Comment every part of the program.

1 files changed, 144 insertions, 3 deletions

diff --git a/blasms.c b/blasms.c
index c8127a0..0687c32 100644
--- a/blasms.c
+++ b/blasms.c
@@ -21,8 +21,10 @@
 #include <stdlib.h>
 #include <string.h>
 
-/* Remove trailing \n */
+/* Remove trailing \n from a string */
 void remtrailn(char* line) {
+    /* If the last character is a \n, change it into the null
+       character (i.e. end of string). */
     if (line[strlen(line) - 1] == '\n') {
         line[strlen(line) - 1] = '\0';
     }
@@ -33,10 +35,15 @@ void replacestr(char* source, int i, int n, char* str) {
     /* Temporary string for building */
     char strtmp[1000];
 
+    /* Copy source string into temporary string */
     strcpy(strtmp, source);
+    /* Copy the first i characters back into the source string */
     strxfrm(source, strtmp, i);
     source[i] = '\0';
+    /* Copy the string to be inserted into the source string */
     strcat(source, str);
+    /* Copy the remainder of the temporary string into the source,
+       string, skipping over n characters. */
     strcat(source, strtmp + i + n);
 }
 
@@ -44,6 +51,8 @@ void replacestr(char* source, int i, int n, char* str) {
 void strtolower(char* destination, char* source) {
     int i;
 
+    /* Loop through each character, converting it into
+       lowercase. */
     for (i = 0; i < strlen(source) + 1; i++) {
         destination[i] = tolower(source[i]);
     }
@@ -51,11 +60,16 @@ void strtolower(char* destination, char* source) {
 
 /* Set a sender's name as part of their number */
 void setname(char* telnum) {
+    /* File pointer */
     FILE *fp;
+    /* String to read each line of file into */
     char line[1024];
+    /* Pointer to store character location searches in */
     char *strchrp;
+    /* For keeping track of where we are */
     int offset = 0;
 
+    /* Attempt to open the file */
     fp = fopen("phonebook.conf", "r");
 
     if (fp == NULL) {
@@ -63,17 +77,27 @@ void setname(char* telnum) {
         return;
     }
 
+    /* Loop through each line of the file */
     while (fgets(line, 1024, fp) != NULL) {
+        /* Remove trailing newline */
         remtrailn(line);
+        /* Attempt to find the end of the first word */
         if ((strchrp = strchr(line + offset, ' ')) != NULL) {
+            /* Convert position of end of first word into an int */
             offset = strchrp - line;
+            /* Check if the first word is the same as the given telnum */
             if ((strlen(telnum) == offset) && !strncmp(telnum, line, offset)) {
+                /* Find the second word (i.e. the name) */
                 if ((strchrp = strchr(line + offset + 1, ' ')) != NULL) {
                     line[strchrp - line] = '\0';
                 }
+                /* Add " (" to the given telnum */
                 strcat(telnum, " (");
+                /* Add the found name to the given telnum */
                 strcat(telnum, line + offset + 1);
+                /* Add ")" to the given telnum */
                 strcat(telnum, ")");
+                /* Leave this procedure */
                 return;
             }
         }
@@ -82,14 +106,23 @@ void setname(char* telnum) {
 
 /* Set a sender's number as part of their name */
 void settelnum(char* telnum, char* sms, int *offsetptr) {
+    /* File pointer */
     FILE *fp;
+    /* String to read each line of file into */
     char line[1024];
+    /* Name to lookup */
     char name[1000];
+    /* Current name in phonebook.conf */
     char curname[1000];
+    /* Pointer to store character location searches in */
     char *strchrp;
+    /* Keep track of where we are, starting from the
+       current point in the calling function. */
     int offset = *offsetptr;
+    /* Some loop iteration variables */
     int i, j;
 
+    /* Attempt to open the phonebook */
     fp = fopen("phonebook.conf", "r");
 
     if (fp == NULL) {
@@ -97,40 +130,68 @@ void settelnum(char* telnum, char* sms, int *offsetptr) {
         return;
     }
 
+    /* Set entire given SMS as the target name for now */
     strcpy(name, sms + offset + 1);
 
+    /* Trim the target name to just the first word of the SMS */
     if ((strchrp = strchr(name, ' ')) != NULL) {
         offset = strchrp - name;
         name[offset] = '\0';
     }
 
+    /* If the name is a wildcard, set it as the telnum
+       for the calling function and leave this function. */
     if (!strcmp(name, "*")) {
         strcpy(telnum, name);
+        /* Advance the offset to go past this wildcard,
+           for the calling function. */
         *offsetptr = *offsetptr + 2;
         return;
     }
 
+    /* Convert the name to lowercase for easier comparison */
     strtolower(name, name);
 
