diff --git a/parser.c b/parser.c new file mode 100644 index 0000000..6db49ae --- /dev/null +++ b/parser.c @@ -0,0 +1,147 @@ +/* + * simple .INI file parser + */ + +#include +#include +#include + +#include "parser.h" + +#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((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 == ';')) { + 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; +} + +/* See documentation in header file. */ +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) */ + char line[INI_MAX_LINE]; + char section[MAX_SECTION] = ""; + char prev_name[MAX_NAME] = ""; + + char* start; + char* end; + char* name; + char* value; + int lineno = 0; + int error = 0; + + /* 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 == ';' || *start == '#') { + /* Per Python ConfigParser, allow '#' comments at start of line */ + } + 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 != ';') { + /* 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 == ';') + *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 (error) + break; + } + + return error; +} + +/* See documentation in header file. */ +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; +} diff --git a/parser.h b/parser.h new file mode 100644 index 0000000..d817192 --- /dev/null +++ b/parser.h @@ -0,0 +1,34 @@ +/* + * .INI file parser + */ + +#include + +/* Parse given INI-style file. May have [section]s, name=value pairs + (whitespace stripped), and comments starting with ';' (semicolon). Section + is "" if name=value pair parsed before any section heading. name:value + pairs are also supported as a concession to Python's ConfigParser. + + For each name=value pair parsed, call handler function with given user + pointer as well as section, name, and value (data only valid for duration + of handler call). Handler should return nonzero on success, zero on error. + + Returns 0 on success, line number of first error on parse error (doesn't + stop on first error), -1 on file open erro. +*/ +int ini_parse(const char* filename, + int (*handler)(void* user, const char* section, + const char* name, const char* value), + void* user); + +/* Same as ini_parse(), but takes a FILE* instead of filename. This doesn't + close the file when it's finished -- the caller must do that. */ +int ini_parse_file(FILE* file, + int (*handler)(void* user, const char* section, + const char* name, const char* value), + void* user); + +/* Maximum line length for any line in INI file. */ +#ifndef INI_MAX_LINE +#define INI_MAX_LINE 200 +#endif