mdriver.c

/*
 * mdriver.c - CS:APP Malloc Lab Driver
 *
 * Uses a collection of trace files to tests a malloc/free/realloc
 * implementation in mm.c.
 *
 * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
 * May not be used, modified, or copied without permission.
 */
#include "config.h"
#include "fsecs.h"
#include "memlib.h"
#include "mm.h"
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <float.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

/**********************
 * Constants and macros
 **********************/

/* Misc */
#define MAXLINE 1024       /* max string size */
#define HDRLINES 4         /* number of header lines in a trace file */
#define LINENUM(i) (i + 5) /* cnvt trace request nums to linenums (origin 1) */

/* Returns true if p is ALIGNMENT-byte aligned */
#define IS_ALIGNED(p) ((((uint64_t)(p)) % ALIGNMENT) == 0)

//Heap size is allowed to be 65536 for free, since this is paltry
#define FREE_HEAP 65536

/******************************
 * The key compound data types
 *****************************/

/* Records the extent of each block's payload */
typedef struct range_t {
    char *lo;             /* low payload address */
    char *hi;             /* high payload address */
    struct range_t *next; /* next list element */
} range_t;

/* Characterizes a single trace operation (allocator request) */
typedef struct {
    enum { ALLOC,
           FREE,
           REALLOC } type; /* type of request */
    int index;             /* index for free() to use later */
    int size;              /* byte size of alloc/realloc request */
} traceop_t;

/* Holds the information for one trace file*/
typedef struct {
    int sugg_heapsize;   /* suggested heap size (unused) */
    int num_ids;         /* number of alloc/realloc ids */
    int num_ops;         /* number of distinct requests */
    int weight;          /* weight for this trace (unused) */
    traceop_t *ops;      /* array of requests */
    char **blocks;       /* array of ptrs returned by malloc/realloc... */
    size_t *block_sizes; /* ... and a corresponding array of payload sizes */
} trace_t;

/*
 * Holds the params to the xxx_speed functions, which are timed by fcyc.
 * This struct is necessary because fcyc accepts only a pointer array
 * as input.
 */
typedef struct {
    trace_t *trace;
    range_t *ranges;
} speed_t;

/* Summarizes the important stats for some malloc function on some trace */
typedef struct {
    char *filename;
    /* defined for both libc malloc and student malloc package (mm.c) */
    double ops;  /* number of ops (malloc/free/realloc) in the trace */
    int valid;   /* was the trace processed correctly by the allocator? */
    double secs; /* number of secs needed to run the trace */

    int ideal_max_heap;
    int max_heap;

    /* defined only for the student malloc package */
    double util; /* space utilization for this trace (always 0 for libc) */

    /* Note: secs and util are only defined if valid is true */
} stats_t;

/********************
 * Global variables
 *******************/
int verbose = 0;       /* global flag for verbose output */
static int errors = 0; /* number of errs found when running student malloc */
char msg[MAXLINE];     /* for whenever we need to compose an error message */


/* Directory where default tracefiles are found */
static char tracedir[MAXLINE] = TRACEDIR;

/* The filenames of the default tracefiles */
static char *default_tracefiles[] = {
    DEFAULT_TRACEFILES, NULL};

/*********************
 * Function prototypes
 *********************/

/* these functions manipulate range lists */
static int add_range(range_t **ranges, char *lo, int size,
                     int tracenum, int opnum);
static void remove_range(range_t **ranges, char *lo);
static void clear_ranges(range_t **ranges);

/* These functions read, allocate, and free storage for traces */
static trace_t *read_trace(char *tracedir, char *filename);
static void free_trace(trace_t *trace);

/* Routines for evaluating the correctness and speed of libc malloc */
static int eval_libc_valid(trace_t *trace, int tracenum);
static void eval_libc_speed(void *ptr);

/* Routines for evaluating correctnes, space utilization, and speed
   of the student's malloc package in mm.c */
static int eval_mm_valid(trace_t *trace, int tracenum, range_t **ranges);
static double eval_mm_util(trace_t *trace, int tracenum, range_t **ranges, int *ideal_m, int *m);
static void eval_mm_speed(void *ptr);

