Amit Gandhi
test
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mbed official
Diff: platform/ATCmdParser.cpp
- Revision:
- 168:e84263d55307
- Child:
- 177:447f873cad2f
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/platform/ATCmdParser.cpp Wed Jun 21 17:46:44 2017 +0100
@@ -0,0 +1,382 @@
+/* Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * @section DESCRIPTION
+ *
+ * Parser for the AT command syntax
+ *
+ */
+
+#include "ATCmdParser.h"
+#include "mbed_poll.h"
+#include "mbed_debug.h"
+
+#ifdef LF
+#undef LF
+#define LF 10
+#else
+#define LF 10
+#endif
+
+#ifdef CR
+#undef CR
+#define CR 13
+#else
+#define CR 13
+#endif
+
+// getc/putc handling with timeouts
+int ATCmdParser::putc(char c)
+{
+ pollfh fhs;
+ fhs.fh = _fh;
+ fhs.events = POLLOUT;
+
+ int count = poll(&fhs, 1, _timeout);
+ if (count > 0 && (fhs.revents & POLLOUT)) {
+ return _fh->write(&c, 1) == 1 ? 0 : -1;
+ } else {
+ return -1;
+ }
+}
+
+int ATCmdParser::getc()
+{
+ pollfh fhs;
+ fhs.fh = _fh;
+ fhs.events = POLLIN;
+
+ int count = poll(&fhs, 1, _timeout);
+ if (count > 0 && (fhs.revents & POLLIN)) {
+ unsigned char ch;
+ return _fh->read(&ch, 1) == 1 ? ch : -1;
+ } else {
+ return -1;
+ }
+}
+
+void ATCmdParser::flush()
+{
+ while (_fh->readable()) {
+ unsigned char ch;
+ _fh->read(&ch, 1);
+ }
+}
+
+
+// read/write handling with timeouts
+int ATCmdParser::write(const char *data, int size)
+{
+ int i = 0;
+ for ( ; i < size; i++) {
+ if (putc(data[i]) < 0) {
+ return -1;
+ }
+ }
+ return i;
+}
+
+int ATCmdParser::read(char *data, int size)
+{
+ int i = 0;
+ for ( ; i < size; i++) {
+ int c = getc();
+ if (c < 0) {
+ return -1;
+ }
+ data[i] = c;
+ }
+ return i;
+}
+
+
+// printf/scanf handling
+int ATCmdParser::vprintf(const char *format, va_list args)
+{
+
+ if (vsprintf(_buffer, format, args) < 0) {
+ return false;
+ }
+
+ int i = 0;
+ for ( ; _buffer[i]; i++) {
+ if (putc(_buffer[i]) < 0) {
+ return -1;
+ }
+ }
+ return i;
+}
+
+int ATCmdParser::vscanf(const char *format, va_list args)
+{
+ // Since format is const, we need to copy it into our buffer to
+ // add the line's null terminator and clobber value-matches with asterisks.
+ //
+ // We just use the beginning of the buffer to avoid unnecessary allocations.
+ int i = 0;
+ int offset = 0;
+
+ while (format[i]) {
+ if (format[i] == '%' && format[i+1] != '%' && format[i+1] != '*') {
+ _buffer[offset++] = '%';
+ _buffer[offset++] = '*';
+ i++;
+ } else {
+ _buffer[offset++] = format[i++];
+ }
+ }
+
+ // Scanf has very poor support for catching errors
+ // fortunately, we can abuse the %n specifier to determine
+ // if the entire string was matched.
+ _buffer[offset++] = '%';
+ _buffer[offset++] = 'n';
+ _buffer[offset++] = 0;
+
+ // To workaround scanf's lack of error reporting, we actually
+ // make two passes. One checks the validity with the modified
+ // format string that only stores the matched characters (%n).
+ // The other reads in the actual matched values.
+ //
+ // We keep trying the match until we succeed or some other error
+ // derails us.
+ int j = 0;
+
+ while (true) {
+ // Ran out of space
+ if (j+1 >= _buffer_size - offset) {
+ return false;
+ }
+ // Recieve next character
+ int c = getc();
+ if (c < 0) {
+ return -1;
+ }
+ _buffer[offset + j++] = c;
+ _buffer[offset + j] = 0;
+
+ // Check for match
+ int count = -1;
+ sscanf(_buffer+offset, _buffer, &count);
+
+ // We only succeed if all characters in the response are matched
+ if (count == j) {
+ // Store the found results
+ vsscanf(_buffer+offset, format, args);
+ return j;
+ }
+ }
+}
+
+
+// Command parsing with line handling
+bool ATCmdParser::vsend(const char *command, va_list args)
+{
+ // Create and send command
+ if (vsprintf(_buffer, command, args) < 0) {
+ return false;
+ }
+
+ for (int i = 0; _buffer[i]; i++) {
+ if (putc(_buffer[i]) < 0) {
+ return false;
+ }
+ }
+
+ // Finish with newline
+ for (size_t i = 0; _output_delimiter[i]; i++) {
+ if (putc(_output_delimiter[i]) < 0) {
+ return false;
+ }
+ }
+
+ debug_if(_dbg_on, "AT> %s\n", _buffer);
+ return true;
+}
+
+bool ATCmdParser::vrecv(const char *response, va_list args)
+{
+restart:
+ _aborted = false;
+ // Iterate through each line in the expected response
+ while (response[0]) {
+ // Since response is const, we need to copy it into our buffer to
+ // add the line's null terminator and clobber value-matches with asterisks.
