SCPI parser and status register model implementation (device side) written in C
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scpi_parser/scpi_parser.c

351 lines
8.0 KiB

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#include <stdint.h>
#include <stdbool.h>
#include <string.h>
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#include "scpi_parser.h"
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#include <stdio.h>
#include <stdlib.h>
typedef enum {
PARS_COMMAND,
// collect generic arg, terminated with comma or newline. Leading and trailing whitespace ignored.
PARS_ARG,
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PARS_ARG_STR_APOS, // collect arg - string with single quotes
PARS_ARG_STR_QUOT, // collect arg - string with double quotes
PARS_ARG_BLOB_PREAMBLE,
// command with no args terminated by whitespace, discard whitespace until newline and then run callback.
// error on non-whitespace
PARS_DISCARD_WHITESPACE_ENDL,
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PARS_DISCARD_LINE, // used after detecting error
} parser_state_t;
/** parser internal state struct */
static struct {
char err_queue[ERR_QUEUE_LEN][MAX_ERROR_LEN];
uint8_t err_queue_i;
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parser_state_t state; // current parser internal state
// string buffer, chars collected here until recognized
char charbuf[256];
uint16_t charbuf_i;
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// recognized complete command level strings (FUNCtion) - exact copy from command struct
char cur_levels[MAX_LEVEL_COUNT][MAX_CMD_LEN];
uint8_t cur_level_i; // next free level slot index
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bool cmdbuf_kept; // set to 1 after semicolon - cur_levels is kept (removed last part)
const SCPI_command_t * matched_cmd; // command is put here after recognition, used as reference for args
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SCPI_argval_t args[MAX_PARAM_COUNT];
uint8_t arg_i; // next free argument slot index
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} pstate = {
// defaults
.err_queue_i = 0,
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.state = PARS_COMMAND,
.charbuf_i = 0,
.cur_level_i = 0,
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.cmdbuf_kept = false,
.matched_cmd = NULL,
.arg_i = 0
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};
static void pars_cmd_colon(void); // colon starting a command sub-segment
static void pars_cmd_space(void); // space ending a command
static void pars_cmd_newline(void); // LF
static void pars_cmd_semicolon(void); // semicolon right after a command
static bool pars_match_cmd(bool partial);
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// char matching
#define INRANGE(c, a, b) ((c) >= (a) && (c) <= (b))
#define IS_WHITESPACE(c) (INRANGE((c), 0, 9) || INRANGE((c), 11, 32))
#define IS_LCASE_CHAR(c) INRANGE((c), 'a', 'z')
#define IS_UCASE_CHAR(c) INRANGE((c), 'A', 'Z')
#define IS_NUMBER_CHAR(c) INRANGE((c), '0', '9')
#define IS_IDENT_CHAR(c) (IS_LCASE_CHAR((c)) || IS_UCASE_CHAR((c)) || IS_NUMBER_CHAR((c)) || (c) == '_' || (c) == '*' || (c) == '?')
#define IS_INT_CHAR(c) IS_NUMBER_CHAR((c))
#define IS_FLOAT_CHAR(c) (IS_NUMBER_CHAR((c)) || (c) == '.' || (c) == 'e' || (c) == 'E' || (e) == '+' || (e) == '-')
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#define CHAR_TO_LOWER(ucase) ((ucase) + 32)
#define CHAR_TO_UPPER(lcase) ((lcase) - 32)
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static void pars_reset_cmd(void)
{
pstate.state = PARS_COMMAND;
pstate.charbuf_i = 0;
pstate.cur_level_i = 0;
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pstate.cmdbuf_kept = false;
pstate.matched_cmd = NULL;
pstate.arg_i = 0;
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}
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static void pars_reset_cmd_keeplevel(void)
{
pstate.state = PARS_COMMAND;
pstate.charbuf_i = 0;
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// rewind to last colon
if (pstate.cur_level_i > 0) {
pstate.cur_level_i--; // keep prev levels
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}
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pstate.cmdbuf_kept = true;
pstate.matched_cmd = NULL;
pstate.arg_i = 0;
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}
void scpi_handle_byte(const uint8_t b)
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{
// TODO handle blob here
const char c = (char) b;
switch (pstate.state) {
case PARS_COMMAND:
// Collecting command
if (pstate.charbuf_i == 0 && pstate.cur_level_i == 0) {
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if (IS_WHITESPACE(c)) {
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// leading whitespace is ignored
break;
}
}
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if (IS_IDENT_CHAR(c)) {
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// valid command char
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if (pstate.charbuf_i < MAX_CMD_LEN) {
pstate.charbuf[pstate.charbuf_i++] = c;
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} else {
printf("ERROR command part too long.\n");//TODO error
pstate.state = PARS_DISCARD_LINE;
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}
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} else {
// invalid or delimiter
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if (IS_WHITESPACE(c)) {
pars_cmd_space(); // whitespace in command - end of command, start of args (?)