/* Various helper routines */
static void printresults(int n, stats_t *stats);
static void usage(void);
static void unix_error(char *msg);
static void malloc_error(int tracenum, int opnum, char *msg);
static void app_error(char *msg);

/**************
 * Main routine
 **************/
int main(int argc, char **argv) {
    int i;
    char c;
    char **tracefiles = NULL;   /* null-terminated array of trace file names */
    int num_tracefiles = 0;     /* the number of traces in that array */
    trace_t *trace = NULL;      /* stores a single trace file in memory */
    range_t *ranges = NULL;     /* keeps track of block extents for one trace */
    stats_t *libc_stats = NULL; /* libc stats for each trace */
    stats_t *mm_stats = NULL;   /* mm (i.e. student) stats for each trace */
    speed_t speed_params;       /* input parameters to the xx_speed routines */
    int *trace_weights;         /* buffer to store the trace weights and use them later in calculations */
    int weight_sum;             /* sum of weights to calculate weighted average */

    int team_check = 1; /* If set, check team structure (reset by -a) */
    int run_libc = 0;   /* If set, run libc malloc (set by -l) */
    int autograder = 0; /* If set, emit summary info for autograder (-g) */

    /* temporaries used to compute the performance index */
    double util, scaled_util, throughput, avg_mm_util, avg_mm_throughput, perfindex; 
    int numcorrect;

    
    /*
     * Read and interpret the command line arguments
     */
    while ((c = getopt(argc, argv, "f:t:hvVgal")) != EOF) {
        switch (c) {
        case 'g': /* Generate summary info for the autograder */
            autograder = 1;
            break;
        case 'f': /* Use one specific trace file only (relative to curr dir) */
            num_tracefiles = 1;
            if ((tracefiles = realloc(tracefiles, 2 * sizeof(char *))) == NULL)
                unix_error("ERROR: realloc failed in main");
            strcpy(tracedir, "./");
            tracefiles[0] = strdup(optarg);
            tracefiles[1] = NULL;
            break;
        case 't':                    /* Directory where the traces are located */
            if (num_tracefiles == 1) /* ignore if -f already encountered */
                break;
            strcpy(tracedir, optarg);
            if (tracedir[strlen(tracedir) - 1] != '/')
                strcat(tracedir, "/"); /* path always ends with "/" */
            break;
        case 'a': /* Don't check team structure */
            team_check = 0;
            break;
        case 'l': /* Run libc malloc */
            run_libc = 1;
            break;
        case 'v': /* Print per-trace performance breakdown */
            verbose = 1;
            break;
        case 'V': /* Be more verbose than -v */
            verbose = 2;
            break;
        case 'h': /* Print this message */
            usage();
            exit(0);
        default:
            usage();
            exit(1);
        }
    }

    /*
     * Check and print team info
     */
    FILE* result_fstream = stdout;
    char hash_cmd[128];
    char hash[7] = {0};
    if (team_check) {
        /* Students must fill in their team information */
        if (!strcmp(team.teamname, "")) {
            printf("ERROR: Please provide your name in mm.c.\n");
            exit(1);
        } else
            fprintf(result_fstream,"YOUR NAME: %s\n", team.teamname);
        if ((*team.name1 == '\0')) {
            printf("ERROR.  You must fill in your information in mm.c!\n");
            exit(1);
        } else {
            fprintf(result_fstream,"YOUR UID: %s\n", team.name1);
            /* Check that UID is number (not malicious code) */
            int uid_len = strlen(team.name1);
            for (i = 0; i < uid_len; i++) {
                if (isdigit(team.name1[i]) == 0) {
                    printf("ERROR.  UID must be a number!\n");
                    exit(1);
                }
            }
            fprintf(result_fstream, "YOUR HASH: ");
            sprintf(hash_cmd, "echo -n %s | md5sum | cut -c -6", team.name1);
            FILE* hashproc = popen(hash_cmd, "r");
            fgets(hash, sizeof(hash), hashproc);
            fprintf(result_fstream, "%s\n", hash);
            pclose(hashproc);
        }
        if (*team.id1 == '\0')
            fprintf(result_fstream,"YOUR COMMENT: None\n");
        else
            fprintf(result_fstream,"YOUR COMMENT: %s\n", team.id1);
    }

