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nuttx-apps/graphics/traveler/tools/libwld/wld_inifile.c

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/****************************************************************************
* apps/graphics/traveler/tools/libwld/wld_inifile.c
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include "wld_inifile.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* The maximum size of a line in the INI file */
#define INFILE_MAXLINE 256
/****************************************************************************
* Private Types
****************************************************************************/
/* A structure that describes one entry from the INI file */
struct inifile_var_s
{
char *variable;
char *value;
};
/* This structure describes the state of one instance of the INI file parser */
struct inifile_state_s
{
FILE *instream;
int nextch;
char line[INFILE_MAXLINE+1];
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static bool inifile_next_line(struct inifile_state_s *priv);
static int inifile_read_line(struct inifile_state_s *priv);
static int inifile_read_noncomment_line(struct inifile_state_s *priv);
static bool inifile_seek_to_section(struct inifile_state_s *priv,
const char *section);
static bool inifile_read_variable(struct inifile_state_s *priv,
struct inifile_var_s *varinfo);
static char *inifile_find_section_variable(struct inifile_state_s *priv,
const char *variable);
static char *inifile_find_variable(struct inifile_state_s *priv,
const char *section, const char *variable);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: inifile_next_line
*
* Description:
* Skip to the first character of the next line. Returns true if the end
* of file was not encountered.
*
****************************************************************************/
static bool inifile_next_line(struct inifile_state_s *priv)
{
/* Search ahead for the end of line mark (or possibly the end of file mark) */
while ((priv->nextch != '\n') && (priv->nextch != EOF))
{
priv->nextch = getc(priv->instream);
}
/* Re-prime the pump with the first character from the next line. NOTE:
* this logic depends on the fact that getc() will return EOF repeatedly.
*/
priv->nextch = getc(priv->instream);
return (priv->nextch != EOF);
}
/****************************************************************************
* Name: inifile_read_line
*
* Description:
* Read the next line from the INI file into the line buffer and return
* the number of characters read into the buffer. If we hit the end of a
* section (or the end of a file), this function will return a count of
* zero.
*
****************************************************************************/
static int inifile_read_line(struct inifile_state_s *priv)
{
int nbytes;
/* Assuming that the file pointer is correctly positioned at the beginning
* of the next line, read until the end of line indication is found (or
* until the line buffer is full). This is basically fgets().
*/
nbytes = 0;
while ((nbytes < INFILE_MAXLINE) &&
(priv->nextch != EOF) &&
(priv->nextch != '\n'))
{
/* Always ignore carriage returns */
if (priv->nextch != '\r')
{
/* Ignore any leading whitespace on the line */
if (nbytes || (priv->nextch != ' ' && priv->nextch != '\t'))
{
/* Add the new character to the line buffer */
priv->line[nbytes] = priv->nextch;
nbytes++;
}
}
/* Get the next character from the INI file */
priv->nextch = getc(priv->instream);
}
/* NUL terminate the string */
priv->line[nbytes] = '\0';
/* Skip to the first character of the next line. This should normally
* just amount to skipping over the newline, but could be more involved
* if we had to truncate the line to fit into the line buffer.
*/
if (priv->nextch != EOF)
{
(void)inifile_next_line(priv);
}
/* And return the number of bytes read (excluding the NUL terminator and
* leading whitespace).
*/
return nbytes;
}
/****************************************************************************
* Name: inifile_read_noncomment_line
*
* Description:
* Read until either a (1) no further lines are found in the file, or (2)
* a line that does not begin with a semi-colon is found
*
****************************************************************************/
static int inifile_read_noncomment_line(struct inifile_state_s *priv)
{
int nbytes;
/* Read until either a (1) no further lines are found in
* the file, or (2) a line that does not begin with a semi-colon
* is found.
*/
do nbytes = inifile_read_line(priv);
while (nbytes > 0 && priv->line[0] == ';');
return nbytes;
}
/****************************************************************************
* Name: inifile_seek_to_section
*
* Description:
* Positions the file pointer to the line containing the first variable
* description within the INI file. Returns 1 if the section was found.
* In this case, the file pointer will be positioned at the beginning of
* the first variable line.
*
****************************************************************************/
static bool inifile_seek_to_section(struct inifile_state_s *priv,
const char *section)
{
int nbytes;
/* Rewind to the beginning of the INI file and re-prime the pump with the
* first character from the INI file.
*/
rewind(priv->instream);
priv->nextch = getc(priv->instream);
/* Loop until either the section is found, or until we hit the end of the
* INI file.
*/
do
{
/* Read the next line into the input buffer. A returned value of zero
* bytes means nothing special here -- could be EOF or a blank line.
*/
nbytes = inifile_read_noncomment_line(priv);
/* It takes at least three bytes of data to be a candidate for a
* section header.
*/
if (nbytes >= 3)
{
/* A section header must begin with a left bracket */
if (priv->line[0] == '[')
{
/* The section name should start with the first character
* after the left bracket.
*/
char *sectend;
/* The section name should extend to the right bracket. */
sectend = strchr(&priv->line[1], ']');
/* Replace the right bracket (if found) with a NULL
* terminator.
*/
if (sectend)
{
*sectend = '\0';
}
/* Then compare the section name to the one we are looking for */
if (strcasecmp(&priv->line[1], section) == 0)
{
/* The section names match! Return success */
return true;
}
}
}
}
while (priv->nextch != EOF);
/* If we got here, we search the whole INI file without finding
* the requested section
*/
return false;
}
/****************************************************************************
* Name: inifile_read_variable
*
* Description:
* Obtain variable info from the next line in the section. This assumes
* that the file pointer is pointing to the beginning of the next line.
* If there is no further data in the section, false is returned.
