/* util.c
 *
 * Copyright (C) 2008 Till Kamppeter <till.kamppeter@gmail.com>
 * Copyright (C) 2008 Lars Uebernickel <larsuebernickel@gmx.de>
 *
 * This file is part of foomatic-rip.
 *
 * Foomatic-rip is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Foomatic-rip is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "util.h"
#include "foomaticrip.h"
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <stdarg.h>
#include <assert.h>


const char* shellescapes = "|;<>&!$\'\"`#*?()[]{}";

const char * temp_dir()
{
    static const char *tmpdir = NULL;

    if (!tmpdir)
    {
        const char *dirs[] = { getenv("TMPDIR"), P_tmpdir, "/tmp" };
        int i;

        for (i = 0; i < (sizeof(dirs) / sizeof(dirs[0])); i++) {
            if (access(dirs[i], W_OK) == 0) {
                tmpdir = dirs[i];
                break;
            }
        }
        if (tmpdir)
        {
            _log("Storing temporary files in %s\n", tmpdir);
            setenv("TMPDIR", tmpdir, 1); /* for child processes */
        }
        else
            rip_die(EXIT_PRNERR_NORETRY_BAD_SETTINGS,
                    "Cannot find a writable temp dir.");
    }

    return tmpdir;
}

int prefixcmp(const char *str, const char *prefix)
{
    return strncmp(str, prefix, strlen(prefix));
}

int prefixcasecmp(const char *str, const char *prefix)
{
    return strncasecmp(str, prefix, strlen(prefix));
}

int startswith(const char *str, const char *prefix)
{
    return str ? (strncmp(str, prefix, strlen(prefix)) == 0) : 0;
}

int endswith(const char *str, const char *postfix)
{
    int slen = strlen(str);
    int plen = strlen(postfix);
    const char *pstr;

    if (slen < plen)
        return 0;

    pstr = &str[slen - plen];
    return strcmp(pstr, postfix) == 0;
}

const char * skip_whitespace(const char *str)
{
    while (*str && isspace(*str))
        str++;
    return str;
}

void strlower(char *dest, size_t destlen, const char *src)
{
    char *pdest = dest;
    const char *psrc = src;
    while (*psrc && --destlen > 0)
    {
        *pdest = tolower(*psrc);
        pdest++;
        psrc++;
    }
    *pdest = '\0';
}

int isempty(const char *string)
{
    return !string || string[0] == '\0';
}

const char * strncpy_omit(char* dest, const char* src, size_t n, int (*omit_func)(int))
{
    const char* psrc = src;
    char* pdest = dest;
    int cnt = n -1;
    if (!pdest)
        return NULL;
    if (psrc) {
        while (*psrc != 0 && cnt > 0) {
            if (!omit_func(*psrc)) {
                *pdest = *psrc;
                pdest++;
                cnt--;
            }
            psrc++;
        }
    }
    *pdest = '\0';
    return psrc;
}
int omit_unprintables(int c) { return c>= '\x00' && c <= '\x1f'; }
int omit_shellescapes(int c) { return strchr(shellescapes, c) != NULL; }
int omit_specialchars(int c) { return omit_unprintables(c) || omit_shellescapes(c); }
int omit_whitespace(int c) { return c == ' ' || c == '\t'; }
int omit_whitespace_newline(int c) { return omit_whitespace(c) || c == '\n'; }

#ifndef HAVE_STRCASESTR
char *
strcasestr (const char *haystack, const char *needle)
{
    char *p, *startn = 0, *np = 0;

    for (p = haystack; *p; p++) {
        if (np) {
	    if (toupper(*p) == toupper(*np)) {
	        if (!*++np)
		    return startn;
	    } else
	        np = 0;
	} else if (toupper(*p) == toupper(*needle)) {
	    np = needle + 1;
	    startn = p;
	}
    }

    return 0;
}
#endif

#ifndef __OpenBSD__
#ifndef HAVE_STRLCPY
size_t strlcpy(char *dest, const char *src, size_t size)
{
    char *pdest = dest;
    const char *psrc = src;

    if (!src) {
        dest[0] = '\0';
        return 0;
    }

    if (size) {
        while (--size && (*pdest++ = *psrc++) != '\0');
        *pdest = '\0';
    }
    if (!size)
        while (*psrc++);
    return (psrc - src -1);
}
#endif /* ! HAVE_STRLCPY */