    /*
     * If no -f command line arg, then use the entire set of tracefiles
     * defined in default_traces[]
     */
    if (tracefiles == NULL) {
        tracefiles = default_tracefiles;
        num_tracefiles = sizeof(default_tracefiles) / sizeof(char *) - 1;
        //printf("Using default tracefiles in %s\n", tracedir);
    }

    if ((trace_weights = malloc(sizeof(int) * num_tracefiles)) == NULL) {
        unix_error("trace_weights malloc in main failed");
    }

    /* Initialize the timing package */
    init_fsecs();

    /*
     * Optionally run and evaluate the libc malloc package
     */
    if (run_libc) {
        if (verbose > 1)
            printf("\nTesting libc malloc\n");

        /* Allocate libc stats array, with one stats_t struct per tracefile */
        libc_stats = (stats_t *)calloc(num_tracefiles, sizeof(stats_t));
        if (libc_stats == NULL)
            unix_error("libc_stats calloc in main failed");

        /* Evaluate the libc malloc package using the K-best scheme */
        for (i = 0; i < num_tracefiles; i++) {
            trace = read_trace(tracedir, tracefiles[i]);
            trace_weights[i] = trace->weight;
            libc_stats[i].ops = trace->num_ops;
            libc_stats[i].filename = tracefiles[i];
            if (verbose > 1)
                printf("Checking libc malloc for correctness, ");
            libc_stats[i].valid = eval_libc_valid(trace, i);
            if (libc_stats[i].valid) {
                speed_params.trace = trace;
                if (verbose > 1)
                    printf("and performance.\n");
                libc_stats[i].secs = fsecs(eval_libc_speed, &speed_params);
            }
            free_trace(trace);
        }

        /* Display the libc results in a compact table */
        if (verbose) {
            printf("\nResults for libc malloc:\n");
            printresults(num_tracefiles, libc_stats);
        }
    }

    /*
     * Always run and evaluate the student's mm package
     */
    if (verbose > 1)
        printf("\nTesting mm malloc\n");

    /* Allocate the mm stats array, with one stats_t struct per tracefile */
    mm_stats = (stats_t *)calloc(num_tracefiles, sizeof(stats_t));
    if (mm_stats == NULL)
        unix_error("mm_stats calloc in main failed");

    int max_heap, ideal_max_heap;
    int trial_counter;
    double prev_secs;
    for (trial_counter = 0; trial_counter < NUM_TRIAL; trial_counter ++) {

        /* Initialize the simulated memory system in memlib.c */
        mem_init();

        for (i = 0; i < num_tracefiles; i++) {
            if (trial_counter == 0) {
                prev_secs = DBL_MAX;
            } else {
                prev_secs = mm_stats[i].secs;
            }
            trace = read_trace(tracedir, tracefiles[i]);
            trace_weights[i] = trace->weight;
            mm_stats[i].ops = trace->num_ops;
            mm_stats[i].filename = tracefiles[i];
            if (verbose > 1)
                printf("Checking mm_malloc for correctness, ");
            mm_stats[i].valid = eval_mm_valid(trace, i, &ranges);
            if (mm_stats[i].valid) {
                if (verbose > 1)
                    printf("efficiency, ");
                mm_stats[i].util = eval_mm_util(trace, i, &ranges, &ideal_max_heap, &max_heap);

                mm_stats[i].max_heap = max_heap;
                mm_stats[i].ideal_max_heap = ideal_max_heap;
                speed_params.trace = trace;
                speed_params.ranges = ranges;
                if (verbose > 1)
                    printf("and performance.\n");
                // get best speed
                mm_stats[i].secs = fsecs(eval_mm_speed, &speed_params);
                if (mm_stats[i].secs > prev_secs) {
                    mm_stats[i].secs = prev_secs;
                }
            }
            free_trace(trace);
        }
    }

    /* Display the mm results in a compact table */
    if (verbose) {
        fprintf(result_fstream,"\nResults for mm malloc:\n");
        printresults(num_tracefiles, mm_stats);
        fprintf(result_fstream,"\n");
    }

