/*
 * Copyright (C) 2008  Kristian Høgsberg <krh@redhat.com>
 * Copyright (C) 2008  Red Hat, Inc
 * Copyright (C) 2009, 2011, 2012, 2014  J. Ali Harlow <ali@juiblex.co.uk>
 *
 * This program 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.
 *
 * This program 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 General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <limits.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#ifdef MSWIN_API
#include <windows.h>
#include <direct.h>
#else
#include <sys/utsname.h>
#endif
#if HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#include <assert.h>

#include "razor.h"
#include "razor-internal.h"

#ifndef O_BINARY
#define O_BINARY	0
#endif

/* Required by gnulib on non-libc platforms */
char *program_name = "librazor";

void *
zalloc(size_t size)
{
	void *p;

	p = malloc(size);
	memset(p, 0, size);

	return p;
}

#if HAVE_SYS_MMAN_H
#define OPEN_FILE_USED		(1U<<0)
#define OPEN_FILE_MMAPPED	(1U<<1)

struct open_file {
	void *addr;
	size_t length;
	uint32_t flags;
};

struct array open_files = { 0, };
#endif	/* HAVE_SYS_MMAN_H */

void *
razor_file_get_contents(const char *filename, size_t *length, int private,
			struct razor_error **error)
{
	int fd;
	struct stat st;
	void *addr = NULL;
	size_t nb;
	ssize_t res;
#if HAVE_SYS_MMAN_H
	struct open_file *of, *ofend;
#endif

	fd = open(filename, O_RDONLY | O_BINARY);
	if (fd < 0) {
		razor_set_error_posix(error, filename);
		return NULL;
	}

	if (fstat(fd, &st) < 0) {
		razor_set_error_posix(error, filename);
		close(fd);
		return NULL;
	}

	*length = st.st_size;

#if HAVE_SYS_MMAN_H
	ofend = open_files.data + open_files.size;
	for (of = open_files.data; of < ofend; of++)
		if (!(of->flags & OPEN_FILE_USED))
			break;
	if (of == ofend) {
		of = array_add(&open_files, sizeof *of);
		of->flags = 0;
	}

	if (!private) {
		addr = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
		if (addr == MAP_FAILED)
			addr = NULL;
		else
			of->flags = OPEN_FILE_USED | OPEN_FILE_MMAPPED;
	}
#endif	/* HAVE_SYS_MMAN_H */
	if (!addr) {
		addr = malloc(st.st_size);
		if (addr) {
#if HAVE_SYS_MMAN_H
			of->flags = OPEN_FILE_USED;
#endif
			nb = 0;
			while(nb < st.st_size) {
				res = read(fd, addr + nb, st.st_size - nb);
				if (res <= 0) {
					razor_set_error_posix(error, filename);
					free(addr);
					addr = NULL;
					break;
				}
				nb += res;
			}
		} else
			razor_set_error(error, RAZOR_POSIX_ERROR, ENOMEM, NULL,
					"Not enough memory");
	}
	close(fd);

#if HAVE_SYS_MMAN_H
	of->addr = addr;
	of->length = st.st_size;
#endif

	return addr;
}

int razor_file_free_contents(void *addr, size_t length)
{
#if HAVE_SYS_MMAN_H
	int retval, mmapped;
	struct open_file *of, *ofend;

	ofend = open_files.data + open_files.size;
	for (of = open_files.data; of < ofend; of++)
		if ((of->flags & OPEN_FILE_USED) && of->addr == addr)
			break;

	if (of == ofend)
		return 1;

	length = of->length;
	mmapped = of->flags & OPEN_FILE_MMAPPED;
	of->flags &= ~OPEN_FILE_USED;

	for (of = open_files.data; of < ofend; of++)
		if (of->flags & OPEN_FILE_USED)
			break;

	if (of == ofend) {
		array_release(&open_files);
		array_init(&open_files);
	}

	if (mmapped)
		return munmap(addr, length);
#endif

	free(addr);
	return 0;
}

struct qsort_context {
	size_t size;
	razor_compare_with_data_func_t compare;
	void *data;
};

static void
qsort_swap(void *p1, void *p2, size_t size)
{
	char buffer[size];

	if (p1 != p2) {
		memcpy(buffer, p1, size);
		memcpy(p1, p2, size);
		memcpy(p2, buffer, size);
	}
}

static void
__qsort_with_data(void *base, size_t nelem, uint32_t *map,
		  struct qsort_context *ctx)
{
	void *p, *start, *end, *pivot;
	uint32_t *mp, *mstart, *mend, tmp;
	int left, right, result;
	size_t size = ctx->size;

	p = base;
	start = base;
	end = base + nelem * size;
	mp = map;
	mstart = map;
	mend = map + nelem;
	pivot = base + (rand() % nelem) * size;

	while (p < end) {
		result = ctx->compare(p, pivot, ctx->data);
		if (result < 0) {
			qsort_swap(p, start, size);
			tmp = *mp;
			*mp = *mstart;
			*mstart = tmp;
			if (start == pivot)
				pivot = p;
			start += size;
			mstart++;
			p += size;
			mp++;
		} else if (result == 0) {
			p += size;
			mp++;
		} else {
 			end -= size;
			mend--;
			qsort_swap(p, end, size);
			tmp = *mp;
			*mp = *mend;
			*mend = tmp;
			if (end == pivot)
				pivot = p;
		}
	}

