First Commit

libraries/SdFat/examples/examplesV1/#attic/fgetsRewrite/fgetsRewrite.ino

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+// Demo of rewriting a line read by fgets
+#include <SPI.h>
+#include "SdFat.h"
+#include "sdios.h"
+
+// SD card chip select pin
+const uint8_t chipSelect = SS;
+
+// file system
+SdFat sd;
+
+// print stream
+ArduinoOutStream cout(Serial);
+//------------------------------------------------------------------------------
+// store error strings in flash memory
+#define error(s) sd.errorHalt(F(s))
+//------------------------------------------------------------------------------
+void demoFgets() {
+  char line[25];
+  int c;
+  uint32_t pos;
+
+  // open test file
+  SdFile rdfile("fgets.txt", O_RDWR);
+
+  // check for open error
+  if (!rdfile.isOpen()) {
+    error("demoFgets");
+  }
+
+  // list file
+  cout << F("-----Before Rewrite\r\n");
+  while ((c = rdfile.read()) >= 0) {
+    Serial.write(c);
+  }
+
+  rdfile.rewind();
+  // read lines from the file to get position
+  while (1) {
+    pos = rdfile.curPosition();
+    if (rdfile.fgets(line, sizeof(line)) < 0) {
+      error("Line not found");
+    }
+    // find line that contains "Line C"
+    if (strstr(line, "Line C")) {
+      break;
+    }
+  }
+
+  // rewrite line with 'C'
+  if (!rdfile.seekSet(pos)) {
+    error("seekSet");
+  }
+  rdfile.println("Line R");
+  rdfile.rewind();
+
+  // list file
+  cout << F("\r\n-----After Rewrite\r\n");
+  while ((c = rdfile.read()) >= 0) {
+    Serial.write(c);
+  }
+
+  // close so rewrite is not lost
+  rdfile.close();
+}
+//------------------------------------------------------------------------------
+void makeTestFile() {
+  // create or open test file
+  SdFile wrfile("fgets.txt", O_WRONLY | O_CREAT | O_TRUNC);
+
+  // check for open error
+  if (!wrfile.isOpen()) {
+    error("MakeTestFile");
+  }
+
+  // write test file
+  wrfile.print(F(
+                 "Line A\r\n"
+                 "Line B\r\n"
+                 "Line C\r\n"
+                 "Line D\r\n"
+                 "Line E\r\n"
+               ));
+  wrfile.close();
+}
+//------------------------------------------------------------------------------
+void setup() {
+  Serial.begin(9600);
+
+  // Wait for USB Serial
+  while (!Serial) {
+    yield();
+  }
+  cout << F("Type any character to start\n");
+  while (!Serial.available()) {
+    yield();
+  }
+
+  // Initialize at the highest speed supported by the board that is
+  // not over 50 MHz. Try a lower speed if SPI errors occur.
+  if (!sd.begin(chipSelect, SD_SCK_MHZ(50))) {
+    sd.initErrorHalt();
+  }
+
+  makeTestFile();
+
+  demoFgets();
+
+  cout << F("\nDone\n");
+}
+void loop() {}