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break;
}
switch (c) {
case ':':
pars_cmd_colon(); // end of a section
break;
case '\n': // line terminator
pars_cmd_newline();
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break;
case ';': // ends a command, does not reset cmd path.
// pars_cmd_semicolon();
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break;
default:
printf("ERROR unexpected char '%c' in command.\n", c);//TODO error
pstate.state = PARS_DISCARD_LINE;
}
}
break;
case PARS_DISCARD_LINE:
// drop it. Clear state on newline.
if (c == '\r' || c == '\n') {
pars_reset_cmd();
}
break;
// TODO
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}
}
static void pars_cmd_colon(void)
{
if (pstate.charbuf_i == 0) {
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// No command text before colon
if (pstate.cur_level_i == 0 || pstate.cmdbuf_kept) {
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// top level command starts with colon (or after semicolon - reset level)
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pars_reset_cmd();
} else {
// colon after nothing - error
printf("ERROR unexpected colon in command.\n");//TODO error
pstate.state = PARS_DISCARD_LINE;
}
} else {
// internal colon - partial match
if (pars_match_cmd(true)) {
printf("OK partial cmd, last segment = %s\n", pstate.cur_levels[pstate.cur_level_i - 1]);
} else {
printf("ERROR no such command (colon).\n");//TODO error
pstate.state = PARS_DISCARD_LINE;
}
}
}
static void pars_cmd_newline(void)
{
if (pstate.cur_level_i == 0 && pstate.charbuf_i == 0) {
// nothing before newline
pars_reset_cmd();
return;
}
// complete match
if (pars_match_cmd(false)) {
if (pstate.matched_cmd->param_cnt == 0) {
// no param command - OK
pstate.matched_cmd->callback(pstate.args); // args are empty
} else {
printf("ERROR command missing arguments.\n");//TODO error
pars_reset_cmd();
}
} else {
printf("ERROR no such command (newline) %s.\n", pstate.charbuf);//TODO error
pstate.state = PARS_DISCARD_LINE;
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}
}
/** Check if chars equal, ignore case */
static bool char_equals_ci(char a, char b)
{
if (IS_LCASE_CHAR(a)) {
if (IS_LCASE_CHAR(b)) {
return a == b;
} else if (IS_UCASE_CHAR(b)) {
return a == CHAR_TO_LOWER(b);
} else {
return false;
}
} else if (IS_UCASE_CHAR(a)) {
if (IS_UCASE_CHAR(b)) {
return a == b;
} else if (IS_LCASE_CHAR(b)) {
return a == CHAR_TO_UPPER(b);
} else {
return false;
}
} else {
return a == b; // exact match, not letters
}
}
/** Check if command matches a pattern */
static bool level_str_matches(const char *test, const char *pattern)
{
const uint8_t testlen = strlen(test);
uint8_t pi, ti;
for (pi = 0, ti = 0; pi < strlen(pattern); pi++) {
if (ti > testlen) return false; // not match
const char pc = pattern[pi];
const char tc = test[ti]; // may be at the \0 terminator
if (IS_LCASE_CHAR(pc)) {
// optional char
if (char_equals_ci(pc, tc)) {
ti++; // advance test string
}
continue; // next pi - tc stays in place
} else {
// require exact match (case insensitive)
if (char_equals_ci(pc, tc)) {
ti++;
} else {
return false;
}
}
}
return (ti >= testlen);
}
// proto
static bool try_match_cmd(const SCPI_command_t *cmd, bool partial);
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static bool pars_match_cmd(bool partial)
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{
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// terminate segment
pstate.charbuf[pstate.charbuf_i] = '\0';
pstate.charbuf_i = 0; // rewind
char *dest = pstate.cur_levels[pstate.cur_level_i++];
strcpy(dest, pstate.charbuf); // copy to level table
for (uint16_t i = 0; i < scpi_cmd_lang_len; i++) {
const SCPI_command_t *cmd = &scpi_cmd_lang[i];
if (cmd->level_cnt > MAX_LEVEL_COUNT) {
// FAIL, too deep. Bad config
continue;
}
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if (try_match_cmd(cmd, partial)) {
if (partial) {
// match found, OK
return true;
} else {
// exact match found
pstate.matched_cmd = cmd;
return true;
}
}
}
return false;
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}
/** Try to match current state to a given command */
static bool try_match_cmd(const SCPI_command_t *cmd, bool partial)
{
if (pstate.cur_level_i > cmd->level_cnt) return false; // command too short
if (pstate.cur_level_i == 0) return false; // nothing to match
if (partial) {
if (pstate.cur_level_i == cmd->level_cnt) {
return false; // would be exact match
}
} else {
if (pstate.cur_level_i != cmd->level_cnt) {
return false; // can be only partial match
}
}
// check for match up to current index
for (uint8_t j = 0; j < pstate.cur_level_i; j++) {
if (!level_str_matches(pstate.cur_levels[j], cmd->levels[j])) {
return false;
}
}
return true;
}