#ifndef HAVE_STRLCAT
size_t strlcat(char *dest, const char *src, size_t size)
{
    char *pdest = dest;
    const char *psrc = src;
    size_t i = size;
    size_t len;

    while (--i && *pdest)
        pdest++;
    len = pdest - dest;

    if (!i)
        return strlen(src) + len;

    while (i-- && *psrc)
        *pdest++ = *psrc++;
    *pdest = '\0';

    return len + (psrc - src);
}
#endif /* ! HAVE_STRLCAT */
#endif /* ! __OpenBSD__ */

void strrepl(char *str, const char *chars, char repl)
{
    char *p = str;

    while (*p) {
        if (strchr(chars, *p))
            *p = repl;
        p++;
    }
}

void strrepl_nodups(char *str, const char *chars, char repl)
{
    char *pstr = str;
    char *p = str;
    int prev = 0;

    while (*pstr) {
        if (strchr(chars, *pstr) || *pstr == repl) {
            if (!prev) {
                *p = repl;
                p++;
                prev = 1;
            }
        }
        else {
            *p = *pstr;
            p++;
            prev = 0;
        }
        pstr++;
    }
    *p = '\0';
}

void strclr(char *str)
{
    while (*str) {
        *str = '\0';
        str++;
    }
}

char * strnchr(const char *str, int c, size_t n)
{
    char *p = (char*)str;

    while (*p && --n > 0) {
        if (*p == (char)c)
            return p;
        p++;
    }
    return p;
}

void escapechars(char *dest, size_t size, const char *src, const char *esc_chars)
{
    const char *psrc = src;

    while (*psrc && --size > 0) {
        if (strchr(esc_chars, *psrc))
            *dest++ = '\\';
        *dest++ = *psrc++;
    }
}

const char * strncpy_tochar(char *dest, const char *src, size_t max, const char *stopchars)
{
    const char *psrc = src;
    char *pdest = dest;
    if (isempty(psrc)) {
       return NULL;
    }
    while (*psrc && --max > 0 && !strchr(stopchars, *psrc)) {
        *pdest = *psrc;
        pdest++;
        psrc++;
    }
    *pdest = '\0';
    return psrc +1;
}

int find_in_path(const char *progname, const char *paths, char *found_in)
{
    char *pathscopy;
    char *path;
    char filepath[PATH_MAX];

    if (access(progname, X_OK) == 0)
        return 1;

    pathscopy = strdup(paths);
    for (path = strtok(pathscopy, ":"); path; path = strtok(NULL, ":")) {
        strlcpy(filepath, path, PATH_MAX);
        strlcat(filepath, "/", PATH_MAX);
        strlcat(filepath, progname, PATH_MAX);

        if (access(filepath, X_OK) == 0) {
            if (found_in)
                strlcpy(found_in, path, PATH_MAX);
            free(pathscopy);
            return 1;
        }
    }

    if (found_in)
        found_in[0] = '\0';
    free(pathscopy);
    return 0;
}

void file_basename(char *dest, const char *path, size_t dest_size)
{
    const char *p = strrchr(path, '/');
    char *pdest = dest;
    if (!pdest)
        return;
    if (p)
        p += 1;
    else
        p = path;
    while (*p != 0 && *p != '.' && --dest_size > 0) {
        *pdest++ = *p++;
    }
    *pdest = '\0';
}

void make_absolute_path(char *path, int len)
{
    char *tmp, *cwd;

    if (path[0] != '/') {
        tmp = malloc(len +1);
        strlcpy(tmp, path, len);

        cwd = malloc(len);
        if (getcwd(cwd, len) != NULL) {
	  strlcpy(path, cwd, len);
	  strlcat(path, "/", len);
	  strlcat(path, tmp, len);
	}

        free(tmp);
        free(cwd);
    }
}

int is_true_string(const char *str)
{
    return str && (!strcmp(str, "1") || !strcasecmp(str, "Yes") ||
        !strcasecmp(str, "On") || !strcasecmp(str, "True"));
}

