From 1e2a8689199ca2d2a8051b83c7358bf225ff343c Mon Sep 17 00:00:00 2001
From: Ali Gholami Rudi <ali@rudi.ir>
Date: Thu, 22 Sep 2011 14:24:47 +0330
Subject: [PATCH] quran: don't use mmap()

---
 quran.c | 64 ++++++++++++++++++++++++++++++++++++----------------------------
 quran.h |  5 ++---
 2 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/quran.c b/quran.c
index 77309e4..01526df 100644
--- a/quran.c
+++ b/quran.c
@@ -1,5 +1,4 @@
 #include <fcntl.h>
-#include <sys/mman.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
@@ -8,52 +7,61 @@
 #include "util.h"
 #include "quran.h"
 
-static size_t file_size(int fd)
-{
-	struct stat st;
-	if (!fstat(fd, &st))
-		return st.st_size;
-	return 0;
-}
+static char abuf[1 << 16];
+static int apos = -1;
+static int acur;
+static int aaya;
 
-static void init_ayas(struct quran *quran)
+static int aya_offset(int fd, int aya)
 {
-	int i = 0;
-	char *s = quran->text;
-	quran->ayas[0] = quran->text;
-	while (i < NAYA && (s = strchr(s, '\n')))
-		quran->ayas[++i] = ++s;
+	char *s;
+	if (aaya > aya || apos == -1) {
+		acur = 0;
+		aaya = 0;
+		apos = 0;
+		lseek(fd, apos, 0);
+		read(fd, abuf, sizeof(abuf));
+	}
+	while (aaya < aya) {
+		while (!(s = memchr(abuf + acur, '\n', sizeof(abuf) - acur))) {
+			acur = 0;
+			apos += sizeof(abuf);
+			lseek(fd, apos, 0);
+			read(fd, abuf, sizeof(abuf));
+		}
+		acur = s - abuf + 1;
+		aaya++;
+	}
+	return apos + acur;
 }
 
 struct quran *quran_alloc(char *path)
 {
 	struct quran *quran = xmalloc(sizeof(struct quran));
+	int i;
 	memset(quran, 0, sizeof(quran));
 	quran->fd = open(path, O_RDONLY);
 	if (quran->fd == -1)
 		xerror(path);
-	quran->text = mmap(NULL, file_size(quran->fd), PROT_READ,
-			   MAP_SHARED, quran->fd, 0);
-	if (quran->text == MAP_FAILED)
-		xerror("mmap");
-	init_ayas(quran);
+	for (i = 0; i < NAYA + 1; i++)
+		quran->ayas[i] = aya_offset(quran->fd, i);
 	return quran;
 }
 
-void quran_aya(struct quran *quran, char *buf, size_t len, int aya)
+void quran_aya(struct quran *quran, char *buf, int len, int aya)
 {
-	char *s = quran->ayas[aya];
-	char *e = strchr(s, '\n');
-	size_t n = e - s;
-	if (n > len - 1)
-		n = len - 1;
-	memcpy(buf, s, n);
-	buf[buf[n - 1] == '\r' ? n - 1 : n] = '\0';
+	int n;
+	if (quran->ayas[aya] + len > quran->ayas[aya + 1])
+		len = quran->ayas[aya + 1] - quran->ayas[aya] - 1;
+	lseek(quran->fd, quran->ayas[aya], 0);
+	n = read(quran->fd, buf, len);
+	while (n > 0 && (buf[n - 1] == '\r' || buf[n - 1] == '\n'))
+		n--;
+	buf[n] = '\0';
 }
 
 void quran_free(struct quran *quran)
 {
-	munmap(quran->text, file_size(quran->fd));
 	close(quran->fd);
 	free(quran);
 }
diff --git a/quran.h b/quran.h
index b99ad35..5ad0f12 100644
--- a/quran.h
+++ b/quran.h
@@ -6,13 +6,12 @@
 #define SAJDA_OBLIG	2
 
 struct quran {
+	long ayas[NAYA + 1];
 	int fd;
-	char *text;
-	char *ayas[NAYA];
 };
 
 struct quran *quran_alloc(char *path);
-void quran_aya(struct quran *quran, char *buf, size_t len, int aya);
+void quran_aya(struct quran *quran, char *buf, int len, int aya);
 void quran_free(struct quran *quran);
 
 int sura_start(int sura);
-- 
2.11.4.GIT