    /*
     * Accumulate the aggregate statistics for the student's mm package
     */
    util = 0;
    throughput = 0;
    numcorrect = 0;
    weight_sum = 0;
    scaled_util = 0;

    for (i = 0; i < num_tracefiles; i++) {
        util += mm_stats[i].util * trace_weights[i];
        throughput += trace_weights[i] / (mm_stats[i].ops / 1000 / mm_stats[i].secs); // weighted harmonic mean 
        weight_sum += trace_weights[i];
        if (mm_stats[i].valid)
            numcorrect++;
    }
    avg_mm_util = util / weight_sum;

    /*
     * Compute and print the performance index
     */
    if (errors == 0) {
        avg_mm_throughput = weight_sum / throughput; // weighted harmonic mean

        scaled_util = (avg_mm_util >= 0.6) ? (avg_mm_util - 0.6) / 0.4 : 0;
        perfindex = scaled_util * scaled_util * avg_mm_throughput / 100;
        fprintf(result_fstream,"Score = (%.3f [scaled util])^2 * (%.3f [avg Kops]) / 100 = %.0f/100\n",
               scaled_util,
               avg_mm_throughput,
               perfindex);
    } else { /* There were errors */
        perfindex = 0.0;
        printf("Terminated with %d errors\n", errors);
    }

    if (autograder) {
        fprintf(result_fstream,"correct:%d\n", numcorrect);
        fprintf(result_fstream,"perfidx:%.0f\n", perfindex);
    }

    fclose(result_fstream);    

    exit(0);
}

/*****************************************************************
 * The following routines manipulate the range list, which keeps
 * track of the extent of every allocated block payload. We use the
 * range list to detect any overlapping allocated blocks.
 ****************************************************************/

/*
 * add_range - As directed by request opnum in trace tracenum,
 *     we've just called the student's mm_malloc to allocate a block of
 *     size bytes at addr lo. After checking the block for correctness,
 *     we create a range struct for this block and add it to the range list.
 */
static int add_range(range_t **ranges, char *lo, int size,
                     int tracenum, int opnum) {
    char *hi = lo + size - 1;
    range_t *p;
    char msg[MAXLINE];

    assert(size > 0);

    /* Payload addresses must be ALIGNMENT-byte aligned */
    if (!IS_ALIGNED(lo)) {
        sprintf(msg, "Payload address (%p) not aligned to %d bytes",
                lo, ALIGNMENT);
        malloc_error(tracenum, opnum, msg);
        return 0;
    }

    /* The payload must lie within the extent of the heap */
    if ((lo < (char *)mem_heap_lo()) || (lo > (char *)mem_heap_hi()) ||
        (hi < (char *)mem_heap_lo()) || (hi > (char *)mem_heap_hi())) {
        sprintf(msg, "Payload (%p:%p) lies outside heap (%p:%p)",
                lo, hi, mem_heap_lo(), mem_heap_hi());
        malloc_error(tracenum, opnum, msg);
        return 0;
    }

    /* The payload must not overlap any other payloads */
    for (p = *ranges; p != NULL; p = p->next) {
        if ((lo >= p->lo && lo <= p->hi) ||
            (hi >= p->lo && hi <= p->hi)) {
            sprintf(msg, "Payload (%p:%p) overlaps another payload (%p:%p)\n",
                    lo, hi, p->lo, p->hi);
            malloc_error(tracenum, opnum, msg);
            return 0;
        }
    }

    /*
     * Everything looks OK, so remember the extent of this block
     * by creating a range struct and adding it the range list.
     */
    if ((p = (range_t *)malloc(sizeof(range_t))) == NULL)
        unix_error("malloc error in add_range");
    p->next = *ranges;
    p->lo = lo;
    p->hi = hi;
    *ranges = p;
    return 1;
}

/*
 * remove_range - Free the range record of block whose payload starts at lo
 */
static void remove_range(range_t **ranges, char *lo) {
    range_t *p;
    range_t **prevpp = ranges;
    //int size;

    for (p = *ranges; p != NULL; p = p->next) {
        if (p->lo == lo) {
            *prevpp = p->next;
            //size = p->hi - p->lo + 1;
            free(p);
            break;
        }
        prevpp = &(p->next);
    }
}