int is_false_string(const char *str)
{
    return str && (!strcmp(str, "0") || !strcasecmp(str, "No") ||
        !strcasecmp(str, "Off") || !strcasecmp(str, "False") ||
        !strcasecmp(str, "None"));
}

int digit(char c)
{
    if (c >= '0' && c <= '9')
        return (int)c - (int)'0';
    return -1;
}

static const char * next_token(const char *string, const char *separators)
{
    if (!string)
        return NULL;

    while (*string && !strchr(separators, *string))
        string++;

    while (*string && strchr(separators, *string))
        string++;

    return string;
}

static unsigned count_separators(const char *string, const char *separators)
{
    const char *p;
    unsigned cnt = 0;

    if (!string)
        return 0;

    for (p = string; *p; p = next_token(p, separators))
        cnt++;

    return cnt;
}

/*
 * Returns a zero terminated array of strings
 */
char ** argv_split(const char *string, const char *separators, int *cntp)
{
    unsigned cnt;
    int i;
    char **argv;

    if (!string)
        return NULL;

    if ((cnt = count_separators(string, separators)) == 0)
        return NULL;

    argv = malloc((cnt +1) * sizeof(char *));
    argv[cnt] = NULL;

    for (i = 0; i < cnt; i++)
    {
        size_t len = strcspn(string, separators);
	char *s;
        s = malloc(len + 1);
        strncpy(s, string, len);
        s[len] = '\0';
	argv[i] = s;
        string = next_token(string, separators);
    }

    if (cntp)
        *cntp = cnt;
    return argv;
}

size_t argv_count(char **argv)
{
    size_t cnt = 0;

    if (!argv)
        return 0;

    while (*argv++)
        cnt++;

    return cnt;
}

void argv_free(char **argv)
{
    char **p;

    if (!argv)
        return;

    for (p = argv; *p; p++)
        free(*p);

    free(argv);
}

int line_count(const char *str)
{
    int cnt = 0;
    while (*str) {
        if (*str == '\n')
            cnt++;
        str++;
    }
    return cnt;
}

int line_start(const char *str, int line_number)
{
    const char *p = str;
    while (*p && line_number > 0) {
        if (*p == '\n')
            line_number--;
        p++;
    }
    return p - str;
}

void unhexify(char *dest, size_t size, const char *src)
{
    char *pdest = dest;
    const char *psrc = src;
    char cstr[3];

    cstr[2] = '\0';

    while (*psrc && pdest - dest < size -1) {
        if (*psrc == '<') {
            psrc++;
            do {
                cstr[0] = *psrc++;
                cstr[1] = *psrc++;
                if (!isxdigit(cstr[0]) || !isxdigit(cstr[1])) {
                    printf("Error replacing hex notation in %s!\n", src);
                    break;
                }
                *pdest++ = (char)strtol(cstr, NULL, 16);
            } while (*psrc != '>');
            psrc++;
        }
        else
            *pdest++ = *psrc++;
    }
    *pdest = '\0';
}

void extract_command(size_t *start, size_t *end, const char *cmdline, const char *cmd)
{
    char *copy = strdup(cmdline);
    char *tok = NULL;
    const char *delim = "|;";

    *start = *end = 0;
    for (tok = strtok(copy, delim); tok; tok = strtok(NULL, delim)) {
        while (*tok && isspace(*tok))
            tok++;
        if (startswith(tok, cmd)) {
            *start = tok - copy;
            *end = tok + strlen(tok) - copy;
            break;
        }
    }

    free(copy);
}

int contains_command(const char *cmdline, const char *cmd)
{
    size_t start = 0, end = 0;

    extract_command(&start, &end, cmdline, cmd);
    if (start == 0 && end == 0)
        return 0;

    return 1;
}

/*
 * Dynamic strings
 */
dstr_t * create_dstr()
{
    dstr_t *ds = malloc(sizeof(dstr_t));
    ds->len = 0;
    ds->alloc = 32;
    ds->data = malloc(ds->alloc);
    ds->data[0] = '\0';
    return ds;
}

void free_dstr(dstr_t *ds)
{
    free(ds->data);
    free(ds);
}

void dstrclear(dstr_t *ds)
{
    ds->len = 0;
    ds->data[0] = '\0';
}

void dstrassure(dstr_t *ds, size_t alloc)
{
	if (ds->alloc < alloc) {
		ds->alloc = alloc;
		ds->data = realloc(ds->data, ds->alloc);
	}
}

