From 4646bb5af526edcf8670933c539e910dca0bffb4 Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Sat, 28 Nov 2015 11:25:59 -0600
Subject: [PATCH 1/7] Added C .gitignore

---
 .gitignore | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ebb6e01
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,35 @@
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Libraries
+*.lib
+*.a
+*.la
+*.lo
+
+# Shared objects (inc. Windows DLLs)
+*.dll
+*.so
+*.so.*
+*.dylib
+
+# Executables
+*.exe
+*.out
+*.app
+*.i*86
+*.x86_64
+*.hex
+
+# Debug files
+*.dSYM/
+
+# Editor
+*.swp

From 68a8e599a8d31a9c33ce51ed222721350a25c3fb Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Thu, 26 Nov 2015 12:14:57 -0600
Subject: [PATCH 2/7] Moved newlines into TPRINTF macro for printf tests

This makes the printf.c and sprintf.c files easier to diff.
---
 test/printf.c | 50 +++++++++++++++++++++++++-------------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/test/printf.c b/test/printf.c
index dd84a9b..915ea9a 100644
--- a/test/printf.c
+++ b/test/printf.c
@@ -13,8 +13,8 @@
 #define UNUSED(x) (void)(x)
 
 #define TPRINTF(expr...) \
-  ({ printf("libc_printf(%s) -> ", #expr); printf(expr); \
-     printf(" tfp_printf(%s) -> ", #expr); tfp_printf(expr); })
+  ({ printf("libc_printf(%s) -> ", #expr); printf(expr); printf("\n"); \
+     printf(" tfp_printf(%s) -> ", #expr); tfp_printf(expr); printf("\n"); })
 
 static void stdout_putf(void *unused, char c)
 {
@@ -28,41 +28,41 @@ int main()
 
   printf("Fun with printf and %%!\n");
 
-  TPRINTF("d1=%016llx d2=%016lx d3=%02x d4=%02X 42=%03d\n",
+  TPRINTF("d1=%016llx d2=%016lx d3=%02x d4=%02X 42=%03d",
           (long long unsigned)0xd1, (long unsigned)0xd2, 0xd3, 0xd4, 42);
-  TPRINTF("d1=%04x d2=%06x d3=%08x %%100\n", 0xd1, 0xd2, 0xd3);
-  TPRINTF("|%-14s| |%-16s| d2=%2x |%-30s|\n", "str14", "str16", 0xd2,
+  TPRINTF("d1=%04x d2=%06x d3=%08x %%100", 0xd1, 0xd2, 0xd3);
+  TPRINTF("|%-14s| |%-16s| d2=%2x |%-30s|", "str14", "str16", 0xd2,
           "12345678901234567890123456789012345");
-  TPRINTF("|%4s|\n", "string4");
-  TPRINTF("|%-4s|\n", "string4");
-  TPRINTF("42=%3d d1=%4.4x |%4s| d2=%8.8x\n", 42, 0xd1, "string4", 0xd2);
-  TPRINTF("42=%3d d1=%4.4x |%-4s| d2=%8.8x\n", 42, 0xd1, "string4", 0xd2);
-  TPRINTF("84=%d 21=%ds |%s| |%sOK| d1=%x d2=%#x\n",
+  TPRINTF("|%4s|", "string4");
+  TPRINTF("|%-4s|", "string4");
+  TPRINTF("42=%3d d1=%4.4x |%4s| d2=%8.8x", 42, 0xd1, "string4", 0xd2);
+  TPRINTF("42=%3d d1=%4.4x |%-4s| d2=%8.8x", 42, 0xd1, "string4", 0xd2);
+  TPRINTF("84=%d 21=%ds |%s| |%sOK| d1=%x d2=%#x",
           84, 21, "hello", "fine", 0xd1, 0xd2);
 
-  TPRINTF("%lld\n", LLONG_MIN);
-  TPRINTF("%lld\n", LLONG_MAX);
-  TPRINTF("%llu\n", ULLONG_MAX);
-  TPRINTF("%llx\n", LLONG_MIN);
-  TPRINTF("%llx\n", LLONG_MAX);
-  TPRINTF("%llx\n", ULLONG_MAX);
+  TPRINTF("%lld", LLONG_MIN);
+  TPRINTF("%lld", LLONG_MAX);
+  TPRINTF("%llu", ULLONG_MAX);
+  TPRINTF("%llx", LLONG_MIN);
+  TPRINTF("%llx", LLONG_MAX);
+  TPRINTF("%llx", ULLONG_MAX);
 