+    /* Loop through each line of the file to find a matching name */
     while (fgets(line, 1024, fp) != NULL) {
+        /* Remove trailing newline */
         remtrailn(line);
+        /* Convert the line to lowercase for easier comparison */
         strtolower(line, line);
+        /* Find the end of the first word (i.e. the number which
+           we don't want for now. */
         for (i = 0; i < strlen(line); i++) {
             if (line[i] == ' ') {
                 break;
             }
         }
+        /* Move past the first space */
         offset = i + 1;
+        /* Loop through each character in the line, skipping the first
+           word (the number). */
         for (i = 0, j = 0; i < strlen(line + offset - 1); i++, j++) {
+            /* If this isn't the end of the word or line, build a name
+               for comparison. */
             if (line[i + offset] != ' ' && line[i + offset] != '\0') {
                 curname[j] = line[i + offset];
+            /* Otherwise, the word or line ended, so check for a match. */
             } else {
+                /* Terminate the current name string */
                 curname[j] = '\0';
+                /* Check to see if the names are a match... */
                 if (!strcmp(name, curname)) {
+                    /* If they match, copy the number from the
+                       line into telnum */
                     strncpy(telnum, line, offset - 1);
+                    /* Terminate the string */
                     telnum[offset - 1] = '\0';
+                    /* Advance the offset paste the name for the
+                       calling function */
                     *offsetptr = *offsetptr + strlen(name) + 1;
                     return;
+                /* ...if they aren't a match, start building a new
+                   name from this line (as it might have multiple
+                   names for the current number). */
                 } else {
                     j = -1;
                 }
@@ -138,12 +199,14 @@ void settelnum(char* telnum, char* sms, int *offsetptr) {
         }
     }
 
+    /* If the name wasn't found, then we don't want to send an SMS,
+       so exit the program. */
     printf("Error: %s not found in phonebook.conf.\n", name);
     exit(1);
 }
 
 int main(int argc, char *argv[]) {
-    /* Telephone number (may contain name)*/
+    /* Telephone number (may contain name) */
     char telnum[100];
     /* Unmodified telephone number length */
     int telnumlen;
@@ -172,11 +235,17 @@ int main(int argc, char *argv[]) {
     /* Command match / telnum set */
     short int match = 0;
 
+    /* Stores the positions in systemcmd of wildcards,
+       for if multiple phonebook looks are to be done. */
     struct {
+        /* Each individual position */
         int pos;
     } wildcard[1000];
+    /* Number of wildcards (i.e. number of wildcard structs used) */
     int wildcards = 0;
 
+    /* Print some usage information if --help was used, or if exactly
+       two arguments weren't given. */
     if (argc != 3 || !strcmp(argv[argc - 1], "--help")) {
         fprintf(stderr, "Usage: %s sender-number send-date\n"
                         "\n"
@@ -217,45 +286,62 @@ int main(int argc, char *argv[]) {
         return 1;
     }
 
+    /* Copy first argument into telnum, so it can be manipulated */
     strcpy(telnum, argv[1]);
 
+    /* Print the arguments (usually number/date) */
     printf("Phone number: %s\n", telnum);
     printf("Date        : %s\n", argv[2]);
 
+    /* Get the actual SMS content from standard input */
     fgets(sms, 500, stdin);
 
+    /* Make sure we got something */
     if (sms != NULL) {
+        /* Remove trailing newline */
         remtrailn(sms);
         printf("Contents    : %s\n", sms);
     }
 
+    /* Open configuration file */
     fp = fopen("blasms.conf", "r");
 
+    /* Make sure file opened OK */
     if (fp == NULL) {
         printf("Error opening blasms.conf.\n");
         return 1;
     }
 
+    /* Read each line from the file */
     while (fgets(line, 1024, fp) != NULL) {
+        /* Remove traliing newline */
         remtrailn(line);
+        /* Try to find the end of the first word (i.e. the first space) */
         if ((strchrp = strchr(line, ' ')) != NULL) {
+            /* Position = address of space - address of start of line */
             offset = strchrp - line;
             if (offset > 10) {
                 printf("Error, command longer than 10 characters in blasms.conf.\n");
                 return 1;
             }
+            /* Copy that first word into configcmd */
             strxfrm(configcmd, line, offset);
             configcmd[offset] = '\0';
+            /* If the command was "default", set it as the default
+               command and move to next line in file. */
             if (!strcmp(configcmd, "default")) {
                 strcpy(defaultcmd, line + offset + 1);
                 continue;
             }
-            /* If the SMS command doesn't end here, continue */
+            /* If the SMS command doesn't end here, continue.  (i.e. it
+               definitely doesn't match the config file command. */
             if (sms[offset] != ' ') {
                 continue;
             }
+            /* If it does end here, copy it to smscommand */
             strxfrm(smscommand, sms, offset);
             smscommand[offset] = '\0';
+            /* If the commands are the same, stop reading the file */
             if (!strcmp(smscommand, configcmd)) {
                 match = 1;
                 break;
@@ -263,73 +349,113 @@ int main(int argc, char *argv[]) {
         }
     }
 
+    /* match was set if a command was found, so set the systemcmd
+       to be the remainder of the current config file line */
     if (match) {
         strcpy(systemcmd, line + offset + 1);
+    /* If not, use the defaultcmd as set above. */
     } else {
         strcpy(systemcmd, defaultcmd);
         offset = -1;
     }
 
+    /* Reset match to 0 as we use it again */
     match = 0;
 
