From d7a4fc9b8e5b301399a4c2cf5fffd954412ba0b4 Mon Sep 17 00:00:00 2001
From: Dan Church <amphetamachine@gmail.com>
Date: Tue, 29 Jun 2021 11:51:50 -0500
Subject: [PATCH] Output number of freed bytes instead of success

---
 optipdf | 78 ++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 64 insertions(+), 14 deletions(-)

diff --git a/optipdf b/optipdf
index f7235e8..440254a 100755
--- a/optipdf
+++ b/optipdf
@@ -18,6 +18,47 @@ file_size() {
         2>/dev/null
 }
 
+# produces a human-readable size from the byte count passed to it
+hr_size() (
+    declare -i BYTES=$1
+
+    #UNITS=(B KB MB GB TB PB EB ZB YB) # shell math can only go so far...
+    UNITS=(B KB MB GB TB)
+    FACT=1024
+    THRESH=9/10
+    DECIMALS=1
+    DECIMALS_FACTOR=$(( 10 ** DECIMALS ))
+
+    # cycle through units from largest to smallest, exiting when it finds the
+    # largest applicable unit
+    for (( EXP = ${#UNITS[@]} - 1; EXP > -1; --EXP )); do
+        # check if the unit is close enough to the unit's size, within the
+        # threshold
+        if [[ $BYTES -gt $((FACT ** EXP * $THRESH)) ]]; then
+            # we found the applicable unit
+
+            # must multiply by a factor of 10 here to not truncate
+            # the given number of decimal places after the point
+            HR_VAL=$(( BYTES * DECIMALS_FACTOR / FACT ** EXP ))
+
+            # put the decimal point in
+            if [[ $DECIMALS -gt 0 ]]; then
+                HR_VAL=$(( HR_VAL / DECIMALS_FACTOR )).$(( HR_VAL % DECIMALS_FACTOR ))
+            fi
+
+            HR_UNIT=${UNITS[$EXP]}
+            break
+        fi
+    done
+
+    if [[ -z $HR_UNIT ]]; then
+        HR_VAL=$BYTES
+        HR_UNIT=${UNITS[0]}
+    fi
+
+    printf '%g %s\n' "$HR_VAL" "$HR_UNIT"
+)
+
 # copies $2 over to $1 if $2 is smaller than $1
 use_smaller() {
     # if `$TEMP' isn't empty and it's of a smaller size than `$FILE',
@@ -64,19 +105,11 @@ use_smaller() {
             "$TEMP" \
             "$FILE"
 
-        local ERR=$?
-        case "$ERR" in
-            '0')
-                printf 'Optimized "%s"\n' \
-                    "$FILE" \
-                    >&2
-                ;;
-            *)
-                printf 'Failed to optimize "%s"!\n' \
-                    "$FILE" \
-                    >&2
-                ;;
-        esac
+        if [[ $? -ne 0 ]]; then
+            printf 'Failed to optimize "%s"!\n' \
+                "$FILE" \
+                >&2
+        fi
 
     fi
 
@@ -90,16 +123,33 @@ TEMP1=$(mktemp -t "${0##*/}.XXXXXX")
 TEMP_FILES+=("$TEMP0" "$TEMP0")
 
 ERRORS=0
+FREED_TOTAL=0
 for FILE; do
     rm -f -- "$TEMP0" "$TEMP1"
-    if !
+    BEGIN_FILESIZE=$(file_size "$FILE")
+
+    if
         qpdf --stream-data=uncompress -- "$FILE" "$TEMP0" &&
         qpdf --stream-data=compress -- "$TEMP0" "$TEMP1" &&
         use_smaller "$FILE" "$TEMP1"; then
+
+        END_FILESIZE=$(file_size "$FILE")
+        FREED=$(( BEGIN_FILESIZE - END_FILESIZE ))
+        FREED_HR=$(hr_size "$FREED")
+        (( FREED_TOTAL += FREED ))
+
+        printf '%s: freed %d bytes (%s)\n' \
+            "$FILE" \
+            "$FREED" \
+            "$FREED_HR"
+    else
         (( ++ERRORS ))
     fi
 done
 
+FREED_TOTAL_HR=$(hr_size "$FREED_TOTAL")
+printf 'all: freed %d bytes (%s)\n' "$FREED_TOTAL" "$FREED_TOTAL_HR"
+
 if [[ $ERRORS -gt 0 ]]; then
     exit 1
 fi