✚ fichier exemple pour lire un CSV

jdequidt
1 parent 687539f6
Showing 1 changed file with 117 additions and 0 deletions Show diff stats
src/csv_reader.c
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+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+// Conditionals
+const bool          IS_DEBUG            = false;
+
+// Constants
+const unsigned int  BUFFER_SIZE         = 2048;
+const unsigned int  FIELD_SIZE          = 20;
+const char          CSV_DELIMITERS[]    = ",";
+
+// Globals
+char**              CSV_HEADER_FIELDS;
+unsigned int        CSV_NB_FIELDS;
+
+void display_header()
+{
+    for(unsigned int i = 0; i < CSV_NB_FIELDS; i++)
+    {
+        printf("%d - %s\n", i, CSV_HEADER_FIELDS[i]);
+    }
+}
+
+void read_csv_header(char * header_line)
+{
+    int     line_length = strlen(header_line);
+    int     nb_fields   = 0;
+    char*   string_ptr  = header_line;
+
+    // Count the occurrences of delimiters
+    while (NULL != string_ptr)
+    {
+        nb_fields++;
+        string_ptr = strpbrk(string_ptr, CSV_DELIMITERS);
+        if (NULL != string_ptr)
+        {
+            string_ptr++;
+        }
+    }
+
+    // Globals allocation
+    CSV_NB_FIELDS       = nb_fields;
+    CSV_HEADER_FIELDS   = malloc( nb_fields * sizeof(char*) );
+
+    char* token         = strtok(header_line, CSV_DELIMITERS);                  // strtok init.
+
+    // Re-read the line to get the header of the columns
+    for (unsigned int i = 0; i < nb_fields; i++)
+    {
+        CSV_HEADER_FIELDS[i] = malloc( FIELD_SIZE * sizeof(char) );             // alloc
+        memset(CSV_HEADER_FIELDS[i], 0, FIELD_SIZE);                            // 0 init.
+        strcpy(CSV_HEADER_FIELDS[i], token);                                    // copy field in the structure
+        token = strtok(NULL, CSV_DELIMITERS);                                   // loop to get a new field label
+    }
+
+    if (IS_DEBUG) display_header();
+}
+
+void read_csv_file(const char * filename)
+{
+    FILE*   fp = fopen(filename, "r");
+    char    buffer[BUFFER_SIZE];
+
+    // Check if the file is really opened
+    if (NULL == fp)
+    {
+        fprintf(stderr, "Unable to open file: %s\n", filename);
+        return;
+    }
+
+    // 1st row is a header with field descriptions
+    fgets(buffer, BUFFER_SIZE, fp);
+    read_csv_header(buffer);
+
+    // Remaining rows are the entries
+    while ( NULL != fgets(buffer, BUFFER_SIZE, fp) )
+    {
+        char*           token;
+        unsigned int    i = 0;
+
+        // strtok init.
+        token = strtok(buffer, CSV_DELIMITERS);
+
+        while (NULL != token)
+        {
+            if (IS_DEBUG) printf("Field %d is %s\n", i++, token); // you can strcpy the `token` string in your data structures
+            token = strtok(NULL, CSV_DELIMITERS);
+        }
+    }
+
+    fclose(fp);
+}
+
+void usage(const char * prog_name)
+{
+    printf("Usage is %s your_csv_file\n\n", prog_name);
+}
+
+int main(int argc, char * argv[])
+{
+    if (2 != argc)
+    {
+        usage(argv[0]);
+        return 0;
+    }
+
+    read_csv_file(argv[1]);
+    for(unsigned int i = 0; i < CSV_NB_FIELDS; i++)
+    {
+        free(CSV_HEADER_FIELDS[i]);
+    }
+    free(CSV_HEADER_FIELDS);
+
+    return 0;
+}
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