM_TYPES ) { successful_read = FALSE; g_warning ( "Line %ld: Unknown type %s", line_num, line+6 ); @@ -351,7 +344,7 @@ static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) } else { - stack->data = (gpointer) vik_layer_create ( type, vp, NULL, FALSE ); + stack->data = (gpointer) vik_layer_create ( type, vp, FALSE ); params = vik_layer_get_interface(type)->params; params_count = vik_layer_get_interface(type)->params_count; } @@ -375,7 +368,7 @@ static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) if ( stack->data && stack->under->data ) { if (VIK_LAYER(stack->under->data)->type == VIK_LAYER_AGGREGATE) { - vik_aggregate_layer_add_layer ( VIK_AGGREGATE_LAYER(stack->under->data), VIK_LAYER(stack->data) ); + vik_aggregate_layer_add_layer ( VIK_AGGREGATE_LAYER(stack->under->data), VIK_LAYER(stack->data), FALSE ); vik_layer_post_read ( VIK_LAYER(stack->data), vp, TRUE ); } else if (VIK_LAYER(stack->under->data)->type == VIK_LAYER_GPS) { @@ -394,7 +387,7 @@ static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) if ( stack->data && vik_layer_get_interface(VIK_LAYER(stack->data)->type)->read_file_data ) { /* must read until hits ~EndLayerData */ - if ( ! vik_layer_get_interface(VIK_LAYER(stack->data)->type)->read_file_data ( VIK_LAYER(stack->data), f ) ) + if ( ! vik_layer_get_interface(VIK_LAYER(stack->data)->type)->read_file_data ( VIK_LAYER(stack->data), f, dirpath ) ) successful_read = FALSE; } else @@ -433,14 +426,21 @@ static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) if ( line[i] == '=' ) eq_pos = i; - if ( stack->under == NULL && eq_pos == 4 && strncasecmp ( line, "xmpp", eq_pos ) == 0) /* "hard coded" params: global & for all layer-types */ - vik_viewport_set_xmpp ( VIK_VIEWPORT(vp), strtod ( line+5, NULL ) ); + if ( stack->under == NULL && eq_pos == 12 && strncasecmp ( line, "FILE_VERSION", eq_pos ) == 0) { + gint version = strtol(line+13, NULL, 10); + g_debug ( "%s: reading file version %d", __FUNCTION__, version ); + if ( version > VIKING_FILE_VERSION ) + successful_read = FALSE; + // However we'll still carry and attempt to read whatever we can + } + else if ( stack->under == NULL && eq_pos == 4 && strncasecmp ( line, "xmpp", eq_pos ) == 0) /* "hard coded" params: global & for all layer-types */ + vik_viewport_set_xmpp ( VIK_VIEWPORT(vp), strtod_i8n ( line+5, NULL ) ); else if ( stack->under == NULL && eq_pos == 4 && strncasecmp ( line, "ympp", eq_pos ) == 0) - vik_viewport_set_ympp ( VIK_VIEWPORT(vp), strtod ( line+5, NULL ) ); + vik_viewport_set_ympp ( VIK_VIEWPORT(vp), strtod_i8n ( line+5, NULL ) ); else if ( stack->under == NULL && eq_pos == 3 && strncasecmp ( line, "lat", eq_pos ) == 0 ) - ll.lat = strtod ( line+4, NULL ); + ll.lat = strtod_i8n ( line+4, NULL ); else if ( stack->under == NULL && eq_pos == 3 && strncasecmp ( line, "lon", eq_pos ) == 0 ) - ll.lon = strtod ( line+4, NULL ); + ll.lon = strtod_i8n ( line+4, NULL ); else if ( stack->under == NULL && eq_pos == 4 && strncasecmp ( line, "mode", eq_pos ) == 0 && strcasecmp ( line+5, "utm" ) == 0) vik_viewport_set_drawmode ( VIK_VIEWPORT(vp), VIK_VIEWPORT_DRAWMODE_UTM); else if ( stack->under == NULL && eq_pos == 4 && strncasecmp ( line, "mode", eq_pos ) == 0 && strcasecmp ( line+5, "expedia" ) == 0) @@ -501,7 +501,7 @@ static gboolean file_read ( VikAggregateLayer *top, FILE *f, VikViewport *vp ) } else { switch ( params[i].type ) { - case VIK_LAYER_PARAM_DOUBLE: x.d = strtod(line, NULL); break; + case VIK_LAYER_PARAM_DOUBLE: x.d = strtod_i8n(line, NULL); break; case VIK_LAYER_PARAM_UINT: x.u = strtoul(line, NULL, 10); break; case