/*
 * clear_ranges - free all of the range records for a trace
 */
static void clear_ranges(range_t **ranges) {
    range_t *p;
    range_t *pnext;

    for (p = *ranges; p != NULL; p = pnext) {
        pnext = p->next;
        free(p);
    }
    *ranges = NULL;
}

/**********************************************
 * The following routines manipulate tracefiles
 *********************************************/

/*
 * read_trace - read a trace file and store it in memory
 */
static trace_t *read_trace(char *tracedir, char *filename) {
    FILE *tracefile;
    trace_t *trace;
    char type[MAXLINE];
    char path[500];
    unsigned index, size;
    unsigned max_index = 0;
    unsigned op_index;

    if (verbose > 1)
        printf("Reading tracefile: %s\n", filename);

    /* Allocate the trace record */
    if ((trace = (trace_t *)malloc(sizeof(trace_t))) == NULL)
        unix_error("malloc 1 failed in read_trance");

    /* Read the trace file header */
    strcpy(path, tracedir);
    strcat(path, filename);
    if ((tracefile = fopen(path, "r")) == NULL) {
        sprintf(msg, "Could not open %s in read_trace", path);
        unix_error(msg);
    }
    fscanf(tracefile, "%d", &(trace->sugg_heapsize)); /* not used */
    fscanf(tracefile, "%d", &(trace->num_ids));
    fscanf(tracefile, "%d", &(trace->num_ops));
    fscanf(tracefile, "%d", &(trace->weight)); /* not used */

    /* We'll store each request line in the trace in this array */
    if ((trace->ops =
             (traceop_t *)malloc(trace->num_ops * sizeof(traceop_t))) == NULL)
        unix_error("malloc 2 failed in read_trace");

    /* We'll keep an array of pointers to the allocated blocks here... */
    if ((trace->blocks =
             (char **)malloc(trace->num_ids * sizeof(char *))) == NULL)
        unix_error("malloc 3 failed in read_trace");

    /* ... along with the corresponding byte sizes of each block */
    if ((trace->block_sizes =
             (size_t *)malloc(trace->num_ids * sizeof(size_t))) == NULL)
        unix_error("malloc 4 failed in read_trace");

    /* read every request line in the trace file */
    index = 0;
    op_index = 0;
    while (fscanf(tracefile, "%s", type) != EOF) {
        switch (type[0]) {
        case 'a':
            fscanf(tracefile, "%u %u", &index, &size);
            trace->ops[op_index].type = ALLOC;
            trace->ops[op_index].index = index;
            trace->ops[op_index].size = size;
            max_index = (index > max_index) ? index : max_index;
            break;
        case 'r':
            fscanf(tracefile, "%u %u", &index, &size);
            trace->ops[op_index].type = REALLOC;
            trace->ops[op_index].index = index;
            trace->ops[op_index].size = size;
            max_index = (index > max_index) ? index : max_index;
            break;
        case 'f':
            fscanf(tracefile, "%ud", &index);
            trace->ops[op_index].type = FREE;
            trace->ops[op_index].index = index;
            break;
        default:
            printf("Bogus type character (%c) in tracefile %s\n",
                   type[0], path);
            exit(1);
        }
        op_index++;
    }
    fclose(tracefile);
    assert(max_index == trace->num_ids - 1);
    assert(trace->num_ops == op_index);

    return trace;
}

/*
 * free_trace - Free the trace record and the three arrays it points
 *              to, all of which were allocated in read_trace().
 */
void free_trace(trace_t *trace) {
    free(trace->ops); /* free the three arrays... */
    free(trace->blocks);
    free(trace->block_sizes);
    free(trace); /* and the trace record itself... */
}

/**********************************************************************
 * The following functions evaluate the correctness, space utilization,
 * and throughput of the libc and mm malloc packages.
 **********************************************************************/

/*
 * eval_mm_valid - Check the mm malloc package for correctness
 */
static int eval_mm_valid(trace_t *trace, int tracenum, range_t **ranges) {
    int i, j;
    int index;
    int size;
    int oldsize;
    char *newp;
    char *oldp;
    char *p;

    /* Reset the heap and free any records in the range list */
    mem_reset_brk();
    clear_ranges(ranges);

    /* Call the mm package's init function */
    if (mm_init() < 0) {
        malloc_error(tracenum, 0, "mm_init failed.");
        return 0;
    }