	left = (start - base) / size;
	right = (base + nelem * size - end) / size;
	if (left > 1)
		__qsort_with_data(base, left, map, ctx);
	if (right > 1)
		__qsort_with_data(end, right, mend, ctx);
}

uint32_t *
razor_qsort_with_data(void *base, size_t nelem, size_t size,
		      razor_compare_with_data_func_t compare, void *data)
{
	struct qsort_context ctx;
	uint32_t *map;
	int i;

	if (nelem == 0)
		return NULL;

	ctx.size = size;
	ctx.compare = compare;
	ctx.data = data;

	map = malloc(nelem * sizeof (uint32_t));
	for (i = 0; i < nelem; i++)
		map[i] = i;

	__qsort_with_data(base, nelem, map, &ctx);

	return map;
}

void environment_init(struct environment *env)
{
	env->is_set = 0;
	array_init(&env->string_pool);
	array_init(&env->vars);
}

void environment_add_variable(struct environment *env,
			      const char *variable, const char *value)
{
	char *s;
	uint32_t *r;
	assert(!env->is_set);

	s = array_add(&env->string_pool,
		      strlen(variable) + strlen(value) + 2);
	sprintf(s, "%s=%s", variable, value);
	r = array_add(&env->vars, sizeof *r);
	*r = s - (char *)env->string_pool.data;
}

void environment_set(struct environment *env)
{
	int i, count;
	char *s;
#ifndef WIN32
	char *t;
#endif
        uint32_t *r;

	if (!env->is_set) {
		count = env->vars.size / sizeof(uint32_t);
		r = (uint32_t *)env->vars.data;
		for (i = 0; i < count; i++) {
			s = env->string_pool.data + *r++;
#ifdef WIN32
			putenv(s);
#else
			t = strchr(s, '=');
			*t = '\0';
			setenv(s, t + 1, 1);
			*t = '=';
#endif
		}

		env->is_set = 1;
	}
}

void environment_unset(struct environment *env)
{
	int i, count;
	char c, *s, *t;
        uint32_t *r;

	if (env->is_set) {
		count = env->vars.size / sizeof(uint32_t);
		r = (uint32_t *)env->vars.data;
		for (i = 0; i < count; i++) {
			s = env->string_pool.data + *r++;
			t = strchr(s, '=');
#ifdef WIN32
			t++;
			c = *t;
			*t = '\0';
			putenv(s);
			*t = c;
#else
			c = *t;
			*t = '\0';
			unsetenv(s);
			*t = c;
#endif
		}

		env->is_set = 0;
	}
}

void environment_release(struct environment *env)
{
	environment_unset(env);
	array_release(&env->string_pool);
	array_release(&env->vars);
}

RAZOR_EXPORT char *razor_concat(const char *s, ...)
{
	va_list args;
	const char *string;
	char *concat;
	size_t n, len;

	va_start(args, s);

	len = strlen(s);
	while((string = va_arg(args, const char *)))
		len += strlen(string);

	va_end(args);

	concat = malloc(len + 1);

	if (!concat)
		return NULL;

	va_start(args, s);

	len = strlen(s);
	memcpy(concat, s, len);
	n = len;
	while((string = va_arg(args, const char *))) {
		len = strlen(string);
		memcpy(concat + n, string, len);
		n += len;
	}

	va_end(args);

	concat[n] = '\0';

	return concat;
}

RAZOR_EXPORT const char *razor_system_arch(void)
{
#ifdef MSWIN_API
	SYSTEM_INFO si;

	GetNativeSystemInfo(&si);
	switch(si.wProcessorArchitecture)
	{
		case PROCESSOR_ARCHITECTURE_INTEL:
			return "i686";
		case PROCESSOR_ARCHITECTURE_AMD64:
			return "x86_64";
		default:
			return NULL;
	}
#else
	static struct utsname un;

	if (uname(&un))
		return NULL;
	else
		return un.machine;
#endif
}

#ifdef MSWIN_API

char *razor_utf16_to_utf8(const wchar_t *utf16, int len)
{
	int n;
	char *utf8;

	if (len == 0)
		return strdup("");

	n = WideCharToMultiByte(CP_UTF8, 0, utf16, len, NULL, 0, NULL, NULL);
	if (len > 0)
		n++;
	utf8 = malloc(n);
	(void)WideCharToMultiByte(CP_UTF8, 0, utf16, len, utf8, n, NULL, NULL);
	if (len > 0)
		utf8[n - 1] = 0;

	return utf8;
}

wchar_t *razor_utf8_to_utf16(const char *utf8, int len)
{
	int n;
	wchar_t *utf16;

	if (len == 0) {
		utf16 = calloc(1, sizeof(wchar_t));
		return utf16;
	}

	n = MultiByteToWideChar(CP_UTF8, 0, utf8, len, NULL, 0);
	if (len > 0)
		n++;
	utf16 = malloc(n * sizeof(wchar_t));
	(void)MultiByteToWideChar(CP_UTF8, 0, utf8, len, utf16, n);
	if (len > 0)
		utf16[n - 1] = 0;

	return utf16;
}

#endif	/* MSWIN_API */