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

310 lines
7.0 KiB

#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
//#include "scpi_parser.h"
#define MAX_CMD_LEN 12
#define MAX_STRING_LEN 12
#define MAX_LEVEL_COUNT 4
#define MAX_PARAM_COUNT 4
#define ERR_QUEUE_LEN 4
#define MAX_ERROR_LEN 100
/** Argument data types */
typedef enum {
SCPI_DT_NONE = 0,
SCPI_DT_FLOAT, // float with support for scientific notation
SCPI_DT_INT, // integer (may be signed)
SCPI_DT_BOOL, // 0, 1, ON, OFF
SCPI_DT_STRING, // quoted string, max 12 chars; no escapes.
SCPI_DT_BLOB, // binary block, callback: uint32_t holding number of bytes
} SCPI_datatype_t;
/** Arguemnt value (union) */
typedef union {
float FLOAT;
int32_t INT;
bool BOOL;
char STRING[MAX_STRING_LEN];
uint32_t BLOB;
} SCPI_argval_t;
/** SCPI command preset */
typedef struct {
const uint8_t level_cnt; // number of used command levels (colons + 1)
const char levels[MAX_LEVEL_COUNT][MAX_CMD_LEN]; // up to 4 parts
const bool quest; // command ends with a question mark
const uint8_t param_cnt; // parameter count
const SCPI_datatype_t params[MAX_PARAM_COUNT]; // parameter types (0 for unused)
// called when the command is completed. BLOB arg must be last in the argument list,
// and only the first part is collected.
void (*callback)(const SCPI_argval_t * args);
} SCPI_command_t;
typedef enum {
PARS_COMMAND,
PARS_ARG, // collect generic arg, terminated with comma or newline. Leading and trailing whitespace ignored.
PARS_ARG_STR_APOS, // collect arg - string with single quotes
PARS_ARG_STR_QUOT, // collect arg - string with double quotes
PARS_ARG_BLOB_PREAMBLE,
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_used;
parser_state_t state; // current parser internal state
// string buffer, chars collected here until recognized
char charbuf[256];
uint16_t charbuf_ptr;
// command buffer, built from recognized parts and colons.
char cmdbuf[(MAX_CMD_LEN + 1)*MAX_LEVEL_COUNT + 1]; // :COMMAND for each level + zero terminator
uint16_t cmdbuf_ptr;
bool cmdbuf_kept; // set to 1 after semicolon
parser_state_t *detected_cmd; // command is put here after recognition, used as reference for args
uint8_t arg_i; // current argument index (0-based)
} pstate = {
// defaults
.err_queue_used = 0,
.state = PARS_COMMAND,
.charbuf_ptr = 0,
.cmdbuf_ptr = 0,
.cmdbuf_kept = false,
.detected_cmd = NULL,
.arg_i = 0
};
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
#define INRANGE(x, a, b) ((x) >= (a) && (x) <= (b))
#define IS_WHITE(x) (INRANGE((x), 0, 9) || INRANGE((x), 11, 32))
static void pars_reset_cmd(void)
{
pstate.state = PARS_COMMAND;
pstate.charbuf_ptr = 0;
pstate.cmdbuf_ptr = 0;
pstate.cmdbuf_kept = false;
pstate.detected_cmd = NULL;
pstate.arg_i = 0;
}
static void pars_reset_cmd_keeplevel(void)
{
pstate.state = PARS_COMMAND;
pstate.charbuf_ptr = 0;
// rewind to last colon
pstate.cmdbuf[pstate.cmdbuf_ptr] = 0; // terminate
const char *cp = strrchr(pstate.cmdbuf, ':'); // find last colon
pstate.cmdbuf_ptr = (uint16_t) (cp - pstate.cmdbuf + 1); // location of one char past the colon
// ↑ FIXME may be broken
pstate.cmdbuf_kept = true;
pstate.detected_cmd = NULL;
pstate.arg_i = 0;
}
void scpi_receive_byte(const uint8_t b)
{
// TODO handle blob here
const char c = (char) b;
switch (pstate.state) {
case PARS_COMMAND:
// Collecting command
if (pstate.charbuf_ptr == 0) {
if (IS_WHITE(c)) {
// leading whitespace is ignored
break;
}
}
if (INRANGE(c, 'a', 'z') || INRANGE(c, 'A', 'Z') || INRANGE(c, '0', '9') || c == '_') {
// valid command char
if (pstate.charbuf_ptr < MAX_CMD_LEN) {
pstate.charbuf[pstate.charbuf_ptr++] = c;
}
} else {
// invalid or delimiter
if (IS_WHITE(c)) {
pars_cmd_space(); // whitespace in command - end of command?