-  TPRINTF("d1=%.1x\n", 0xd1);
-  TPRINTF("d1=%4.1x\n", 0xd1);
-  TPRINTF("d1=%4.x\n", 0xd1);
+  TPRINTF("d1=%.1x", 0xd1);
+  TPRINTF("d1=%4.1x", 0xd1);
+  TPRINTF("d1=%4.x", 0xd1);
 
   {
     char blah[256];
-    TPRINTF("a=%zd\n", sizeof(blah));
-    TPRINTF("a=%zu\n", sizeof(blah));
-    TPRINTF("a=%zi\n", sizeof(blah));
-    TPRINTF("a=0x%zx\n", sizeof(blah));
+    TPRINTF("a=%zd", sizeof(blah));
+    TPRINTF("a=%zu", sizeof(blah));
+    TPRINTF("a=%zi", sizeof(blah));
+    TPRINTF("a=0x%zx", sizeof(blah));
   }
 
   {
     int in_stack;
-    TPRINTF("Adddress of main: %p\n", main);
-    TPRINTF("Adddress of stack variable: %p\n", &in_stack);
+    TPRINTF("Adddress of main: %p", main);
+    TPRINTF("Adddress of stack variable: %p", &in_stack);
   }
 
   return 0;

From afe2c78f785a883e832a8f55f5825bac3cf912dc Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Thu, 26 Nov 2015 12:19:37 -0600
Subject: [PATCH 3/7] Synchronized test cases in printf.c and sprintf.c

One of the sprintf.c test cases is failing, which needs to be resolved.
---
 test/printf.c  | 3 +++
 test/sprintf.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/test/printf.c b/test/printf.c
index 915ea9a..3485a32 100644
--- a/test/printf.c
+++ b/test/printf.c
@@ -50,6 +50,7 @@ int main()
   TPRINTF("d1=%.1x", 0xd1);
   TPRINTF("d1=%4.1x", 0xd1);
   TPRINTF("d1=%4.x", 0xd1);
+  TPRINTF("d1=%4.4x", 0xd1);
 
   {
     char blah[256];
@@ -59,6 +60,8 @@ int main()
     TPRINTF("a=0x%zx", sizeof(blah));
   }
 
+  TPRINTF("Hello |%15s|.", "12345678901234");
+
   {
     int in_stack;
     TPRINTF("Adddress of main: %p", main);
diff --git a/test/sprintf.c b/test/sprintf.c
index 06a01ed..5227603 100644
--- a/test/sprintf.c
+++ b/test/sprintf.c
@@ -58,6 +58,9 @@ int main()
   TPRINTF("%llx", LLONG_MAX);
   TPRINTF("%llx", ULLONG_MAX);
 
+  TPRINTF("d1=%.1x", 0xd1);
+  TPRINTF("d1=%4.1x", 0xd1);
+  TPRINTF("d1=%4.x", 0xd1);
   TPRINTF("d1=%4.4x", 0xd1);
 
   {

From c9a7169a855e511375ea5b97e05fb993d1842540 Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Sat, 28 Nov 2015 01:46:42 -0600
Subject: [PATCH 4/7] Added precision support

All features of precision should work, except that numbers get limited
to 10 or 20 characters for precision (depending on if LONG is
supported). This seemed like a reasonable complexity trade-off, since it
would allow precision-based zero padding to the maximum character width
of the largest integer type.
---
 test/sprintf.c |  34 ++++++++++++-
 tinyprintf.c   | 131 +++++++++++++++++++++++++++++++------------------
 tinyprintf.h   |   9 ++--
 3 files changed, 121 insertions(+), 53 deletions(-)

diff --git a/test/sprintf.c b/test/sprintf.c
index 5227603..cb1d5c3 100644
--- a/test/sprintf.c
+++ b/test/sprintf.c
@@ -51,6 +51,27 @@ int main()
   TPRINTF("84=%d 21=%ds |%s| |%sOK| d1=%x d2=%#x",
           84, 21, "hello", "fine", 0xd1, 0xd2);
 
