write_custom.c

Example use of custom file writer callbacks

#include "tools.h"
 
void print_write_custom_help() {
    printf("Usage: write_custom -s [source file] -d [destination file]");
}
 
// Custom callbacks
typedef struct {
    int data;
} ObserverData;
 
error_type on_initializing(void* user_data, InputOutputStreamHandle* input_output_stream) {
    ObserverData* observer_data = (ObserverData*) user_data;
    offset_type current_offset = 0;
    long long current_offset_converted = 0;
 
    OutputStreamHandle* output_stream = NULL;
 
    UNUSED(observer_data);
 
    // Do something with the output stream
    RETURN_ERROR_IF_NOT_SUCCESS(InputOutputStream_ToOutputStream(input_output_stream, &output_stream));
    RETURN_ERROR_IF_NOT_SUCCESS(OutputStream_GetOutputPosition(output_stream, &current_offset));
    RETURN_ERROR_IF_NOT_SUCCESS(OutputStream_Release(output_stream));
 
    // Convert to long long for printf
    current_offset_converted = current_offset;
 
    printf("File writer is initializing\n");
    printf("Current output position: %lld\n", current_offset_converted);
 
    return VANILLAPDF_ERROR_SUCCESS;
}
 
error_type on_finalizing(void* user_data, InputOutputStreamHandle* input_output_stream) {
    ObserverData* observer_data = (ObserverData*) user_data;
    offset_type current_offset = 0;
    long long current_offset_converted = 0;
 
    OutputStreamHandle* output_stream = NULL;
 
    UNUSED(observer_data);
 
    // Do something with the output stream
    RETURN_ERROR_IF_NOT_SUCCESS(InputOutputStream_ToOutputStream(input_output_stream, &output_stream));
    RETURN_ERROR_IF_NOT_SUCCESS(OutputStream_GetOutputPosition(output_stream, &current_offset));
    RETURN_ERROR_IF_NOT_SUCCESS(OutputStream_Release(output_stream));
 
    // Convert to long long for printf
    current_offset_converted = current_offset;
 
    printf("File writer is finalizing\n");
    printf("Current output position: %lld\n", current_offset_converted);
 
    return VANILLAPDF_ERROR_SUCCESS;
}
 
int process_write_custom(int argc, char *argv[]) {
    string_type source_file_path = NULL;
    string_type destination_file_path = NULL;
 
    FileWriterHandle* file_writer = NULL;
    FileHandle* source_file = NULL;
    FileHandle* destination_file = NULL;
 
    ObserverData observer_data = { 0 };
    FileWriterObserverHandle* file_writer_observer = NULL;
 
    integer_type i = 0;
 
    for (i = 0; i < argc; ++i) {
 
        // source document path
        if (strcmp(argv[i], "-s") == 0 && (i + 1 < argc)) {
            source_file_path = argv[i + 1];
            i++;
 
            // destination file path
        } else if (strcmp(argv[i], "-d") == 0 && (i + 1 < argc)) {
            destination_file_path = argv[i + 1];
            i++;
        } else {
            print_write_custom_help();
            return VANILLAPDF_TOOLS_ERROR_INVALID_PARAMETERS;
        }
    }
 
    if (source_file_path == NULL || destination_file_path == NULL) {
        print_write_custom_help();
        return VANILLAPDF_TOOLS_ERROR_INVALID_PARAMETERS;
    }
 
    RETURN_ERROR_IF_NOT_SUCCESS(File_Open(source_file_path, &source_file));
    RETURN_ERROR_IF_NOT_SUCCESS(File_Create(destination_file_path, &destination_file));
    RETURN_ERROR_IF_NOT_SUCCESS(File_Initialize(source_file));
 
    // Unused callbacks can be set to NULL
    RETURN_ERROR_IF_NOT_SUCCESS(FileWriterObserver_CreateCustom(on_initializing, on_finalizing, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &observer_data, &file_writer_observer));
 
    RETURN_ERROR_IF_NOT_SUCCESS(FileWriter_Create(&file_writer));
    RETURN_ERROR_IF_NOT_SUCCESS(FileWriter_Subscribe(file_writer, file_writer_observer));
    RETURN_ERROR_IF_NOT_SUCCESS(FileWriter_Write(file_writer, source_file, destination_file));
    RETURN_ERROR_IF_NOT_SUCCESS(FileWriter_Release(file_writer));
 
    RETURN_ERROR_IF_NOT_SUCCESS(FileWriterObserver_Release(file_writer_observer));
 
    RETURN_ERROR_IF_NOT_SUCCESS(File_Release(destination_file));
    RETURN_ERROR_IF_NOT_SUCCESS(File_Release(source_file));
 
    return VANILLAPDF_TOOLS_ERROR_SUCCESS;
}