From 1e279d3cb80822e772dd7cf285601c835b5e73c4 Mon Sep 17 00:00:00 2001
From: Yury Popov <dev@syncleo-iot.com>
Date: Tue, 15 Nov 2022 09:58:29 +0300
Subject: [PATCH] Add PRNG and use it instead of rand()

---
 src/libespeak-ng/common.c  | 13 +++++++++++++
 src/libespeak-ng/common.h  |  3 +++
 src/libespeak-ng/klatt.c   |  7 ++-----
 src/libespeak-ng/speech.c  |  3 +++
 src/libespeak-ng/wavegen.c |  3 ++-
 5 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/libespeak-ng/common.c b/src/libespeak-ng/common.c
index f44cf5e3..8b2bb872 100644
--- a/src/libespeak-ng/common.c
+++ b/src/libespeak-ng/common.c
@@ -326,4 +326,17 @@ int towlower2(unsigned int c, Translator *translator)
 	return ucd_tolower(c);
 }
 
+static uint32_t espeak_rand_state = 0;
+
+long espeak_rand(long min, long max) {
+	// Ref: https://github.com/bminor/glibc/blob/glibc-2.36/stdlib/random_r.c#L364
+	espeak_rand_state = (((uint64_t)espeak_rand_state * 1103515245) + 12345) % 0x7fffffff;
+	long res = (long)espeak_rand_state;
+	return (res % (max-min+1))-min;
+}
+
+void espeak_srand(long seed) {
+	espeak_rand_state = (uint32_t)(seed);
+	(void)espeak_rand(0, 1); // Dummy flush a generator
+}
 
diff --git a/src/libespeak-ng/common.h b/src/libespeak-ng/common.h
index 76fff8bf..ecec0d0e 100644
--- a/src/libespeak-ng/common.h
+++ b/src/libespeak-ng/common.h
@@ -26,6 +26,9 @@
 extern ESPEAK_NG_API int GetFileLength(const char *filename);
 extern ESPEAK_NG_API void strncpy0(char *to, const char *from, int size);
 
+void espeak_srand(long seed);
+long espeak_rand(long min, long max);
+
 int IsAlpha(unsigned int c);
 int IsBracket(int c);
 int IsDigit(unsigned int c);
diff --git a/src/libespeak-ng/klatt.c b/src/libespeak-ng/klatt.c
index 55d294f7..954553c0 100644
--- a/src/libespeak-ng/klatt.c
+++ b/src/libespeak-ng/klatt.c
@@ -35,6 +35,7 @@
 #include <espeak-ng/speak_lib.h>
 
 #include "klatt.h"
+#include "common.h"      // for espeak_rand
 #include "synthesize.h"  // for frame_t, WGEN_DATA, STEPSIZE, N_KLATTP, echo...
 #include "voice.h"       // for voice_t, N_PEAKS
 #ifdef INCLUDE_SPEECHPLAYER
@@ -46,11 +47,7 @@ extern unsigned char *out_end;
 static int nsamples;
 static int sample_count;
 
-#ifdef _MSC_VER
-#define getrandom(min, max) ((rand()%(int)(((max)+1)-(min)))+(min))
-#else
-#define getrandom(min, max) ((rand()%(long)(((max)+1)-(min)))+(min))
-#endif
+#define getrandom(min, max) espeak_rand((min), (max))
 
 // function prototypes for functions private to this file
 
diff --git a/src/libespeak-ng/speech.c b/src/libespeak-ng/speech.c
index ed704623..6d05512b 100644
--- a/src/libespeak-ng/speech.c
+++ b/src/libespeak-ng/speech.c
@@ -404,6 +404,9 @@ ESPEAK_NG_API espeak_ng_STATUS espeak_ng_Initialize(espeak_ng_ERROR_CONTEXT *con
 	option_phonemes = 0;
 	option_phoneme_events = 0;
 
+	// Seed random generator
+	espeak_srand(time(NULL));
+
 	return ENS_OK;
 }
 
diff --git a/src/libespeak-ng/wavegen.c b/src/libespeak-ng/wavegen.c
index cc9d9dd4..5762c988 100644
--- a/src/libespeak-ng/wavegen.c
+++ b/src/libespeak-ng/wavegen.c
@@ -33,6 +33,7 @@
 #include <espeak-ng/speak_lib.h>
 
 #include "wavegen.h"
+#include "common.h"                   // for espeak_rand
 #include "synthesize.h"               // for WGEN_DATA, RESONATOR, frame_t
 #include "mbrola.h"                  // for MbrolaFill, MbrolaReset, mbrola...
 
@@ -668,7 +669,7 @@ static int ApplyBreath(void)
 	int ix;
 
 	// use two random numbers, for alternate formants
-	noise = (rand() & 0x3fff) - 0x2000;
+	noise = espeak_rand(-0x2000, 0x1fff);
 
 	for (ix = 1; ix < N_PEAKS; ix++) {
 		int amp;