+  TPRINTF("|%.6s|", "stringXXX");
+  TPRINTF("|%10.6s|", "stringXXX");
+  TPRINTF("|%-10.6s|", "stringXXX");
+  TPRINTF("|%.20s|", "stringXXX");
+  TPRINTF("|%.s|", "stringXXX");
+  TPRINTF("|%.50s|", "0123456789012345678901234567890123456789");
+
+  TPRINTF("%d", INT_MIN);
+  TPRINTF("%d", INT_MAX);
+  TPRINTF("%u", UINT_MAX);
+  TPRINTF("%x", INT_MIN);
+  TPRINTF("%x", INT_MAX);
+  TPRINTF("%x", UINT_MAX);
+
+  TPRINTF("%ld", LONG_MIN);
+  TPRINTF("%ld", LONG_MAX);
+  TPRINTF("%lu", ULONG_MAX);
+  TPRINTF("%lx", LONG_MIN);
+  TPRINTF("%lx", LONG_MAX);
+  TPRINTF("%lx", ULONG_MAX);
+
   TPRINTF("%lld", LLONG_MIN);
   TPRINTF("%lld", LLONG_MAX);
   TPRINTF("%llu", ULLONG_MAX);
@@ -58,10 +79,21 @@ int main()
   TPRINTF("%llx", LLONG_MAX);
   TPRINTF("%llx", ULLONG_MAX);
 
+  TPRINTF("d1=%.x", 0xd1);
   TPRINTF("d1=%.1x", 0xd1);
-  TPRINTF("d1=%4.1x", 0xd1);
+  TPRINTF("d1=%.2x", 0xd1);
+  TPRINTF("d1=%.4x", 0xd1);
+
   TPRINTF("d1=%4.x", 0xd1);
+  TPRINTF("d1=%4.1x", 0xd1);
+  TPRINTF("d1=%4.2x", 0xd1);
   TPRINTF("d1=%4.4x", 0xd1);
+  TPRINTF("d1=%4.20x", 0xd1);
+  TPRINTF("d1=%8.4x", 0xd1);
+
+  TPRINTF("0=|%.d|", 0);
+  TPRINTF("0=|%.4d|", 0);
+  TPRINTF("0=|%4.d|", 0);
 
   {
     char blah[256];
diff --git a/tinyprintf.c b/tinyprintf.c
index bb22700..7c980eb 100644
--- a/tinyprintf.c
+++ b/tinyprintf.c
@@ -19,8 +19,9 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 */
 
-#include "tinyprintf.h"
+#include <stddef.h>
 
+#include "tinyprintf.h"
 
 /*
  * Configuration
@@ -38,10 +39,6 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 /*
  * Configuration adjustments
  */
-#ifdef PRINTF_SIZE_T_SUPPORT
-#include <sys/types.h>
-#endif
-
 #ifdef PRINTF_LONG_LONG_SUPPORT
 # define PRINTF_LONG_SUPPORT
 #endif
@@ -66,6 +63,14 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 # define _TFP_GCC_NO_INLINE_
 #endif
 
+#define IS_DIGIT(x) ((x) >= '0' && (x) <= '9')
+
+#ifdef PRINTF_LONG_SUPPORT
+#define BF_MAX 20 /* long = 64b on some architectures */
+#else
+#define BF_MAX 10 /* int = 32b on some architectures */
+#endif
+
 /*
  * Implementation
  */
@@ -74,10 +79,13 @@ struct param {
     char alt:1;         /**<  alternate form */
     char uc:1;          /**<  Upper case (for base16 only) */
     char align_left:1;  /**<  0 == align right (default), 1 == align left */
+    char prec_used:1;   /**<  precision specified */
     unsigned int width; /**<  field width */
+    unsigned int prec;  /**<  precision */
     char sign;          /**<  The sign to display (if any) */
     unsigned int base;  /**<  number base (e.g.: 8, 10, 16) */
     char *bf;           /**<  Buffer to output */
+    size_t bf_len;      /**<  Buffer length */
 };
 
 
@@ -85,21 +93,28 @@ struct param {
 static void _TFP_GCC_NO_INLINE_ ulli2a(
     unsigned long long int num, struct param *p)
 {
-    int n = 0;
     unsigned long long int d = 1;
     char *bf = p->bf;
-    while (num / d >= p->base)
+    int prec = p->prec;
+    if (p->prec_used && (prec == 0) && (num == 0))
+            return;
+    if (prec > BF_MAX)
+        prec = BF_MAX;
+    /* at least one digit */
+    prec--;
+    while (num / d >= p->base) {
         d *= p->base;
+        prec--;
+    }
+    while (prec-- > 0)
+        *bf++ = '0';
     while (d != 0) {
         int dgt = num / d;
         num %= d;
         d /= p->base;
-        if (n || dgt > 0 || d == 0) {
-            *bf++ = dgt + (dgt < 10 ? '0' : (p->uc ? 'A' : 'a') - 10);
-            ++n;
-        }
+        *bf++ = dgt + (dgt < 10 ? '0' : (p->uc ? 'A' : 'a') - 10);
     }
-    *bf = 0;
+    p->bf_len = bf - p->bf;
 }
 