    /* Interpret each operation in the trace in order */
    for (i = 0; i < trace->num_ops; i++) {
        index = trace->ops[i].index;
        size = trace->ops[i].size;

        switch (trace->ops[i].type) {

        case ALLOC: /* mm_malloc */

            /* Call the student's malloc */
            if ((p = mm_malloc(size)) == NULL) {
                malloc_error(tracenum, i, "mm_malloc failed.");
                return 0;
            }

            /*
	     * Test the range of the new block for correctness and add it
	     * to the range list if OK. The block must be  be aligned properly,
	     * and must not overlap any currently allocated block.
	     */
            if (add_range(ranges, p, size, tracenum, i) == 0)
                return 0;

            /* ADDED: cgw
	     * fill range with low byte of index.  This will be used later
	     * if we realloc the block and wish to make sure that the old
	     * data was copied to the new block
	     */
            memset(p, index & 0xFF, size);

            /* Remember region */
            trace->blocks[index] = p;
            trace->block_sizes[index] = size;
            break;

        case REALLOC: /* mm_realloc */

            /* Call the student's realloc */
            oldp = trace->blocks[index];
            if ((newp = mm_realloc(oldp, size)) == NULL) {
                malloc_error(tracenum, i, "mm_realloc failed.");
                return 0;
            }

            /* Remove the old region from the range list */
            remove_range(ranges, oldp);

            /* Check new block for correctness and add it to range list */
            if (add_range(ranges, newp, size, tracenum, i) == 0)
                return 0;

            /* ADDED: cgw
	     * Make sure that the new block contains the data from the old
	     * block and then fill in the new block with the low order byte
	     * of the new index
	     */
            oldsize = trace->block_sizes[index];
            if (size < oldsize)
                oldsize = size;
            for (j = 0; j < oldsize; j++) {
                if (newp[j] != (index & 0xFF)) {
                    malloc_error(tracenum, i, "mm_realloc did not preserve the "
                                              "data from old block");
                    return 0;
                }
            }
            memset(newp, index & 0xFF, size);

            /* Remember region */
            trace->blocks[index] = newp;
            trace->block_sizes[index] = size;
            break;

        case FREE: /* mm_free */

            /* Remove region from list and call student's free function */
            p = trace->blocks[index];
            remove_range(ranges, p);
            mm_free(p);
            break;

        default:
            app_error("Nonexistent request type in eval_mm_valid");
        }
    }

    /* As far as we know, this is a valid malloc package */
    return 1;
}

/*
 * eval_mm_util - Evaluate the space utilization of the student's package
 *   The idea is to remember the high water mark "hwm" of the heap for
 *   an optimal allocator, i.e., no gaps and no internal fragmentation.
 *   Utilization is the ratio hwm/heapsize, where heapsize is the
 *   size of the heap in bytes after running the student's malloc
 *   package on the trace. Note that our implementation of mem_sbrk()
 *   doesn't allow the students to decrement the brk pointer, so brk
 *   is always the high water mark of the heap.
 *
 */
static double eval_mm_util(trace_t *trace, int tracenum, range_t **ranges, int *ideal_max_heap, int *max_heap) {
    int i;
    int index;
    int size, newsize, oldsize;
    int max_total_size = FREE_HEAP;
    int total_size = 0;
    char *p;
    char *newp, *oldp;

    /* initialize the heap and the mm malloc package */
    mem_reset_brk();
    if (mm_init() < 0)
        app_error("mm_init failed in eval_mm_util");

    for (i = 0; i < trace->num_ops; i++) {
        void *old_lo = mem_heap_lo();
        void *old_hi = mem_heap_hi();

        switch (trace->ops[i].type) {

        case ALLOC: /* mm_alloc */
            index = trace->ops[i].index;
            size = trace->ops[i].size;

            if ((p = mm_malloc(size)) == NULL)
                app_error("mm_malloc failed in eval_mm_util");

            /* Remember region and size */
            trace->blocks[index] = p;
            trace->block_sizes[index] = size;

            /* Keep track of current total size
	     * of all allocated blocks */
            total_size += size;

