inih/ini.c

/* inih -- simple .INI file parser */

/* Copyright (c) 2009, Brush Technology -- New BSD license, see ini.h */

#include <stdio.h>
#include <ctype.h>
#include <string.h>

#include "ini.h"

#define MAX_LINE 200
#define MAX_SECTION 50
#define MAX_NAME 50

/* 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(*--p))
        *p = '\0';
    return s;
}

/* Return pointer to first non-whitespace char in given string. */
static char* lskip(const char* s)
{
    while (*s && isspace(*s))
        s++;
    return (char*)s;
}

/* Return pointer to first char c or ';' in given string, or pointer to
   null at end of string if neither found. */
static char* find_char_or_comment(const char* s, char c)
{
    while (*s && *s != c && *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;
}

/* See documentation in header file. */
int ini_parse(const char* filename,
              int (*handler)(void*, const char*, const char*, const char*),
              void* user)
{
    /* Uses a fair bit of stack (use heap instead if you need to) */
    char line[MAX_LINE];
    char section[MAX_SECTION] = "";
    char prev_name[MAX_NAME] = "";

    FILE* file;
    char* start;
    char* end;
    char* name;
    char* value;
    int lineno = 0;
    int error = 0;

    file = fopen(filename, "r");
    if (!file)
        return -1;

    /* Scan through file line by line */
    while (fgets(line, sizeof(line), file) != NULL) {
        lineno++;
        start = lskip(rstrip(line));

#if INI_ALLOW_MULTILINE
        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;
        }
        else
#endif
        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 != ';') {
            /* Not a comment, must be a name=value pair */
            end = find_char_or_comment(start, '=');
            if (*end == '=') {
                *end = '\0';
                name = rstrip(start);
                value = lskip(end + 1);
                end = find_char_or_comment(value, ';');
                if (*end == ';')
                    *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 '=' found on name=value line */
                error = lineno;
            }
        }
    }

    fclose(file);

    return error;
}