void dstrcpy(dstr_t *ds, const char *src)
{
    size_t srclen;

    if (!src) {
        ds->len = 0;
        ds->data[0] = '\0';
        return;
    }

    srclen = strlen(src);

    if (srclen >= ds->alloc) {
        do {
            ds->alloc *= 2;
        } while (srclen >= ds->alloc);
        ds->data = realloc(ds->data, ds->alloc);
    }

    strcpy(ds->data, src);
    ds->len = srclen;
}

void dstrncpy(dstr_t *ds, const char *src, size_t n)
{
    if (n >= ds->alloc) {
        do {
            ds->alloc *= 2;
        } while (n >= ds->alloc);
        ds->data = realloc(ds->data, ds->alloc);
    }

    strncpy(ds->data, src, n);
    ds->len = n;
    ds->data[ds->len] = '\0';
}

void dstrncat(dstr_t *ds, const char *src, size_t n)
{
    size_t needed = ds->len + n;

    if (needed >= ds->alloc) {
        do {
            ds->alloc *= 2;
        } while (needed >= ds->alloc);
        ds->data = realloc(ds->data, ds->alloc);
    }

    strncpy(&ds->data[ds->len], src, n);
    ds->len = needed;
    ds->data[ds->len] = '\0';
}

void dstrcpyf(dstr_t *ds, const char *src, ...)
{
    va_list ap;
    size_t srclen;

    va_start(ap, src);
    srclen = vsnprintf(ds->data, ds->alloc, src, ap);
    va_end(ap);

    if (srclen >= ds->alloc) {
        do {
            ds->alloc *= 2;
        } while (srclen >= ds->alloc);
        ds->data = realloc(ds->data, ds->alloc);

        va_start(ap, src);
        vsnprintf(ds->data, ds->alloc, src, ap);
        va_end(ap);
    }

    ds->len = srclen;
}

void dstrputc(dstr_t *ds, int c)
{
    if (ds->len +1 >= ds->alloc) {
        ds->alloc *= 2;
        ds->data = realloc(ds->data, ds->alloc);
    }
    ds->data[ds->len++] = c;
    ds->data[ds->len] = '\0';
}

void dstrcat(dstr_t *ds, const char *src)
{
    size_t srclen = strlen(src);
    size_t newlen = ds->len + srclen;

    if (newlen >= ds->alloc) {
        do {
            ds->alloc *= 2;
        } while (newlen >= ds->alloc);
        ds->data = realloc(ds->data, ds->alloc);
    }

    memcpy(&ds->data[ds->len], src, srclen +1);
    ds->len = newlen;
}

void dstrcatf(dstr_t *ds, const char *src, ...)
{
    va_list ap;
    size_t restlen = ds->alloc - ds->len;
    size_t srclen;

    va_start(ap, src);
    srclen = vsnprintf(&ds->data[ds->len], restlen, src, ap);
    va_end(ap);

    if (srclen >= restlen) {
        do {
            ds->alloc *= 2;
            restlen = ds->alloc - ds->len;
        } while (srclen >= restlen);
        ds->data = realloc(ds->data, ds->alloc);

        va_start(ap, src);
        srclen = vsnprintf(&ds->data[ds->len], restlen, src, ap);
        va_end(ap);
    }

    ds->len += srclen;
}

size_t fgetdstr(dstr_t *ds, FILE *stream)
{
    int c;
    size_t cnt = 0;

    ds->len = 0;
    if (ds->alloc == 0) {
        ds->alloc = 256;
        ds->data = malloc(ds->alloc);
    }

    while ((c = fgetc(stream)) != EOF) {
        if (ds->len +1 == ds->alloc) {
            ds->alloc *= 2;
            ds->data = realloc(ds->data, ds->alloc);
        }
        ds->data[ds->len++] = (char)c;
        cnt ++;
        if (c == '\n')
            break;
    }
    ds->data[ds->len] = '\0';
    return cnt;
}

