ini.cpp

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/** \file ini.cpp
 * \author Jared R. Males
 * \brief Implementation of the The inih  ini-style, file parser modified for mxlib.
 *
 * \ingroup mxApp_files
 *
 */
 
#ifndef INI_COMMENT_CHAR
   #define INI_COMMENT_CHAR ('#')
#endif
 
/* Nonzero to allow multi-line value parsing, in the style of Python's
   ConfigParser. If allowed, ini_parse() will call the handler with the same
   name for each subsequent line parsed. */
#ifndef INI_ALLOW_MULTILINE
#define INI_ALLOW_MULTILINE 1
#endif
 
/* Nonzero to allow a UTF-8 BOM sequence (0xEF 0xBB 0xBF) at the start of
   the file. See http://code.google.com/p/inih/issues/detail?id=21 */
#ifndef INI_ALLOW_BOM
#define INI_ALLOW_BOM 1
#endif
 
/* Nonzero to use stack, zero to use heap (malloc/free). */
#ifndef INI_USE_STACK
#define INI_USE_STACK 0
#endif
 
/* Stop parsing on first error (default is to stop parsing). */
#ifndef INI_STOP_ON_FIRST_ERROR
#define INI_STOP_ON_FIRST_ERROR 0
#endif
 
/* Maximum line length for any line in INI file. */
#ifndef INI_MAX_LINE
#define INI_MAX_LINE 1024
#endif
 
#define MAX_SECTION 50
#define MAX_NAME 50
 
#if !INI_USE_STACK
#include <stdlib.h>
#endif
 
#include "app/ini.hpp"
 
/* Strip whitespace chars off end of given string, in place. Return s. */
static char* rstrip(char* s)
{
    char* p = s + strlen(s);
    while (p > s && isspace((unsigned char)(*--p)))
        *p = '\0';
    return s;
}
 
/* Return pointer to first non-whitespace char in given string. */
static char* lskip(const char* s)
{
    while (*s && isspace((unsigned char)(*s)))
        s++;
    return (char*)s;
}
 
/* Return pointer to first char c or ';' comment in given string, or pointer to
   null at end of string if neither found. ';' must be prefixed by a whitespace
   character to register as a comment. */
static char* find_char_or_comment(const char* s, char c)
{
    int was_whitespace = 0;
    while (*s && *s != c && !(was_whitespace && *s == INI_COMMENT_CHAR)) {
        was_whitespace = isspace((unsigned char)(*s));
        s++;
    }
    return (char*)s;
}
 
/* Version of strncpy that ensures dest (size bytes) is null-terminated. */
static char* strncpy0(char* dest, const char* src, size_t size)
{
    strncpy(dest, src, size);
    dest[size - 1] = '\0';
    return dest;
}
 
int ini_parse_file(FILE* file,
                   int (*handler)( void*, const char*, const char*, const char*),
                   void* user
                  )
{
    /* Uses a fair bit of stack (use heap instead if you need to) */
#if INI_USE_STACK
    char line[INI_MAX_LINE];
#else
    char* line;
#endif
    char section[MAX_SECTION] = "";
    char prev_name[MAX_NAME] = "";
 
    char* start;
    char* end;
    char* name;
    char* value;
    int lineno = 0;
    int error = 0;
 
#if !INI_USE_STACK
    line = (char*)malloc(INI_MAX_LINE);
    if (!line) {
        return -2;
    }
#endif
 
    /* Scan through file line by line */
    while (fgets(line, INI_MAX_LINE, file) != NULL) {
        lineno++;
 
        start = line;
#if INI_ALLOW_BOM
        if (lineno == 1 && (unsigned char)start[0] == 0xEF &&
                           (unsigned char)start[1] == 0xBB &&
                           (unsigned char)start[2] == 0xBF) {
            start += 3;
        }
#endif
        start = lskip(rstrip(start));
 
        if (*start == INI_COMMENT_CHAR || *start == '#') {
            /* Per Python ConfigParser, allow '#' comments at start of line */
        }
#if INI_ALLOW_MULTILINE
        else if (*prev_name && *start && start > line) {
            /* Non-black line with leading whitespace, treat as continuation
               of previous name's value (as per Python ConfigParser). */
            if (!handler(user, section, prev_name, start) && !error)
                error = lineno;
        }
#endif
        else if (*start == '[') {
            /* A "[section]" line */
            end = find_char_or_comment(start + 1, ']');
            if (*end == ']') {
                *end = '\0';
                strncpy0(section, start + 1, sizeof(section));
                *prev_name = '\0';
            }
            else if (!error) {
                /* No ']' found on section line */
                error = lineno;
            }
        }
        else if (*start && *start != INI_COMMENT_CHAR) {
            /* Not a comment, must be a name[=:]value pair */
            end = find_char_or_comment(start, '=');
            if (*end != '=') {
                end = find_char_or_comment(start, ':');
            }
            if (*end == '=' || *end == ':') {
                *end = '\0';
                name = rstrip(start);
                value = lskip(end + 1);
                end = find_char_or_comment(value, '\0');
                if (*end == INI_COMMENT_CHAR)
                    *end = '\0';
                rstrip(value);
 
                /* Valid name[=:]value pair found, call handler */
                strncpy0(prev_name, name, sizeof(prev_name));
                if (!handler(user, section, name, value) && !error)
                    error = lineno;
            }
            else if (!error) {
                /* No '=' or ':' found on name[=:]value line */
                error = lineno;
            }
        }
 
#if INI_STOP_ON_FIRST_ERROR
        if (error)
            break;
#endif
    }
 
#if !INI_USE_STACK
    free(line);
#endif
 
    return error;
}
 
int ini_parse(const char* filename,
              int (*handler)(void*, const char*, const char*, const char*),
              void* user
             )
{
    FILE* file;
    int error;
 
    file = fopen(filename, "r");
    if (!file)
        return -1;
    error = ini_parse_file(file, handler, user);
    fclose(file);
    return error;
}