 static void lli2a(long long int num, struct param *p)
@@ -115,21 +130,28 @@ static void lli2a(long long int num, struct param *p)
 #ifdef PRINTF_LONG_SUPPORT
 static void uli2a(unsigned long int num, struct param *p)
 {
-    int n = 0;
     unsigned long int d = 1;
     char *bf = p->bf;
-    while (num / d >= p->base)
+    int prec = p->prec;
+    if (p->prec_used && (prec == 0) && (num == 0))
+            return;
+    if (prec > BF_MAX)
+        prec = BF_MAX;
+    /* at least one digit */
+    prec--;
+    while (num / d >= p->base) {
         d *= p->base;
+        prec--;
+    }
+    while (prec-- > 0)
+        *bf++ = '0';
     while (d != 0) {
         int dgt = num / d;
         num %= d;
         d /= p->base;
-        if (n || dgt > 0 || d == 0) {
-            *bf++ = dgt + (dgt < 10 ? '0' : (p->uc ? 'A' : 'a') - 10);
-            ++n;
-        }
+        *bf++ = dgt + (dgt < 10 ? '0' : (p->uc ? 'A' : 'a') - 10);
     }
-    *bf = 0;
+    p->bf_len = bf - p->bf;
 }
 
 static void li2a(long num, struct param *p)
@@ -144,21 +166,28 @@ static void li2a(long num, struct param *p)
 
 static void ui2a(unsigned int num, struct param *p)
 {
-    int n = 0;
     unsigned int d = 1;
     char *bf = p->bf;
-    while (num / d >= p->base)
+    int prec = p->prec;
+    if (p->prec_used && (prec == 0) && (num == 0))
+            return;
+    if (prec > BF_MAX)
+        prec = BF_MAX;
+    /* at least one digit */
+    prec--;
+    while (num / d >= p->base) {
         d *= p->base;
+        prec--;
+    }
+    while (prec-- > 0)
+        *bf++ = '0';
     while (d != 0) {
         int dgt = num / d;
         num %= d;
         d /= p->base;
-        if (n || dgt > 0 || d == 0) {
-            *bf++ = dgt + (dgt < 10 ? '0' : (p->uc ? 'A' : 'a') - 10);
-            ++n;
-        }
+        *bf++ = dgt + (dgt < 10 ? '0' : (p->uc ? 'A' : 'a') - 10);
     }
-    *bf = 0;
+    p->bf_len = bf - p->bf;
 }
 
 static void i2a(int num, struct param *p)
@@ -172,7 +201,7 @@ static void i2a(int num, struct param *p)
 
 static int a2d(char ch)
 {
-    if (ch >= '0' && ch <= '9')
+    if (IS_DIGIT(ch))
         return ch - '0';
     else if (ch >= 'a' && ch <= 'f')
         return ch - 'a' + 10;
@@ -203,10 +232,10 @@ static void putchw(void *putp, putcf putf, struct param *p)
     char ch;
     int n = p->width;
     char *bf = p->bf;
+    size_t bf_len = p->bf_len;
 
     /* Number of filling characters */
-    while (*bf++ && n > 0)
-        n--;
+    n -= p->bf_len;
     if (p->sign)
         n--;
     if (p->alt && p->base == 16)
@@ -239,8 +268,7 @@ static void putchw(void *putp, putcf putf, struct param *p)
     }
 
     /* Put actual buffer */
-    bf = p->bf;
-    while ((ch = *bf++))
+    while ((bf_len-- > 0) && (ch = *bf++))
         putf(putp, ch);
 
     /* Fill with space to align to the left, after string */
@@ -253,13 +281,8 @@ static void putchw(void *putp, putcf putf, struct param *p)
 void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
 {
     struct param p;
-#ifdef PRINTF_LONG_SUPPORT
-    char bf[23];  /* long = 64b on some architectures */
-#else
-    char bf[12];  /* int = 32b on some architectures */
-#endif
+    char bf[BF_MAX];
     char ch;
-    p.bf = bf;
 
     while ((ch = *(fmt++))) {
         if (ch != '%') {
@@ -271,9 +294,14 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             /* Init parameter struct */
             p.lz = 0;
             p.alt = 0;
-            p.width = 0;
+            p.uc = 0;
             p.align_left = 0;
+            p.prec_used = 0;
+            p.width = 0;
+            p.prec = 0;
             p.sign = 0;
+            p.bf = bf;
+            p.bf_len = 0;
 
             /* Flags */
             while ((ch = *(fmt++))) {
@@ -294,19 +322,17 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             }
 