/*
 * Replace the first occurrence of 'find' after the index 'start' with 'repl'
 * Returns the position right after the replaced string
 */
int dstrreplace(dstr_t *ds, const char *find, const char *repl, int start)
{
    char *p;
    dstr_t *copy = create_dstr();
    int end = -1;

    dstrcpy(copy, ds->data);

    if ((p = strstr(&copy->data[start], find)))
    {
        dstrncpy(ds, copy->data, p - copy->data);
        dstrcatf(ds, "%s", repl);
        end = ds->len;
        dstrcatf(ds, "%s", p + strlen(find));
    }

    free_dstr(copy);
    return end;
}

void dstrprepend(dstr_t *ds, const char *str)
{
    dstr_t *copy = create_dstr();
    dstrcpy(copy, ds->data);
    dstrcpy(ds, str);
    dstrcatf(ds, "%s", copy->data);
    free_dstr(copy);
}

void dstrinsert(dstr_t *ds, int idx, const char *str)
{
    char * copy = strdup(ds->data);
    size_t len = strlen(str);

    if (idx >= ds->len)
        idx = ds->len;
    else if (idx < 0)
        idx = 0;

    if (ds->len + len >= ds->alloc) {
        do {
            ds->alloc *= 2;
        } while (ds->len + len >= ds->alloc);
        free(ds->data);
        ds->data = malloc(ds->alloc);
    }

    strncpy(ds->data, copy, idx);
    ds->data[idx] = '\0';
    strcat(ds->data, str);
    strcat(ds->data, &copy[idx]);
    ds->len += len;
    free(copy);
}

void dstrinsertf(dstr_t *ds, int idx, const char *str, ...)
{
    va_list ap;
    char *strf;
    size_t len;

    va_start(ap, str);
    len = vsnprintf(NULL, 0, str, ap);
    va_end(ap);

    strf = malloc(len +1);
    va_start(ap, str);
    vsnprintf(strf, len +1, str, ap);
    va_end(ap);

    dstrinsert(ds, idx, strf);

    free(strf);
}

void dstrremove(dstr_t *ds, int idx, size_t count)
{
    char *p1, *p2;

    if (idx + count >= ds->len)
        return;

    p1 = &ds->data[idx];
    p2 = &ds->data[idx + count];

    while (*p2) {
        *p1 = *p2;
        p1++;
        p2++;
    }
    *p1 = '\0';
}

static inline int isnewline(int c)
{
    return c == '\n' || c == '\r';
}

void dstrcatline(dstr_t *ds, const char *str)
{
    size_t eol = strcspn(str, "\n\r");
    if (isnewline(str[eol]))
        eol++;
    dstrncat(ds, str, eol);
}

int dstrendswith(dstr_t *ds, const char *str)
{
    int len = strlen(str);
    char *pstr;

    if (ds->len < len)
        return 0;
    pstr = &ds->data[ds->len - len];
    return strcmp(pstr, str) == 0;

}

void dstrfixnewlines(dstr_t *ds)
{
    if (ds->data[ds->len -1] == '\r') {
        ds->data[ds->len -1] = '\n';
    }
    else if (ds->data[ds->len -2] == '\r') {
        ds->data[ds->len -1] = '\n';
        ds->data[ds->len -2] = '\0';
        ds->len -= 1;
    }
}

void dstrremovenewline(dstr_t *ds)
{
    if (!ds->len)
        return;

    if (ds->data[ds->len -1] == '\r' || ds->data[ds->len -1] == '\n') {
        ds->data[ds->len -1] = '\0';
        ds->len -= 1;
    }

    if (ds->len < 2)
        return;

    if (ds->data[ds->len -2] == '\r') {
        ds->data[ds->len -2] = '\0';
        ds->len -= 2;
    }
}

void dstrtrim(dstr_t *ds)
{
    int pos = 0;

    while (pos < ds->len && isspace(ds->data[pos]))
        pos++;

    if (pos > 0) {
        ds->len -= pos;
        memmove(ds->data, &ds->data[pos], ds->len +1);
    }
}

void dstrtrim_right(dstr_t *ds)
{
    if (!ds->len)
        return;

    while (isspace(ds->data[ds->len -1]))
        ds->len -= 1;
    ds->data[ds->len] = '\0';
}