+ //
+ // We just use the beginning of the buffer to avoid unnecessary allocations.
+ int i = 0;
+ int offset = 0;
+ bool whole_line_wanted = false;
+
+ while (response[i]) {
+ if (response[i] == '%' && response[i+1] != '%' && response[i+1] != '*') {
+ _buffer[offset++] = '%';
+ _buffer[offset++] = '*';
+ i++;
+ } else {
+ _buffer[offset++] = response[i++];
+ // Find linebreaks, taking care not to be fooled if they're in a %[^\n] conversion specification
+ if (response[i - 1] == '\n' && !(i >= 3 && response[i-3] == '[' && response[i-2] == '^')) {
+ whole_line_wanted = true;
+ break;
+ }
+ }
+ }
+
+ // Scanf has very poor support for catching errors
+ // fortunately, we can abuse the %n specifier to determine
+ // if the entire string was matched.
+ _buffer[offset++] = '%';
+ _buffer[offset++] = 'n';
+ _buffer[offset++] = 0;
+
+ debug_if(_dbg_on, "AT? %s\n", _buffer);
+ // To workaround scanf's lack of error reporting, we actually
+ // make two passes. One checks the validity with the modified
+ // format string that only stores the matched characters (%n).
+ // The other reads in the actual matched values.
+ //
+ // We keep trying the match until we succeed or some other error
+ // derails us.
+ int j = 0;
+
+ while (true) {
+ // Receive next character
+ int c = getc();
+ if (c < 0) {
+ debug_if(_dbg_on, "AT(Timeout)\n");
+ return false;
+ }
+ // Simplify newlines (borrowed from retarget.cpp)
+ if ((c == CR && _in_prev != LF) ||
+ (c == LF && _in_prev != CR)) {
+ _in_prev = c;
+ c = '\n';
+ } else if ((c == CR && _in_prev == LF) ||
+ (c == LF && _in_prev == CR)) {
+ _in_prev = c;
+ // onto next character
+ continue;
+ } else {
+ _in_prev = c;
+ }
+ _buffer[offset + j++] = c;
+ _buffer[offset + j] = 0;
+
+ // Check for oob data
+ for (struct oob *oob = _oobs; oob; oob = oob->next) {
+ if ((unsigned)j == oob->len && memcmp(
+ oob->prefix, _buffer+offset, oob->len) == 0) {
+ debug_if(_dbg_on, "AT! %s\n", oob->prefix);
+ oob->cb();
+
+ if (_aborted) {
+ debug_if(_dbg_on, "AT(Aborted)\n");
+ return false;
+ }
+ // oob may have corrupted non-reentrant buffer,
+ // so we need to set it up again
+ goto restart;
+ }
+ }
+
+ // Check for match
+ int count = -1;
+ if (whole_line_wanted && c != '\n') {
+ // Don't attempt scanning until we get delimiter if they included it in format
+ // This allows recv("Foo: %s\n") to work, and not match with just the first character of a string
+ // (scanf does not itself match whitespace in its format string, so \n is not significant to it)
+ } else {
+ sscanf(_buffer+offset, _buffer, &count);
+ }
+
+ // We only succeed if all characters in the response are matched
+ if (count == j) {
+ debug_if(_dbg_on, "AT= %s\n", _buffer+offset);
+ // Reuse the front end of the buffer
+ memcpy(_buffer, response, i);
+ _buffer[i] = 0;
+
+ // Store the found results
+ vsscanf(_buffer+offset, _buffer, args);
+
+ // Jump to next line and continue parsing
+ response += i;
+ break;
+ }
+
+ // Clear the buffer when we hit a newline or ran out of space
+ // running out of space usually means we ran into binary data
+ if (c == '\n' || j+1 >= _buffer_size - offset) {
+ debug_if(_dbg_on, "AT< %s", _buffer+offset);
+ j = 0;
+ }
+ }
+ }
+
+ return true;
+}
+
+// Mapping to vararg functions
+int ATCmdParser::printf(const char *format, ...)
+{
+ va_list args;
+ va_start(args, format);
+ int res = vprintf(format, args);
+ va_end(args);
+ return res;
+}
+
+int ATCmdParser::scanf(const char *format, ...)
+{
+ va_list args;
+ va_start(args, format);
+ int res = vscanf(format, args);
+ va_end(args);
+ return res;
+}
+
+bool ATCmdParser::send(const char *command, ...)
+{
+ va_list args;
+ va_start(args, command);
+ bool res = vsend(command, args);
+ va_end(args);
+ return res;
+}
+
+bool ATCmdParser::recv(const char *response, ...)
+{
+ va_list args;
+ va_start(args, response);
+ bool res = vrecv(response, args);
+ va_end(args);
+ return res;
+}
+
+// oob registration
+void ATCmdParser::oob(const char *prefix, Callback<void()> cb)
+{
+ struct oob *oob = new struct oob;
+ oob->len = strlen(prefix);
+ oob->prefix = prefix;
+ oob->cb = cb;
+ oob->next = _oobs;
+ _oobs = oob;
+}
+
+void ATCmdParser::abort()
+{
+ _aborted = true;
+}