*
****************************************************************************/
static bool inifile_read_variable(struct inifile_state_s *priv,
struct inifile_var_s *varinfo)
{
char *ptr;
/* Read until either (1) the end of file is found, (2) the end of
* the section is found, or (3) a valid variable assignment is found.
*/
for (;;)
{
/* Read the next line in the buffer */
int nbytes = inifile_read_noncomment_line(priv);
/* Make sure that the line is non-NULL and that this is not the
* beginning of a new section
*/
if (!nbytes || priv->line[0] == '[')
{
return false;
}
/* Search for the '=' delimiter. NOTE the line is guaranteed to
* be NULL terminated by inifile_read_noncomment_line().
*/
ptr = strchr(&priv->line[1], '=');
/* If the delimiter was found, return success */
if (ptr)
{
/* Put NUL termination between the variable name and the
* variable value (replacing the equal sign).
*/
*ptr = '\0';
/* Set up the return structure. NOTE: value may point at
* a NULL string
*/
varinfo->variable = (char*)priv->line;
varinfo->value = (ptr + 1);
return true;
}
}
}
/****************************************************************************
* Name: inifile_find_section_variable
*
* Description:
* Find the value string associated with the variable name. This function
* will return NULL on failure to find the variable. It will return a
* pointer to an empty string is the variable is found, but not assigned a
* value.
*
****************************************************************************/
static char *inifile_find_section_variable(struct inifile_state_s *priv,
const char *variable)
{
/* Loop until either (1) we hit the end of file, (2) we hit the end
* of the section, or (3) we find the variable that we are looking
* for/
*/
for (;;)
{
/* Get the next variable from this section. */
struct inifile_var_s varinfo;
bool found = inifile_read_variable(priv, &varinfo);
/* Is there anything left in the section? */
if (!found)
{
return NULL;
}
/* Does the variable name match the one we are looking for? */
if (strcasecmp(varinfo.variable, variable) == 0)
{
/* Yes... then we have it! */
return varinfo.value;
}
}
}
/****************************************************************************
* Name: inifile_find_variable
*
* Description:
* Obtains the specified string value for the specified variable name
* within the specified section of the INI file.
*
****************************************************************************/
static char *inifile_find_variable(struct inifile_state_s *priv,
const char *section,
const char *variable)
{
char *ret = NULL;
/* Seek to the first variable in the specified section of the INI file */
if (priv->instream && inifile_seek_to_section(priv, section))
{
/* If the seek was successful, then find the value string within
* the section
*/
char *value = inifile_find_section_variable(priv, variable);
if (value && *value)
{
ret = value;
}
}
/* Return the string that we found. */
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: inifile_initialize
*
* Description:
* Initialize for access to the INI file 'inifile_name'
*
****************************************************************************/
INIHANDLE inifile_initialize(const char *inifile_name)
{
/* Allocate an INI file parser state structure */
struct inifile_state_s *priv =
(struct inifile_state_s *)malloc(sizeof(struct inifile_state_s));
if (!priv)
{
return (INIHANDLE)NULL;
}
/* Open the specified INI file for reading */
priv->instream = fopen(inifile_name, "r");
/* Prime the pump */
if (priv->instream)
{
priv->nextch = getc(priv->instream);
return (INIHANDLE)priv;
}
else
{
return (INIHANDLE)NULL;
}
}
/****************************************************************************
* Name: inifile_uninitialize
*
* Description:
* Free resources commit to INI file parsing
*
****************************************************************************/
void inifile_uninitialize(INIHANDLE handle)
{
struct inifile_state_s *priv = (struct inifile_state_s *)handle;
if (priv)
{
/* Close the INI file stream */
if (priv->instream)
{
fclose(priv->instream);
}
/* Release the state structure */
free(priv);
}
}
/****************************************************************************
* Name: inifile_read_string
*
* Description:
* Obtains the specified string value for the specified variable name
* within the specified section of the INI file. The receiver of the
* value string should call inifile_free_string when it no longer needs
* the memory held by the value string.
*
****************************************************************************/
char *inifile_read_string(INIHANDLE handle,
const char *section,
const char *variable,
const char *defvalue)
{
struct inifile_state_s *priv = (struct inifile_state_s *)handle;
char *ret = NULL;
const char *value;
/* Get a reference to the volatile version of the string */
value = inifile_find_variable(priv, section, variable);
/* If the variable was not found, then use the default value */
if (!value)
{
/* Selecting the default string */
value = defvalue;
}
/* If this was successful, create a non-volatile copy of the string
* We do this even if the default value is used because the caller
* will (eventually) deallocate it.
*/
if (value)
{
ret = strdup(value);
}
/* Return the string that we found. */
return ret;
}
/****************************************************************************
* Name: inifile_read_integer
*
* Description:
* Obtains the specified integer value for the specified variable name
* within the specified section of the INI file
*
****************************************************************************/
long inifile_read_integer(INIHANDLE handle,
const char *section,
const char *variable,
long defvalue)
{
struct inifile_state_s *priv = (struct inifile_state_s *)handle;
char *value;
long ret = defvalue;
/* Get the value as a string first */
value = inifile_find_variable(priv, section, variable);
/* If this was successful, then convert the string to an integer value. */
if (value)
{
/* Then convert the string to an integer value (accept any base, and
* ignore all conversion errors.
*/
ret = strtol(value, NULL, 0);
}
/* Return the value that we found. */
return ret;
}
/****************************************************************************
* Name: inifile_free_string
*
* Description:
* Release resources allocated for the value string previously obtained
* from inifile_read_string. The purpose of this inline function is to
* hide the memory allocator used by this implementation.
*
****************************************************************************/
void inifile_free_string(char *value)
{
if (value)
{
free(value);
}
}
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