             /* Width */
-            if (ch >= '0' && ch <= '9') {
+            if (IS_DIGIT(ch)) {
                 ch = a2u(ch, &fmt, 10, &(p.width));
             }
 
-            /* We accept 'x.y' format but don't support it completely:
-             * we ignore the 'y' digit => this ignores 0-fill
-             * size and makes it == width (ie. 'x') */
+            /* Precision */
             if (ch == '.') {
-              p.lz = 1;  /* zero-padding */
-              /* ignore actual 0-fill size: */
-              do {
                 ch = *(fmt++);
-              } while ((ch >= '0') && (ch <= '9'));
+                p.prec_used = 1;
+                if (IS_DIGIT(ch)) {
+                    ch = a2u(ch, &fmt, 10, &(p.prec));
+                }
             }
 
 #ifdef PRINTF_SIZE_T_SUPPORT
@@ -406,9 +432,20 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
                 putf(putp, (char)(va_arg(va, int)));
                 break;
             case 's':
+            {
+                unsigned int prec = p.prec;
+                char *b;
                 p.bf = va_arg(va, char *);
+                b = p.bf;
+                while (*b++) {
+                    if (p.prec_used && (prec == 0)) {
+                        break;
+                    }
+                    p.bf_len++;
+                    prec--;
+                }
                 putchw(putp, putf, &p);
-                p.bf = bf;
+            }
                 break;
             case '%':
                 putf(putp, ch);
diff --git a/tinyprintf.h b/tinyprintf.h
index a769f4a..d384067 100644
--- a/tinyprintf.h
+++ b/tinyprintf.h
@@ -34,7 +34,10 @@ functions ('snprintf', 'sprintf', 'vsnprintf', 'vsprintf').
 The formats supported by this implementation are:
 'c' 'd' 'i' 'o' 'p' 'u' 's' 'x' 'X'.
 
-Zero padding and field width are also supported.
+Zero padding, field width, and precision are also supported. When precision
+is used for 'd', 'i', 'o', 'u', 'x', and 'X', the precision is limited to the
+max number of digits used by the largest supported size (either 10 or 20
+characters).
 
 If the library is compiled with 'PRINTF_SUPPORT_LONG' defined, then
 the long specifier is also supported. Note that this will pull in some
@@ -125,10 +128,6 @@ regs Kusti, 23.10.2004
 
 /* Optional external types dependencies */
 
-#if TINYPRINTF_DEFINE_TFP_SPRINTF
-# include <sys/types.h>  /* size_t */
-#endif
-
 /* Declarations */
 
 #ifdef __GNUC__

From 82d24852b9ba070b94009dca206f795bafd2ba4a Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Sat, 28 Nov 2015 10:25:34 -0600
Subject: [PATCH 5/7] Added argument defined width/precision (using '*')

This standard format string feature allows the width or precision to be
provided as an additional argument.
---
 test/sprintf.c |  6 ++++++
 tinyprintf.c   | 10 ++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/test/sprintf.c b/test/sprintf.c
index cb1d5c3..c8a13c9 100644
--- a/test/sprintf.c
+++ b/test/sprintf.c
@@ -95,6 +95,12 @@ int main()
   TPRINTF("0=|%.4d|", 0);
   TPRINTF("0=|%4.d|", 0);
 
+  TPRINTF("42=|%*d|", 5, 42);
+  TPRINTF("42=|%-*d|", 5, 42);
+  TPRINTF("42=|%0*d|", 5, 42);
+  TPRINTF("42=|%.*d|", 5, 42);
+  TPRINTF("42=|%-*.*d|", 10, 5, 42);
+
   {
     char blah[256];
     TPRINTF("a=%zd", sizeof(blah));
diff --git a/tinyprintf.c b/tinyprintf.c
index 7c980eb..9037d45 100644
--- a/tinyprintf.c
+++ b/tinyprintf.c
@@ -322,7 +322,10 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             }
 
             /* Width */
-            if (IS_DIGIT(ch)) {
+            if (ch == '*') {
+                ch = *(fmt++);
+                p.width = va_arg(va, unsigned int);
+            } else if (IS_DIGIT(ch)) {
                 ch = a2u(ch, &fmt, 10, &(p.width));
             }
 
@@ -330,7 +333,10 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             if (ch == '.') {
                 ch = *(fmt++);
                 p.prec_used = 1;
-                if (IS_DIGIT(ch)) {
+                if (ch == '*') {
+                    ch = *(fmt++);
+                    p.prec = va_arg(va, unsigned int);
+                } else if (IS_DIGIT(ch)) {
                     ch = a2u(ch, &fmt, 10, &(p.prec));
                 }
             }