break;
}
switch (c) {
case ':':
pars_cmd_colon(); // end of a section
break;
case '\n': // line terminator
pars_cmd_newline();
break;
case ';': // ends a command, does not reset cmd path.
pars_cmd_semicolon();
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
}
}
// whitespace (INRANGE(c, 0, 9) || INRANGE(c, 11, 32))
static void pars_cmd_colon(void)
{
if (pstate.charbuf_ptr == 0) {
// No command text before colon
// TODO FIXME should keep parsed command parts in array rather than a combined string
if (pstate.cmdbuf_ptr == 0 || pstate.cmdbuf_kept) {
// top level command starts with optional colon (or after semicolon reset level)
pars_reset_cmd();
} else {
// colon after nothing - error
printf("ERROR unexpected colon in command.\n");//TODO error
pstate.state = PARS_DISCARD_LINE;
}
} else {
while(pstate.charbuf_ptr > 0 && IS_WHITE(pstate.charbuf[pstate.charbuf_ptr - 1])) {
pstate.charbuf_ptr--;
}
if (pstate.charbuf_ptr){
printf("ERROR only whitespace before colon.\n");//TODO error
pstate.state = PARS_DISCARD_LINE; // this error shouldn't happen
return;
}
pstate.charbuf[pstate.charbuf_ptr] = '\0'; // terminator
}
}
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
//----------------------- TESTS ----------------------
void cmd_aIDNq_cb(const SCPI_argval_t *args);
void cmd_APPL_SIN_cb(const SCPI_argval_t *args);
void cmd_APPL_TRI_cb(const SCPI_argval_t *args);
void cmd_FREQ_cb(const SCPI_argval_t *args);
const SCPI_command_t lang[] = {
{
.level_cnt = 1, .levels = {"*IDN"},
.quest = true,
.param_cnt = 0, .params = {},
.callback = cmd_aIDNq_cb
},
{
.level_cnt = 2, .levels = {"APPLy", "SINe"},
.quest = false,
.param_cnt = 3, .params = {SCPI_DT_INT, SCPI_DT_FLOAT, SCPI_DT_FLOAT},
.callback = cmd_APPL_SIN_cb
},
{
.level_cnt = 2, .levels = {"APPLy", "TRIangle"},
.quest = false,
.param_cnt = 3, .params = {SCPI_DT_INT, SCPI_DT_FLOAT, SCPI_DT_FLOAT},
.callback = cmd_APPL_TRI_cb
},
{
.level_cnt = 1, .levels = {"FREQuency"},
.quest = false,
.param_cnt = 1, .params = {SCPI_DT_INT},
.callback = cmd_FREQ_cb
},
};
int main(int argc, const char**argv)
{
const char *inp = argv[1];
}
void cmd_aIDNq_cb(const SCPI_argval_t *args)
{
printf("cb *IDN?\n");
}
void cmd_APPL_SIN_cb(const SCPI_argval_t *args)
{
printf("cb APPLy:SINe\n");
}
void cmd_APPL_TRI_cb(const SCPI_argval_t *args)
{
printf("cb APPLy:TRIangle\n");
}
void cmd_FREQ_cb(const SCPI_argval_t *args)
{
printf("cb FREQuency\n");
}