VIK_LAYER_PARAM_INT: x.i = strtol(line, NULL, 10); break; case VIK_LAYER_PARAM_BOOLEAN: x.b = TEST_BOOLEAN(line); break; @@ -542,14 +542,14 @@ name=this { if ( stack->under && stack->under->data && stack->data ) { - vik_aggregate_layer_add_layer ( VIK_AGGREGATE_LAYER(stack->under->data), VIK_LAYER(stack->data) ); + vik_aggregate_layer_add_layer ( VIK_AGGREGATE_LAYER(stack->under->data), VIK_LAYER(stack->data), FALSE ); vik_layer_post_read ( VIK_LAYER(stack->data), vp, TRUE ); } pop(&stack); } if ( ll.lat != 0.0 || ll.lon != 0.0 ) - vik_viewport_set_center_latlon ( VIK_VIEWPORT(vp), &ll ); + vik_viewport_set_center_latlon ( VIK_VIEWPORT(vp), &ll, TRUE ); if ( ( ! VIK_LAYER(top)->visible ) && VIK_LAYER(top)->realized ) vik_treeview_item_set_visible ( VIK_LAYER(top)->vt, &(VIK_LAYER(top)->iter), FALSE ); @@ -577,7 +577,7 @@ if "[LayerData]" /* ---------------------------------------------------- */ -static FILE *xfopen ( const char *fn, const char *mode ) +static FILE *xfopen ( const char *fn ) { if ( strcmp(fn,"-") == 0 ) return stdin; @@ -599,7 +599,7 @@ static void xfclose ( FILE *f ) gboolean check_file_magic_vik ( const gchar *filename ) { gboolean result = FALSE; - FILE *ff = xfopen ( filename, "r" ); + FILE *ff = xfopen ( filename ); if ( ff ) { result = check_magic ( ff, VIK_MAGIC ); xfclose ( ff ); @@ -607,58 +607,110 @@ gboolean check_file_magic_vik ( const gchar *filename ) return result; } +/** + * append_file_ext: + * + * Append a file extension, if not already present. + * + * Returns: a newly allocated string + */ +gchar *append_file_ext ( const gchar *filename, VikFileType_t type ) +{ + gchar *new_name = NULL; + const gchar *ext = NULL; + + /* Select an extension */ + switch (type) + { + case FILE_TYPE_GPX: + ext = ".gpx"; + break; + case FILE_TYPE_KML: + ext = ".kml"; + break; + case FILE_TYPE_GEOJSON: + ext = ".geojson"; + break; + case FILE_TYPE_GPSMAPPER: + case FILE_TYPE_GPSPOINT: + default: + /* Do nothing, ext already set to NULL */ + break; + } + + /* Do */ + if ( ext != NULL && ! a_file_check_ext ( filename, ext ) ) + new_name = g_strconcat ( filename, ext, NULL ); + else + /* Simply duplicate */ + new_name = g_strdup ( filename ); + + return new_name; +} + VikLoadType_t a_file_load ( VikAggregateLayer *top, VikViewport *vp, const gchar *filename_or_uri ) { g_return_val_if_fail ( vp != NULL, LOAD_TYPE_READ_FAILURE ); char *filename = (char *)filename_or_uri; - if (strncmp(filename, "file://", 7) == 0) + if (strncmp(filename, "file://", 7) == 0) { + // Consider replacing this with: + // filename = g_filename_from_uri ( entry, NULL, NULL ); + // Since this doesn't support URIs properly (i.e. will failure if is it has %20 characters in it) filename = filename + 7; - - FILE *f = xfopen ( filename, "r" ); + g_debug ( "Loading file %s from URI %s", filename, filename_or_uri ); + } + FILE *f = xfopen ( filename ); if ( ! f ) return LOAD_TYPE_READ_FAILURE; VikLoadType_t load_answer = LOAD_TYPE_OTHER_SUCCESS; + gchar *dirpath = g_path_get_dirname ( filename ); // Attempt loading the primary file type first - our internal .vik file: if ( check_magic ( f, VIK_MAGIC ) ) { - if ( file_read ( top, f, vp ) ) + if ( file_read ( top, f, dirpath, vp ) ) load_answer = LOAD_TYPE_VIK_SUCCESS; else load_answer = LOAD_TYPE_VIK_FAILURE_NON_FATAL; } + else if ( a_jpg_magic_check ( filename ) ) { + if ( ! a_jpg_load_file ( top, filename, vp ) ) + load_answer = LOAD_TYPE_UNSUPPORTED_FAILURE; + } else { // For all other file types which consist of tracks, routes and/or waypoints, // must be loaded into a new TrackWaypoint layer (hence