From 6268c398d7b34fbb2d383e63899d0d771bc6b792 Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Sat, 28 Nov 2015 11:30:31 -0600
Subject: [PATCH 6/7] Simplified integer precision handling

As a side effect, integer precision is no longer bounded by BF_MAX.
Precision should now be fully compatible with the standard printf.
---
 test/sprintf.c |  5 +++--
 tinyprintf.c   | 53 +++++++++++++++++---------------------------------
 tinyprintf.h   |  5 +----
 3 files changed, 22 insertions(+), 41 deletions(-)

diff --git a/test/sprintf.c b/test/sprintf.c
index c8a13c9..d5d7792 100644
--- a/test/sprintf.c
+++ b/test/sprintf.c
@@ -88,8 +88,9 @@ int main()
   TPRINTF("d1=%4.1x", 0xd1);
   TPRINTF("d1=%4.2x", 0xd1);
   TPRINTF("d1=%4.4x", 0xd1);
-  TPRINTF("d1=%4.20x", 0xd1);
-  TPRINTF("d1=%8.4x", 0xd1);
+  TPRINTF("d1=%4.50x", 0xd1);
+  TPRINTF("d1=|%8.4x|", 0xd1);
+  TPRINTF("d1=|%-8.4x|", 0xd1);
 
   TPRINTF("0=|%.d|", 0);
   TPRINTF("0=|%.4d|", 0);
diff --git a/tinyprintf.c b/tinyprintf.c
index 9037d45..8d0ca04 100644
--- a/tinyprintf.c
+++ b/tinyprintf.c
@@ -95,19 +95,11 @@ static void _TFP_GCC_NO_INLINE_ ulli2a(
 {
     unsigned long long int d = 1;
     char *bf = p->bf;
-    int prec = p->prec;
-    if (p->prec_used && (prec == 0) && (num == 0))
+    if (p->prec_used && (p->prec == 0) && (num == 0))
             return;
-    if (prec > BF_MAX)
-        prec = BF_MAX;
-    /* at least one digit */
-    prec--;
     while (num / d >= p->base) {
         d *= p->base;
-        prec--;
     }
-    while (prec-- > 0)
-        *bf++ = '0';
     while (d != 0) {
         int dgt = num / d;
         num %= d;
@@ -132,19 +124,11 @@ static void uli2a(unsigned long int num, struct param *p)
 {
     unsigned long int d = 1;
     char *bf = p->bf;
-    int prec = p->prec;
-    if (p->prec_used && (prec == 0) && (num == 0))
+    if (p->prec_used && (p->prec == 0) && (num == 0))
             return;
-    if (prec > BF_MAX)
-        prec = BF_MAX;
-    /* at least one digit */
-    prec--;
     while (num / d >= p->base) {
         d *= p->base;
-        prec--;
     }
-    while (prec-- > 0)
-        *bf++ = '0';
     while (d != 0) {
         int dgt = num / d;
         num %= d;
@@ -168,19 +152,11 @@ static void ui2a(unsigned int num, struct param *p)
 {
     unsigned int d = 1;
     char *bf = p->bf;
-    int prec = p->prec;
-    if (p->prec_used && (prec == 0) && (num == 0))
+    if (p->prec_used && (p->prec == 0) && (num == 0))
             return;
-    if (prec > BF_MAX)
-        prec = BF_MAX;
-    /* at least one digit */
-    prec--;
     while (num / d >= p->base) {
         d *= p->base;
-        prec--;
     }
-    while (prec-- > 0)
-        *bf++ = '0';
     while (d != 0) {
         int dgt = num / d;
         num %= d;
@@ -230,22 +206,26 @@ static char a2u(char ch, const char **src, int base, unsigned int *nump)
 static void putchw(void *putp, putcf putf, struct param *p)
 {
     char ch;
-    int n = p->width;
+    int width = p->width;
+    int prec = p->prec;
     char *bf = p->bf;
     size_t bf_len = p->bf_len;
 
     /* Number of filling characters */
-    n -= p->bf_len;
+    width -= bf_len;
+    prec -= bf_len;
     if (p->sign)
-        n--;
+        width--;
     if (p->alt && p->base == 16)
-        n -= 2;
+        width -= 2;
     else if (p->alt && p->base == 8)
-        n--;
+        width--;
+    if (prec > 0)
+        width -= prec;
 
     /* Fill with space to align to the right, before alternate or sign */
     if (!p->lz && !p->align_left) {
-        while (n-- > 0)
+        while (width-- > 0)
             putf(putp, ' ');
     }
 