            /* Update statistics */
            max_total_size = (total_size > max_total_size) ? total_size : max_total_size;
            break;

        case REALLOC: /* mm_realloc */
            index = trace->ops[i].index;
            newsize = trace->ops[i].size;
            oldsize = trace->block_sizes[index];

            oldp = trace->blocks[index];
            if ((newp = mm_realloc(oldp, newsize)) == NULL)
                app_error("mm_realloc failed in eval_mm_util");

            /* Remember region and size */
            trace->blocks[index] = newp;
            trace->block_sizes[index] = newsize;

            /* Keep track of current total size
	     * of all allocated blocks */
            total_size += (newsize - oldsize);

            /* Update statistics */
            max_total_size = (total_size > max_total_size) ? total_size : max_total_size;
            break;

        case FREE: /* mm_free */
            index = trace->ops[i].index;
            size = trace->block_sizes[index];
            p = trace->blocks[index];

            mm_free(p);

            /* Keep track of current total size
	     * of all allocated blocks */
            total_size -= size;

            break;

        default:
            app_error("Nonexistent request type in eval_mm_util");
        }
        if (old_lo != mem_heap_lo() || old_hi > mem_heap_hi())
            app_error("Error, tampering with mem_heap_lo/hi");
    }

    *max_heap = mem_heapsize() > FREE_HEAP ? mem_heapsize() : FREE_HEAP;
    *ideal_max_heap = max_total_size;
    return ((double)*ideal_max_heap / (double)*max_heap);
}

/*
 * eval_mm_speed - This is the function that is used by fcyc()
 *    to measure the running time of the mm malloc package.
 */
static void eval_mm_speed(void *ptr) {
    int i, index, size, newsize;
    char *p, *newp, *oldp, *block;
    trace_t *trace = ((speed_t *)ptr)->trace;

    /* Reset the heap and initialize the mm package */
    mem_reset_brk();
    if (mm_init() < 0)
        app_error("mm_init failed in eval_mm_speed");

    /* Interpret each trace request */
    for (i = 0; i < trace->num_ops; i++)
        switch (trace->ops[i].type) {

        case ALLOC: /* mm_malloc */
            index = trace->ops[i].index;
            size = trace->ops[i].size;
            if ((p = mm_malloc(size)) == NULL)
                app_error("mm_malloc error in eval_mm_speed");
            trace->blocks[index] = p;
            break;

        case REALLOC: /* mm_realloc */
            index = trace->ops[i].index;
            newsize = trace->ops[i].size;
            oldp = trace->blocks[index];
            if ((newp = mm_realloc(oldp, newsize)) == NULL)
                app_error("mm_realloc error in eval_mm_speed");
            trace->blocks[index] = newp;
            break;

        case FREE: /* mm_free */
            index = trace->ops[i].index;
            block = trace->blocks[index];
            mm_free(block);
            break;

        default:
            app_error("Nonexistent request type in eval_mm_valid");
        }
}

/*
 * eval_libc_valid - We run this function to make sure that the
 *    libc malloc can run to completion on the set of traces.
 *    We'll be conservative and terminate if any libc malloc call fails.
 *
 */
static int eval_libc_valid(trace_t *trace, int tracenum) {
    int i, newsize;
    char *p, *newp, *oldp;

    for (i = 0; i < trace->num_ops; i++) {
        switch (trace->ops[i].type) {

        case ALLOC: /* malloc */
            if ((p = malloc(trace->ops[i].size)) == NULL) {
                malloc_error(tracenum, i, "libc malloc failed");
                unix_error("System message");
            }
            trace->blocks[trace->ops[i].index] = p;
            break;

        case REALLOC: /* realloc */
            newsize = trace->ops[i].size;
            oldp = trace->blocks[trace->ops[i].index];
            if ((newp = realloc(oldp, newsize)) == NULL) {
                malloc_error(tracenum, i, "libc realloc failed");
                unix_error("System message");
            }
            trace->blocks[trace->ops[i].index] = newp;
            break;

        case FREE: /* free */
            free(trace->blocks[trace->ops[i].index]);
            break;

        default:
            app_error("invalid operation type  in eval_libc_valid");
        }
    }

