modem.cpp

00001 /*
00002   modem.cpp
00003   2015 Copyright (c) Seeed Technology Limited.  All right reserved.
00004 */
00005 
00006 #include "modem.h"
00007 #include <stdarg.h>
00008 
00009 #define DEBUG
00010 
00011 #ifdef DEBUG
00012 #include "USBSerial.h"
00013 extern USBSerial pc;
00014 #define LOG(args...)        pc.printf(args)
00015 #else
00016 #define LOG(args...)
00017 #endif
00018 
00019 int Modem::readline(char *buf, int len, uint32_t timeout)
00020 {
00021     int bytes = 0;
00022     uint32_t start = us_ticker_read();
00023     timeout = timeout * 1000;               // ms to us
00024     
00025     while (bytes < len) {
00026         if (readable()) {
00027             char ch = getc();
00028             if (ch == '\n') {
00029                 if (bytes > 0 && buf[bytes - 1] == '\r') {
00030                     bytes--;
00031                 }
00032                 
00033                 if (bytes > 0) {
00034                     buf[bytes] = '\0';
00035                     
00036                     return bytes;
00037                 }
00038             } else {
00039                 buf[bytes] = ch;
00040                 bytes++;
00041             }
00042         } else {
00043             if ((uint32_t)(us_ticker_read() - start) > timeout) {
00044                 LOG("wait for a line - timeout\r\n");
00045                 return -1;
00046             }
00047         }
00048     }
00049     
00050     // buffer is not enough
00051     LOG("%s %d line buffer is not enough (max_buf_size: %d)!\r\n", __FILE__, __LINE__, len);
00052 
00053     return 0;
00054 }
00055 
00056 int Modem::command(const char* format, ...)
00057 {
00058     
00059     char buffer[64];
00060     memset(buffer, 0, sizeof(buffer));
00061     int r = 0;
00062 
00063     va_list arg;
00064     va_start(arg, format);
00065     r = vsprintf(buffer, format, arg);
00066     // this may not hit the heap but should alert the user anyways
00067     if(r > sizeof(buffer)) {
00068         error("%s %d buffer overwrite (max_buf_size: %d exceeded: %d)!\r\n", __FILE__, __LINE__, sizeof(buffer), r);
00069         va_end(arg);
00070         return 0;
00071     }
00072     va_end(arg);
00073     
00074     
00075     while (!writeable()) {
00076     }
00077     flush();
00078 
00079     r = BufferedSerial::write(buffer, r);   // send command
00080     
00081     char response[64] = {0,};
00082     readline(response, sizeof(response));       // echo enabled
00083     
00084     readline(response, sizeof(response));
00085     
00086     if (strcmp(response, "OK") == 0) {
00087         return 0;
00088     }
00089     
00090     LOG("cmd failed - w(%s), r(%s)\r\n", buffer, response);
00091 
00092     return -1;
00093 }
00094 
00095 int Modem::match(const char *str, uint32_t timeout)
00096 {
00097     const char *ptr = str;
00098     uint32_t start = us_ticker_read();
00099     timeout = timeout * 1000;               // ms to us
00100 
00101     while(*ptr) {
00102         if(readable()) {
00103             char c = getc();
00104             if (*ptr == c) {
00105                 ptr++;
00106             } else {
00107                 ptr = str;
00108             }
00109         } else {
00110             if ((uint32_t)(us_ticker_read() - start) > timeout) {
00111                 LOG("wait for [%s] - timeout\r\n", str);
00112                 return -1;
00113             }
00114         }
00115     }
00116 
00117     return 0;
00118 }
00119 
00120 void Modem::flush()
00121 {
00122     while (readable()) {                    // flush
00123         getc();
00124     }
00125 }
00126 
00127 uint8_t Modem::read()
00128 {
00129     while (!readable()) {
00130     }
00131     
00132     return getc();
00133 }
00134