@@ -262,8 +242,10 @@ static void putchw(void *putp, putcf putf, struct param *p)
     }
 
     /* Fill with zeros, after alternate or sign */
+    while (prec-- > 0)
+        putf(putp, '0');
     if (p->lz) {
-        while (n-- > 0)
+        while (width-- > 0)
             putf(putp, '0');
     }
 
@@ -273,7 +255,7 @@ static void putchw(void *putp, putcf putf, struct param *p)
 
     /* Fill with space to align to the left, after string */
     if (!p->lz && p->align_left) {
-        while (n-- > 0)
+        while (width-- > 0)
             putf(putp, ' ');
     }
 }
@@ -450,6 +432,7 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
                     p.bf_len++;
                     prec--;
                 }
+                p.prec = 0;
                 putchw(putp, putf, &p);
             }
                 break;
diff --git a/tinyprintf.h b/tinyprintf.h
index d384067..7ecde57 100644
--- a/tinyprintf.h
+++ b/tinyprintf.h
@@ -34,10 +34,7 @@ functions ('snprintf', 'sprintf', 'vsnprintf', 'vsprintf').
 The formats supported by this implementation are:
 'c' 'd' 'i' 'o' 'p' 'u' 's' 'x' 'X'.
 
-Zero padding, field width, and precision are also supported. When precision
-is used for 'd', 'i', 'o', 'u', 'x', and 'X', the precision is limited to the
-max number of digits used by the largest supported size (either 10 or 20
-characters).
+Zero padding, field width, and precision are also supported.
 
 If the library is compiled with 'PRINTF_SUPPORT_LONG' defined, then
 the long specifier is also supported. Note that this will pull in some

From cf56af99c848a7430ad29bba116eefb5ed11d53b Mon Sep 17 00:00:00 2001
From: Hans Anderson <hans@hanscanderson.com>
Date: Sat, 28 Nov 2015 11:37:27 -0600
Subject: [PATCH 7/7] Made precision and '*' specifiers conform to C99
 specifications

If zero padding is specified when either left-justify or precision are
used, the zero padding should be ignored. The '*' specifiers can be
integers, where negatives are handled in specific ways. The prec_used
flag is no longer needed with these changes.
---
 test/sprintf.c |  6 ++++-
 tinyprintf.c   | 61 ++++++++++++++++++++++++++++++++++----------------
 2 files changed, 47 insertions(+), 20 deletions(-)

diff --git a/test/sprintf.c b/test/sprintf.c
index d5d7792..43800e5 100644
--- a/test/sprintf.c
+++ b/test/sprintf.c
@@ -95,12 +95,16 @@ int main()
   TPRINTF("0=|%.d|", 0);
   TPRINTF("0=|%.4d|", 0);
   TPRINTF("0=|%4.d|", 0);
+  TPRINTF("0=|%4.*d|", -1, 0);
 
   TPRINTF("42=|%*d|", 5, 42);
   TPRINTF("42=|%-*d|", 5, 42);
   TPRINTF("42=|%0*d|", 5, 42);
   TPRINTF("42=|%.*d|", 5, 42);
-  TPRINTF("42=|%-*.*d|", 10, 5, 42);
+  TPRINTF("42=|%*.*d|", 10, 5, 42);
+  TPRINTF("42=|%*.*d|", -10, 5, 42);
+  TPRINTF("42=|%*.*d|", 10, -5, 42);
+  TPRINTF("42=|%-*.*d|", -10, 5, 42);
 