/*
 *  LIST
 */

list_t * list_create()
{
    list_t *l = malloc(sizeof(list_t));
    l->first = NULL;
    l->last = NULL;
    return l;
}

list_t * list_create_from_array(int count, void ** data)
{
    int i;
    list_t *l = list_create();

    for (i = 0; i < count; i++)
        list_append(l, data[i]);

    return l;
}

void list_free(list_t *list)
{
    listitem_t *i = list->first, *tmp;
    while (i) {
        tmp = i->next;
        free(i);
        i = tmp;
    }
}

size_t list_item_count(list_t *list)
{
    size_t cnt = 0;
    listitem_t *i;
    for (i = list->first; i; i = i->next)
        cnt++;
    return cnt;
}

list_t * list_copy(list_t *list)
{
    list_t *l = list_create();
    listitem_t *i;

    for (i = list->first; i; i = i->next)
        list_append(l, i->data);
    return l;
}

void list_prepend(list_t *list, void *data)
{
    listitem_t *item;

    assert(list);

    item = malloc(sizeof(listitem_t));
    item->data = data;
    item->prev = NULL;

    if (list->first) {
        item->next = list->first;
        list->first->next = item;
        list->first = item;
    }
    else {
        item->next = NULL;
        list->first = item;
        list->last = item;
    }
}

void list_append(list_t *list, void *data)
{
    listitem_t *item;

    assert(list);

    item = malloc(sizeof(listitem_t));
    item->data = data;
    item->next = NULL;

    if (list->last) {
        item->prev = list->last;
        list->last->next = item;
        list->last = item;
    }
    else {
        item->prev = NULL;
        list->first = item;
        list->last = item;
    }
}

void list_remove(list_t *list, listitem_t *item)
{
    assert(item);

    if (item->prev)
        item->prev->next = item->next;
    if (item->next)
        item->next->prev = item->prev;
    if (item == list->first)
        list->first = item->next;
    if (item == list->last)
        list->last = item->prev;

    free(item);
}

listitem_t * list_get(list_t *list, int idx)
{
    listitem_t *i;
    for (i = list->first; i && idx; i = i->next)
        idx--;
    return i;
}

listitem_t * arglist_find(list_t *list, const char *name)
{
    listitem_t *i;
    for (i = list->first; i; i = i->next) {
        if (!strcmp((const char*)i->data, name))
            return i;
    }
    return NULL;
}

listitem_t * arglist_find_prefix(list_t *list, const char *name)
{
    listitem_t *i;
    for (i = list->first; i; i= i->next) {
        if (!prefixcmp((const char*)i->data, name))
            return i;
    }
    return NULL;
}


char * arglist_get_value(list_t *list, const char *name)
{
    listitem_t *i;
    char *p;

    for (i = list->first; i; i = i->next) {
        if (i->next && !strcmp(name, (char*)i->data))
            return (char*)i->next->data;
        else if (!prefixcmp((char*)i->data, name)) {
            p = &((char*)i->data)[strlen(name)];
            return *p == '=' ? p +1 : p;
        }
    }
    return NULL;
}

char * arglist_get(list_t *list, int idx)
{
    listitem_t *i = list_get(list, idx);
    return i ? (char*)i->data : NULL;
}

int arglist_remove(list_t *list, const char *name)
{
    listitem_t *i;
    char *i_name;

    for (i = list->first; i; i = i->next) {
        i_name = (char*)i->data;
        if (i->next && !strcmp(name, i_name)) {
            list_remove(list, i->next);
            list_remove(list, i);
            return 1;
        }
        else if (!prefixcmp(i_name, name)) {
            list_remove(list, i);
            return 1;
        }
    }
    return 0;
}

int arglist_remove_flag(list_t *list, const char *name)
{
    listitem_t *i = arglist_find(list, name);
    if (i) {
        list_remove(list, i);
        return 1;
    }
    return 0;
}

int copy_file(FILE *dest,
              FILE *src,
              const char *alreadyread,
              size_t alreadyread_len)
{
    char buf[8192];
    size_t bytes;

    if (alreadyread && alreadyread_len)
    {
        if (fwrite(alreadyread, 1, alreadyread_len, dest) < alreadyread_len)
        {
            _log("Could not write to temp file\n");
            return 0;
        }
    }

    while ((bytes = fread(buf, 1, 8192, src)))
        fwrite(buf, 1, bytes, dest);

    return !ferror(src) && !ferror(dest);
}