    return 1;
}

/*
 * eval_libc_speed - This is the function that is used by fcyc() to
 *    measure the running time of the libc malloc package on the set
 *    of traces.
 */
static void eval_libc_speed(void *ptr) {
    int i;
    int index, size, newsize;
    char *p, *newp, *oldp, *block;
    trace_t *trace = ((speed_t *)ptr)->trace;

    for (i = 0; i < trace->num_ops; i++) {
        switch (trace->ops[i].type) {
        case ALLOC: /* malloc */
            index = trace->ops[i].index;
            size = trace->ops[i].size;
            if ((p = malloc(size)) == NULL)
                unix_error("malloc failed in eval_libc_speed");
            trace->blocks[index] = p;
            break;

        case REALLOC: /* realloc */
            index = trace->ops[i].index;
            newsize = trace->ops[i].size;
            oldp = trace->blocks[index];
            if ((newp = realloc(oldp, newsize)) == NULL)
                unix_error("realloc failed in eval_libc_speed\n");

            trace->blocks[index] = newp;
            break;

        case FREE: /* free */
            index = trace->ops[i].index;
            block = trace->blocks[index];
            free(block);
            break;
        }
    }
}

/*************************************
 * Some miscellaneous helper routines
 ************************************/

/*
 * printresults - prints a performance summary for some malloc package
 */
static void printresults(int n, stats_t *stats) {
    int i;
    double secs = 0;
    double ops = 0;
    double util = 0;

    /* Print the individual results for each trace */
    printf("%35s%7s %9s%8s%5s %8s%10s%6s\n",
           "trace", " valid", "idealheap", "maxheap", "util", "ops", "secs", "Kops");
    for (i = 0; i < n; i++) {
        if (stats[i].valid) {
            printf("%35s%7s %8.0fk%7.0fk%5.0f%%%8.0f%10.6f%6.0f\n",
                   stats[i].filename,
                   "yes",
                   (double)(stats[i].ideal_max_heap) / 1024.0,
                   (double)(stats[i].max_heap) / 1024.0,
                   stats[i].util * 100.0,
                   stats[i].ops,
                   stats[i].secs,
                   (stats[i].ops / 1e3) / stats[i].secs);
            secs += stats[i].secs;
            ops += stats[i].ops;
            util += stats[i].util;
        } else {
            printf("%35s%10s%6s%8s%10s%6s\n",
                   "-",
                   "no",
                   "-",
                   "-",
                   "-",
                   "-");
        }
    }

    /* Print the aggregate results for the set of traces */
    if (errors == 0) {
        printf("%42s%18s%5.0f%%%8.0f%10.6f%6.0f\n",
               "Total       ",
               " ",
               (util / n) * 100.0,
               ops,
               secs,
               (ops / 1e3) / secs);
    } else {
        printf("%35s%6s%8s%10s%6s\n",
               "Total       ",
               "-",
               "-",
               "-",
               "-");
    }
}

/*
 * app_error - Report an arbitrary application error
 */
void app_error(char *msg) {
    printf("%s\n", msg);
    exit(1);
}

/*
 * unix_error - Report a Unix-style error
 */
void unix_error(char *msg) {
    printf("%s: %s\n", msg, strerror(errno));
    exit(1);
}

/*
 * malloc_error - Report an error returned by the mm_malloc package
 */
void malloc_error(int tracenum, int opnum, char *msg) {
    errors++;
    printf("ERROR [trace %d, line %d]: %s\n", tracenum, LINENUM(opnum), msg);
}

/*
 * usage - Explain the command line arguments
 */
static void usage(void) {
    fprintf(stderr, "Usage: mdriver [-hvVal] [-f <file>] [-t <dir>]\n");
    fprintf(stderr, "Options\n");
    fprintf(stderr, "\t-a         Don't check the team structure.\n");
    fprintf(stderr, "\t-f <file>  Use <file> as the trace file.\n");
    fprintf(stderr, "\t-g         Generate summary info for autograder.\n");
    fprintf(stderr, "\t-h         Print this message.\n");
    fprintf(stderr, "\t-l         Run libc malloc as well.\n");
    fprintf(stderr, "\t-t <dir>   Directory to find default traces.\n");
    fprintf(stderr, "\t-v         Print per-trace performance breakdowns.\n");
    fprintf(stderr, "\t-V         Print additional debug info.\n");
}