   {
     char blah[256];
diff --git a/tinyprintf.c b/tinyprintf.c
index 8d0ca04..5f77594 100644
--- a/tinyprintf.c
+++ b/tinyprintf.c
@@ -79,9 +79,8 @@ struct param {
     char alt:1;         /**<  alternate form */
     char uc:1;          /**<  Upper case (for base16 only) */
     char align_left:1;  /**<  0 == align right (default), 1 == align left */
-    char prec_used:1;   /**<  precision specified */
-    unsigned int width; /**<  field width */
-    unsigned int prec;  /**<  precision */
+    int width;          /**<  field width */
+    int prec;           /**<  precision */
     char sign;          /**<  The sign to display (if any) */
     unsigned int base;  /**<  number base (e.g.: 8, 10, 16) */
     char *bf;           /**<  Buffer to output */
@@ -95,7 +94,7 @@ static void _TFP_GCC_NO_INLINE_ ulli2a(
 {
     unsigned long long int d = 1;
     char *bf = p->bf;
-    if (p->prec_used && (p->prec == 0) && (num == 0))
+    if ((p->prec == 0) && (num == 0))
             return;
     while (num / d >= p->base) {
         d *= p->base;
@@ -124,7 +123,7 @@ static void uli2a(unsigned long int num, struct param *p)
 {
     unsigned long int d = 1;
     char *bf = p->bf;
-    if (p->prec_used && (p->prec == 0) && (num == 0))
+    if ((p->prec == 0) && (num == 0))
             return;
     while (num / d >= p->base) {
         d *= p->base;
@@ -152,7 +151,7 @@ static void ui2a(unsigned int num, struct param *p)
 {
     unsigned int d = 1;
     char *bf = p->bf;
-    if (p->prec_used && (p->prec == 0) && (num == 0))
+    if ((p->prec == 0) && (num == 0))
             return;
     while (num / d >= p->base) {
         d *= p->base;
@@ -278,9 +277,8 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             p.alt = 0;
             p.uc = 0;
             p.align_left = 0;
-            p.prec_used = 0;
             p.width = 0;
-            p.prec = 0;
+            p.prec = -1;
             p.sign = 0;
             p.bf = bf;
             p.bf_len = 0;
@@ -303,25 +301,46 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
                 break;
             }
 
+            if (p.align_left)
+                p.lz = 0;
+
             /* Width */
             if (ch == '*') {
                 ch = *(fmt++);
-                p.width = va_arg(va, unsigned int);
+                p.width = va_arg(va, int);
+                if (p.width < 0) {
+                    p.align_left = 1;
+                    p.width = -p.width;
+                }
             } else if (IS_DIGIT(ch)) {
-                ch = a2u(ch, &fmt, 10, &(p.width));
+                unsigned int width;
+                ch = a2u(ch, &fmt, 10, &(width));
+                p.width = width;
             }
 
             /* Precision */
             if (ch == '.') {
                 ch = *(fmt++);
-                p.prec_used = 1;
                 if (ch == '*') {
+                    int prec;
                     ch = *(fmt++);
-                    p.prec = va_arg(va, unsigned int);
+                    prec = va_arg(va, int);
+                    if (prec < 0)
+                        /* act as if precision was omitted */
+                        p.prec = -1;
+                    else
+                        p.prec = prec;
                 } else if (IS_DIGIT(ch)) {
-                    ch = a2u(ch, &fmt, 10, &(p.prec));
+                    unsigned int prec;
+                    ch = a2u(ch, &fmt, 10, &(prec));
+                    p.prec = prec;
+                } else {
+                    p.prec = 0;
                 }
             }
+            if (p.prec >= 0)
+                /* precision causes zero pad to be ignored */
+                p.lz = 0;
 
 #ifdef PRINTF_SIZE_T_SUPPORT
 # ifdef PRINTF_LONG_SUPPORT
@@ -354,6 +373,8 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
                 goto abort;
             case 'u':
                 p.base = 10;
+                if (p.prec < 0)
+                    p.prec = 1;
 #ifdef PRINTF_LONG_SUPPORT
 #ifdef PRINTF_LONG_LONG_SUPPORT
                 if (2 == lng)
@@ -370,6 +391,8 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             case 'd':
             case 'i':
                 p.base = 10;
+                if (p.prec < 0)
+                    p.prec = 1;
 #ifdef PRINTF_LONG_SUPPORT
 #ifdef PRINTF_LONG_LONG_SUPPORT
                 if (2 == lng)
@@ -398,6 +421,8 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
             case 'X':
                 p.base = 16;
                 p.uc = (ch == 'X')?1:0;
+                if (p.prec < 0)
+                    p.prec = 1;
 #ifdef PRINTF_LONG_SUPPORT
 #ifdef PRINTF_LONG_LONG_SUPPORT
                 if (2 == lng)
@@ -413,6 +438,8 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
                 break;
             case 'o':
                 p.base = 8;
+                if (p.prec < 0)
+                    p.prec = 1;
                 ui2a(va_arg(va, unsigned int), &p);
                 putchw(putp, putf, &p);
                 break;
@@ -425,14 +452,10 @@ void tfp_format(void *putp, putcf putf, const char *fmt, va_list va)
                 char *b;
                 p.bf = va_arg(va, char *);
                 b = p.bf;
-                while (*b++) {
-                    if (p.prec_used && (prec == 0)) {
-                        break;
-                    }
+                while ((prec-- != 0) && *b++) {
                     p.bf_len++;
-                    prec--;
                 }
-                p.prec = 0;
+                p.prec = -1;
                 putchw(putp, putf, &p);
             }
                 break;