it be created) gboolean success = TRUE; // Detect load failures - mainly to remove the layer created as it's not required - VikLayer *vtl = vik_layer_create ( VIK_LAYER_TRW, vp, NULL, FALSE ); + VikLayer *vtl = vik_layer_create ( VIK_LAYER_TRW, vp, FALSE ); + vik_layer_rename ( vtl, a_file_basename ( filename ) ); // In fact both kml & gpx files start the same as they are in xml - if ( check_file_ext ( filename, ".kml" ) && check_magic ( f, GPX_MAGIC ) ) { + if ( a_file_check_ext ( filename, ".kml" ) && check_magic ( f, GPX_MAGIC ) ) { // Implicit Conversion - if ( ! ( success = a_babel_convert_from ( VIK_TRW_LAYER(vtl), "-i kml", filename, NULL, NULL ) ) ) { + if ( ! ( success = a_babel_convert_from ( VIK_TRW_LAYER(vtl), "-i kml", filename, NULL, NULL, NULL ) ) ) { load_answer = LOAD_TYPE_GPSBABEL_FAILURE; } } // NB use a extension check first, as a GPX file header may have a Byte Order Mark (BOM) in it // - which currently confuses our check_magic function - else if ( check_file_ext ( filename, ".gpx" ) || check_magic ( f, GPX_MAGIC ) ) { + else if ( a_file_check_ext ( filename, ".gpx" ) || check_magic ( f, GPX_MAGIC ) ) { if ( ! ( success = a_gpx_read_file ( VIK_TRW_LAYER(vtl), f ) ) ) { load_answer = LOAD_TYPE_GPX_FAILURE; } } else { // Try final supported file type - if ( ! ( success = a_gpspoint_read_file ( VIK_TRW_LAYER(vtl), f ) ) ) { - // Failure here means we don't know how to handle the file + if ( ! ( success = a_gpspoint_read_file ( VIK_TRW_LAYER(vtl), f, dirpath ) ) ) { + // Failure here means we don't know how to handle the file load_answer = LOAD_TYPE_UNSUPPORTED_FAILURE; - } + } } + g_free ( dirpath ); // Clean up when we can't handle the file if ( ! success ) { @@ -667,9 +719,8 @@ VikLoadType_t a_file_load ( VikAggregateLayer *top, VikViewport *vp, const gchar } else { // Complete the setup from the successful load - vik_layer_rename ( vtl, a_file_basename ( filename ) ); vik_layer_post_read ( vtl, vp, TRUE ); - vik_aggregate_layer_add_layer ( top, vtl ); + vik_aggregate_layer_add_layer ( top, vtl, FALSE ); vik_trw_layer_auto_set_view ( VIK_TRW_LAYER(vtl), vp ); } } @@ -689,8 +740,26 @@ gboolean a_file_save ( VikAggregateLayer *top, gpointer vp, const gchar *filenam if ( ! f ) return FALSE; + // Enable relative paths in .vik files to work + gchar *cwd = g_get_current_dir(); + gchar *dir = g_path_get_dirname ( filename ); + if ( dir ) { + if ( g_chdir ( dir ) ) { + g_warning ( "Could not change directory to %s", dir ); + } + g_free (dir); + } + file_write ( top, f, vp ); + // Restore previous working directory + if ( cwd ) { + if ( g_chdir ( cwd ) ) { + g_warning ( "Could not return to directory %s", cwd ); + } + g_free (cwd); + } + fclose(f); f = NULL; @@ -698,21 +767,10 @@ gboolean a_file_save ( VikAggregateLayer *top, gpointer vp, const gchar *filenam } -const gchar *a_file_basename ( const gchar *filename ) -{ - const gchar *t = filename + strlen(filename) - 1; - while ( --t > filename ) - if ( *(t-1) == FILE_SEP ) - break; - if ( t >= filename ) - return t; - return filename; -} - /* example: - gboolean is_gpx = check_file_ext ( "a/b/c.gpx", ".gpx" ); + gboolean is_gpx = a_file_check_ext ( "a/b/c.gpx", ".gpx" ); */ -gboolean check_file_ext ( const gchar *filename, const gchar *fileext ) +gboolean a_file_check_ext ( const gchar *filename, const gchar *fileext ) { g_return_val_if_fail ( filename != NULL, FALSE ); g_return_val_if_fail ( fileext && fileext[0]=='.', FALSE ); @@ -727,15 +785,31 @@ gboolean check_file_ext ( const gchar *filename, const gchar *fileext ) return FALSE; } -gboolean a_file_export ( VikTrwLayer *vtl, const gchar *filename, VikFileType_t file_type, VikTrack *trk ) +/** + * a_file_export: + * @vtl: The TrackWaypoint to export data from + * @filename: The name of the file to be written + * @file_type: Choose one of the supported file types for the export + * @trk: If specified then only export this track rather than the whole layer + * @write_hidden: Whether to write invisible items + * + * A general export command to convert from Viking TRW layer data to an external supported format. + * The write_hidden option is provided mainly to be able to transfer selected items when uploading to a GPS + */ +gboolean a_file_export ( VikTrwLayer *vtl, const gchar *filename, VikFileType_t file_type, VikTrack *trk, gboolean write_hidden ) { + GpxWritingOptions options = { FALSE, FALSE, write_hidden, FALSE }; FILE *f = g_fopen ( filename, "w" ); if ( f ) { + gboolean result = TRUE; + if ( trk ) { switch ( file_type ) { case FILE_TYPE_GPX: - a_gpx_write_track_file ( trk, f ); + // trk defined so can set the option + options.is_route = trk->is_route; + a_gpx_write_track_file ( trk, f, &options ); break; default: g_critical("Houston, we've had a problem. file_type=%d", file_type); @@ -746,24 +820,27 @@ gboolean a_file_export ( VikTrwLayer *vtl, const gchar *filename, VikFileType_t a_gpsmapper_write_file ( vtl, f ); break; case FILE_TYPE_GPX: - a_gpx_write_file ( vtl, f ); + a_gpx_write_file ( vtl, f, &options ); break; case FILE_TYPE_GPSPOINT: a_gpspoint_write_file ( vtl, f ); break; + case FILE_TYPE_GEOJSON: + result = a_geojson_write_file ( vtl, f ); + break; case FILE_TYPE_KML: fclose ( f ); f = NULL; switch ( a_vik_get_kml_export_units () ) { case VIK_KML_EXPORT_UNITS_STATUTE: - return a_babel_convert_to ( vtl, "-o kml", filename, NULL, NULL ); + return a_babel_convert_to ( vtl, NULL, "-o kml", filename, NULL, NULL ); break; case VIK_KML_EXPORT_UNITS_NAUTICAL: - return a_babel_convert_to ( vtl, "-o kml,units=n", filename, NULL, NULL ); + return a_babel_convert_to ( vtl, NULL, "-o kml,units=n", filename, NULL, NULL ); break; default: // VIK_KML_EXPORT_UNITS_METRIC: - return a_babel_convert_to ( vtl, "-o kml,units=m", filename, NULL, NULL ); + return a_babel_convert_to ( vtl, NULL, "-o kml,units=m", filename, NULL, NULL ); break; } break; @@ -773,8 +850,164 @@ gboolean a_file_export ( VikTrwLayer *vtl, const gchar *filename, VikFileType_t } fclose ( f ); f = NULL; - return TRUE; + return result; } return FALSE; } +/** + * a_file_export_babel: + */ +gboolean a_file_export_babel ( VikTrwLayer *vtl, const gchar *filename, const gchar *format, + gboolean tracks, gboolean routes, gboolean waypoints ) +{ + gchar *args = g_strdup_printf("%s %s %s -o %s", + tracks ? "-t" : "", + routes ? "-r" : "", + waypoints ? "-w" : "", + format); + gboolean result = a_babel_convert_to ( vtl, NULL, args, filename, NULL, NULL ); + g_free(args); + return result; +} + +/** + * Just a wrapper around realpath, which itself is platform dependent + */ +char *file_realpath ( const char *path, char *real ) +{ + return realpath ( path, real ); +} + +#ifndef MAXPATHLEN +#define MAXPATHLEN 1024 +#endif +/** + * Always return the canonical filename in a newly allocated string + */ +char *file_realpath_dup ( const char *path ) +{ + char real[MAXPATHLEN]; + + g_return_val_if_fail(path != NULL, NULL); + + if (file_realpath(path, real)) + return g_strdup(real); + + return g_strdup(path); +} + +/** + * Permission granted to use this code after personal correspondance + * Slightly reworked for better cross platform use, glibisms, function rename and a compacter format + * + * FROM http://www.codeguru.com/cpp/misc/misc/fileanddirectorynaming/article.php/c263 + */ + +// GetRelativeFilename(), by Rob Fisher. +// rfisher@iee.org +// http://come.to/robfisher + +// The number of characters at the start of an absolute filename. e.g. in DOS, +// absolute filenames start with "X:\" so this value should be 3, in UNIX they start +// with "\" so this value should be 1. +#ifdef WINDOWS +#define ABSOLUTE_NAME_START 3 +#else +#define ABSOLUTE_NAME_START 1 +#endif + +// Given the absolute current directory and an absolute file name, returns a relative file name. +// For example, if the current directory is C:\foo\bar and the filename C:\foo\whee\text.txt is given, +// GetRelativeFilename will return ..\whee\text.txt. + +const gchar *file_GetRelativeFilename ( gchar *currentDirectory, gchar *absoluteFilename ) +{ + gint afMarker = 0, rfMarker = 0; + gint cdLen = 0, afLen = 0; + gint i = 0; + gint levels = 0; + static gchar relativeFilename[MAXPATHLEN+1]; + + cdLen = strlen(currentDirectory); + afLen = strlen(absoluteFilename); + + // make sure the names are not too long or too short + if (cdLen > MAXPATHLEN || cdLen < ABSOLUTE_NAME_START+1 || + afLen > MAXPATHLEN || afLen < ABSOLUTE_NAME_START+1) { + return NULL; + } + + // Handle DOS names that are on different drives: + if (currentDirectory[0] != absoluteFilename[0]) { + // not on the same drive, so only absolute filename will do + strcpy(relativeFilename, absoluteFilename); + return relativeFilename; + } + + // they are on the same drive, find out how much of the current directory + // is in the absolute filename + i = ABSOLUTE_NAME_START; + while (i < afLen && i < cdLen && currentDirectory[i] == absoluteFilename[i]) { + i++; + } + + if (i == cdLen && (absoluteFilename[i] == G_DIR_SEPARATOR || absoluteFilename[i-1] == G_DIR_SEPARATOR)) { + // the whole current directory name is in the file name, + // so we just trim off the current directory name to get the + // current file name. + if (absoluteFilename[i] == G_DIR_SEPARATOR) { + // a directory name might have a trailing slash but a relative + // file name should not have a leading one... + i++; + } + + strcpy(relativeFilename, &absoluteFilename[i]); + return relativeFilename; + } + + // The file is not in a child directory of the current directory, so we + // need to step back the appropriate number of parent directories by + // using "..\"s. First find out how many levels deeper we are than the + // common directory + afMarker = i; + levels = 1; + + // count the number of directory levels we have to go up to get to the + // common directory + while (i < cdLen) { + i++; + if (currentDirectory[i] == G_DIR_SEPARATOR) { + // make sure it's not a trailing slash + i++; + if (currentDirectory[i] != '\0') { + levels++; + } + } + } + + // move the absolute filename marker back to the start of the directory name + // that it has stopped in. + while (afMarker > 0 && absoluteFilename[afMarker-1] != G_DIR_SEPARATOR) { + afMarker--; + } + + // check that the result will not be too long + if (levels * 3 + afLen - afMarker > MAXPATHLEN) { + return NULL; + } + + // add the appropriate number of "..\"s. + rfMarker = 0; + for (i = 0; i < levels; i++) { + relativeFilename[rfMarker++] = '.'; + relativeFilename[rfMarker++] = '.'; + relativeFilename[rfMarker++] = G_DIR_SEPARATOR; + } + + // copy the rest of the filename into the result string + strcpy(&relativeFilename[rfMarker], &absoluteFilename[afMarker]); + + return relativeFilename; +} +/* END http://www.codeguru.com/cpp/misc/misc/fileanddirectorynaming/article.php/c263 */