quicksort

TODO.md

@@ -4,7 +4,7 @@
 - [ ] a tape type - representing a file?
 - [x] a record type - x1,x2,x3,x4,x5
   - [x] comparing records
-- [ ] buffer merge sort
+- [x] buffer quick sort
 - [x] configuration
   - [x] cmd args - man getopts
 - [x] file input

main.c

@@ -1,3 +1,5 @@
+#include "record.h"
+#include "tape.h"
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -81,7 +83,7 @@ int process_args(int argc, char** argv, options* opts)
         fprintf(stderr, "No file specified, aborting\n");
         return ERROR;
     }
-    opts->input = fopen(filename, "a+");
+    opts->input = fopen(filename, "r");
     if (!opts->input) {
         fprintf(stderr, "Error: Cannot open file '%s'\n", filename);
         return ERROR;
@@ -99,6 +101,18 @@ void write_file(options* opts)
 
 void sort_file(options* opts)
 {
+    tape a = { 0, 0, opts->input };
+    buffer buff;
+    buff.capacity = 100;
+    buff.location = malloc(sizeof(record) * buff.capacity);
+    int status = read_buffer(&buff, &a);
+    if (status != SUCCESS && status != EOF) {
+        printf("Error reading file: %d\n", status);
+    }
+    fclose(a.file);
+    a.file = stdout;
+    sort_buffer(&buff);
+    free(buff.location);
 }
 
 int main(int argc, char** argv)

makefile

@@ -1,5 +1,13 @@
-build/main: main.c build
-	clang main.c -o build/main
+CFLAGS = -g
+
+build/main: build/main.o build/tape.o build
+	clang $(CFLAGS) build/main.o build/tape.o -o build/main
+
+build/main.o: main.c build
+	clang $(CFLAGS) -c main.c -o build/main.o
+
+build/tape.o: tape.c build
+	clang $(CFLAGS) -c tape.c -o build/tape.o
 
 build:
 	mkdir -p build
@@ -10,4 +18,7 @@ clean:
 run: build/main
 	build/main -f tests/1.in
 
+debug: build/main
+	lldb -- build/main -f tests/1.in
+
 .PHONY: clean run 

record.h

@@ -1,5 +1,6 @@
 #pragma once
 #include <stdio.h>
+#include <stdlib.h>
 
 typedef struct {
     int a[5];
@@ -21,21 +22,24 @@ static inline int compare_records(const void* a, const void* b)
 {
     const record* ra = (const record*)a;
     const record* rb = (const record*)b;
-    const int ga = g(ra);
-    const int gb = g(rb);
-    return (ga > gb) - (ga < gb);
+    int ga = g(ra);
+    int gb = g(rb);
+    int result = (ga > gb) - (ga < gb);
+    return result;
 }
 
 static inline void print_record(FILE* stream, const record* out)
 {
-    fprintf(stream, "[%d %d %d %d %d] x=%d, g=%d",
-        out->a[0], out->a[1], out->a[2], out->a[3], out->a[4], out->x, g(out));
+    fprintf(stream, "%d %d %d %d %d %d",
+        out->a[0], out->a[1], out->a[2], out->a[3], out->a[4], out->x);
 }
 
 static inline int read_record(FILE* stream, record* out)
 {
-    int result = fscanf(stream, "%d %d %d %d %d %d", &out->a[0], &out->a[1], &out->a[2], &out->a[3], &out->a[4], &out->x);
+    record tmp;
+    int result = fscanf(stream, "%d %d %d %d %d %d", &tmp.a[0], &tmp.a[1], &tmp.a[2], &tmp.a[3], &tmp.a[4], &tmp.x);
     if (result == 6) {
+        *out = tmp;
         return 0;
     }
     if (result == EOF) {

tape.c

@@ -0,0 +1,75 @@
+#include "record.h"
+#include "tape.h"
+
+int partition(record* arr, int start, int end)
+{
+    int i = start;
+    record* pivot = arr;
+    pivot += end;
+    for (int j = start; j < end; j++) {
+        record* current = arr;
+        current += j;
+        if (compare_records(current, pivot) > 0) {
+            continue;
+        }
+        record* i_rec = arr;
+        i_rec += i;
+        record tmp = *i_rec;
+        *i_rec = *current;
+        *current = tmp;
+        i++;
+    }
+    record* i_rec = arr;
+    i_rec += i;
+    record tmp = *i_rec;
+    *i_rec = *pivot;
+    *pivot = tmp;
+    return i;
+}
+
+void quicksort(record* arr, int start, int end, int depth)
+{
+    if (start >= end || start < 0) {
+        return;
+    }
+
+    int p = partition(arr, start, end);
+    quicksort(arr, start, p - 1, depth + 1);
+    quicksort(arr, p + 1, end, depth + 1);
+}
+
+void sort_buffer(buffer* buff)
+{
+    quicksort(buff->location, 0, buff->length - 1, 0);
+}
+
+int read_buffer(buffer* buff, tape* tape)
+{
+    int status;
+    record* destination = buff->location;
+    buff->length = 0;
+    while (buff->capacity > buff->length) {
+        status = read_record(tape->file, destination);
+        if (status != 0) {
+            return status;
+        }
+        destination++;
+        buff->length++;
+        tape->reads++;
+    }
+    return 0;
+}
+
+int write_buffer(buffer* buff, tape* tape)
+{
+    record* current = buff->location;
+    record* last = current;
+    last += buff->length;
+    while (current < last) {
+        print_record(tape->file, current);
+        fprintf(tape->file, "\n");
+        current++;
+        tape->reads++;
+    }
+    return 0;
+}

tape.h

@@ -14,11 +14,11 @@ typedef struct {
 } buffer;
 
 // sorts the entire buffer
-void quicksort(buffer* buff);
+void sort_buffer(buffer* buff);
 
 // reads [capacity] records
-void read_buffer(buffer* buff, tape* tape);
+int read_buffer(buffer* buff, tape* tape);
 // writes everything
-void write_buffer(buffer* buff, tape* tape);
+int write_buffer(buffer* buff, tape* tape);
 
 void clear_tape(tape* tape);

tests/1.in

@@ -1,4 +1,4 @@
-12312 312312 312 312 323 3
+11 123 312 312 323 3
 543 3435 34 5342 532 54
 344 43534 222 435 2345 23
 2345 234 23423 455 44 4