+    /* Go through each character of systemcmd, looking for
+       recognised macros */
     for (i = 0; i < strlen(systemcmd); i++) {
+        /* If a % is found, we might be about to find a macro. */
         if (systemcmd[i] == '%') {
+            /* Check the next character for recognised macros */
             switch (systemcmd[i+1]) {
+                /* Sender number with name lookup */
                 case 'N':
+                    /* Attempt to look up number to find a name */
                     setname(telnum);
+                    /* Insert number (or number + name) into systemcmd */
                     replacestr(systemcmd, i, 2, telnum);
                     break;
+                /* Sender number only */
                 case 'n':
+                    /* Insert number into systemcmd */
                     replacestr(systemcmd, i, 2, telnum);
                     break;
+                /* Date */
                 case 'd':
+                    /* Insert date into systemcmd */
                     replacestr(systemcmd, i, 2, argv[2]);
                     break;
+                /* SMS content, minus the initial command (if any) */
                 case 's':
+                    /* Insert SMS content into systemcmd */
                     replacestr(systemcmd, i, 2, sms + offset + 1);
                     break;
+                /* Interpret second word of SMS as a name to be looked up */
                 case 'P':
+                    /* If name hasn't already been found, try to find it */
                     if (!match) {
                         settelnum(telnum, sms, &offset);
+                        /* If found, no need to try again. */
                         match = 1;
                     }
+                    /* If telnum was a wildcard, keep track of its position. */
                     if (!strcmp(telnum, "*")) {
                         wildcard[wildcards].pos = i;
                         wildcards++;
                     }
+                    /* Insert telnum into systemcmd */
                     replacestr(systemcmd, i, 2, telnum);
                     break;
+                /* Intepret the second word (i.e. after the command) of the SMS
+                   as a filename, attempt to open the file pending/filename, treating
+                   the first word of it as a number, attempting to look up its name,
+                   and insert a colon between it and the rest of the file. */
                 case 'M':
+                    /* Build the path */
                     strcpy(telnum, "pending/");
                     strcat(telnum, sms + offset + 1);
 
+                    /* Open the file */
                     fp = fopen(telnum, "r");
 
+                    /* If the file didn't open, abort this macro. */
                     if (fp == NULL) {
                         printf("Error opening message file.\n");
                         break;
                     }
 
+                    /* If the first line can't be read, abort this macro. */
                     if (fgets(line, 1024, fp) == NULL) {
                         printf("Error reading message file.\n");
                         break;
                     }
 
+                    /* Close the file after reading the first line */
                     fclose(fp);
 
+                    /* Attempt to find the end of the first word */
                     if ((strchrp = strchr(line + offset, ' ')) != NULL) {
+                        /* Remove trailing newline */
                         remtrailn(line);
+                        /* Copy the first word into telnum */
                         strncpy(telnum, line, strchrp - line);
                         telnum[strchrp - line] = '\0';
+                        /* Set the length of the unmodified number */
                         telnumlen = strlen(telnum);
+                        /* Attempt to look up the number */
                         setname(telnum);
+                    /* If a first word couldn't be determined, abort this macro. */
                     } else {
                         printf("Error, malformed message file.\n");
                         break;
                     }
 
+                    /* Insert the number (or number + name) into systemcmd */
                     replacestr(systemcmd, i, 2, telnum);
+                    /* Insert a colon */
                     replacestr(systemcmd, i + strlen(telnum), 0, ":");
+                    /* Insert the remainder of the file */
                     replacestr(systemcmd, i + strlen(telnum) + 1, 0, line + telnumlen);
 
                     break;
@@ -337,28 +463,43 @@ int main(int argc, char *argv[]) {
         }
     }
 
+    /* Execute a single command, or multiple command, depending on
+       whether the systemcmd contained wildcards. */
     if (wildcards) {
+        /* Try to open the phonebook to look up each number to send to */
         fp = fopen("phonebook.conf", "r");
 
+        /* Exit if the file couldn't be opened */
         if (fp == NULL) {
             printf("Error opening phonebook.conf.\n");
             return 1;
         }
 
+        /* Read each line in the file */
         while (fgets(line, 1024, fp) != NULL) {
+            /* Attempt to find the first word (hopefully a number) */
             if ((strchrp = strchr(line, ' ')) != NULL) {
+                /* Set initial offset in systemcmd (1, as in a single *) */
                 offset = 1;
+                /* Copy systemcmd into wildcardcmd for manipulation */
                 strcpy(wildcardcmd, systemcmd);
                 line[strchrp - line] = '\0';
+                /* Loop through each wildcard that we tracked earlier */
                 for (i = 0; i < wildcards; i++) {
+                    /* Insert the first word of the phonebook (hopefully a number) into
+                       wildcardcmd at each wildcard position.  Adjust the wildcard position
+                       each time to take into account the length of the previous inserted
+                       number. */
                     replacestr(wildcardcmd, wildcard[i].pos + (int)strlen(line) * i - i, 1, line);
                 }
                 printf("Executing: %s\n", wildcardcmd);
+                /* Execute the command */
                 system(wildcardcmd);
             }
         }
     } else {
         printf("Executing: %s\n", systemcmd);
+        /* Execute command */
         system(systemcmd);
     }